Researcher dispute How much fruits and vegetables daily?

400 or 650 grams daily dose ?: fruits and vegetables are healthy

07/30/2014

It is recommended by the German Nutrition Society to take five servings of fruits and vegetables with a total of at least 650 grams per day. British researchers came to the conclusion a few months ago that it should be seven servings for the sake of health. A recent analysis of studies suggests that 400 grams could be enough.

Optimum dose of fruits and vegetables
The dispute over the optimal dose of fruits and vegetables a person should eat a day does not stop. The German Nutrition Society (DGE) has been campaigning for some time „5 a day“, according to which there should be five servings of fruits and vegetables daily, which are consumed. These include for health's sake at least 400 grams of vegetables and 250 grams of fruit a day. British researchers from University College London concluded in a study a few months ago that it should be seven instead of five servings of fruits and vegetables to achieve a greater health protection effect. A recent meta-analysis suggests that 400 grams could be enough.

Lower risk of dying prematurely
An im „British Medical Journal“ (BMJ) showed that those who eat plenty of fruits and vegetables have a lower risk of dying prematurely. Above all, the risk of fatal cardiovascular diseases is lower for them. This is reported by Wei Bao's research team from the National Institutes of Health in Rockville, Maryland, and Frank Hu from the Harvard School of Public Health in Boston, Massachusetts. The two scientists evaluated 16 studies with their colleagues, in which a total of around 833,000 people had participated.

Lower risk of cardiovascular disease
The various investigations ran between four and 26 years. Within the study period, approximately 56,400 participants died, of which 11,500 had cardiovascular disease and 16,800 had cancer. Also included were factors such as age, body mass index and cigarette consumption. The dietary habits were mostly determined by questionnaire, in some studies also by keeping a book in which the participants wrote what they ate. In the studies, one serving was equivalent to about 80 grams of fruit or vegetables. According to the analysis, the risk of premature death per daily serving of fruit or vegetables dropped by about five percent. Thus, those who ate five servings a day were reduced by about 25 percent. In addition, the risk of dying from cardiovascular disease decreased by about four percent per daily serving. The risk of a fatal cancer did not change.

Sense of observational studies questioned
However, it can not be directly deduced from the data whether the increased fruit and vegetable consumption is responsible for the reduced mortality, since the researchers only evaluated observational studies. For example, factors that were not sufficiently considered could be crucial. Nutrition research has long been concerned with the question of how useful observational studies are at all. Last year, for example, US professor of medicine John Ioannidis, Stanford University, commented on the food science dilemma in a BMJ publication. He said many study results were „completely unbelievable“ and also one „another million observational studies“ would not provide any definitive solutions.

Fruits and vegetables are healthy
However, older studies in which people ate more fruits and vegetables for more than several weeks showed that, among other things, this lowers blood pressure, according to researchers in the specialist journals „The Lancet“ such as „The New England Journal of Medicine“ wrote. This, in turn, has a positive effect on the cardiovascular system if hypertension is alleviated. If a diet is also high in fiber thanks to a lot of fruits and vegetables, it also helps to stimulate digestion and reduce the risk of overweight and obesity. This in turn reduces the risk of diabetes.

Optimal dose will probably remain contentious
According to the study, more than five servings of fruits and vegetables per day have no further measurable effect on mortality. The analysis thus contradicts the recently published British study, which states that it should better be seven servings daily. It also differs from the DGE recommendation. Although this also recommends five servings a day, but at the DGE corresponds to a serving around 130 grams - and not 80 grams, which count on British and Americans. Whether the optimal dose of 650 grams of fruit and vegetables, as recommended by the DGE, or 560 grams, as in the British study, or as the current meta-analysis is 400 grams to lower the mortality, is probably in Future remain in dispute. (Ad)