By Dr. Marianna Pochelli, Prevent Disease, June 15, 2015
Eating nuts daily has been linked to lower all-cause mortality in many studies. Dutch researchers have now found that snacking on just half a handful of nuts every day could significantly lower overall and cause-specific mortality.
The protective effects on human metabolism from nuts is largely explained by their ability to regulate inflammation and oxidation. Almonds, Brazil nuts, cashews, hazelnuts, macadamias, pecans, pine nuts, pistachios and walnuts are all examples of tree nuts which have demonstrated profound effects on our health.
The study, published in International Journal of Epidemiology, noted that previous research has associated nut intake with lower mortality, but few studies have investigated causes of death other than cardiovascular disease – or questioned whether there is a dose-response relationship.
– folate and other B vitamins: these may reduce the risk of heart disease by lowering blood levels of homocysteine.
– copper, potassium, and magnesium–all three linked to heart health–and other minerals.
– vitamin E, possibly cardio-protective.
– arginine, an amino acid that helps relax blood vessels and inhibits blood clotting.
– fiber, with all its health benefits.
– phytochemicals (notably sterols, ellagic acid, polyphenols, and saponins) that may act as antioxidants and lower cholesterol.
Led by Professor Piet van den Brandt from Maastricht University, the research team found a 23% lower chance of death during the 10-year study in people eating at least 10g (0.3oz) of nuts or peanuts a day. There was no benefit for peanut butter, which is high in salt and trans fats.
“Total nut intake was related to lower overall and cause-specific mortality (cancer, diabetes, cardiovascular, respiratory, neurodegenerative diseases, other causes) in men and women,” wrote the authors.
“Peanuts and tree nuts were inversely related to mortality, whereas peanut butter was not.”
van den Brandt told the BBC had taken into account the mitigating factor that nut consumers ate more fruit and vegetables and that women who ate nuts were often leaner, and adjusted the results accordingly.
“It was remarkable that substantially lower mortality was already observed at consumption levels of 15g of nuts or peanuts on average per day,” he added.
A recent large pooled analysis of two of the Harvard cohorts and a recent meta-analysis of prospective cohort studies also tied daily nut consumption to lower all-cause mortality rates. Recent evidence that tree nuts lower cholesterol also resulted in an FDA-qualified health claim and their inclusion in heart association guidelines for cardiovascular risk reduction.
Researchers used data from the Netherlands Cohort Study, which has been running since 1986 among more than 120,000 Dutch men and women, aged 55 to 69.
They assessed how often people ate peanuts, other nuts, and peanut butter, and how much of these foods they consumed. Mortality rates and causes of mortality were then assessed ten years after the initial assessment took place.
The team then analysed the relationship between nut consumption and overall mortality from any cause, and death from a specific cause – revealing a link between tree nut and peanut consumption and cardiovascular deaths that backs up earlier results from American and Asian studies.
However, the new study also found that mortality due to cancer, diabetes, respiratory, and neurodegenerative diseases was also lowered among people who eat peanuts and tree nuts.
Broad range of benefits
A recent review of 12 clinical trials found that daily intake of tree nuts improve glycemic control in adults with type 2 diabetes.
The data, from a large-scale prospective study, investigated the association between nut consumption and risk of pancreatic cancer in more than 75,000 women who took part in the Nurses’ Health Study, and had no previous history of cancer.
“Frequent nut consumption is inversely associated with risk of pancreatic cancer in this large prospective cohort of women, independent of other potential risk factors for pancreatic cancer,” explained the research team – led by Dr Ying Bao of Brigham and Women’s Hospital and Harvard Medical School and published in the British Journal of Cancer.
Professor Piet van den Brandt and his team found that there was an average 23% lower risk of 10-year mortality across all diseases, with a decrease of:
45% for neurodegenerative disease
39% for respiratory disease
30% for diabetes
Led by Dr Wendie Robbins at the University of California, Los Angeles, USA, a research team revealed that eating 75 grams of walnuts a day improves the vitality, motility, and morphology of sperm in healthy men aged 21 to 35. The study was published in Biology of Reproduction.
Which Nut Is Best
All nuts have a lot in common. Most have 160 to 190 calories and 14 to 19 grams of fat per ounce; at least three-quarters of the calories come from fat. They are also among the best plant sources of protein.
There are some nutritional differences. Walnuts are richest in heart-healthy alpha-linolenic acid (an omega-3 fatty acid similar to those in fish); almonds are richest in calcium and vitamin E; brazil nuts are the best dietary source of selenium. Macadamia nuts have the most calories and fat; chestnuts the least (just 70 calories and 1 gram of fat). And peanuts are not true nuts, but legumes (like dried beans). Similar nutritionally to nuts, peanuts contain some resveratrol, a beneficial compound found in grapes.
Stick To Raw and Unprocessed
Nuts tend to be satisfying and, according to some studies, help reduce hunger longer than many foods. But only if you eat them without sugar or salt coatings which can have the opposite effect. Roasted and processed nuts destroy much of the nutritional content so stick with raw nuts when possible.
An ounce or two a day will do. Instead of using nuts as a snack, when you might eat large amounts, use them as part of a meal. Chopped nuts are tasty in fruit or vegetable salads, yogurt, oatmeal and breakfast cereals. When possible, substitute nuts for foods rich in saturated fat. Organic raw peanut butter, for instance, is definitely a healthier choice for a sandwich than cheese or most meats.
And spread the news: Raw nut butters have the same nutritional advantages as nuts.
Dr. Marianna Pochelli is a Doctor of Naturopathic Medicine specializing in the treatment of disease through superfoods and herbal strategies. She actively promotes detoxification, colon cleansing, and a vegetarian lifestyle using living foods as a platform to health.