Lest the message be misconstrued, I'm not out to knock the 5-a-day concept. The rep of fruit and veg as a virtuous food is totally justified, with a plentiful intake linked to less heart disease, high blood pressure and stroke, lower cancer risk, less diabetes, and even stronger bones. In short, it's all good. But so relentlessly is the message drummed into us that you'd be forgiven for thinking that fruits and vegetables have quasi-mythical health powers that profoundly elevate them above all other foods. I'm not so sure about that, and research published this week got me asking whether it's time to take fruits and vegetables off their pedestal, and starting thinking more broadly about our phytonutrients intake from a range of plant foods.
A study published this week in the journal Neurology followed 37,103 Swedish men for just over a decade and found that high chocolate consumption was associated with a lower risk of stroke [1]. So, men with the high intakes (averaging 63g per week) had a 17% reduced risk of stroke compared to those who didn't consume chocolate. To bolster this finding, when all the data from five such studies were added together, in what's known as a meta-analysis, similar results emerged, with the highest chocolate consumers having a 19% lower risk of stroke compared with the non-chocolate eaters. Indeed, each increase in chocolate consumption of 50g per week reduced the risk of stroke by about 14%.
It goes without saying that this type of research is only observational in nature (not something that can provide hard and fast proof), but it does fit with a wider body of evidence that shows cocoa-containing foods and beverages may influence such aspects of our cardiovascular health as improving endothelial function, reducing blood pressure and improving insulin sensitivity - all good things for reducing cardiovascular disease risk. These quite marked health benefits of chocolate are most likely due its rich content of a family of plant compounds known as flavonoids, in fact, similar to what you would find in many fruits and vegetables such as onions, apples, citrus fruits and berries.
It begs the question, why don't we give more credence to phytonutrients-rich offerings beyond fruits and vegetables? To this list we could add tea, specifically green tea, which bursting with flavonoids, also appears to confer protection against heart disease [2], and possibly common cancers such as prostate cancer and lung cancer too [3, 4]. And while we're at it, let's not forget coffee. Much bemoaned by the holier-than-though health fanatics and self-professed nutrition experts (who know little if anything about the actual research), there is increasingly compelling evidence that this phytonutrient packed beverage could proffer substantial protection against diabetes [5].
The irony is that foods such as dark chocolate are frequently castigated for being high in fat and sugar, and thus eyed with suspicion, yet what is fruit if it's not a high sugar food? Indeed, fruit juice, an accepted way to notch up one of your five-a-day, is nothing short of a catastrophic sugar dump (a mere 250ml serving of orange juice 'naturally' contains a whopping 26 grams of sugar - the exact same as a 250ml serving of Coca Cola), which rather than being healthy is actually likely to increase diabetes risk [6].
Ultimately, I'm interested in how diet can be used to lessen the spiralling burden of chronic disease that besets modern society. With that in mind, is it time that other phytonutrient-rich foods enjoyed the same status proffered to the exclusive 5-a-day club?
[1] Larsson SC et al (2012) Chocolate consumption and risk of stroke: A prospective cohort of men and meta-analysis. Neurology Aug 29. [Epub ahead of print]
[2] Wang ZM et al (2011) Black and green tea consumption and the risk of coronary artery disease: a meta-analysis. Am J Clin Nutr 93(3):506-15
[3] Zheng J et al (2011) Green tea and black tea consumption and prostate cancer risk: an exploratory meta-analysis of observational studies. Nutr Cancer 63(5):663-72.
[4] Tang N et al (2009) Green tea, black tea consumption and risk of lung cancer: a meta-analysis. Lung Cancer 65(3):274-83
[5] Huxley et al (2009) Coffee, decaffeinated coffee, and tea consumption in relation to incident type 2 diabetes mellitus: a systematic review with meta-analysis. Arch Intern Med 169 (22)2053-2063
[6] Bazzano LA et al (2008) Intake of fruit, vegetables, and fruit juices and risk of diabetes in women. Diabetes Care 31(7):1311-7