Are you what you eat?
Jim takes expressions such as “you are what you eat” literally. In his mind, he sees a vegetarian turning into a broccoli, a pescatarian joining a school of fish, and a carnivore taking the shape of a cow grazing in a vast meadow. I am afraid that in an attempt to remain who he is, Jim will develop a taste for people, and become a cannibal.
What does the expression “you are what you eat” really mean? For help, I turned to a recent article in the New England Journal of Medicine.
The main author, Mercedes Sotos-Prieto from the Harvard T.H. Chan School of Public Health, and her colleagues analyzed data on participants in two large and long-standing studies: 25,745 men who participated in The Health Professional Follow-up Study, and 47,994 registered female nurses who participated in The Nurses’ Health Study.
The information collected in these two studies is considered invaluable. These studies examined two very large groups of healthcare professionals who would, one assumes, see great value in health-related research. The data, collected over many years, allows researchers to examine the effect of a variety of factors on health over time.
The participants volunteered to provide information on their medical history, lifestyle practices, and the development of chronic disease. They filled a detailed questionnaire at baseline and every two years thereafter.
Every four years, the participants were also asked how often, on average, they consumed each food of a standard portion size in the past year. For example: Over the past year, how often did you consume fruits? And the responses would range from never, less than once-a-month, to six-or-more times a day.
The authors examined the improvement (or lack of) in the participants’ diet over a period of 12 years. They rated the quality of their diet using three different diet scores:
The Alternate Healthy Eating Index score – a measure of diet quality that assesses conformance to the diet recommendations made in the US federal dietary guidance: eat fruits, vegetables (french fries don’t count), whole grains, and healthy proteins (fish, poultry, beans and nuts); limit red meat and cheese; avoid bacon, cold cuts, and processed meat, and drink water (limit milk, avoid sugary drinks).
The Alternate Mediterranean Diet score – indicating compliance with the Mediterranean diet (cereals, legumes, fruits, vegetable, olive oil, and fish; avoid red meat).
The Dietary Approach to Stop Hypertension score (DASH diet) – indicating compliance with a diet designed to prevent high blood pressure by reducing levels of salt (sodium) intake and increasing the consumption of food rich in potassium, calcium, and magnesium.
The researchers found that conforming to any of the above diets was associated with reduced rate of mortality. Those who maintained a stable, high-quality diet throughout the 12 year period did better (their mortality rates were 9-14% lower) than those who had low diet scores.
Those who improved their diet over time, did better than those whose diet remained stable. A 20 percentile improvement in the diet-quality scores was associated with 8-17% reduction in mortality. On the other hand, worsening diet quality was associated with an increase of 6-12% in mortality.
The researchers proved that there is an association between improved diet quality and decreased risk of all-cause mortality (mortality from all causes, including heart disease, stroke, cancer and all other causes of death). They proved that improved diet quality is specifically associated with decreased mortality from cardiovascular disease (heart disease and strokes). The study did not show, however, that improved diet quality had any substantial effect on mortality from cancer alone.
“It is not necessary to conform to a single diet plan to achieve healthy eating patterns,” the authors report. Instead, any of these dietary patterns, “although different in description and composition, capture the essential elements of a healthy diet,” they claim.
The results indicate that even a small change in diet may lead to significant improvement in the rate of mortality: “an increase in consumption of nuts and legumes, for example, from no serving to 1 serving per day, or the reduction of red meat and processed meats from 1.5 servings per day to little consumption.”
What are the the common food groups in each score that contributed most to the improvement in the rate of mortality? These are: whole grains, vegetables, fruits, and fish or Omega-3 fatty acids (found in plant oil, nuts, and fish).
Reading Mercedes Sotos-Prieto’s article, I quickly concluded: although you are not what you eat (at least not literally), what you eat may determine for how long you are going to live.
Dr. Shahar Madjar is a urologist working at Aspirus Keweenaw Hospital. He sees patients in Laurium, Houghton and L’Anse. Contact him at firstname.lastname@example.org.