THE EFFECT OF MRLK CGNSUMPTEON AR!)
EXERCESE QM THE SERUM CHOLESTERGL QF
RAT AND MAN

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ABSTRACT

THE EF ECT OF MILK CONSUHPTION AND EXERCISE
ON THE SERUM CHOLESTEROL
OF RAT AND MAN

by Jeanne Sherburne

A study was conducted to investigate the effects
of milk consumption and exercise on the serum cholesterol
concentrations of rat and man. Forty—eight male rats were
divided into three groups, one of which was sedentary. Two
groups were exercised daily by swimming. Powdered whole
milk was added to the diet of one of these groups in amounts
to provide thirty per cent of the calories. At the end
of twelve experimental weeks blood was secured from the
animals by cardiac puncture and cholesterol determinations
were made on the sera by a modification of the Schoenheimer-
Sperry method. The sedentary rats had higher cholesterol
concentrations and greater weights than the exercised rats.

The higher cholesterol concentrations appeared
to be related to changes in weight and only indirectly to
the absence of exercise. The inclusion of powdered whole
milk had no effect upon serum cholesterol concentrations
or body weights in the exercised rats.

Nine athletes were divided into two groups, with

Jeanne Sherburne

and without milk, cheese and ice cream in the diet. They
exercised three times weekly on the motor-driven treadmill
for eight experimental weeks. Before the beginning of the
experiment and also during the first experimental week,
twenty-four hour recall diets were secured for seven days
by a graduate dietitian. Nutrient intakes were evaluated.
Before the beginning of the experiment and during the last
week of the experiment blood samples were taken by veni-
puncture and cholesterol determinations were made on the
sera by a modification of the Schoenheimer—Sperry method.
Body weights remained constant for the two groups. No sig-
nificant effects of exercise, with or without milk consump—
tion, were noted on blood cholesterol concentrations. There
was a decreased intake of calcium, riboflavin and fat and
an increased intake of carbohydrate in the restricted diet
group. Intakes of calcium and riboflavin were below the
amounts recommended by the Food and Nutrition Board of the
National Research Council.

According to the results of this study, it is
not advantageous to attempt to alter blood cholesterol con-
centrations of humans by changes in milk intake. There
appears to be an indirect advantage in the control of serum
cholesterol concentrations through the regulation of exer—

cise and diet for caloric equilibrium.

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ACKNOWLEDGEENTS

The author expresses her gratitude to Dr. Evelyn M.
Jones, Associate Professor of Foods and Nutrition, for her
guidance and assistance in the completion of the problem
and thesis; to Lt. Colonel Helen M. Davis, USA (Ret.),
former Chief, Dietitian Section, Army Medical Specialist
Corps, for the appointment to the Army graduate school
program; and to Lt. Colonel Katharine E. Manchester, Chief,
Dietitian Section, Army Medical Specialist Corps, for making

it possible to complete the work.

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Lean serum cholesterol concentrations
body weights of rats on stock diet compared by
test . . .

paired "t"

Mean serum cholesterol concentrations
body weights of exercised rats compared by

"t" test. . .

Comparison of effects of exercise,

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out milk consumption,
concentrations of athletes.

Analysis of variance for body weight.

Nutritional intake. Co

week two for

each group

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with and with-
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weekly mean weights of athletes in milk and non—
D1111: gl‘oups O O O O O O O O O O O O O O O I O O

LIST OF APPENDICES

Composition of stock diet for rats. . . . .
Twenty-Four Hour Diet Recall. . . . . . . .

Serum cholesterol concentrations of rats. .

Serum cholesterol concentrations of athletes.

1I‘ve-igl’lts Of SHbjGCtS o o o o o o o o o o o o

Nutritional evaluation of diets of athletes

vi

NTRODUCTION

Atherosclerosis is a common medical problem today.
It is believed to be related to serum cholesterol concen-
trations. Because of the present interest in attempts
to change blood cholesterol concentrations, there has been
much research on this subject in recent years. host of
the work has been concerned with altering the amounts of
fat or saturated fatty acids in the diet. Some research
has involved changes in physical activity. The present
investigation into the effects of milk consumption and
exercise on serum cholesterol concentrations combines both

dietary components and physical activity.

REVIEJ OE LITERATURE

It is generally agreed that dietary cholesterol
has little effect on serum cholesterol concentrations and
that the fat content of the diet appears to be a determin-
ing factor. In an early eXperiment, hessinger ('50) demon-
strated that the addition of powdered egg yolks to the
diet of man caused a gr ater elevation in the blood serum
cholesterol concentrations than did the inclusion of the
same amount of pure cholesterol. The difference in response
was attributed to the fat content of the egg yolk. Authori-
ties are not in agreement on the exact causative factor.
Some support the contention that it is the fat per se, and
others maintain it is related to the degree of saturation

in the fatty acids of the fat.

Animal Studies

Dietary Experiments

 

Portman and coworkers ('56) reported the effects
of dietary cholesterol on the serum cholesterol concentra—
tion of three groups of Cebus monkeys placed on iso-caloric
diets. These diets contained fixed amounts of protein

and cholesterol with different amounts of corn oil and

sucrose. After eight weeks of the diet, with corn oil
comprising 10%, 32% and 42% of the calories, the serum
cholesterol concentrations of the monkeys were greater

in the medium and high fat groups than in the low fat group.
When corn oil was lowered to 10% of the calories, the serum
cholesterol concentration decreased; and when the corn

oil was increased, the serum cholesterol concentration

also increased. After changing the diets to hydrogenated
cottonseed oil, these associates observed increases in serum
cholesterol concentrations. However, the hydrogenated cot—
tonseed oil did not have any more elevating effect on the
serum cholesterol than did the plain corn oil, when dietary
cholesterol was not added. Diets containing lard and added
cholesterol raised serum lipids more than diets containing
corn oil and added cholesterol. Hydrogenated cottonseed
oil raised the serum cholesterol concentrations even higher
than nonhydrogenated cottonseed oil.

Later Portman and Sinisterra ('57) showed that
with Cebus monkeys dietary hypercholesterolemia resembled
essential hypercholesterolemia in man. No tissue liposis
occurred after several months of serum cholesterol concentra-
tions of 600 mgfi or greater. There was a delayed rate of
esterification of injected radiocholesterol in dietary hyper-
cnolesterolemia in monkeys which was similar to endogenous

radiocholesterol in xanthoma tuberosum in man. The

disappearance curves of labeled exogenous cholesterol were
similar both quantitatively and qualitatively to those ob-
served in man. Portman and Sinisterra observed that the
effects of different fats on cholesterol concentrations
were not due to the difference in division of cholesterol
between the serum and the other tissues. Monkeys on diets
with lard and cholesterol develOped serum cholesterol con-
centrations much higher than those on diets with corn oil
and cholesterol, though the analyses of other tissues were
similar. Differences in absorption and turnover of exogenous
radiocholesterol depended on the fatty acid or fat used for
administration. The tests showed that cholesterol esters
of linoleic and oleic acids were well absorbed but choles-
terol stearate was not, probably because stearic acid is
poorly absorbed. The fats which caused lowered blood cho-
lesterol concentrations were high in linoleic acid, and
those which increased cholesterol concentrations were low
in linoleic and high in oleic acid. The highest concentra—
tions of serum cholesterol were obtained when 45% of the
calories were fed as triolein.

Alfin-Slater and coworkers ('54) examined the
effect of essential fatty acid deficiency on the plasma
and liver cholesterol in the rat. Contrary to their expec—
tations, the concentrations of the cholesterol esters did

not decrease when the fatty acids of the diet were reduced.

\J'l

These authors postulated that since oleic acid and other
more saturated fatty acids formed cholesterol esters which
were not metabolized rapidly, it was probable that the con-
centration of plasma cholesterol in the rat did not reflect
the body stores.

