July 31, 2014
Five Servings Of Fruit, Vegetables May Be The Magic Number For Lowering Risk Of Death
April Flowers for redOrbit.com - Your Universe Online
There is no question that the nutrients found in fruits and vegetables are beneficial for your health, and that they can lower the risk of many diseases and increase the longevity of your life. The results of the various studies, however, are not consistent. The question under debate, therefore, is how much is enough to reach these benefits?
An international team of researchers, led by the Harvard School for Public Health, performed an analysis of 16 studies. Their findings, published in the British Medical Journal, reveal that five is the magic number, and that additional servings don't have additional results.
Dr. Frank Hu, a professor of nutrition and epidemiology at the Harvard School of Public Health, said that the human body may only be able to process a certain amount of fruits and vegetables effectively each day, limiting the ability to absorb nutrients from extra servings.
"It is possible that the digestibility of fruits and vegetables and the availability of nutrients and other bioactive compounds of these foods may have reached a plateau at five servings per day for most people," Hu said. "More research is clearly needed in this area."
The sixteen studies contained the data from a total of 833,234 participants and 56,423 deaths. Hu and his colleagues took into account differences in study design and quality in order to minimize bias. The researchers found that all the studies agreed a higher consumption of fruits and vegetables is significantly associated with a lower risk of death from all causes, but especially from cardiovascular disease and cancer.
For each serving, WebMD reports that the average risk of death from all causes was decreased by five percent. For cardiovascular diseases in particular, the risk was reduced by four percent. They did not find an association between consumption of fruits and vegetables and a person's specific risk of death from cancer. They emphasize that the adverse effects of obesity, physical inactivity, smoking and high alcohol intake on cancer risk should be taken into account along with fruit and vegetable consumption.
Hu cautions that the study is only designed to reveal the association between fruit and vegetable consumption and the risk of death. The results should not be taken as proof that eating fruits and vegetables is the cause of the reduction in risk, only that consumption is associated with the reduction.
A wide variety of nutrients, vitamins and minerals can be found in fruits and vegetables. Because they are typically low calorie, consumption allows a person to gain much of the needed nutrition without worrying about gaining weight. They are also a source of dietary fiber, which aids in gut health, weight loss and a reduction in heart disease risk.
The researchers did not review the benefits of vegetarianism vs. a diet containing meat, so they cannot comment on whether vegetarians are more or less healthy because of the leveling of benefits after five servings a day.
The results of this study are not definitive, however. For example, a recent study in the BMJ's Journal of Epidemiology and Community Health indicated that seven or more daily servings were linked to the lowest risk of death.