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Why Five Portions of Fruit and Veg?
In Britain we have been told to eat "five portions of fruit and vegetables a day" for ever, it seems. The question is: Why 5 portions? because there doesn't seem to be any evidence that doing so will make us healthier. Coronary Heart DiseaseFor example: In 2003 a Greek study did show that 2 portions conveyed some benefit in heart disease, but there was not much benefit after that amount:"Our findings support that . . . Consumption of 2 or more servings per week is associated with about 70% reduction in relative risk." Note that's two servings per week, not even two portions per day, let alone 5 portions. This study was reported in the Daily Mail in September 2003 (they reported it as two portions per day). In the report, Professor Sir Charles George, medical director of the British Heart Foundation, was asked why, in view of this study, he advised people to eat 5 portions of fruit and veg a day. He stated that: "There is some argument about how much you need. I think five may be an arbitrary figure." And, by so doing, admitted that this was another example of dietary advice which was based on nothing more than guesswork or wishful thinking. CancerThe following year, results of a US study suggested that a diet of 5 portions of fruit and vegetables is not much help with cancer either.A research team, led by Dr Hsin-Chia Hung from Harvard School of Public Health in Boston, Massachusetts, explains that eating 5 portions of fruit and vegetables each day or more has been recommended to reduce the risk of cardiovascular disease and cancer. But they add that, although a number of studies have evaluated the association between fruit and vegetable intake and the reduction in risk of a number of specific diseases, overall associations with cardiovascular disease and cancer have rarely been assessed in large population studies. To address this, the researchers studied data from two large studies – the Nurses' Health Study and the Health Professionals' Follow-up Study – involving more than 100,000 participants. Information on dietary habits and the incidence of cardiovascular disease and cancer were available for all those taking part in the study. The team found that "Increased fruit and vegetable consumption was associated with a modest although not statistically significant reduction in the development of major chronic disease. The benefits appeared to be primarily for cardiovascular disease and not for cancer." (emphasis added ) Further analysis of different groups of fruit and vegetables revealed that the consumption of green leafy vegetables, such as spinach and kale, provided the strongest protective effect against cardiovascular disease. But again 5 portions weren't needed: it needed only two portions of these vegetables each day to reduce the risk by 70%. They conclude: "However, the benefit of increasing intake of fruits and vegetables appears to be due primarily to a lower risk of cardiovascular disease, not cancer." References 1. Panagiotakos DB, Pitsavos C, Kokkinos P, et al. Consumption of fruits and vegetables in relation to the risk of developing acute coronary syndromes; the CARDIO2000 case-control study. Nutr J 2003; 2: 2 2. Hung H-C, Joshipura KJ, Jiang R, et al. Fruit and Vegetable Intake and Risk of Major Chronic Disease. J Nat Canc Inst 2004; 96: 1577-1584 Despite studies such as this, supporters of the "5-a-day" campaign still insist that eating the recommended number of fruit and vegetables has numerous health benefits, as well as pointing to other research findings that support the link between fruit and vegetable intake and the likelihood of developing specific cancers. But if all this advice is based on calculated "risk," when the risk factors themselves are in dispute and (therefore) any statistical analysis based on these "risk factors" may be fundamentally flawed, how much faith should we place in them? Bear in mind that there are many peoples on this Earth who eat no vegetables or fruit at all – from the Maasia, Samburu, etc at the equator to the Inuit of the Arctic – and yet the diseases such as heart disease and cancer are completely unknown. And it is possible to eat too much, particularly of fruit. All sugars damage the immune system and make us more likely to catch infectious diseases and cancer. And note that the worst sugar for this is fructose, the sugar found in fruit. |
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