-After analysis of cholesterol esters in liver and
plasma of rats receiving varying amounts of linoleic acid,
Klein ('57) reported that linoleic acid was the major poly—
unsaturated constituent of the liver esters. In the plasma
other fatty acids increased as the linoleic acid in the diet
increased, and there were significant quantities oftetra-
enoic acid. The polyunsaturated fatty acid content of the
plasma esters exceeded that of the liver esters by a factor
as large as ten. The metabolism of plasma cholesterol dif-
fered from that of liver cholesterol, and the esters were
not in simple equilibrium.

Klein ('58) later reported that rats fed corn
oil or hydrogenated cottonseed oil showed increasing plasma
and liver cholesterol concentrations as the linoleic acid
of the diet was raised. Hence, Klein concluded that rat
cholesterol concentrations were related directly to the
polyunsaturated fatty acid content of the diet and not to
the total fat.

By feeding thirteen different fats, with and with-
out l% of added cholesterol, Okey and associates ('59)

studied the effects of unsaturated dietary fats upon the

liver and serum lipids. The rats consuming butterfat de—
veloped higher cholesterol concentrations than those on all
other rations except menhaden oil. hats fed butter alone
did not have any higher concentrations of liver and serum
cholesterol than those consuming fats with a lower natural
content of cholesterol. However, when cholesterol was added
to the butter diet, the liver cholesterol concentrations
were the lowest observed, except for the rats on coconut
oil diets. After butter was centrifuged to remove the phos-
pholipid and then was included in the diet, it produced
elevated liver cholesterol concentrations in the rats which
were fed cholesterol. The liver cholesterol concentrations
tended to diminish when there was a decrease in iodine number
of the food fats, though the serum cholesterol concentra—
tions remained at a constant level. These results supported
the conclusion that the composition of the fatty acid frac-
tion of cholesterol esters was somewhat influenced by the
amount of linoleate in the diet.

Tillman and coworkers ('60) tested the effects
of diet upon clotting time and lysis of plasma in three
groups of rats on diets containing propylthiouracil. These
diets had previously produced myocardial infarctions in
other animal experiments when butter was used. Rats con—
suming a normal diet remained healthy, with normal serum
cholesterol concentrations. Rats on a corn oil diet ate

only half as much as the normal rats and stOpped growing.

The third group, with isocaloric amounts of butter, had
higher plasma cholesterol concentrations and greater plasma
turbidity than the rats in the corn oil group. Plasma
cholesterol concentrations in the corn oil-fed rats were
only slightly higher than in the normal group. Twenty per
cent of the butter-fed rats developed myocardial infarc-
tions. None of the rats consuming corn oil or the normal

diet develOped myocardial infarctions.

Exercise experiments

 

Wong and associates ('56) tested the effects of
exercise on experimental atherosclerosis in chicks treated
with androgens and found that exercising on the treadmill
did not affect the blood cholesterol concentrations but
did reduce the formation of atheromatous plaques in the ab-
dominal aorta. However, later work (Wong g£_§l., '57) with
cockerels showed that exercise could overcome the effects
of an atherogenic diet by lowering blood cholesterol con—
centrations as well as reducing the atheromatous plaques.

Brown and coworkers ('56) tested the effects of
exercise in preventing coronary atherosclerosis in rabbits
and showed that exercise caused a lowering of total serum
cholesterol concentrations but did not alter free unesteri-
fied cholesterol concentrations. No essential differences

in the atheromatous plaques in the blood vessels of these

animals were observed. Apparently once atheromata were
develOped, exercise did not affect the rapidity of the de—
posit or the resorption of cholesterol from the vessels.

In a study of the effects of physical exercise
on atherosclerosis, Lyasnikov ('58) used 10 rabbits as con-
trols and added cholesterol to their diets for six months.
Twenty—five rabbits receiving cholesterol in the diet were
exercised on the electric treadmill daily, until fatigued.
Eight rabbits received no cholesterol in the diet but were
exercised on the treadmill. The cholesterol concentrations
were analyzed twice each month, and after six months the
rabbits were sacrificed. The aorta, coronary arteries and
myocardium of each were studied for atherosclerotic plaques.
Exercise caused a definite decrease in blood cholesterol
in those animals receiving cholesterol in the diet. The
physical exercise, because of intensifying metabolism in
the body, resulted in more intensive assimilation of ali-
mentary cholesterol, thereby lowering the blood cholesterol
concentration. The exercised rabbits on diets without added
cholesterol showed no morpholOgical changes except for hy-

pertrophy of the myocardium.

Human Studies

Dietary Studies

 

Population Surveys. Kinsell and coworkers ('52)

 

showed large amounts of vegetable fats in the diet caused a
lowering of the concentration of serum cholesterol. At the
same time Keys and associates ('52) reported serum choles-
terol concentrations of populations on high fat diets ad-
vanced with age; while the citizens of haples, who subsisted
on low fat diets, did not have increases in serum cholesterol
after age thirty. This was important because Gertler and
coworkers ('50), in relating serum cholesterol concentrations
to coronary artery disease, had found a steady significant
rise in serum cholesterol concentrations with advancing age.
Bronte~Stewart and coworkers ('55) reported an
inter-racial survey from South Africa, with a highly signifi-
cant difference in the cholesterol concentrations when clas-
sified according to race. The greatest difference in the
environmental factors was the diet. A later investigation
(Bronte-Stewart et al., '56) showed a correlation between
changes in cholesterol and changes in fat intake. Olive oil
did not raise cholesterol concentrations, while butter, beef

drippings and beef muscle did have an elevating effect.

Group Studies. By 1954 it had become obvious

 

that increasing cholesterol intakes did not always show

a correlating rise in serum cholesterol. Hardinge and Stare
('54) studied 86 vegetarians who included milk and eggs

in their diet, 26 pure vegetarians, and 88 non-vegetarians.

The average calories from fat were approximately 38 per cent.

10

The non—vegetarians had slightly higher intakes of animal
fat and total fat calories than did the other two groups.
The non—vegetarians had a greater intake of dietary choles-
terol than the vegetarians who consumed milk and eggs, while
the pure vegetarians had practically cholesterol-free diets.
No significant difference was found between the serum cho-
lesterol concentrations of the non—vegetarians and the vege-
tarians with added milk and eggs. This indicated a direct
correlation between the blood cholesterol concentration

and the intake of animal fat. The pure vegetarians, vith
liberal use of plant oils and no animal fat had the lowest
cholesterol concentrations of the three groups. There was
no correlation between the weights of the subjects and their
cholesterol concentrations, though the mean weight of the
pure vegetarians was twenty pounds less than the mean weight
of the non-vegetarians. Perhaps this indicated that cal-
orie utilization was less effective when the food source

was plants rather than a combination of plant and animal
foods.

Paterson and Derrick ('57), in a long range ob—
servation of the relationship of serum cholesterol concen—
trations to lipid deposits in coronary arteries, obtained
blood samples from a series of 800 patients in a veterans
hospital, twice in 1953 and yearly thereafter. The serum
from each collection was kept frozen, and after the death

of the patient the cholesterol concentrations of the serum

11

and of the fresh coronary arterial tissue were compared.
At the time of the second interim report in 1957 there had
been l29 deaths, ~nd the post mortem studies had been com—
pleted on 88 patients. ho significant relationship was
established between the cholesterol concent“ations of the
serum and the lipid deposits in arterial tissue. Paterson
and Derrick proposed that a study should be carried over

a long period of tine, since it was possible that lipid
deposits might occur in waves and might continue after the
cause for them no longer existed.

In a study of the causes of coronary heart diseas-
es, Bawber and coworkers ('57) found that there was an in—
creased risk of arteriosclerotic heart disease in persons
with serum cholesterol concentrationsabove 260 mg per cent.
There was little relationship between obesity and choles—

terol concentrations.

Laboratory Studies

 

Mayer and associates ('54) reported that there
was a significant increa e in cholesterol concentration
as the prOportion of dietary fat, regardless of the source
of the fat, was increased; and that alterations in the
amounts of dietary fat, whether aninal or vegetable, pro—
duced parallel changes in plasma cholesterol.

