You can eat as many fruits and veggies as you like, but the benefits stop at five servings, a new Harvard School of Public Health study shows.
The study, published in the British Medical Journal (BMJ) last week, examined the relationship between fruit and vegetable consumption and overall risk of mortality. The results found that consuming five servings of fruits and vegetables decreases your risk of dying by a whopping 25 percent. Consuming more than five servings doesn’t hurt, but it doesn’t help either.
The comprehensive study analyzed health data on 833,200 subjects from 16 cohort studies. During follow-up periods ranging from five to 26 years, 56,400 subjects died due to various causes (16,800 from cancer, 11,500 from cardiovascular disease, and 28,100 from other causes). The Harvard University, National Institutes of Health, and Chinese University researchers found that the more fruits and veggies subjects consumed, the lower their risk of dying.
The results show a “dose-response relation,’’ meaning that overall risk of mortality decreased with each additional serving of fruits and vegetables. But here’s the catch: consuming six, seven, or eight servings had the same effect as consuming five.
According to the results, higher fruit and vegetable consumption was more effective at decreasing the risk of dying from cardiovascular disease than dying of cancer. For each additional combined daily serving of fruits and vegetables, risk of heart disease-related death decreased by about four percent while risk of cancer mortality decreased by just one percent.
The study also examined the effects of fruit and vegetable consumption independently, exposing a two-serving threshold for fruit and a three-serving threshold for vegetable benefits. Consuming more than these amounts does not further decrease risk of mortality.
Now, don’t use this study as an excuse to steer clear of the salad bar. Five servings is still a lot. The average American adult consumes just 1.1 servings of fruit and 1.6 servings of vegetables each day, according to the Centers for Disease Control and Prevention.
Further, the study only analyzed the effect of fruit and vegetable consumption on mortality risk so additional servings may have other health benefits.
“Dietary recommendations are based on the relationships of a food/food group with not only morality, but also morbididty as well as meeting certain dietary requirements,’’ lead author Dr. Frank HU, a professor of nutrition and epidemiology at the Harvard School of Public Health, said in an email interview. “Our meta-analysis looks at only mortality and found that the benefits on reducing mortality plateaued around five serivngs per day of fruits and veggies. However, it is possible that higher intake may confer additional benefits on prevention of some chronic diseases such as stroke.’’