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Biomedical subjects

F M Sacks

Publications and source records attributed to F M Sacks.

121 records · Page 7Linked to original sources
PubMed1985

Plasma lipoprotein levels in vegetarians. The effect of ingestion of fats from dairy products.

The influence of dairy foods in the diet on plasma levels of total, low-density lipoprotein, and high-density lipoprotein cholesterol (TC, LDL-C, and HDL-C, respectively) was studied in 75 adult lactovegetarians living in the northeastern United States. Dairy products were the major sources of dietary saturated fat and cholesterol. The plasma TC level was positively correlated with dietary saturated fat and dietary cholesterol, and inversely correlated with the ratio of polyunsaturated to saturated fats in the diet. Correlations between the LDL-C level and the nutrients were similar to those of the TC level. The HDL-C level was not significantly related to any nutrients in the diet. The cholesterol levels of the lactovegetarians were compared with those of strict vegetarians. Lactovegetarians had 24% higher LDL-C levels and 7% higher HDL-C levels than strict vegetarians. Analysis within and among vegetarian populations suggests that ingestion of fatty dairy products raises the LDL-C level on a percentage basis about three times more than it raises the HDL-C level.

Adult↗
PubMed1984

Ingestion of egg raises plasma low density lipoproteins in free-living subjects.

In addition to their usual diet, 17 lactovegetarian college students consumed 400 kcal of test foods per day containing one extra-large egg for three weeks and similar isocaloric eggless foods for an additional three weeks in a randomised double-blind crossover trial. Ingestion of the egg increased dietary cholesterol from 97 to 418 mg per day. Mean plasma low density lipoprotein (LDL) cholesterol was 12% higher (p = 0.005) and mean plasma apolipoprotein B was 9% higher (p = 0.007) when eggs were being consumed than during the eggless period. Mean plasma high density lipoprotein cholesterol, apolipoproteins A-I and A-II, very low density lipoprotein cholesterol, and total triglycerides did not change significantly. Thus, ingestion of egg seems selectively to raise cholesterol and protein in LDL particles in the plasma of free-living normal people. Plasma LDL may be more sensitive to cholesterol at low intakes than at moderate to high intakes.

Adolescent↗
PubMed1983

Lack of an effect of dairy protein (casein) and soy protein on plasma cholesterol of strict vegetarians. An experiment and a critical review.

In animals, ingestion of casein, the principal protein in milk, causes hypercholesterolemia, whereas in humans this effect has not been documented. We added 27 g of casein (the amount in 1.1 liters of skim milk and nearly twice the average U.S. intake) for 20 days, and 27 g of soy protein for an additional 20 days to the daily diet of 13 strict vegetarians who consumed no other animal protein during the study period. The protein supplementation increased the ad libitum daily protein intake from 59 g to 82 g. Levels of plasma LDL, HDL, and total cholesterol were not significantly affected by either the casein or the soy supplementation. Over the 40 days of protein supplementation, there were progressive decreases in VLDL cholesterol (VLDL-C) and increases in triglycerides (TG) from pre-study levels, demonstrated by an overall change in the VLDL-C/TG ratio from 0.30 to 0.17 (P = 0.003). Caloric intake and body weight did not change significantly. From the literature on dietary protein and blood lipid levels and from the present data, it appears that neither the amount of protein in the diet nor whether the protein comes from animal or vegetable sources has an important effect on plasma LDL and HDL levels in humans when consumed in physiologic amounts.

Adult↗
PubMed1981

Effect of ingestion of meat on plasma cholesterol of vegetarians.

In a controlled trial, 21 strict vegetarians were studied prospectively for eight weeks: a two-week control period of the usual vegetarian diet was followed by four weeks, during which 250 g of beef was added isocalorically to the daily vegetarian diet and then by two weeks of the control diet. Plasma high-density lipoprotein-cholesterol did not change during the study, whereas plasma total cholesterol rose significantly by 19% at the end of the meat-eating period. Systolic blood pressure (BP) increased significantly during the meat eating by 3% over control values, whereas diastolic BP showed no major changes. Plasma renin activity, prostaglandin A and E levels, and urinary kallikrein, norepinephrine, and epinephrine excretions were within normal limits and did not change notably throughout the trial. The study suggests an adverse effect of consumption of beef on plasma lipid and BP levels.

Adult↗
PubMed1975

Plasma lipids and lipoproteins in vegetarians and controls.