Keys and coworkers ('55) found the average

12

concentration of cholesterol in the sera of men whose diets
were high in fat was 25fi to 50% greater than the average
when the diets were low in fat, and alterations in dietary
fat produced significant changes in serum cholesterol con—
centrations within a few weeks.

Beveridge and associates ('55) reported changes
in proportion of vegetable fat and animal fat in diets of
five male subjects, aged 53 to 41. The first experimental
diet, with 28.4fi of the calories as vegetable fat, caused
a serum cholesterol decrease of 55 mg per cent. Jhen the
calories from vegetable fat were increased to 58.5}, the
serum cholesterol concentration decreased by 47 mg per cent.
When isocaloric quantities of butter were consumed, the
serum cholesterol concentration increased above the control
diet by the fourth and seventh day, and then drOpped on
the eleventh day to the same initial level. Addition to
the vegetable fat diet of an amount of cholesterol equal
to that in the animal fat diet produced a decrease of 38
mg W in the serum cholesterol by the eleventh day. Con—
sumption of a diet high in animal fat resulted in increased
plasma lipids. These findings suggested that vegetable
fat alone had no tendency to increase the plasma lipids,
but, in conjunction with some unknown substance of animal
origin which was present in a non-vegetable diet, it did
produce a higher concentration of the lipids.

Later these associates (Beveridge et al., '56)

13

reported that the change from a diet with 58.5% of the cal-
ories from corn oil to a diet containing isocaloric quanti-
ties of butterfat, lard, beef drippings and chicken fat
caused increased plasma cholesterol. Butterfat exerted a
more marked effect than the other fats. Changing from a
mixed free choice diet to a formula diet did not alter plasma
cholesterol concentration, even though the formula contained
60% of the calories as butterfat. When increasing amounts
of butterfat were replaced by corn oil, however, there was

a significantly progressive decrease in cholesterol concen-
tration.

Beveridge ('57) later tested the effects of the
various components of corn oil on the concentrations of
plasma cholesterol. Alpha-tOCOpherol had no effect, but
beta—sitosterol caused nearly as much decrease in serum
cholesterol concentrations as did the original corn oil.

The intimate mixing of beta-sitosterol with the rest of

the diet probably permitted the formation of a mixed crystal
complex, and therefore decreased the absorption of choles—
terol. Beta-sitosterol was not effective when it was fed
before or after the meal. Beveridge proposed that corn

oil also formed the mixed crystal complex with cholesterol
when fed as part of the diet.

Keys and coworkers ('57) reported that serum cho—
lesterol concentrations changed in response to the kind

of fat in the diet, with the largest part of the change

14

occurring during the first week. Four oils were tested:
corn oil (iodine number 120, linoleic acid content 45%);
sunflower seed oil (iodine number l5l, linoleic acid con—
tent 6lfi); sardine oil (iodine number 188, linoleic acid
content O-2fi); and butterfat (iodine number 52, linoleic
acid content 5%). The butterfat diet caused cholesterol
concentrations which were 52 mgfi higher than the corn oil
diet, 55.8 mgfl higher than the sunflower seed oil diet,
and 59.8 mgfi higher than the sardine oil diet. These find-
ings did not support the theory that the serum cholesterol
concentration in man is a simple inverse function of the
essential fatty acid content or the degree of unsaturation,
since the sardine oil was the most highly unsaturated and
the sunflower seed oil had the highest linoleic acid con-
tent. All serum cholesterol concentrations in this experi-
ment were significantly lower on corn oil than on the other
oils. Keys and associates prOposed that serum cholesterol
concentrations were related to total fat rather than in-
versely to the essential fatty acids and that the observed
effect of vegetable oil in lowering serum cholesterol con-
centrations was not due to the essential fatty acids.
Kinsell and Sinclair ('57) objected to these con—
clusions (Keys et al., '57) in that the actual quality and
quantity of the fatty acids had not been determined and
that the linoleic acid values were not established by lab—

oratory analysis but were taken from the literature.

l5

Sunflower seed (iodine number 151) was assumed to have a
linoleic acid content of 615, but variations of 195 to 72$
have been known. Corn oil was assumed to have a linoleic
acid content of 45$, but samples of U.S. corn oil have as—
sayed at 165 to 68% linoleic acid. Therefore, Kinsell and
Sinclair prOposed that heys' figure of 45% for the linoleic
acid content of corn oil was too low; that iodine numbers
are not adequate for determining unsaturation of oils in
relation to their effects on serum cholesterol concentra-
tions; and that the efficiency of absorption of the oils
must be determined. These associates observed from their
own data that vegetable oils which are fresh, readily ab-
sorbable, and under controlled conditions caused a decrease
in serum cholesterol concentration which was approximately
proportional to the iodine number.

Because of the controversy initiated by Kinsell
and Sinclair ('57), Keys and associates ('57b) published
additional data on the iodine values and percentage satura-
tion of the fatty acids in the oils which they had used.
Although they did not deny the role of the amount of satur-
ation in the fatty acids and its effect on the serum cho-
lesterol, they reasserted their_thesis that saturated fats
had a great effect in elevating the serum cholesterol con—
centrations, and that corn oil had a lowering effect which
was additional to that which was due to its fatty acid con-

tent.

16

In another report, Keys et al. ('570) stated that
the saturated fatty acids had twice as much effect on the
serum cholesterol concentrations as the polyethenoids which
acted in the Opposite direction. Oleic acid, a monoethenoid,
had a small but uncertain effect on the raising of serum
cholesterol concentrations. Keys and coworkers predicted,
on the basis of previous laboratory work, that the removal
of 1 oz of butter (57¢ saturated with 4d polyethenoid fatty
acids) would produce a three times greater decrease in cho-
lesterol concentration than the addition of 1 oz of sunflower
seed oil (105 saturated with 62” linoleic acid content).

Thus they expected the substitution of 1 oz of sunflower
seed oil for 1 oz of butterfat to cause a decrease of 20 mgfi

in the serum cholesterol concentration, with three quarters

.C‘

01 the change caused by the reduction in butterfat content
of the diet. These associates predicted this cholesterol
concentration decrease for a man in caloric equilibrium
at 2600 calories, with cholesterol concentrations under
250 mgp when subsisting on an ordinary high fat diet. Greater
reductions were eXpected in serum cholesterol concentrations
for people who were hype*cholesterolemic.

ncCann and coworkers ('59) reported studies on
the effects of vegetable oils on serum lipids in subjects
with serum cholesterol concentrations above the mean for

their ages. During the experimental period the subjects

l7

consumed approximately 80 ml of peanut oil formula in three
doseo daily, before each meal. The formula supplied 960
calories, 96 g fat, 24 g carbohydrate and 25 g linoleic

acid. Two samples of blood were taken for control measure-
ments at intervals of one week, and additional samples were
collected weekly. In the second study safflower oil was

used in amounts to provide 250 calories, 28 g fat and 20 g
linoleic acid. The dietary fat from animal sources was
decreased from 769 to 35p, and cholesterol intake from 707mg
to 497 milligrams. The mean ratio of satura ed to unsaturated
fats was reduced by 553 while the essential fatty acid intake

per cent. thann and coworkers observed

(

was increased 100
a sharp drop in serum cholesterol concentrations after the
first week, followed by a rise during the second and third
week. During the fourth week the concentrations decreased
to a level equal to that at the end of the first week.
Both peanut oil and safflower oil were effective in causing
a slight lowering of serum cholesterol concentrations, and
it was concluded that unsaturated fatty acids should be
incorporated into the diet pattern for best results.
Schendel and Hansen ('58) studied 48 infants with
.kwashiorkor and measured serum cholesterol concentrations
during an eleven month period in which skim milk formulas,
twith no added fat, were given to the infants. As the kwash—

iorkor improved, serum cholesterol concentrations rose.

