Importance of Eating Your Fruits and Veggies and How Many Servings A Day
You probably already know that eating fruits and vegetables is good for your health – but do you know why and how many servings of fruits and vegetables is optimal?
Answering these questions becomes a bit confusing, especially if you begin to review the different recommended fruits and vegetable servings made by different countries and organizations. For example, if you looked at the World Health Organization and England, the recommended daily intake is about 5 servings – however, in the USA the recommendation is to eat about 8 to 10 servings per day.
An article published in the International Journal of Epidemiology, the official peer-reviewed journal of the International Epidemiological Association, helps answer these questions for you. The study is called Fruits 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.
The researchers in this study used Embase and PubMed databases to conduct a literature review to find prospective studies of fruit and vegetable intake and the risk of incidence or mortality from coronary heart disease, total cardiovascular disease, total cancer, and all-cause mortality. Studies were included in their review if they reported adjusted estimates of the relative risk (RR) and 95% confidence intervals. The studies also had to have a quantitative measure of fruit and vegetable intake available.
Now, I won’t get into the details of the statistical analyses conducted because it gets a little complicated but the link to the article is posted below for your review. What I will state about their statistical analyses is that, from what I understand, they seemed to be valid and appropriate (if you’re a statistician and think otherwise please, please comment or contact us – we’d love to learn why).
Also, on the podcast I made mention of the importance of heterogeneity of the studies included in a meta-analysis such as this one and I’m happy to see that the researchers did evaluate heterogeneity and publication bias of the studies they included.
The researchers ended up including a total of 142 publications from 95 cohort studies in their analyses. There was a total of 44 studies from Europe, 26 from the USA, 20 from Asia, and 5 from Australia. The number of participants in each analyses they conducted ranged from 226,910 to 2,123,415.
Overall, what the researchers found was that for every 200 g/day increment intake of fruits and vegetables (80g = 1 serving), there was a 8-16% reduction in the RR of coronary heart disease, 13-18% reduction in the RR of stroke, 8-13% reduction in the RR of cardiovascular disease, 3-4% reduction in the RR of total cancer, and 10-15% reduction in the RR of all-cause mortality. Whereas an intake of 800 g/day was associated with 24% reduction in the RR of coronary heart disease, 33% reduction in the RR of stroke, 28% reduction in the RR of cardiovascular disease, 14% reduction in the RR of total cancer, and 31% reduction in the RR of all-cause mortality.
The researchers also estimated the number of premature deaths attributed to eating a diet of fruits and vegetables below 500 g/day and 800 g/day. The estimated number of premature deaths for eating less than 500 g/day was 710,000 coronary heart disease deaths, 1.47 million stroke deaths, 560,000 cancer deaths, and 5.4 million all-cause mortality. The estimated number of premature deaths increased when they looked at data for eating less than 800 g/day to 1.34 million for coronary heart disease deaths, 2.68 million for stroke deaths, 660,000 for cancer deaths, and 7.8 million for all-cause mortality.
The fruits and vegetables that the researchers found were best at reducing risk of coronary heart disease, stroke, or cardiovascular disease are apples, pears, citrus fruits, cruciferous vegetables, green leafy vegetables, tomatoes, and beta-carotene-rich and vitamin C rich fruits and vegetables.
The fruits and vegetables that the researchers found were best at reducing the risk of total cancer are cruciferous vegetables, potatoes, and green leafy vegetables/salads.
The fruits and vegetables that the researchers found were best at reducing risk of all-cause mortality are apples, pears, berries, citrus fruits, cooked vegetables, cruciferous vegetables, potatoes, and green leafy vegetables/salads.
Interestingly enough, an increased risk of cardiovascular disease and all-cause mortality was found with the intake of canned fruits.
There were several limitations to this study. Going back to the issue with heterogeneity, the researchers stated that they found low heterogeneity in the analyses of coronary heart disease, moderate to high for stroke, cardiovascular disease, and total cancer, and high for all-cause mortality.
There is also the issue of confounding factors. Individuals who have a high intake of fruits and vegetables many times have other health-promoting lifestyle factors such as a lower prevalence for smoking, they may be less overweight or obese, and they may have a higher level of physical activity.
In addition, there are some regional limitations. There were no prospective cohort data found for Africa, West Asia, and South and Latin America. Finally, the estimates for premature deaths were made based on several assumptions, such as a casual relationship between fruit and vegetable intake and these outcomes and lack of confounding factors.
Overall, this study was an interesting find and considering benefits vs. risks (if any) of incorporating more fruits and vegetables into your diet – I say why not? It’s great for your health and may possibly decrease your risk of these diseases in the future! Plus, you might end up saving some money by replacing your processed, boxed foods with fresh vibrant fruits and veggies, especially if you shop at your local farmer’s market like Michelle and I. I got all the veggies you see in the picture below for a little over $20 and they lasted me for an entire week!
Take home point: eat 10 servings of fruits and vegetables per day for optimal health. And please REMEMBER to talk to your trusted health care provider before making changes to your diet.
- Fruits 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.