All well-controlled trials of cholesterol-reducing diets and drugs have failed to reduce coronary (CHD) mortality and morbidity. Nevertheless, commercial, professional, and even government-sponsored propaganda continues. Experimentally some vegetable oils and hardened fats can be more damaging to arteries than butter. There are other hazards to heart muscle from vegetable oils. Israelis consume a high polyunsaturated fat diet equal to that recommended for prevention of CHD in USA but their CHD incidence is very high. Urban Bedouins are also affected. The primary clofibrate prevention trial underlines unacceptable risks which could apply also to diets. Official medical endorsement of these cholesterol reducing measures should be withdrawn. (+info)
Dietary fat, fat subtypes, and breast cancer in postmenopausal women: a prospective cohort study.
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BACKGROUND: The intake of total dietary fat and of certain fat subtypes has been shown to be strongly associated with breast cancer in international comparisons and in animal experiments. However, observational epidemiologic studies have generally reported either weak positive or no associations. To extend the prospective epidemiologic evidence on this question, we examined the association between adult dietary intake of fat, fat subtypes, and breast cancer in a large, prospective cohort of postmenopausal women. METHODS: Participants were selected from a national breast cancer mammography screening program conducted from 1973 through 1981 at 29 centers throughout the United States. From 1987 through 1989, 40022 postmenopausal women satisfactorily completed a mailed, self-administered questionnaire that included a 60-item National Cancer Institute/Block food-frequency questionnaire. Women were then followed for an average of 5.3 years; 996 women developed breast cancer. Risk was assessed by use of Cox proportional hazard regression, with age as the underlying time metric. All statistical tests were two-sided. RESULTS: Compared with women in the lowest quintile (Q1) of percentage of energy from total fat, the adjusted risk ratio (RR) and 95% confidence interval (CI) for women in the highest quintile (Q5) was 1.07 (95% CI = 0.86-1.32). In analyses stratified by history of benign breast disease (BBD), a positive association was observed among only women with no history of BBD (RR (Q5 versus Q1) = 2.20; 95% CI = 1.41-3.42; test for trend, P =.0003). The increased risk in these women appeared to be attributable to unsaturated fat intake and oleic acid in particular. CONCLUSIONS: In this study, there was no overall association between fat intake during adulthood and breast cancer risk; however, among women with no history of BBD, there appeared to be a positive association between total and unsaturated fat intake and breast cancer risk. (+info)
Effects of quantity and unsaturation of dietary fat on serum components in normal and diabetic Macaca nigra.
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Dietary fat affects serum lipids independently of dietary cholesterol. Normal and diabetic monkeys (Macaca nigra) were fed cereal-based, specially formulated diets with either a low fat (LF = 2.5%) or a higher fat (13.2%) content; the latter had varying concentrations of safflower and coconut oil to attain greater polyunsaturation (SFO) or saturation (CCO) in the diets. Dietary cholesterol was less than 0.01%. Serum triglyceride concentrations were greatest when monkeys consumed the LF (higher carbohydrate) diet and lowest when they consumed the SFO diet. Concentrations were greater in diabetic than in normal monkeys fed the LF and SFO diets, but both groups had similar concentrations when fed the CCO diet. Cholesterol levels in diabetic monkeys were only slightly higher than in normals regardless of diet; in both groups, levels were lowest when the LF diet was fed and highest when the CCO diet was fed. The quantity of fat had a greater effect on serum cholesterol than did the degree of polyunsaturation. In both groups, triglyceride concentrations correlated significantly with VLDL protein, and cholesterol levels correlated with LDL protein. Thus the responses of Macaca nigra to dietary fat manipulation depend upon both the diet fat content and composition as well as the normal or diabetic metabolic state of each monkey. (+info)
Serum aminopeptidase A activity of mice is related to dietary fat saturation.
