Saturday, November 23, 2013

Health Benefits of Nut Consumption

Nut consumption = reduced death rate

In a study published in the New England Journal of Medicine, researchers looked at the association of nut consumption with total and cause-specific mortality among 76,464 women in the Nurses' Health Study and 42,498 men in the Health Professionals Follow-up Study. Consumption of nuts, including tree nuts (such as almonds, Brazil nuts, cashews, hazelnuts, macadamias, pecans, pine nuts, pistachios and walnuts), was inversely associated with total mortality in both men and women, independent of other predictors for death. In addition, there were significant inverse associations for deaths due to cancer, heart disease and respiratory disease.

"Compared with those who did not eat nuts, individuals who consumed nuts (serving size of one ounce) seven or more times per week had a 20% lower death rate and this association was dose-dependent," Nuts contain important nutrients such as unsaturated fats, high quality protein, vitamins (i.e., vitamin E, folate and niacin) minerals (i.e., magnesium, calcium and potassium) and phytochemicals—all of which may offer cardioprotective, anticarcinogenic, anti-inflammatory and antioxidant properties.

Tree nut consumption associated with reduced risk of pancreatic cancer in women

In a large prospective study published online in the British Journal of Cancer, researchers looked at the association between nut consumption and risk of pancreatic cancer among 75,680 women in the Nurses' Health Study, with no previous history of cancer. Consumption of nuts, including tree nuts (such as almonds, Brazil nuts, cashews, hazelnuts, macadamias, pecans, pine nuts, pistachios and walnuts), was inversely associated with risk of pancreatic cancer, independent of other potential risk factors for pancreatic cancer.

Women who consumed a one-ounce serving of nuts two or more times per week had a significantly reduced risk of pancreatic cancer compared to those who largely abstained from nuts.

New findings on tree nuts and health

Three new studies involving tree nuts (almonds, Brazil nuts, cashews, hazelnuts, macadamias, pecans, pine nuts, pistachios and walnuts) were presented this week at the Experimental Biology Meeting in Boston, MA. Tree nut consumption was associated with a better nutrient profile and diet quality; lower body weight and lower prevalence of metabolic syndrome; and a decrease in several cardiovascular risk factors compared to those seen among non-consumers.

Tree Nut Consumption = Lower Body Weight & Fewer Health Risks

In a study published in the Journal of the American College of Nutrition, researchers compared risk factors for heart disease, type 2 diabetes and metabolic syndrome of nut consumers versus those who did not consume nuts. Tree nut (almonds, Brazil nuts, cashews, hazelnuts, macadamias, pecans, pine nuts, pistachios and walnuts) consumption specifically, was associated with higher levels of high-density lipoprotein-cholesterol (good cholesterol) and lower levels of C-reactive protein, a marker for inflammation which can lead to a variety of chronic diseases including heart disease.

“One of the more interesting findings was the fact that tree nut consumers had lower body weight, as well as lower body mass index (BMI) and waist circumference compared to nonconsumers.

Nuts and Seeds for Health

by Dr. John Livesey, Department of Endocrinology Christchurch Hospital New Zealand

“Frequent eating of nuts appears to dramatically improve health. In particular, nut eating greatly lowers the risk of heart disease. In 1992 researchers working on the Adventist Health Study at Loma Linda University in California reported that those eating nuts daily had up to 60% fewer heart attacks than those who ate nuts less than once per month3. The beneficial effect of nut consumption was found for men, women, vegetarians, meat-eaters, fatter people, thinner people, the old, the young, those who did much exercise and those who did little exercise. The study was large, comprising 31,000 white Californian Seventh Day Adventists and similar benefits of nut eating were subsequently found for African Americans4. Prior to the publication of these results, nutritional advice had usually been to minimize nut consumption on the grounds that they were a "fatty" food.

Four other large studies have since confirmed the benefits to the heart of nut eating. In addition to the cardiac benefits of consuming nuts, the risks of having a stroke, of developing type 2 diabetes, of developing dementia, of advanced macular degeneration and of gallstones have all been found to be lowered by eating nuts.

Calculations suggest that daily nut eaters gain an extra five to six years of life free of coronary disease14 and that regular nut eating appears to increase longevity by about 2 years..

The more often nuts are eaten the better as the benefits appear to increase as the frequency of nut consumption increases. The risk of fatal coronary disease and the risk of developing type 2 diabetes both appear to decrease steadily as nut consumption increases from less than once a week to once or more per day.

Just what quantity of nuts should be eaten? The studies above suggest that 30 to 60 grams (1-2oz) of nuts should be consumed daily to gain the maximum benefits seen. Whether even larger amounts confer further benefits is currently unknown.

Nuts are of course a fatty food and many might worry that they will put on weight by eating more nuts. After all, 30 grams (or one ounce) of most nuts contain about 800 kilojoules (200 kilocalories). Happily though, on present evidence, nuts do not seem to cause weight gain1,17. For example in the Nurses' Study the frequent nut consumers were actually a little thinner on average than those who almost never consumed nuts6, and daily supplements of almonds or peanuts for six months resulted in little or no increase in body weight18. Nuts appear to satisfy hunger sufficiently well to appropriately reduce the consumption of other food.

Which nuts are best?

The definitive answer to this question is currently unknown. In the Adventist Study about about 32 percent of the nuts eaten were peanuts, 29 percent almonds, 16 percent walnuts, and 23 percent other types. These researchers did not ascertain whether the nuts were fresh, oil-roasted, or dry-roasted. The Nurses' Study found that peanuts, which are legumes, appeared to be just as effective in reducing the risk of coronary heart disease as tree nuts. Experiments where volunteers were fed nuts as part of their diet for several weeks have found that walnuts19-22, almonds22-25, hazelnuts26, peanuts27, pecans28, pistachio nuts29 and macadamia nuts30 all alter the composition of the blood in ways that would be expected to reduce the risk of coronary disease. Chestnuts, a nut unusually low in fat, do not yet seem to have been studied. The best advice currently is probably to eat a variety of nuts.”

Researchers found that people who eat nuts regularly have lower risks of heart disease. In 1996, the Iowa Women's Healthy Study found that women who ate nuts more than 4 times a week were 40% less likely to die of heart disease. Two years later, another study conducted by the Harvard School of Public Health found a similar result in another group of women subjects. Furthermore, potential heart health benefits of nuts were also found among men. In 2002, the Physician's Health Study found that men who consumed nuts 2 or more times per week had reduced risks of sudden cardiac death.

FDA only approved the heart health claim for almonds, hazelnuts, peanuts, pecans, some pine nuts, pistachios and walnuts as these nuts contain less than 4g of saturated fats per 50g. The FDA said: "Scientific evidence suggests but does not prove that eating 1.5 oz per day of most nuts as part of a diet low in saturated fat and cholesterol may reduce the risk of heart disease."

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