A paper investigating whether the consumption of fruit and vegetables actually affects health in the general population of England was published online in the Journal of Epidemiology and Community Health last week (1). The paper measured health as death due to any cause, and also specifically due to cancer and cardiovascular disease as they are the two biggest killers of older adults in developed countries (1-3). They found that consumption of 7 or more servings of fruit and vegetables per day reduced risk of death by 42% in the general English population, a finding which is making a major media splash. This paper and the reactions against it are interesting for several reasons. First, let’s talk how the study was done and what the results actually mean.
The authors of the paper took data from the Health Survey for England, which is an annual national survey assessing the health of the nation. Data on over 65,000 people aged 35 and over who participated in the survey from 2001 to 2008 were included in the newly published paper. All of the participants were asked about all vegetables and fresh, canned, and frozen fruit, and salad, pulses, dried fruit, and fruit juice/smoothies they consumed (1). The study authors then linked data on fruit and vegetable intake to mortality data, with people being followed up for an average of 7.7 years between the time when their intake was measured and mortality data collected. The authors then modelled the association between an increasingly greater amount of fruit and vegetables per day (0 to less than 1 portion, 1 to 2 portions, 3 to 4 portions, 5 to 6 portions, and 7 or more portions) and risk of dying. They found that people who ate 7 or more portions per day of fruit and vegetables had a 42% lower chance of dying (1). They accounted for factors including age, sex, social class, cigarette smoking, body mass index, education, physical activity, and alcohol intake, meaning that the effect of fruit and vegetable intake on death was independent of all of these factors.
This finding obviously sounds very splashy, and was highly media worthy. The reduced risk of death was true for cancer and cardiovascular diseases, in addition to all other causes (1). If we all ate more fruit and veg every day, we could all live longer. Sounds simple, right? One problem is that knowledge often doesn’t translate to behaviour. We all know that eating greens is good for us, but we don’t always do it. With respect to this latest finding, media frenzy over health issues has given epidemiological research a bad rap by causing uncertainty and confusion over what’s healthy and what’s not. We hear news all of the time about some new magic bullet or evil detrimental factor to health, and sometimes things fall into both categories in the news. A great example is alcohol, where some research shows that drinking low-to-moderate amounts of red wine appears beneficial to health, but large amounts of alcohol consumption cause increased risk for several chronic diseases (4-7). Given our continual frustrated experiences with gaining health information through the media (8), it would be no surprise if people tend to glaze over when reading the new 7 per day headline in the news.
One reaction against the new research in the media is backlash against state-backed recommendations for individual dietary choices. A Guardian commentator, Alex Renton, makes the mildly inflammatory point, ‘Nanny Britain’s fruit and veg regime will never work while the list includes fruitcake and sugar-laden drinks’ (9). This point is interesting. Leaving aside the welfare state discussion, the question of responsibility for individual dietary intake in the context of what is available given the food industry is interesting. The onus is largely on individuals when it comes to fruit and vegetable intake – one only needs look at the NHS ‘5-a-day’ website or the American equivalent to see this. However, it can be difficult to eat 5 servings of fruit and vegetables per day when so many processed and refined foods that taste good and are easy to access are available. Particularly for people on a low income, the most cost effective foods in terms of energy density are usually not fruit and vegetables[LCK11] . The food industry places governments in a catch-22 of providing recommendations for the public on healthy eating and other behaviours, which is certainly easier than regulating the food industry, but can be called ‘nannying’. So, what are governments to do? Alex Renton of the Guardian says that the state must police the business sector in order to make it feasible for people to follow dietary recommendations (9). He laments that this doesn’t happen, and it certainly doesn’t seem like it will change.
Given that our health is in our hands, what do we do as individuals? First, empower yourself with knowledge. We now know that eating an abundance of fruit and vegetables can help us live longer (1). These results are sound, although there is a question left unanswered – because the study didn’t account for total caloric intake or dietary fat, we don’t know whether the people in the study who ate 7 or more servings per day experienced a lower risk of dying directly from eating fruit and vegetables, or if they were eating less unhealthy foods and/or overall calories because they were eating more fruit and vegetables. Regardless, eating plants doesn’t hurt. Echoing the famous words of Michael Pollan, who said ‘Eat food. Not too much. Mostly plants’, Alex Renton states ‘Don’t eat crap. Three times a day. And try to cook something every day that makes you and those you love happy’ (9).
I wholeheartedly agree with these words. Michael Pollan’s book, ‘In Defense of Food: an Eater’s Manifesto’ is worthwhile read. For something a bit more bite-sized, the BBC has compiled a fabulous list of tips for eating 7-a-day, as has the Guardian.
1) Oyebode O, Gordon-Dseagu V, Walker A, Mindell J. Fruit and vegetable consumption and all-cause, cancer, and CVD mortality: analysis of Health Survey for England data. J Epidemiol Community Health Published Online First: [31 March 2014] doi:10.1136/jech-2013-203500
2) Office for National Statistics. Leading Causes of Death. http://www.ons.gov.uk/ons/rel/vsob1/mortality-statistics–deaths-registered-in-england-and-wales–series-dr-/2012/info-causes-of-death.html (accessed 08 April 2014).
3) Centers for Disease Control and Prevention. Leading Causes of Death. http://www.cdc.gov/nchs/fastats/lcod.htm (accessed 08 April 2014).
4) Corder R, Mullen W, Khan NQ, Marks SC, Wood EG, Carrier MJ, et al. Red wine procyanidins and vascular health. Nature 2006;444:566.
5) Ronksley PE, Brien SE, Turner BJ, Mukamal KJ, Ghali WA. Association of alcohol consumption with selected cardiovascular disease outcomes: a systematic review and meta-analysis. BMJ 2011;342:d671.
6) Boffetta P, Hashibe M. Alcohol and Cancer. Lancet Oncol 2006;7(2):149-56.
7) Kozararevic DJ, Vojvodic N, Dawber T, McGee D, Racic Z, Gordon T, et al. Frequency of alcohol consumption and morbidity and mortality: the Yugoslavia Cardiovascular Disease Study. Lancet 1980;315(8169):613-6.
8) Arora NK, Hesse BW, Rimer BK, Viswanath K, Clayman ML, Croyle RT. Frustrate and confused: the American public rates its cancer-related information-seeking experiences. J Gen Intern Med 2007;23(3):223-8.
9) Renton A. So now it’s seven a day? Here’s my easy alternative: just stop eating rubbish. The Guardian. 6 April 2014. http://www.theguardian.com/commentisfree/2014/apr/06/seven-a-day-fruit-vegetable (accessed 8 April 2014).