18

At the beginning of the observation, mean total cholesterol
was 95 mgfi, compared with normal controls of 175 mg per
cent. As the infants responded to the treatment, choles—
terol concentrations were doubled, but there was no signifi—
cant change in cholesterol concentrations in infants who
did not show a clinical reaponse. Sitosterol might have
been responsible for the original low cholesterol levels,
since the diet was almost totally vegetable. The synthesis
of cholesterol may have been reduced, and diarrhea may have
led to increased excretion of sterols. Schendel and Hansen
concluded that increases in cholesterol concentration which
correlated with clinical improvement reflected the renewal
of esterification mechanisms in the liver.

Davis and associates ('60) gave formulas contain—
ing 21% fat, 64p carbohydrate and 155 protein to ten patients
with coronary leart disease, while adjusting calories so
that body weight remained constant. Cholesterol concentra-
tions were measured during two weeks' intake of safflower
oil formula and two weeks of equal quantities of safflower
oil and coconut oil. Serum cholesterol concentrations were
reduced as well with 20% fat as with higher amounts of un-
saturated fat in formula feedings. These researchers con-
cluded that wide variations of fat levels in formula feed-
ings showed similar results, and that the optimal fat level

was perhaps in the 20% to 40% range.

19

Exercise Studies

 

horris and associates ('53) reported a study of
the incidence of coronary heart disease in various occupa-
tions in England. The incidence of heart disease in bus
drivers was greater than in bus conductors. These authors
related this to the increased physical activity in the work
of the conductors. A study of the heart disease incidence
in postal workers showed that there was less disease in
those with active jobs than in more sedentary work. Further
observations showed that differences in incidence of death
rate and history of coronary heart disease were due to dif—
ferences in physical activity. These associates concluded
that physical activity might act upon the coronary circula-
tion in addition to creating the demands made upon it.

mann and associates ('55) reported that differences
in cholesterol concentrations of Nigerian subjects in three
separate areas of the country could not be attributed to
total caloric or total fat content of the diet, since these
were similar. These authors believed that a difference in
muscular exercise might have had an effect in reducing or
controlling serum cholesterol concentrations in a manner
similar to the effect of exercise on carbohydrate tolerance
in diabetics. According to this theory, the lower concen-
trations of cholesterol were Caused by muscular activity and

energy expenditure, and a large muscle mass or large.muscular

2O

expenditure was important in the prevention of hyperlipemia

1

and perhaps in tie pievention of atherosclerosis.

Keys (' 56 ) concluded from his observations with
the Bantu that differences in physical activity do not ex-
plain large variations in serum cholesterol concentrations.
hen on heavy manual laoor also consumed diets which were
lower in fat than those of the other Bantu; hence, Keys
attribute d the lower choles rol concentr.ations to the fa t
content of the diet rather than to the physical activity.

In an investigation of the serum lipids and athero-
sclerosis among Yeme n1 ite immigrants in Israel, Toor and
coworkers ('57) reported that the recent immigrants had
lo.”er serum cholesterol concentrations and lower mortality
due to atherosclerosis than those who had lived in Israel
longer. The only dif erences in the pOpulations were in-
come and total food intake. Because the recent immigrants
worked harder, with less food, they were in a state of cal—
oric imbalance and tilerefor e deveIOped lower cholesterol
concentrations. Four years later, Toor and associates ('60)
investigated this same group of immigrants who had then
been in Israel for five years. These immigrants were now
living under better conditions, with a higher caloric intake
and a higher percentage of calories from fat than in their
previous diet. Their serum cholesterol concentrations were
also higher than previously, and were caused by the increased

calorie and fat intake, as well as the change in ratio of

21

saturated and unsaturated fatty acids.

‘

hxercise Experiments

 

Taylor and associates ('57) tested the effects
of physical activity on serum cholesterol, by increasing
physical activity by 1300 calories on the motor driven tread-
mill and adjusting food intake so that there was no loss
in weight and no change in proportion of calories from fat.
he changes were observed in serum cholesterol. Therefore
it was concluded that serum cholesterol concentrations are
related to the proportion of the total calories derived
from fat, and that they are determined by the fat transport
load from the intestine to the liver and from the liver
to the fat depots. This fat transport load is influenced

by the circulation rate, which is influenced by exercise.

(1)

Though the fat intak was increased by 46 g daily, the in-
crease in circulation pre ented an increase in serum choles-
terol concentrations.

In an earlier report from the same laboratories
(Anderson et al., '55), physical activity was kept constant
at 2 l/2 miles of walking daily, and energy balances were
changed. After a period of semi—starvation, the serum total
cholesterol was 66p of that of the controls, and at the

end of a refeeding period of 5500 calories it was 152fi of

the controls maintained on a constant diet of 5200 calories.

This e1:peri.ent was repeated. The cholesterol concentra—

tions were 78p of the controls 1urin semi—starvation and

1126 of the controls after refeedinj with 40J0 calories.
another repoit (1nd ers on at al., '56) showed that

in Obese subjects maintained on 1200 calorie reducing diets,

scie with ”as of the calories as fat and some with lap of

ti 1e ca‘ lories as fat, there 'was a deCie ase in serum choles—

terol conce Mtirblouo in all subjects 0, \den exercise was

1?

t constant. The reduction of choles te1 ol concentrati ions

7;-
v

——.I
'7.)

was greater in the low fat than in the high fat group when
the weight loss was identical for both groups. These authors
concluded tl1at in caloric uh\er1utrition and in low fat

consumption, serum cholesterol concentrations are lowered

by both factors worhinr i1de endently and simultaneously

- I)

(L

This ehoeii1ent was repeated 'tceot that the sub-

jects were overfed, (1n1der son et al., '57). During a 20-
week period with an intake of 5400 calories, the men who
gained the h ost we'ght had increased se1u1.1 choleste rols

by 40 mop during he first 10 weeks, with no change in cho—
lesterol during the last 10 weeks, though the 1eiaht gain
continued. Anderson and coworkers concluded tlat a gain

in body weight might be used to predict an increase in cho-
lesterol during the beginning phase of period of weight

at intake was increased, there was an ac-

F1)

increa<5e. When

companying rise in the se rum c11olesterol co11centrations,

23

even though the percentage of calories from fat was decreased.
This probably occurred because cholesterol was part of the
lipOprotein—fat transport system.

hann and coworkers ('55) further investigated
this subject to determine whether the amount of total cal-
oric turnover controlled the serun lipOprotein concentra-
tions and whether the disposition of calories from the diet
controlled the serum cholesterol concentration. According
to this hypothesis, an excess of food that was converted
to body fat would cause high concentrations of serum cho—
lesterol, and caloric balance or deficit would result in
low concentrations. By varying the total caloric turnover
and the disposition of the excessive calories, these asso-
ciates concluded that young men on high fat diets were able
to double their caloric supply without increasing the con—
centrations of the serum lipids, as long as the excess cal-
ories were used up in exercise. However, when exercise was
restricted so that fat deposition occurred, there was an
approximate doubling of serum cholesterol concentrations
when the caloric intake was doubled. During a period of
weight reduction serum cholesterol concentrations promptly
returned to the original levels.

Chailley-Bert and coworkers ('55) found that cho-
lesterol concentrations of active subjects were lower than
hose of sedentary subjects. Daily exercise in three seden-
tary hypercholesterenic subjects caused lowered total cho-

lesterol concentrations.

24

Montoye and associates ('59) observed 16 male
subjects in a supervised exercise program of swimming and
calisthenics and 15 sedentary controls. To appreciable
difference was found in the serum cholesterol concentrations
within either group when initial and final values were com—
pared. when the subjects of both groups were combined,
changes in serum cholesterol concentrations usually accom-
panied changes in body weight, regardless of exercise.

These authors concluded that the effects of exercise in
decreasing serum cholesterol concentrations were indirect
and were related to loss of weight.

The literature which was reviewed was primarily
concerned with the hypercholesterolenic effect of butterfat
and the hypocholesterolemic effects of exercise. In order
to investigate these further, two studies vere designed
to test both the dietary and the exercise factors. These
experiments, one with rats and one with humans, were planned
to test the effects of milk consumption upon serum choles-
terol concentrations while maintaining exercise at a high

level.

