Nuts and healthy diets
Examines the history and composition of a variety of nuts from around the world. States that since ancient times; nuts and oil seeds have been considered healthful foods worldwide. Outlines various methods and results of studies previously undertaken on the effects of nuts as part of the diet; in particular the relationship between nuts and coronary heart disease (CHD) Concludes that nuts are an under-recognized and under-consumed food In modern diets. They provide an abundance of nutritional value and can play an important role as individuals move from animal-based diets to plant-based diets.
A clinical trial of the effects of dietary patterns on blood pressure
Background: It is known that obesity, sodium intake, and alcohol consumption factors influence blood pressure. In this clinical trial, Dietary Approaches to Stop Hypertension, we assessed the effects of dietary patterns on blood pressure. Methods: We enrolled 459 adults with systolic blood pressures of less than 160 mm Hg and diastolic blood pressures of 80 to 95 mm Hg. For three weeks, the subjects were fed a control diet that was low in fruits, vegetables, and dairy products, with a fat content typical of the average diet in the United States. They were then randomly assigned to receive for eight weeks the control diet, a diet rich in fruits and vegetables, or a "combination" diet rich in fruits, vegetables, and low-fat dairy products and with reduced saturated and total fat. Sodium intake and body weight were maintained at constant levels. Results: At base line, the mean (+/-SD) systolic and diastolic blood pressures were 131.3+/-10.8 mm Hg and 84.7+/-4.7 mm Hg, respectively. The combination diet reduced systolic and diastolic blood pressure by 5.5 and 3.0 mm Hg more, respectively, than the control diet (P<0.001 for each); the fruits-and-vegetables diet reduced systolic blood pressure by 2.8 mm Hg more (P<0.001) and diastolic blood pressure by 1.1 mm Hg more than the control diet (P=0.07). Among the 133 subjects with hypertension (systolic pressure, > or =140 mm Hg; diastolic pressure, > or =90 mm Hg; or both), the combination diet reduced systolic and diastolic blood pressure by 11.4 and 5.5 mm Hg more, respectively, than the control diet (P<0.001 for each); among the 326 subjects without hypertension, the corresponding reductions were 3.5 mm Hg (P<0.001) and 2.1 mm Hg (P=0.003). Conclusions: A diet rich in fruits, vegetables, and low-fat dairy foods and with reduced saturated and total fat can substantially lower blood pressure. This diet offers an additional nutritional approach to preventing and treating hypertension.
Effects of diets rich in monounsaturated fatty acids on plasma lipoproteins-the Jerusalem nutrition study: high MUFAs vs high PUFAs in USA
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.
Health benefits of nuts: potential role of antioxidants
A diet rich in fruits; vegetables and minimally refined cereals is associated with lower risk for chronic degenerative diseases. Since oxidative stress is common in chronic degenerative disease; it has been assumed that dietary antioxidants may explain this protective effect. Every dietary plant contains numerous types of antioxidants with different properties. Many of these antioxidants cooperate in oxidative stress reduction in plants; and we hypothesize that many different antioxidants may also be needed for the proper protection of animal cells. To test this hypothesis; it is useful to identify dietary plants with high total antioxidant content. Several nuts are among the dietary plants with the highest content of total antioxidants. Of the tree nuts; walnuts; pecans and chestnuts have the highest contents of antioxidants. Walnuts contain more than 20 mmol antioxidants per 100 g; mostly in the walnut pellicles. Peanuts (a legume) also contribute significantly to dietary intake of antioxidants. These data are in accordance with our present extended analysis of an earlier report on nut intake and death attributed to various diseases in the Iowa Women's Health Study. We observed that the hazard ratio for total death rates showed a U-shaped association with nut/peanut butter consumption. Hazard ratio was 0.89 (CI =0.81-0.97) and 0.81 (CI =0.75-0.88) for nut/peanut butter intake once per week and 1-4 times per week; respectively. Death attributed to cardiovascular and coronary heart diseases showed strong and consistent reductions with increasing nut/peanut butter consumption. Further studies are needed to clarify whether antioxidants contribute to this apparent beneficial health effect of nuts.
Pistachio intake increases high density lipoprotein levels and inhibits low-density lipoprotein oxidation in rats. Tohoku
There is increasing evidence that nuts have protective effects against coronary artery disease by improving lipid profile and inhibiting lipid oxidation. However; data about pistachio nuts are limited; and to our knowledge; there is no study investigating the effects of pistachio intake on lipid oxidation and serum antioxidant levels. This study; therefore; sought to determine the effects of pistachio intake on serum lipids and determine whether consumption of pistachio would alter serum antioxidant levels. Rats were randomly divided into three groups (n = 12 for each): control group fed basic diet for 10 weeks and treated groups fed basic diet plus pistachio which constituted 20% and 40% of daily caloric intake; respectively. Consumption of pistachio as 20% of daily caloric intake increased high-density lipoprotein (HDL) levels and decreased total cholesterol (TC)/HDL ratio; compared with those not taking pistachio. However; TC; low-density lipoprotein (LDL) cholesterol and triglyceride levels were unaffected by pistachio consumption. Consumption of pistachio as 20% of daily caloric intake increased serum paraoxonase activity by 35% and arylesterase activity by 60%; which are known to inhibit LDL cholesterol oxidation; compared with the control group. However; increased antioxidant activity was blunted when pistachio intake was increased to 40% of daily caloric intake. In conclusion; the present results show that consumption of pistachio as 20% of daily caloric intake leads to significant improvement in HDL and TC/HDL ratio and inhibits LDL cholesterol oxidation. These results suggest that pistachio may be beneficial for both prevention and treatment of coronary artery disease.
Nut consumption and decreased risk of sudden cardiac death in the Physicians' Health Study
BACKGROUND: Dietary nut intake has been associated with a reduced risk of coronary heart disease mortality; however; the mechanism is unclear. Since components of nuts may have antiarrhythmic properties; part of the benefit may be due to a reduction in sudden cardiac death. METHODS: We prospectively assessed whether increasing frequency of nut consumption; as ascertained by an abbreviated food frequency questionnaire at 12 months of follow-up; was associated with a lower risk of sudden cardiac death and other coronary heart disease end points among 21 454 male participants enrolled in the US Physicians' Health Study. Participants were followed up for an average of 17 years. RESULTS: Dietary nut intake was associated with a significantly reduced risk of sudden cardiac death after controlling for known cardiac risk factors and other dietary habits (P for trend;.01). Compared with men who rarely or never consumed nuts; those who consumed nuts 2 or more times per week had reduced risks of sudden cardiac death (relative risk; 0.53; 95% confidence interval; 0.30-0.92) and total coronary heart disease death (relative risk; 0.70; 95% confidence interval; 0.50-0.98). In contrast; nut intake was not associated with significantly reduced risks of nonsudden coronary heart disease death or nonfatal myocardial infarction. CONCLUSION: These prospective data in US male physicians suggest that the inverse association between nut consumption and total coronary heart disease death is primarily due to a reduction in the risk of sudden cardiac death.