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Research Nut: Mixed Nuts

Anti-atherogenic effect of nuts: is the answer NO?

Cooke, J.P., P. Tsao, A. Singer, B.Y. Wang, J. Kosck, H. Drexler, 1993.  Anti-atherogenic effect of nuts: is the answer NO? Arch Intern Med. 153:896, 899, 902.

In a commentary regarding the Seventh Day Adventist study, the authors highlight the fact that frequent nut consumption reduced the risk of experiencing fatal or nonfatal heart attacks by 50%.  A possible explanation for the protective effect may be that nuts are high in arginine, a basic amino acid that is a precursor to nitric oxide (NO). The latter is known to inhibit plaque formation, or atherogenesis, which can lead to heart attacks.  Studies have shown that people with hypercholesterolemia have reduced activity of NO.  Adding arginine-rich nuts to the diet may help increase NO activity and thereby reduce the risk of heart attacks.

An Indian experiment with nutritional modulation in acute myocardial infarction.

Singh, R.B., S.S. Rastogi, R.Verma, L. Bolaki, R. Singh, 1992. An Indian experiment with nutritional modulation in acute myocardial infarction. Am J Cardiol. 69:879-85.

In a randomized, single-blind intervention trial, 406 patients 24 to 48 hours after acute myocardial infarction (AMI) were assigned to either diet A (204 patients, group A) or B (202 patients, group B) for 6 weeks. At entry to the study, mean age, male sex, risk factors, complications, possible and definite AMI, and drug therapy were comparable between the 2 groups. Dietary adherence to intervention and control diets was checked by questionnaire, and drug therapy by tablet count. Group A received significantly lower calories, a higher percentage of calories from complex carbohydrates, vegetable/fish proteins, polyunsaturated fatty acids, and a higher polyunsaturated/saturated fat ratio diet than did group B (higher total calories and saturated fatty acids). Group A also received less dietary cholesterol, salt and caffeine, and higher soluble dietary fiber, vitamins and minerals than did group B. After 6 weeks, group A had a significant decrease in mean serum total (-20.5 vs -8.6 mg/dl) and low-density lipoprotein (-16.6 vs -6.4 mg/dl) cholesterols, and triglycerides (-15.5 vs -7.6 mg/dl), with no decrease in high-density lipoprotein cholesterol (-1.5 vs -1.3 mg/dl) compared with the initial levels and changes in group B. Group A also had a greater decrease in mean body weight (3.4 vs 1.3 kg) than that of group B.

A possible protective effect of nut consumption on risk of coronary heart disease.

Fraser, G.E., J. Sabaté, W.L. Beeson, T.M. Strahan, 1992.  A possible protective effect of nut consumption on risk of coronary heart disease. Arch Intern Med. 152:1416-24.

BACKGROUND–Although dietary factors are suspected to be important determinants of coronary heart disease (CHD) risk, the direct evidence is relatively sparse. METHODS–The Adventist Health Study is a prospective cohort investigation of 31,208 non-Hispanic white California Seventh-Day Adventists. Extensive dietary information was obtained at baseline, along with the values of traditional coronary risk factors. These were related to risk of definite fatal CHD or definite nonfatal myocardial infarction. RESULTS–Subjects who consumed nuts frequently (more than four times per week) experienced substantially fewer definite fatal CHD events (relative risk, 0.52; 95% confidence interval [CI], 0.36 to 0.76) and definite nonfatal myocardial infarctions (relative risk, 0.49; 95% CI, 0.28 to 0.85), when compared with those who consumed nuts less than once per week. These findings persisted on covariate adjustment and were seen in almost all of 16 different subgroups of the population. Subjects who usually consumed whole wheat bread also experienced lower rates of definite nonfatal myocardial infarction (relative risk, 0.56; 95% CI, 0.35 to 0.89) and definite fatal CHD (relative risk, 0.89; 95% CI, 0.60 to 1.33) when compared with those who usually ate white bread. Men who ate beef at least three times each week had a higher risk of definite fatal CHD (relative risk, 2.31; 95% CI, 1.11 to 4.78), but this effect was not seen in women or for the nonfatal myocardial infarction end point. CONCLUSION–Our data strongly suggest that the frequent consumption of nuts may protect against risk of CHD events. The favorable fatty acid profile of many nuts is one possible explanation for such an effect.

Effects of diets rich in monounsaturated fatty acids on plasma lipoproteins-the Jerusalem Nutrition Study. II monounsaturated fatty acids vs. carbohydrates.

Berry, E.M., S. Eisenberg, Y. Friedlander, D. Haratz, N.A. Kaufmann, Y. Norman, Y. Stein, 1992. Effects of diets rich in monounsaturated fatty acids on plasma lipoproteins – the Jerusalem Nutrition Study. II monounsaturated fatty acids vs. carbohydrates. Am J Clin Nutr. 56:394-403.

Seventeen male Yeshiva students were randomly allocated to a crossover study with two 12-wk dietary periods of monounsaturated fatty acids (MUFAs) vs a carbohydrate (CHO)-rich diet while concentrations of saturated (SFAs) and polyunsaturated (PUFAs) fatty acids were kept similar. Total plasma cholesterol (TC) decreased significantly by approximately 7.7% and low-density-lipoprotein cholesterol (LDL-C) by 14.4% on the MUFA diet, whereas on the CHO diet no significant change in cholesterol concentrations occurred, in contrast to that predicted by the equations of Keys and Hegsted. Concentrations of high-density- lipoprotein cholesterol (HDL-C) did not change significantly on either diet. On the MUFA diet there was a significantly lower proneness to peroxidation of plasma and LDL lipids and less extensive metabolism of conditioned LDL by peritoneal macrophages. We conclude that dietary MUFAs lower TC and LDL-C concentrations, independently of other dietary fatty acids and in addition may reduce the susceptibility of LDL to oxidative stress.