EXPERIJEITAL LETEOD

Animalsl

Sixteen weanling litter-mate trios of male rats
of the Sprague-Dawley strain were housed individually in
cages in a room with no direct sunlight. The cages (5" x
5” x 12") were rotated daily to compensate for possible
light and temperature deviations. This study was carried
out over a six month period. For two months the rats con—
sumed a stock diet (Appendix A). The animals were then
divided into three experimental groups by alternating the
ranked weights within each litter, and the animals were
numbered. During a period of twelve weeks the following
regimes were continued: Group A (animals l-l6) received
a stock diet and were exercised; group B (animals 17—32)
received a stock diet with 50% of the daily caloric intake
supplied by powdered whole milk and were exercised; group
C (animals 53—48) received a stock diet and were sedentary.

Each animal in the two exercise groups received

equal amounts of conditioning. They swam in their respective

 

1This study was carried out under the direction
of Dr. Henry J. hontoye, Department of Health, Physical
Education and hecreation, michigan State University, as
part of mSU Research Project Number 941, 1957. Details
are reported by Ackerman ('59).

25

26

groups twice daily, Londar through Friday, and once on Sat—
urda y for twelve we ehs. During the first week the periods

of swimming were short. During the second and third weeks

the swimming periods were ten minutes in length, and me tal
weights equal to four per cent of the body weight were at—
tached to the re ts. Beginning with week four, no weights

were attached to the animals and sw1muing times were increased
to thirty minutes, twice daily. Thereafter the srimhin

by five uinutes weekly, until a one

91

times were incre ”LS

hour period was attained. The water temperature was stand—

CL

ardize d at 36—37° Centigra'e.

At the end of ""h tzelfth e :peri.;:1ental Heel: the
animals were anesthetized with sodium pentobarbital and
blood was obtained by cardiac puncture. The blood samples
were allowed to clot and then were centrifuged. The clear

supernatant serum was pipetted off and was Iro zen.

. , _
Ill/11-1 E"; n 5

Seven university freshmen who were candidates

‘

ents who had been

.1.
(1

DJ

for the track tean and two graduate s u

“cts.

( j)
(‘1')
(1)
$1.:
0
C.)

durance 1unners were selecte1

its

outstanding e1

 

lriis study ma

;S carried out under t‘1e direction
of Dr. Gale 3. Lickles and Dr. Jajhe Van dues, Dewartnen+
cf'1Lealtx1, lir,sical-‘£iucr on a1r“ Lcc116rt on, :i i_
Universitj. This was part of a stunlv o: the effects of
:ilLLIi on eruiuitn1ce Luh1io11urch .hiici1 was sapcn s<1 -‘

tion11 Dairy Council.

C0
(-
11'
(

1,.J

good ghysical condition for

.1 ' ' 1“ ' 1, -' .1 ,3 1 1 1 :11. :11 .. .. - ,1. . , ' .
»artic11ation 1n an endurance stuuj. ineg ranged in see

N

‘ J

.1': ‘fl 1 \ ‘ f) .",_‘3 1% "i I"- J“ \ 1‘ . ' " 1' ~; ~ r -;.I" ~~rrx
iion lg to 44 years enceyt ior subjeCt hunger 9 Lao usS 32.

 

For three weeks prior to the beginning of the

L.

experiment, all subjects trained to exhaustion on the motor-
4.

driven treadmill, running twice each week at 10 mph up an

/' _

1.) o 053 U

grade. Three ines each week the subjects ran at vary—
ing syeeds on the level treadnill, in order to determine

the fastest rate at which all subjects could attain a steady
state and continue for fifteen minutes. The steady state
was assumed when the yulse rate leveled off and did not
increase again during the fifteen-minute period. The maxi—
mal speed which could be attained by the most poorly con-

ditioned subject was 6 mbh.

Blood samples

 

During the week trior to the synerinent, lO—nl
samples of blood were taken from each subject three times
by venipuncture. The blood samples were allowed to clot
and were centrifuged. The clear supernatant serum was
pipetted off and was frozen. During the last week of the
eXperiment three samples of blood, taken from each subject

by venipuncture, were treated in the same manner.

23

Grouping of subjects

 

'2

L;

signed at random to each

,

Four subjects were a.
of two groups. Group I (subjects 1, 2, 5, and 4) was in—
structed to consume a self—selected diet, including at least
three pints of milk daily and two pints of ice cream weekly.
Group II (subjects 5, 6, 7 and 8) was instructed to elimi—
nate milk, cheese and ice cream from the diet. ho attempt
was made to eliminate milk and cheese in cooked dishes.

rhe ninth subject was arbitrarily assigned to group II.
Subjects 1, 6 and 9 ate in their respective homes. The
other six subjects ate in a university dining hall. It

was decided that when milk, cheese or ice cream were served
in the dining hall all subjects would accept the food, and
those in group II would give their restricted foods to those
in group I. This resulted in a higher intake of these foods
for group I than would have been possible without special

arrangements.

Dietary records

 

For one week before the start of the experiment,
a graduate dietitian secured twenty—four hour recall diets
(Appendix B) from each subject by daily interview. Dining
hall menus were used to verify the Specific foods served.
During the first experimental week recall diets were again

secured from each subject daily. Nutritional intakes of

29

each subject vere calculated, using the method of Leichsen—
ring and dilson ('51). Sizes of portions were estimated
from observations of the dining hall procedures and serving
utensils.

The nutritional intakes were compared with the
recommendations of the Food an Nutrition Board of the ha—
tional Research Council ('58) for boys 16-19. The food
consumption of subject 9 was not included in the compari—
sons because no pre—experimental diet was available. The
intakes for week one were compared with week two for each
group by the Student "t" test for paired variates (Goulden,

'52).

haperinental‘period

 

For eight eXperimental weeks each subject ran
once weekly for fifteen minutes at 6 mph on the flat. Twice
weekly, each ran to exhaustion at 10 mph up the 8.69 grade.
During this time respiratory gases were collected and an-
alyzed. Details of this study were reported in 1961 (Van Kuss

et al., '61).

Chemical hethod

Cholesterol determinations of the sera were made
in triplicate by the Schoenheimer-Sperry method ('34), modi-

fied by Sperry ('57) and Foldes and wilson ('50). Serum

50

was added to an alcohol—acetone mixture, the protein was
precipitated and filtered, and the cholesterol was precipi-
tated as the digitonide. The sample was washed once with

an acetone-ether mixture and twice with anhydrous ether.
After drying, the digitonide was dissolved in glacial acetic
acid and treated with Liebernann—Eur hard reagent (acetic
anhydride and sulfuric acid). A color reaction was produced
which followed Beer's law. The cholesterol concentration
was determined by a comparison with the color produced by

a standard cholesterol solution with a heckman Spectrophoto—

meter, model LU.

RESULTS

Animal S

A total of thirteen rat cholesterol analyses were
unavailable due to drowning of rats during swimming, dif-
ficulty in securing blood by cardiac puncture, and labora—
to*y losses during cholesterol determinations. The mean
cholesterol concentratio s and mean body weights of the
two groups of rats on the stock diet are listed in Table l.
The mean cholesterol concentrations and mean body weights
of the exercised rats are listed in Table 2. Individual
data are recorded in Appendix C. Significant differences
in total and free cholesterol concentrations and in body
weights were observed when the exercise group on the stock
diet and the sedentary group were compared by the paired
"t" test (Goulden, '52). No significant differences were

observed between the two exercise groups.

