The key to living a long and healthy life might be in the palm of your hand — with a handful of nuts, that is.
A new study found that eating three or more servings of nuts each week was tied to a decreased chance of dying from heart disease, cancer and other causes.
Consuming walnuts alone was linked to a 45 percent decreased risk of dying.
These findings suggest that nuts could play a protective role for consumers, according to the researchers.
"Eat a handful of nuts two or three times a week."
Marta Guasch-Ferré, from the Human Nutrition Unit at the Hospital Universitari de Sant Joan de Reus and the Universitat Rovira i Virgili in Spain, led a team of researchers to see whether eating nuts was tied to the risk of dying among 7,216 Spanish men and women. According to these researchers, Spain has a high average nut intake per person.
The study's participants had type 2 diabetes or at least three of several other risk factors for heart disease. These risk factors included smoking, hypertension, low levels of HDL ("good") cholesterol, being overweight or obese and having a family history of heart disease.
All participants were instructed to consume a Mediterranean diet rich in fruits, vegetables and healthy fats. The participants, who were 67 years of age on average, were then divided into one of three groups.
In combination with the Mediterranean diet, the first group also consumed an extra 16 grams per day of mixed nuts on average.
The second group consumed extra virgin olive oil along with the Mediterranean diet and the third group was instructed to eat a low-fat diet to compare results.
The researchers noted the amount and type of nuts consumed by participants at the start of the study. They later tracked the number of deaths that occurred after about five years by looking through medical records and the National Death Index in Spain.
In total, 323 deaths occurred, with 130 of them caused by cancer and another 81 by heart disease.
The researchers found that eating three servings of nuts per week was linked to a 39 percent reduced chance of dying compared to people who did not eat nuts. In this study, 28 grams was considered one serving.
Participants who consumed walnuts lowered their risk of dying by 45 percent and non-walnut consumers reduced their risk by 34 percent.
Of the group who did not eat nuts, 5.6 percent died. In total, 4.2 percent of those who ate one to three servings of nuts per week died while 3.8 percent of those who had more than three servings a week died.
Walnuts are richer in free and total polyphenols, which are antioxidants that can help fight cancer. This might be why people who ate walnuts had a reduced chance of dying, according to the researchers.
Those who ate nuts in general had a lower body mass index (BMI) than those who did not eat nuts. BMI is a measure used to tell if someone is of a healthy weight.
In addition, participants who ate nuts were less likely to smoke and were more physically active than those who rarely or never ate nuts.
"Nuts are high in monounsaturated fatty acids, fiber, minerals, vitamins and many bioactive compounds; all these nutrients may partly explain the beneficial effects on health that nuts have been shown to exert," the researchers wrote in their report.
Deborah Gordon, MD, a dailyRx Contributing Expert who focuses on conventional medicine, alternative care and educating patients, said that the reduction in deaths among participants in the study over such a short period of time is truly astounding and wonderful news for people with heart problems.
"What could be better than three handfuls a week of different nuts as a helpful intervention to protect your heart!" Dr. Gordon said in an email. "I would presume that what the nuts are providing are a delicious source of magnesium, a nutrient pervasively deficient in most diets and thus most people, and found in great supply in nuts and seeds."
The authors noted a few limitations to their study, including that they could not determine for sure if nut consumption actually caused the decreasing number of deaths. Other factors could have caused the decline in deaths.
In addition, the researchers said that the findings might not be generalizable to other populations beyond this older Mediterranean population.
This study, funded in part by the Spanish Ministry of Health (ISCIII), Thematic Network, Fondo Europeo de Desarrollo Regional (FEDER) and the Centre Català de la Nutrició de l’Institut d’Estudis Catalans, was published online July 16 in the journal BMC Medicine.
A couple of the authors received grants from the Nut and Dried Fruit Foundation and the California Walnut Commission. The same authors were also non-paid members of the Scientific Advisory Board of the International Nut and Dried Fruit Foundation and the Scientific Advisory Committee. No other conflicts of interest were declared.