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A high intake of monounsaturated fat has been proposed to be a dietary factor that can decrease the incidence of cardiovascular disease and hypertension. In addition, increasing dietary fat saturation has been shown to increase plasma total cholesterol and elevate systolic and diastolic blood pressures. We demonstrated previously that cholesterol selectively increases in vitro aminopeptidase A activity, which is related to angiotensin metabolism. In this study, we investigated the effect of different degrees of dietary fatty acid saturation on serum aminopeptidase activities in vivo. Serum total cholesterol concentrations were also measured. Five groups of male Balb/C mice were fed for 10 wk diets containing 2.4 g/100 g of sunflower oil, fish oil, olive oil, lard or coconut oil. We measured alanyl-, arginyl-, cystinyl-, pyroglutamyl-, aspartyl- and glutamyl-specific aminopeptidase activities using arylamides as substrates. Serum total cholesterol levels were higher in mice fed diets containing saturated oils (lard and coconut) than in those consuming sunflower oil, which is unsaturated. Two of the serum aminopeptidase A activities (aspartyl and glutamyl aminopeptidase) increased progressively with the degree of saturation of the dietary fatty acids; activities were significantly greater in mice fed coconut oil than in those fed sunflower or fish oil. Therefore, the substrates hydrolyzed by this activity as well as their functions may be similarly affected. These results may have some implication for the treatment of cardiovascular disease. (+info)
Titrating dietary linoleate to in vivo platelet function in man.
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Platelet aggregation time significantly increased within 48 hours in response to an increase in dietary linoleate of 4% of calories while disaggregation time decreased significantly in 96 hours. A change as small as 0.5% of calories was associated with significant alterations within 4 days. In this group, dietary linoleate appears to be related to platelet function by the equations Aggregation time equals 41.14 plus 2.79 linoleate Disaggregation time equals 11.04 minus 25.52 linoleate. (+info)
Inhibition of lymphocyte function in rats fed higher-fat diets.
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Concanavalin A-induced blastogenesis of spleen lymphocytes was significantly inhibited when lymphocytes from rats on a high-polyunsaturated-fat diet were compared to lymphocytes from rats on a low-fat diet. Responsiveness was dependent on source of serum since lymphocytes from rats fed a low-fat diet were suppressed in serum from rats fed a high-polyunsaturated-fat diet. Alternatively, lymphocytes from rats on a high-polyunsaturated-fat diet were more responsive in serum from low-fat-fed rats compared to their response in autologous serum. One of the inhibiting factors in serum was the lipoprotein fraction; however, rats on a high-polyunsaturated-fat diet probably had additional inhibitors in their serum. While tumor incidence was highest in rats with the least responsive lymphocytes was highest in rats with the least responsive lymphocytes and lowest in rats with the most responsive lymphocytes, the significance of the observation is not known. (+info)
Cholesterol kinetic analysis in normal and cholesterol-fed rabbits; effects of saturated versus polyunsaturated fat and of cholestyramine.
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A model for cholesterol metabolism in rabbits has been demonstrated based on kinetic analysis and total carcass analysis. As has been shown for humans and primates, the model conforms to a two-exchangeable pool model with a third pool not exchangeing during the time interval studied. Alterations in turnover rate, sizes of pools, and exchange rates were demonstrated when rabbits were fed diets containing increased amounts of cholesterol and fat. Evidence was presented that indicated that the there may be differences in tissue distribution of cholesterol, dependent on whether the fat fed with choleserol is saturated or polyunsaturated. These differences include: in rabbits fed cholesterol plus coconut oil is compared with those fed cholesterol plus corn oil, the ratio of the amount of cholesterol in plasma to the amount of cholesterol in pool B was higher, and the rate constant for transfer from pool B was higher. The serum cholesterol concentration of rabbits fed cholesterol plus coconut oil was lowered slightly by feeding cholestyramine. Cholestyramine administration at the dose fed failed to produce statistically significant alterations in pool sizes or serum cholesterol concentration in control rabbits; it did lower serum cholesterol concentration in rabbits fed cholesterol plus coconut oil. (+info)
Beneficial effect of increased dietary linoleate upon in vivo platelet function in man.
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The effect of increasing dietary linoleate upon in vivo platelet aggregation and disaggregation in 20 males and 46 female adult humans was studied. In creasing exogenous linoleate for 2 weeks from 2.89 +/- 0.11 to 5.00 +/- 0.26% of energy was associated with the doubling of the aggregation time and halving of the disaggregation time. Decreasing dietary linoleate in the following 2-week feeding period was associated with a reversal of the effect. (+info)