Every extra of fruit or vegetable consumed daily could cut the risk of heart disease by four percent, says a meta-analysis of almost a quarter of a million people, giving people even more reason to seek out the nutrient-rich foods.
The Five-a-day message is well known, but applying this does not seem to be filtering down into everyday life. Indeed, recent studies have shown that the average consumption of people in developed countries is three portions a day.
The meta-analysis by scientists from France's INSERM in Paris, Lille's Pasteur Institute, and Rouen's Department of Epidemiology and Public Health, pooled nine cohort studies giving an overall study population of 91,379 men, 129,701 women, and 5,007 coronary heart disease events.
Studies were included in the meta-analysis if they reported relative risks for coronary heart disease or mortality and if fruit and vegetable intake was quantitatively assessed.
The analysis, published in the current issue of the Journal of Nutrition (Vol. 136, pp. 2588-2593), found that the risk of coronary heart disease (CHD), conditions that cause of 20 per cent of deaths in the US and 17 per cent of deaths in Europe, was cut by four per cent for each additional fruit and vegetable portion consumed, and by seven per cent for fruit portion intake.
The link between the risk of CHD and vegetable intake however was mixed with a more beneficial relationship observed for general cardiovascular mortality (26 per cent risk reduction) than for the more specific fatal and nonfatal heart attacks (myocardial infarction) (five per cent).
"This meta-analysis of cohort studies shows that fruit and vegetable consumption is inversely associated with the risk of CHD," concluded the reviewers.
"The causal mechanism of this association, however, remains to be demonstrated."
The analysis has several strengths, including the well-defined inclusion criteria and the large sample population, but some limitations are inherent. The analysis is based on cohort studies that are observational by nature and therefore subject to errors. Also, no distinction could be made between different fruit and vegetables. Indeed, the researchers suggest that the calculated relative risks were "probably overestimated".
A report from the European Union showed that global fruit and vegetable production was over 1 230 million tonnes in 2001-2002, worth over $50bn (€41 000m). Asia produced 61 per cent, with Europe and North/Central America both producing nine per cent.