Cholesterol

The average serum crolesterol concentrations for
the two groups of the athletes are shown in Table 3. Indi-

vidual data are recorded in Appendix D. Some of the

31

Table 1. Mean serum cholesterol concentrations and mean

body weights of r

paired "t" test

0+1‘1

LLUD

on stock diet compared by

 

Exercise
group

Sedentary
group

Ihnnber‘ t
of
litters

 

Total serum
cholesterol

Free serum
cholesterol

Final body
weight

74.7 mg/100 ml

20.9 mg/100 ml

414.1 g

4

25.1 mg/lOO

5

3

93.1 mg/lOO

.4 g

ml 8 2.59*

ml 8 2.88*

10 4.22**

 

* Significant at 0.05 level
**Significant at 0.01 level

33

Table 2. mean serum cholesterol concentrations and mean
body weights of exercised rats compared by paired

"til

test

 

Added Stock Ho. of t
milk diet litters
group

 

Total serum
cholesterol

Free serum
cholesterol

Final body
“'8 ioilt

54.9 mg/100 ml 74.8 mg/100 ml 9 1.63

23.4 mg/100 ml 20.9 mg/100 ml 9 1.21

417.7 3 415.1 g 10 0.26

 

Table 3. Comparison of effects of exercise, with and with-
out milk consumption, on mean seruh cholesterol
concentrations of athletes

 

 

 

Serum Jilk Diet t Restricted Diet t
choles-
terol initial Final 1nitia1 Final

 

mg/100 ml hg/lCO n1 hg/100 n1 Lj/IOO m1
Total 180.1 39. .47 190.3 20
Free 51.6 53.8 1.21 55.7 6u.6 1.90

 

 

 

\)J

'r 4 a an 1" ~3n-‘L' 1 -,~ “'1
Pie—eu'brlhbutal saxples.re1e st dur ing 1au01atory pio—
“ 4-" - - . » ~ ~ ‘ w . h fir“ '0 '1 ~
cedurcs. Two s? p123 01 Sara Jeie av ilaole 101 all sub-
Jeots e:c t hunter one. 1&10809M91c8 o: sera were avail—
- 5" ‘ - .».‘ . \ - fi 5" ~ r '2" 71‘. a 3— .~ 7 ~ ~ 5" ‘ 7 7 '
ble 1or all siujects 1 1 in; ehp-.1 Wheel police. .o
significant dii ecences xere s.n wn in either the tOt 1
.., - 1’. .w- 1- 1.. .. -1. ,,, L- - 3, , .1. ° ,- - .,

or liee ouolesterol by t.e "t" test Ldbueju 1-1tia1 Ldl
3.: ‘ r F‘ , v - . [:1r.|1.. .. '7
1.4.1153]. Values 1.]. Cd 3. 11 :21 'j‘h‘.) (10.4.ch )) o
nody wei'nt

"f . ., - . .u-i ."a J”... Q ‘~ 3—. n ‘ .1 -- .1.‘ 1

1A“ mean weights 01 the two Urouse 01 athletes
.'.. , ”.1”... ‘ “.0, ~,. _ ' 1 1:: -.._ *4. ' f', ‘. ._. ' 1.1-
an w€<..~-1y 111061173153 atJ. ‘ 53.1 «.’11 111 1*.L‘Jv11'“ l. 111xllv'l'oulcll ‘.‘.‘3l‘.;-1bs
was w: ~: 51 x '1 n 31’ 2? ~ ~n" 1*
d a 10001ubu 1n 43.0hd14 h. n o jrsis 01 V l1.hcc 1or
g ~, 1 . ,j . -1 , 1 ,
bouy weigh s is shown in 1ab1e 4.
List

fr. ' '. a“ r- at ‘ ‘ r~ \ ‘1’. w " 7. ’1 r' “. .

1ne nutritional analysis 01 the lecall d1ets is

listed in Table

mi ‘- '1
111s changes in

for

mental and the

The changes in

.’..

I-

were Si hiliCE

Y£18

of calcium

1

O

I)

l...)

es,

(5‘.

l

H
t)
c'r

0

significance

5, with individual data in Apeendi” F.
dietary intake of the athletes were tested

by the ”t" test, comparing the nee—experi—
eXperiaental weeks for each of tee two groups.

intake of f t, rbomytreto and riboflavin
t at the 5b 1ev 'l. The change in intake

significant the 1}

were

'4

7l.50

71.25

71.00

70.75

70.50

70.25

Body Weight (kg.)

70.00

69.75

69.50

Figure l.

 

L
/\
.. // \\/\
v \
.\l \,
\/ b’

 

0—4/1
-<
r.

t

Weeks of Training

 

Milk Group --- Non—Milk

Weekly mean weights of athletes in milk and
non-milk groups

Table 4. Analysis of variance for body weight

 

 

Sour es of Degrees of Sum of Lean F—Va ue
variance freedom squares square

Total 69* 907

Groups 1 10 10.00 25.00**
deeks 7 3 0.45 1.07
Individuals 7 870 124.2L 510.73**

G x J inter-
action 7 5 0.71 1.78

Error 47 19 0.40

 

* Two degre
values we
a

e- of freedom were lost because two missing
. 1
** Signific

s
“e estimated.
t at the 0.01 level.

moonmzoaa¢ cowsosiooom HHoQSOo gohmommm ammoflpmm .thom COHPflmPSE Ugo doom ***
Ho>ma Ho.o map pm pngflMflqmfim **
H®>ma mo.o map pm pewOflmflenHm *

 

**sm.mn mo.H mm.m o¢.H ms.m ss.m H.m Amav gfl>sHmOpfls
mo.ou cuss News om.H ems» same ooom ADHV e sflawpfl>

rs **Ho.s- os.o mm.H mm.H Hm.m Ho.m e.H Amv ESHOHso
fl; *sm.s see man HH.H Hos mmm smqmflfipwpmm pom Amv

mpmscxnophoo

 

 

*ms.mu sHH HmH mm.o wma mma emnmfifinspmm pom Amv psm
se.H- sea wHH ms.m snfl mma OOH Amv eflmpogm
mm.fi cwmm msmm mo.m seam Hmmm comm mmfiyoamo
Amauma msomv
=p= HH some H smm: =p= HH swan H some. mmogsaoafle
ammpoflm

poflm wopofihpmom PmHQ @mPOHHPmoHSD ***@mwsmaaoomm mpcmfispsy

 

mgpmaepm mo

GSosm mono Mom esp Moos npfls mQO woo: Mo Somflsmmaoo .oxmpqfi HGQOHPHHPSZ .m magma

Cg

39

A comparison was made of nutrients in the experi—
mental diets and those recommended by the Food an Nutrition
Board of the National nesearch Council ('55). Standards

for boys 16-19 years were used because all subjects with

'3

dietary analys s were under 25 years of age. After milk

(U

restriction the calcium and riboflavin in akes fell below

the recommended allowances (Table 5).

DISCUSSION

Animals

The mean total cholesterol concentration of the
exercised rats on t ;;e stock diet was si fin w.ntly differ-
ent from that of the sedentary group. The rats in the sed-
entary group had the hi her serum total and free cholesterol

eans and the are Late r mean weight. This would be expected
with lesser amounts of exercise aLd unrestricted food.

.1.

Tie above results are in accordance with the findings of
nontoye and associates ('59) who reported that in middle—
aged men changes in cholesterol concentrations were reflec—
tions of changes in weight. Although exyeri her tal results
cannot be transferred from one Species to another, it is not
unreasonable to exoect that hi her cholesterol cor centra—
tions would be observed in the he avier rats as an indirect
result of the lack of exercise. This relations dip between
changes in bO'y wei ht and in serum cholesterol concentra—
tions is also in agreehent with the findings of Taylor and
comvo w} are (' 57) i1 studies with huhals. If cha gee in serum
cholesterol are related to the fat transport per unit of
circulation, then lack of exercise with subseauent Ucirnt

1

Q ain would cause hi ner amounts of

F:

at per unit of circu—

lation, as evidenced b; raised serum cholesterol concentrations.

41

Therefore, the higher cholesterol concentrations in the
sedentary rate may be related to the exercise and calorie

imbalance.

(p

The exercised rats receiving stock diet plus milk

a

did not have sienificantlv dif erent scrun total and free
H d

cholesterol concentrations from those on the stock diet

,.. -

without milk. since exercise was similar in both groups,

it can be concluded that the reylacement o” 30% of calories

with powdered whole milk had no effect.

