Have you gone nuts yet? Perhaps you should. According to a new study published in the New England journal of Medicine, there is an association between nut consumption and mortality. And those who consume nuts are less likely to die.
Just by way of clarification, when the researchers - Ying Bao and collaborators from Harvard Medical School and other distinguished institutions - say that your chance of dying decreases, it does not mean that you would become immortal. It just means that you would die later in life. Nothing, even eating nuts, will save you from the inevitable finality of life.
The researchers studied two large populations: 121,700 female nurses from 11 U.S. states enrolled in the Nurses Health Study, and 51,529 male health professionals from 50 states enrolled in the Health Professional Follow-up Study. These men and women were asked to fill a medical and lifestyle questionnaire every 2 to 4 years. They were also asked to fill a food-frequency questionnaire and to report on the frequency at which they consumed a serving of nuts (1 ounce) during the preceding year.
Shahar Madjar, M.D.
The researchers then searched the records of postal authorities, states, and the National Death Index to find out which of the participants had died. The death certificate and medical records of the deceased were then evaluated for the cause of death.
They found that during the 30 year follow-up, participants who consumed nuts seven or more times a week had 20 percent lower death rates when compared with participants who did not consume nuts at all. The effect of nut consumption was dose-dependent: the more nuts consumed, the lower the death rate was (for example, consuming nuts once a week resulted in'only 11 percent lower death rate). They found that participants who consumed nuts were less likely to die of cancer, heart disease, and lung disease. They found that no matter whether the nuts consumed were peanuts or tree nuts, the beneficial effect was similar.
Does eating nuts really prolong life? Does it really prevent heart and lung disease, even cancer? When presented with such a strong association between nut consumption and its benefits (or with any other strong statistical associations), it is the natural tendency of the human mind to assume a cause-and-effect relationship. Seeking cause-and-effect relationship is always tempting, sometimes irresistible, and often wrong.
It turns out, for example, that the participants in this study who consumed nuts were a healthy bunch. Despite higher consumption of nuts (which are rich in calories) they were leaner. They were also more likely to exercise; less likely to smoke; and more likely to eat more fruits and vegetables. Who knows? Perhaps their longer life should be attributed to their other healthy habits and not to their nut consumption?
In their article, Ying Bao and her collaborators addressed this question. Using a sophisticated set of statistical analyses, they examined factors other than nut consumption that could have influenced the results. They looked at smoking, body mass index, total sodium intake, Mediterranean-diet score, intake of olive oil, and other variables that could have influenced the results. They then adjusted their analysis accordingly. And the association between nut consumption and health benefits remained strong.
Dr. Bao's article, "Association of Nut Consumption with Total and Cause-Specific Mortality," adds to significant volume of evidence attesting to the value of nuts as an important part of our diet. Nuts are rich in nutrients that are considered beneficial: unsaturated fatty acids, high quality protein, fiber minerals and vitamins. It adds to the findings in another study, "Primary Prevention of Cardiovascular Disease with a Mediterranean diet" (which I discussed in a previous article in the spring of 2013). And nuts are tasty too. So this holiday season, pull out your nutcrackers and go nuts. In my next column, I promise, I will bring to you my best recipe: chicken with red and yellow peppers (or mushrooms), all cooked to perfection in an inferno-hot wok, with crunchy, healthier than ever nuts.
Editor's note: Dr. Shahar Madjar is a urologist at Bell Hospital in Ishpeming. Read and comment on prior columns by Dr. Madjar at DrMadjar.com.