Effects of diets rich in monounsaturated fatty acids on plasma lipoproteins – the Jerusalem Nutrition Study: high MUFAs vs. high PUFAs.

Berry, E.M., S. Eisenberg, D. Haratz, Y. Friedlander, Y. Norman, N.A. Kaufmann, Y. Stein, 1991.  Effects of diets rich in monounsaturated fatty acids on plasma lipoproteins – the Jerusalem Nutrition Study: high MUFAs vs. high PUFAs. Am J Clin Nutr. 53:899-907.

Twenty-six Yeshiva students were randomly assigned to a 24-wk crossover study of monounsaturated fatty acid (MUFA) vs polyunsaturated fatty acid (PUFA) diets (50% carbohydrate, 32% fat, 18% protein) fed alternately during two 12-wk periods. Total plasma cholesterol (TC) decreased significantly by approximately 10% and approximately 16% on the MUFA and PUFA diets, respectively. Plasma triglyceride response was variable. Low-density-lipoprotein cholesterol (LDL-C) decreased in both groups with an additional significant effect between periods. Concentrations of high-density-lipoprotein cholesterol did not change significantly. LDL-receptor status in fresh monocytes, affinity of LDL towards the LDL receptor in cultured fibroblasts, zonal-centrifugation profiles, and lipoprotein composition were not significantly different between the diets. There was a significantly higher tendency toward lipid peroxidation on the PUFA diet, as ascertained by more thiobarbituric acid-reactive-substances formation on that diet. Dietary PUFA results in somewhat lower TC and LDL-C concentrations whereas with MUFA the susceptibility of LDL to oxidative stress is lower.

Cohort study of diet, lifestyle, and prostate cancer in Adventist men.

Mills, P.K., W.L. Beeson, R.L. Phillips, G.E. Fraser, 1989.  Cohort study of diet, lifestyle, and prostate cancer in Adventist men. Cancer. 64:598-604.

Dietary and lifestyle characteristics were evaluated in relation to subsequent prostatic cancer risk in a cohort of approximately 14,000 Seventh-day Adventist men who completed a detailed lifestyle questionnaire in 1976 and who were monitored for cancer incidence until the end of 1982. During the 6-year follow-up period, 180 histologically confirmed prostatic cancers were detected among some 78,000 man-years of follow-up. Increasing educational attainment was associated with significantly decreased risk of prostate cancer in this study; age at first marriage was also inversely associated with risk, although this was not significant. There was no relationship between body mass index (as measured by Quetelet’s Index) and risk. A history of prostate “trouble” was associated with a 60% increase in risk which was highly significant. Although there were suggestive relationships between increasing animal product consumption and increased risk, these results did not persist after accounting for the influence of fruit and vegetable consumption. Nor was exposure to the vegetarian lifestyle during the childhood years associated with alterations in subsequent risk. However, increasing consumption of beans, lentils and peas, tomatoes, raisin, dates, and other dried fruit were all associated with significantly decreased prostate cancer risk.

Case-control study of dietary etiological factors: the Melbourne colorectal cancer study.

Kune, S., G.A. Kune, L.F. Watson, 1987.  Case-control study of dietary etiological factors: the Melbourne colorectal cancer study. Nutr Cancer. 9:21-42.

A brief description is given of a large and comprehensive population-based investigation of colorectal cancer with a new study design. The study design allows the simultaneous examination of the incidence pattern, all the hypothesized causes and all the survival determinants of colorectal cancer of a defined population in a single data set. The relevance of this approach to surgeons in the primary prevention of and screening for colorectal cancer is illustrated in relation to the findings. Thus a diet with a low intake of fat and red meat and high intake of plant foods seems the most important factor in the primary prevention of colorectal cancer. In the screening for this cancer, high-risk groups include those with a previous colorectal cancer, a previous adenomatous polyp, a family history of colorectal cancer in first-degree relatives, Jews, those with an unsatisfactory diet and for rectal cancer, also those who are heavy beer consumers.

Colorectal cancer in rural Nebraska.

Pickle, L.W., M.H. Greene, R.G. Ziegler, A. Toledo, R. Hoover, H.T. Lynch, J.F. Fraumeni, Jr., 1984.  Colorectal cancer in rural Nebraska. Cancer Research. 44:363-9.

A case-control interview study of colorectal cancer was conducted in two rural counties of eastern Nebraska to determine reasons for the elevated colon cancer mortality rates during 1950 to 1969. Comparison of the information provided by 86 colorectal cancer cases and 176 matched controls (or their next of kin) revealed an increased risk among persons of Czech background, with  persons of Bohemian and Moravian extraction predominating in this area. The data suggest an interaction between Bohemian ancestry and certain dietary patterns in the pathogenesis of colon cancer in this region. Colon cancer risk was elevated among commercial beer drinkers regardless of their ethnic back ground, although Bohemians reported heavier consumption. An excess risk was also associated with intestinal polyps, reported more often by Moravians, and with familial occurrence of gastrointestinal and other cancers. Since 1969, the mortality and incidence rates for colon cancer in this area have declined, possibly as a consequence of acculturation of the American-born descendants of Czech immigrants.