Humans

Cholesterol concentrations

The initial and final serum cholesterol concen-
trations were not significantly different, whether or not
milk was included in the diet. This would be eXpected in

who reported that serum cholesterol concentrations in young

\Jl

accordance with the findings of Kenn and associates ('5

men did not change as long as excess calories were used

up in exerci e. The fat intake was constant in the unre—

0')

re of calories from fat

:3

stricted diet groug. The percenta
was decreased from 36p to 50% in the restricted diet group.
The stability of the serum Cholesterol concentrations is

in agreement with the proposal of Davis and coworkers ('60)

that changes in dietary fat levels in the range of 209—40fi

of the total calories do not affect serum cholesterol con-

centrations.

Bo d1 we igh t

The significant F value for individuals indicates
that the subjects differed in body weight. The significant
F value for groups shows that the two groups differed sig—
nificantly in we ei511t. This difference is due to the groups
not being matched in body weight at the beginning of the
eXperiment and is not due to the effect of milk. The in-
significant F value for wee1zs indicates that there was no
sL fllllCuflb chanre as the e: {perinent progressed due to fac-
tors other than milk restriction. The insignificant value
for group—weeks interaction indicates that the change in
wei hts for t e two groups was not different as the experi-
ment progressed, and that therefore milk restriction did
not have any effect on body weight. Since body weight was
constant, changes in serum cholesterol concentrations would

not be eknected (nontoye et al., '59, Taylor et al., :57).

Dietary»Evaluation

 

The nutritional evaluation shows that when milk,
cheese, and ice cream were eliminated from the diets, the
calcium and riboflavin intakes were below t1m recommended

aw

allowances of the od and 1Wu ri “ ion Board of the Lational

Research Council ('58) exceyt for one subject. Ehe intake
for this subject was sufficient because he consumed an aver-

age of twelve servin s of enriched cereal pro oduCts dailv

C0
(’1‘
:7
C U
0
(D
1.1
(D
L3
H

which was ayproxinately one and one—half time
int he of the other subjects on the restricted diet.

Qne calorie intake was mailmt ined by the increased
consumption of fruits, cereals, gravies, desserts, soft
drinks and candies. Ihe raised intake of carbohydrate foods,
esbeciall; she desserts, soft drinks and candies, is not
nutritionally (esirable, since the calories are accompanied
by very few other nutrients.

1"." 1, ~1hm ' ,1
10L o1 niln, cheese 1nd ice

(U

31:10: t-1e <.3111.‘1j.."31a

F1
(1)
c-
C
9
g.
0)
(
C.»
a
."J
(1
C
1..
(1
cr
(‘3
H
c.
H
(D
<
11
i. J
(O
O
H»
O
(3
1.4
O
!_J
g

crean from the d

45m

and riboflavin fall below tnose recomnended b" the 3——

tional hesearch Council ('53), attenpts to lower blood cho—

lest rol concentrations b“r this tVue of diet would a: ear
J 1.1. 1-
to be undesirable. Since many colle;e fiesh1en have not

attair We ccnnlete growth, it is 1n1c ative that their food
guate intaxes of the essential nutrients. hore—

over, the use of :1, non-11111: diet at the collage level- would

wrooabid be rc109ted in the hi4h school ”Valhl‘: of athletes,
at an a;e then calciun is CSJCCiflllJ 1n1o tent for ‘one

1‘ r ‘, ~ 1‘ ~' I 4‘ |_ (A. 1‘- ‘ ‘ '::1 (x -‘ I . V ’I N p r‘ o 1

n. 1ne lov intanes 01 oa101un and r1bo1laV1n could
- ‘ firx" '1‘1-‘1‘1 J "1 ‘- in “ .-1‘ -1 ‘. ‘7 ‘ 1 .\ - 31 ,

nave 1a“—1each1nQ f1ects because other young peogle have

tendenog' to copy the athletes' die

9')

l

in bong arcu)‘

_. a _ .. V '1 'r‘ W . ‘ ‘_‘
rcccimcnce ailc;iuc:o

”.‘-... 1‘ - _ 4...;
lcicr c141011c CޢASdukbi

‘ol'cus 10 ‘Uu’b—L “\l‘t 4—0:)

(0
(‘Q
0

were Laintcining c

5

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u - o l .. ‘ '4“ u 1‘ A 1
vet, it is EOaSlLlc t3?

c critical.

An experiment was devised to test the effects
of milk consumption and exercise on concentrations of blood
cholesterol (free and total) in rat and man. The sedentary
rats had higher cholesterol concentrations and greater weights
than the exercise rats. The higher cholesterol concentra-
tions appear to be related to the increase in weight and
only indirectly to absence of exercise. No changes in the
cholesterol concentrations or body weights of the exercised
animals were observed when 30% of the calories were replaced
by whole milk solids.

In two groups of trackmen, who were in good phys-
ical condition, exercise was maintained at a high level and

‘

milk consumption was varied. Jo changes in weight or in
cholesterol concentrations were observed in either group.
Exercise was a factor in maintaining constant weight and
cholesterol concentrations. Elimination of milk, cheese

and ice cream from the diet resulted in decreased dietary
intakes of calcium, riboflavin and fat; and increased con-
sumption of carbohydrate. On the restricted diet, intakes
of calcium and riboflavin were below the amounts recommended

by the Food and Nutrition Board of National Research Council.

According to the results of this study, it is not

45

46

advantageous to attempt to alter blood cholesterol concen-
trations by changes in milk intake. r‘here appears to be

an indirect advantage in the control of serum cholesterol
concentrations through the regulation of exercise and diet

for caloric equilibrium.

LITERATURE CITED

Ackerman, K. J. 1959 An investigation of the effects of
a twelve week conditioning program on the electro-
cardiograms of albino rats. Unpublished Master's
thesis, hichigan State University, East Lansing,
Michigan.

Alfin—Slater, h. B., L. Aftergood, A. F. Wells and H. J.
Deuel 1954 The effect of essential fatty acid
deficiency on the distribution of endogenous cho-
lesterol in the plasma and liver of the rat.
Arch. Biochem. Biophys., 52:180.

Anderson, J. T., F. Grande and A. Keys 1955 Serum choles-
terol concentration of men in semistarvation and
in refeeding. Federation Proc., 14:426.

Anderson, J. T., H. L. Taylor and A. Keys 1956 Serum cho-
1esterol in subjects on diets high and low in fat.
Federation Froc., 15:542.

Anderson, J. T., A. Lawler and A. Keys 1957 Weight gain
from simple overeating. II. Serum lipids and
blood volume. J. Clin. Invest., 56:81.

Beveridge, J. M. R., W. F. Connell, G. A. Mayer, J. B. First-
brook and h. S. Dewolfe 1955 The effects of
certain vegetable and animal fats on the plasma
lipids of humans. J. Iutrition, 56:511.

Beveridge, J. m. 3., W. F. Connell, and G. A. Mayer 1956
Dietary factors affecting the level of plasma
cholesterol in humans: The role of fat. Canad.
J. Biochem., 34:44.

Beveridge, J. h. R., W. F. Connell, and G. A. Mayer 1957
The nature of the substances in dietary fat af—
fecting the level of plasma cholesterol in humans.
Canad. J. Biochem. Phys., 55:257.

Brown, C. E., T. C. Huang, E. L. Bortz, and C. M. McCay

1956 Observations on blood vessels and exercise.
J. Gerontol., 11:292.

47

48

Bronte-Stewart, B., A. Antonie, L. Bales and J. F. Brock
1956 Effects of feeding different fats on serum-
cholesterol level. Lancet, 1:521.

Bronte-Stewart, B., A. Keys and T. F. Brock 1955 Serum-
cholesterol, diet, and coronary heart-disease.
An inter-racial survey in the Cape Peninsula.
Lancet, 2:1105.

Chailley—Bert, P. Labignette and Fabre—Chevalier 1955
Contribution a 1'etude des variations du choles-
terol sanguin au cours des activites physiques.
Presse Hed., 65:415.

