An analysis of several studies shows that eating nuts every day can reduce people’s risk of coronary heart disease, strokes, cancer and premature death.
The assessment also found that other conditions such as diabetes, respiratory disease, and infectious diseases can be avoided with a daily portion of 20 grams of nuts including tree nuts, and peanuts, which are in fact legumes. The meta-study included 29 published studies from the United States, Europe, Asia, and Australia. It involved up to 819 thousand participants and included more than 12 thousand cases of coronary heart disease, 9,272 cases of stroke, 18,655 cases of cardiovascular disease, 18,460 cancer cases, and over 85 thousand deaths.
The research was led by scientists from Imperial College London and the Norwegian University of Science and Technology. It was published in the journal BMC Medicine, and it is based on several studies from two databases: PubMed and EMBASE.
Previous nutritional research has assessed nuts health outcomes regarding big killers such as heart disease and cancer, but the recent meta-study includes data for respiratory illness, diabetes, and other conditions for the first time, said study co-author Dagfinn Aune from the School of Public Health at Imperial College.
“We found a consistent reduction in risk across many different diseases, which is a strong indication that there is a real underlying relationship between nut consumption and different health outcomes. It’s quite a substantial effect on such a small amount of food,” added Aune.
Nuts’ benefits go beyond preventing heart disease and cancer
Nuts are a great source of dietary fiber, magnesium, polyunsaturated fats, vitamin E, and antioxidants, all of which reduce risks of cardiovascular diseases. Nuts nutrients lower insulin resistance, cholesterol concentrations, and oxidative stress.
Regarding cancer, nuts contain bioactive compounds such as ellagic acid, anacardic acid, genistein, resveratrol and inositol phosphates. All those elements reduce cancer risk because nuts induce cell cycle arrest, inhibition of cell proliferation and the development of new cells.
A handful of tree nuts, including walnuts, almonds, hazelnuts, cashews, pistachios and pecans -also Brazil nuts and peanuts although they are botanically considered legumes- are enough to reduce coronary disease by 30 percent and risk of cancer by 15 percent.
Twenty grams on a daily basis also reduces the risk of premature death by 22 percent. Nuts consumption was also associated with reducing diabetes and respiratory disease by 40 percent, although there are fewer studies about those conditions.
Additionally, nuts could help with obesity. Dagfinn Aune explained that even when nuts are high in fat, their high fiber levels and protein have been proven to reduce risks of obesity over time.
More and more studies have collected evidence suggesting nut consumption can indeed reduce coronary heart disease and mortality. And while research on how nuts intake helps reducing overall cancer risk and other conditions, the meta-study said a weak association cannot be excluded.
The study: Going through over 48 thousand studies to find the most relevant articles to assess nuts health outcomes
The Imperial College researchers ruled out over 48 thousand studies because of their relevance to nuts benefits analysis. In the end, 20 cohort studies, which accounted for 29 publications, were used to determined how much a handful of nuts reduces risks of heart disease and cancer. Studies that analyzed nuts intake and its relation to respiratory illness, diabetes, neurodegenerative conditions, infections and kidney disease were also taken into consideration.
The meta-study found that eating between 15-20 grams of nuts per day, or between 5-6 servings per week can reduce by 52 percent the relative risk of respiratory disease, and diabetes by 39 percent. Infectious disease mortality risk reduction related to nuts intake was 75 percent.
The intake of both tree nuts and peanuts was linked to a decreased risk of coronary disease, cardiovascular disease and mortality in general. The exclusive consumption of peanuts was associated with reduced risk of stroke while the intake of only tree nuts was related to reduced cancer risk.
Nut consumption could prevent over 4 million premature deaths
The Imperial College team calculated that approximately 4.4 million premature deaths in North and South America, Europe, Southern Asia and Western Pacific could be related to a nut intake below 20 grams.
For specific causes of death, the meta-study estimated that in 2013, 1.19 million death due to coronary heart disease, 469 thousand due to cancer, 1.07 million due to respiratory illness, and 138 thousand due to diabetes might have been prevented with a daily consumption of 20 grams of nuts or more, including peanuts.
The study findings are consistent with nutritional research that recommends an increase in nut intake to reduce chronic disease risk and overall mortality. The Mediterranean diet, known for its health benefits, includes frequent nuts consumption.
The Imperial team continues to work with large published databases to make new recommendations for other food groups, including vegetables, to reduce risks of suffering a wider range of diseases, including those mentioned in the recent meta-study and more.
Source: Imperial College London