Physical Activity, Serum Cholesterol and Other Lipids in Man.

Abstract

Anderson, Lawler and Keys( 1) have proposed the hypothesis that, other things being equal, the serum cholesterol concentration in man is determined by the fat transport load imposed on the blood per unit of circulation. The transport of fat from intestines to liver and from liver to fat depots is thought to be primarily involved. The transport of fat from the fat depots to the point of metabolism appears to be less directly concerned because the serum cholesterol concentration falls during negative calorie balance in spite of the fact that a great deal of fat is mobilized from the fat depots in this situation(2,3). The hypothesis explains: 1) The increase in serum cholesterol concentration observed on high fat diets and in overnutrition with a positive calorie balance; 2) The stability of serum cholesterol during calorie equilibrium and a constant fat intake and 3 ) The decrease in serum cholesterol on low fat diets and in negative calorie balance. The role of physical activity in this scheme needs clarification. The acute effects of physical activity have been studied in connection with dietary cholesterol loading(4) and it has been shown that when calories and activity are increased to the same extent so that calorie equilibrium is maintained, no increase in serum cholesterol concentration results ( 5 ) . However, in the latter work only 3 subjects were studied, the quantity of fat in the diet was held constant while the physical activity was increased so that the proportion of calories represented by fat metabolism decreased sharply, and calorie equilibrium was not exact. It is of interest to discover whether increasing the fat content of the diet in proportion to the calories consumed by physical activity will affect the serum cholesterol concentration. This paper presents data bearing on this point . Subjects, conditions and methods. The sub-*This work was supported in par;t by grant from Nutrition Foundation, N. Y.jects were 9 clinically healthy university students who volunteered to participate in the experiment. The mean age was 23.3 years with a range of 21 to 28 and the mean relative weight was 108.3 with a range of 93 to 128. None of the men was excessively fat or thin. Two of the 9 played in intramural basketball but the others did not take part in organized sports.All meals were prepared and measured in the laboratory and 2 meals a day were served in the laboratory dining room. Box lunches consisting of sandwiches, fruit and milk were carried by the subjects and eaten outside of the laboratory. All food items were served as weighed portions and the rejections were tabulated and used in calculating the composition of the diet. The diet was designed to approximate the current American practice of using liberal quantities of meat, milk, butter and eggs. It was fully adequate in vitamins and minerals. The calorie, fat and protein content are presented in Table I.During the period of increased physical activity, the men walked for 2 hours a day on the motor driven treadmill at 3.5 miles per hour on a 10% ...

Long-term decay of serum cholesterol radioactivity: body cholesterol metabolism in normals and in patients with hyperlipoproteinemia and atherosclerosis

“…The Table I. The variations were totally erratic and were entirely comparable to data reported by a large number of investigators (17)(18)(19)(20) in long-term longitudinal studies in patients in the apparent steady state. It is highly improbable that the steady-state conditions were significantly altered in the present study, and thus caused the modification of the rate of the decay of specific activity.…”

The Lipid–Heart Hypothesis and the Keys Equation Defined the Dietary Guidelines but Ignored the Impact of Trans-Fat and High Linoleic Acid Consumption

“…However, many regained the weight by the end of the study, and TC levels also rose in most cohorts. The NDHS report noted that, when people in previous metabolic ward studies gained weight, the average TC rose sharply, and TC decreased with weight loss, but once the weight stabilized at the new weight, the TC level tended to return to the baseline levels [118][119][120][121]. Regression analyses of the First Study results found that "There was an apparent effect of both recent and remote weight change on TC levels-even after [the] effects of reported dietary fats had been allowed for" ([77], Suppl.…”

Interrelationship of thyroxine, exercise, and feed intake on serum and hepatic cholesterol levels

“…Similarly, evidences for the relationship between hypocholesteremia and hyperthyroidism is well documented (Kunde et al, 1932;Turner, 1933;Turner et al, 1938;Schmidt and Huges, 1938;Fleischmann et al, 1940;Fleischmann and Shumacher, 1942;Entenman et al, 1942;Fleischmann and Fried, 1945;Chanutin et ^., 1947;Dauber et al, 1949;Stamler et al, 1950;Marx et al, 1950;Rosenman et a]^., 1952a, b;Marx et al, 1953;Byers, 1958;Duncan and Best, 1958a;Gould, 1959;Boyd, 1959;Boyd and Oliver, 1960a, b;Cuthbertson et al, 1960;Best and Duncan, 1960;Kritchevsky, 1960;Kritchevsky et al, 1960;Boyd, 1961;Kritchevsky et al, 1961;Greene et al, 1961;Wells and Ershoff, 1962;Ellefson and Mason, 1962;Davis et al, 1962;Jepson, 1963;Patek et al, 1963;My ant, 1964;Felt, 1966;Kritchevsky and Tepper, 1967;Miettlnen, 1968;and Young, 1968). It has long been known that milk will induce a significant rise in blood cholesterol level (Beveridge et al, 1956;Anderson, 1959;Keys et al, 1957;…”