Dawber, T. B., F. E. moore, and G. V. hann 1957 II.
Coronary heart disease in the Framingham study.
Am. J. Pub. Health, 47:Supp. 4.

Davis, C. B., B. E. Clancy, B. E. Cooney, D. H. Hegsted
and J. H. Hall 1960 Effect of mixed fat formula
feeding on serum cholesterol level in man. II.
Further study utilizing a twenty per cent fat
formula. Am. J. Clin. Nut., 8:808.

Foldes, F. F., and Wilson, B. C. 1950 Determination of
cholesterol-adaptation of Schoenheimer and Sperry's

method to photoelectric instruments. Anal. Chem.,
22:1210.

Gertler, n. A., S. h. Garn and E. F. Bland 1950 Age, serum
cholesterol and coronary artery disease. Cir.,
2:517.

Goulden, C. H. 1952 hethods of statistical analysis New
York.

Hardinge, m. G., and F. J. Stare 1954 Nutritional studies
of vegetarians. 2. Dietary and serum levels
of cholesterol. Am. J. Clin. Nutrition, 2:85.

Keys, A., F. Fidanza, V. Scardi and G. Bergami 1952 The
trend of serum cholesterol levels with age.
Lancet, 2:209.

Keys, A., J. T. Anderson, F. Fidanza, h. H. Keys and B.
Swahn 1955 Effects of diet on blood lipids in
man. Clin. Chem., 1:54.

49

Keys, A. 1956 Physical activity and the diet in popula-
tions differing in serum cholesterol. J. Clin.
Invest., 35:1175.

Keys, A., J. T. Anderson and F. Grande 1957a "Essential"
fatty acids, degree of unsaturation, and effect
of corn (maize) oil on the serum—cholesterol level
in man. Lancet, 1:66.

Keys, A., J. T. Anderson and F. Grands 1957b Fats and
disease. Lancet, 1:992.

Keys, A., J. T. Anderson and F. Grande 1957c Serum—cho—
lesterol response to dietary fat. Lancet, 2:787.

Klein, P. D. 1957 Polyunsaturated fatty acid composition
of cholesterol esters in rat liver and plasma.
Arch. Biochem. Biophys., 72:258.

Klein, P. D. 1958 Linoleic acid and cholesterol metabolism
in the rat. 1. The effect of dietary fat and
linoleic acid levels on the content and composi-
tion of cholesterol esters in liver and plasma.
Arch. Biochem. BiOphys., 76:56.

Kinsell, L. W., and H. M. Sinclair 1957 Fats and disease.
Lancet, 1:885.

Kinsell, L. W., J. W. Partridge, L. Boling, S. Margen and
G. Michaela 1952 Dietary modification of serum
cholesterol and phospholipid levels. J. Clin.
Endocrin., 12:909.

Leichsenring, J. m., and E. D. Wilson 1951 Food composi-
tion table for short method of dietary analysis
(2nd revision). J. Am. Dietet. A., 27:586.

Hayer, G. A., W. F. Connell, H. S. DeWolfe, and J. M. R.
Beveridge 1954 Diet and plasma cholesterol
levels. Am. J. Clin. Nutrition, 2:516.

Mann, G. V., B. M. Nicol and F. J. Stare 1955 The beta-
lipOprotein and cholesterol concentrations in
sera of Nigerians. Brit. Med. J., 2:1008.

Mann, G. V., K. Teel, 0. Haye, A. HcNally and D. Bruno
1955 Exercise in the disposition of dietary
calories. New Eng. J. Med., 255:549.

50

McCann, M. B., M. F. Trulson, W. h. Waddell, W. Dalrymple
and F. J. Stare 1959 The effects of various
vegetable oils on the serum lipids of adult Amer—
ican males. Am. J. Clin. Nutrition, 7:55.

Messinger, W. J. 1950 Effect of feeding egg yolk and
cholesterol on serum cholesterol levels. Arch.
Int. Lied. , 86:189.

horris, J. N., J. A. Heady, P. A. B. Baffle, C. G. Roberts
and J. J. Parks 1955 Coronary heart-disease
and physical activity of work. Lancet, 2:1055.

hontoye, H. J., W. D. Van Huss, W. D. Brewer, E. H. Jones,
n. A. 0h1son, E. Hahoney and H. Olson 1959 The
effects of exercise on blood cholesterol in middle—
aged men. Am. J. Clin. Nutrition, 7:159.

hyasnikov, A. L. 1958 Influence of some factors on de-
velopment of experimental cholesterol athero-
sclerosis. Cir., 17:99.

National Academy of Science 1958 National Research Coun-
cil Bulletin 589.

Okey, B., n. m. Lyman, A. G. Harris, B. Einset and W. main
1959 Dietary fat and cholesterol metabolism:
Effects of unsaturation of dietary fats on liver
and serum lipids. hetab., 8:241.

Portmal, 0. A., and L. Sinisterra 1957 Dietary fat and
hypercholesteremia in the cebus monkey. II.
Esterification and disappearance of cholesterol -
4 - C 14. J. Exp. Hed., 106:727.

.Portman, 0. J., M. Hegsted, F. J. Stare, D. Bruno, L. Sin-
isterra and R. murphy 1956 Effect of the level
and type of dietary fat on themetabolism of cho-
lesterol and beta lipoproteins in the cebus monkey.
J. Exp. med., 104:817.

Paterson, J. 0., and J. B. D. Derrick 1957 Comparison
of total cholesterol levels in blood serum with
lipid concentrations in human coronary arteries.
(A second interim report) Canad. J. Biochem.
Phys., 35:869.

Schoenheimer, B., and W. H. Sperry 1954 A micro—method
for the determination of free and combined cho—
lesterol. J. Biol. Chem., 106:745.

51

Sperry, W. h. 1957 The determination of cholesterol.
J. Biol. Chem., 118:577.

Schendel, H. E., and J. D. L. Hansen 1958 Studies on
fat metabolism in Kwashiorkor: 1. Total serum
cholesterol. hetab., 7:751.

Taylor, H. L., J. T. Anderson and A. Keys 1957 Physical
activity, serum cholesterol and other lipids in
man. Proc. Soc. Exp. Biol. hed., 95:585.

Tillman, H. L., R. M. O'neal, W. A. Thomas and B. B. Hixon
1960 Butter, corn oil and fibrinolysis in rats.
Cir. hes., 8:425.

Toor, M., A. Katchalsky, J. Agmon and D. Allalouf 1957
Serum—lipids and atherosclerosis among Yemenite
immigrants in Israel. Lancet, 2:1270.

Toor, m” A. Katchalsky, J. Agmon and D. Allouf 1960 Ath-
erosclerosis and related factors in immigrants
in Israel. Circulation, 22:265.

Wong, H. Y. C., H. L. Simmons and E. W. Hawthorne 1956
Effects of controlled exercise on experimental
atherosclerosis in androgen—treated chicks.
Federation Proc., 15:205.

Wong, H. Y. C., H. B. Anderson, J. K. Kim, D. J. Liu and
E. W. Hawthorne 1957 Hypocholesterolizing ef—
fect of exercise on cholesterol-fed cockerels.
Federation Proc., 16:158.

Van Hues, W. D., G. Hikles, E. M. Jones, H. J. Hontoye,
D. C. Cederquist and L. Smedley 1961 Research
Quarterly (In press).

Appendix A. composition of stock diet for rats

40.1 5 Ground Corn
0 Soybean Oil heal (44} Prctnin)
10.0 Fish meal

0

l7} Detyirtted Alfalfa Leal

[“1
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l
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Ow
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nerck B Vitamins

Vitamin A and D mix

C
C)
U1

0
o

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20 g/100 f Tocopherol Acetate

52

Appendix 3.

Date

 

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Appendix 0. Serum cholesterol concen rations of rats
Exercise Exercise Sedentary
Stock Diet Added milk Stock Liet
Total Free Total Free Total Free
choles— choles- choles— choles- choles- choles—
terol terol terol terol terol terol
mg/ mg/ mg/ mg/ mg ug/
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