The possible effect of diet on plasma lipids was investigated in a group of vegetarians. Seventy-three men and 43 women who had adhered to a vegetarian diet for an average of three years were studied in the fasting state and compared with a randomly selected group of controls matched for age and sex. Mean cholesterol levels in milligrams per deciliter for vegetarians and controls, respectively, were 126 and 184; low-density lipoprotein, 73 and 118; very-low-density lipoprotein, 11.8 and 17.2; high-density lipoproteins, 42 and 49; and mean triglyceride levels 59 and 86. Mean weight and subscapular skinfold thicknesses were 58 kg and 6 mm for vegetarians and 73 kg and 17 mm for controls. Similar differences in lipid levels were found between subgroups of 42 vegetarians and controls with identical mean weights. Multiple regression analyses showed that consumption of dairy foods and eggs, but not body weight, was associated with the lipoprotein and cholesterol findings.

Adolescent↗
PubMedDate not supplied

Very low density lipoproteins stimulate cholesteryl ester formation in U937 macrophages. Heterogeneity and biologic variation among normal humans.

Normolipidemic fasting VLDL stimulated the formation of cholesteryl ester in the human macrophage-like cell line, U937. VLDL from different persons exhibited heterogeneity over a 10-fold range in stimulating cholesterol esterification, and were 7% to 98% as active as human LDL. The effects of VLDL in U937 cells were highly correlated to those in normal human fibroblasts. VLDL did not induce cholesterol esterification in resident mouse peritoneal macrophages, nor in fibroblasts that lacked LDL receptors, suggesting that receptors for LDL, rather than for beta-VLDL, mediate the effects of VLDL. The active VLDL particles were found in the dense VLDL subfraction, Sf20 to 60, but not in Sf60 to 100 or Sf100 to 400. The activity of unfractionated VLDL was correlated directly with % cholesteryl ester in total or Sf20 to 60 VLDL, and inversely with VLDL triglycerides. Biologic variation of fasting VLDL activity in U937 cells was found in 13 normolipidemic ambulatory subjects. As compared to the correlation between the activity of two VLDL samples derived from a single aliquot of blood (r = 0.90), the correlation was lower (r = 0.60) between the activity of samples taken on successive days, and even less (r = 0.05) between VLDL samples obtained 2 weeks apart. Substantial biologic variation also occurred in VLDL composition except for VLDL unesterified cholesterol. These findings suggest an environmental influence on VLDL metabolism by macrophages.

Arteriosclerosis↗
PubMedDate not supplied

Lack of an effect of dietary saturated fat and cholesterol on blood pressure in normotensives.

The effect on blood pressure (BP) levels of modifying the saturated fat and cholesterol content in the diet was studied in two separate protocols in normotensive volunteers. For 3 months, 19 men and women, aged 14 to 54 years, adhered to a diet that eliminated meat, poultry, eggs, and dairy fat from the subjects' customary nonvegetarian diet, which had included 71 g/day (35%) of dietary fat. The experimental diet reduced the consumption of saturated fat from 21 to 10 g, dietary cholesterol was lowered from 398 to 69 mg per day, but consumption of polyunsaturated fatty acids, carbohydrates, and dietary fiber was unchanged. Body weight and urinary sodium and potassium excretion were not significantly altered. Mean BP before and after the low fat diet was 116/74 and 115/74 mm Hg, respectively. A second double-blind study tested the effect on BP of dietary cholesterol at levels of 155 and 471 mg/day. Seventeen semivegetarian college students consumed one egg per day concealed in desserts for 3 weeks, and identical desserts containing no eggs for an additional 3 weeks. Mean BP at the end of the egg and eggless periods was 108/69 and 107/69 mm Hg, respectively. Thus, in short-term nutritional studies, dietary saturated fat and cholesterol at low-to-moderate levels of intake have no significant effects on BP in normotensive adults.

Adolescent↗
PubMedDate not supplied

Stability of blood pressure in vegetarians receiving dietary protein supplements.

Vegetarians have relatively low blood pressure (BP) levels and consume less protein than do nonvegetarians , and there have been suggestions that certain proteins may raise BP. To determine whether dietary protein supplements raise the BP of vegetarians, 58 g/per day of a 60:40 mixture of soy and wheat proteins and an isocaloric low protein supplement supplying 7 g/day of rice protein were added for 6-week periods to the diet of 18 vegetarians in a 2-group crossover design. Mean daily protein intake during consumption of the low and high protein supplements was 63 and 119 g, respectively. Mean BP was 109/72 mm Hg after the high protein and 108/71 mm Hg after the low protein diet. Consumption of other major nutrients, mean body weight, and sodium and potassium excretion did not change significantly. Thus, protein supplementation of a vegetarian diet that contained a below average but nutritionally adequate amount of protein did not significantly affect BP over 6 weeks.

Adult↗