Healthy diets contain fruit & vegetables
Fruit and vegetables are vital elements of a healthy, balanced diet.
They are important sources of energy, contain lots of vitamins, minerals and fibre, as well as important phytonutrients that are potentially incredibly beneficial to health. Population studies looking at behaviour across large groups of people have shown that high intakes of fruit and vegetables are associated with a lower risk of chronic diseases; particularly, cardiovascular disease (1-3), type 2 diabetes (4) and cancer (5).
In 2003 The World Health Organisation (WHO) and The United Nations Food and Agriculture Organisation (FAO) recommended a minimum daily intake of 400g of fruit and vegetables (excluding potatoes and other starchy tubers). This recommendation was designed to prevent chronic diseases such as heart disease, cancer, diabetes and obesity, as well as lowering the risk of micronutrient deficiencies in less developed countries. Many individual countries followed suit recommending either 400-600g per day or 5-a-day, either with or without including potatoes. 400g of fruit or vegetables and 5-a-day are considered to be roughly equivalent (6).
The UK brought in the recommendation of 5-a-day at the same time as the WHO and devised the Healthy Eating Plate in 2006. At this time the UK was consuming on average around 258g/day or 2.4 portions. The latest National Diet and Nutrition Survey (NDNS) 2014, shows intake in the UK is improving with adults aged 19 to 64 years consuming around 4.1 portions a day and the over 65’s 4.6 portions. The news is not as good for children though with boys (11 to 18 years) eating just 3.0-a-day and girls (11-18yrs) even worse at just 2.7 portions per day, hardly different from ten years ago. At the time of the survey in 2014 only 30% of adults met the “5-a-day” recommendation and just 10% of boys and 7% of girls (11-18yrs) (7).
As more and more research is done, evidence is increasingly showing that the ‘things’ in fruit and vegetables are particularly good for you and promote good health. In 2012/13 the WHO published a paper saying that there was growing evidence that people should eat even more fruit and particularly vegetables and recommending daily intakes of 400g of vegetables and 250g of fruit a day. A number of countries followed suit and it was at this time that Harvard University devised their healthy eating plate. This recommends that half or everything you eat should be fruit or vegetables and that vegetables should be eaten in greater quantities than fruit.
In the last month there have been a number of press stories suggesting that 5-a-day is no longer considered to be enough (10,11,12). These headlines originate from an article published in the International Journal of Epidemiology in February (13). The research was carried out by a combination of academic and medical institutions in Norway, the UK, and the US.
The first thing to say is that this was not new research. What the scientists did was look at all the other studies that have been published in the last few years and combine their results. This meta-analysis included 95 studies that had looked a people’s health and diets overtime. In particular they were looking at studies that monitored fruit and vegetable intake and the risk of getting or dying from coronary heart disease, stroke, total cardiovascular disease, all cancers and all other causes. What they found by combining all this research into one mega study was that the risk getting or dying from each disease was reduced with each extra 200g a day of fruit and vegetables you ate, up to 800g a day (600g a day for cancer).
Eating 800g a day of fruit and vegetables gave the biggest reduction in risk
The researchers estimated that globally, 5.6 million early deaths (in 2013) could be put down to low intakes of fruit and vegetables (less than 500g).
The study also looked at specific fruit and vegetable consumption to see if any one fruit or vegetable was particularly good. What they found was that:
- Eating apples or pears, citrus fruit, fruit juices, green leafy vegetables, beta carotene-rich vegetables such as carrots and sweet potato, and vitamin C-rich fruit and vegetables was associated with lower risk of coronary heart disease.
- Eating apples or pears, citrus fruit, green leafy vegetables and pickled vegetables was associated with lower risk of stroke.
- Eating apples or pears, citrus fruit, carrots, green leafy vegetables and non-cruciferous vegetables such as butternut squash was associated with lower risk of cardiovascular disease.
- Eating cruciferous vegetables such as cauliflower and broccoli was associated with lower cancer risk.
- Eating apples or pears, berries, citrus fruit, cooked or raw vegetables, cruciferous vegetables, potatoes and green leafy vegetables or salads was associated with lower all cause mortality risk.
800g a day and mostly vegetables
It seems a no-brainer but before we start upping the grocery order there are a few things to consider. This type of research can include a number of confounding factors that affect the results. It might be that people who eat a lot of fruit and vegetables are also more likely to be physically active, consume less alcohol, not smoke and be a healthy weight, they may live in more rural locations, take more holidays and have smaller families – these or many 100s of other things might also influence health outcomes or it might not be the fruit and vegetables at all. It is also worth noting that the studies included varied in several ways, asking slightly different questions and looking at slightly different things. Different countries may prepare foods in different ways or have different fruits and vegetables available. The vegetables most associated with better outcomes, may have just been the ones that were available in more places and so included more often. More research is almost certainly needed.
However, despite these concerns, this is a strong piece of research with very good design and statistical methodology and its worth noting that every one of the underlying studies is saying much the same thing – “when it comes to fruit and vegetables, eat lots and as big a variety and as many colours as possible”. You should definitely eat 5 a day (400g) and if you can eat more, up to 800g then do.
1. Mirmiran P, et al. (2009). Fruit and vegetable consumption and risk factors for cardiovascular disease. Metabolism 58(4):460-468.
2. Hung HC, et al. (2004). Fruit and vegetable intake and risk of major chronic disease. Journal of the National Cancer Institute 96(21):1577-1584.
3. Rissanen TH, et al. (2003). Low intake of fruits, berries and vegetables is associated with excess mortality in men: the Kuopio Ischaemic Heart Disease Risk Factor (KIHD) Study. Journal of Nutrition 133(1):199-204.
4. Harding AH, et al. (2008). Plasma vitamin C level, fruit and vegetable consumption, and the risk of new-onset type 2 diabetes mellitus: the European prospective investigation of cancer–Norfolk prospective study. Archives of Internal Medicine 168(14):1493-1499.
5. World Cancer Research Fund (WCRF) Panel (2007). Food, Nutrition, Physical Activity, and the Prevention of Cancer: A Global Perspective. World Cancer Research Fund: Washington, DC
6. World Health Organisation Paper. Promoting Fruit and Vegetable consumption around the world. http://www.who.int/dietphysicalactivity/fruit/en/
7. UK Diet and Nutrition Survey (2014) https://www.gov.uk/government/news/new-national-diet-and-nutrition-survey-shows-uk-population-is-eating-too-much-sugar-saturated-fat-and-salt
8. European Food Safety Authority (2008). Concise Database summary statistics – Total population
9. Harvard University Healthy Eating Plate and Healthy Eating Pyramid (2011) https://www.hsph.harvard.edu/nutritionsource/healthy-eating-plate/
10. Guardian 22nd February 2017 https://www.theguardian.com/society/2017/feb/23/five-day-10-portions-fruit-veg-cut-early-death
11. Telegraph 23rd February 2017 http://www.telegraph.co.uk/news/2017/02/23/five-a-day-fruit-veg-must-double-10-major-study-finds/
12. BBC 23rd February 2017 http://www.bbc.co.uk/news/health-39057146
13. Dagfinn et al (2017). Fruit and vegetable intake and the risk of cardiovascular disease, total cancer and all-cause mortality–a systematic review and dose-response meta-analysis of prospective studies. https://academic.oup.com/ije/article/3039477/Fruit