We have always understood the importance of fruit and vegetables to human health. Along with sleep, water, and exercise, fruit and veg consumption has been a consistent element in health messaging around the world. However, despite the recognised benefits of fresh produce, the recommended amount and ratio of fruit and veg intake has been far from consistent. A huge new global study has shed light on the issue. Five daily servings of fruit and vegetables is the recommended amount, with the ideal ratio being two servings of fruit and three servings of vegetables.  

According to the study, which was published in the American Heart Association's Circulation journal and based on data from nearly 2 million adults, 5-a-day should be the consistent message going forward. Currently, most adults do not consume nearly enough fruit and veg, with limited consumption having an adverse effect on numerous health outcomes. For example, people who don't eat enough fruit and vegetables are at a greater risk of cardiovascular disease, cancer, respiratory disease, and death from all causes.

According to the lead author of the study, Dong D. Wang, consistent recommendations are possible for the entire global population: "While groups like the American Heart Association recommend four to five servings each of fruits and vegetables daily, consumers likely get inconsistent messages about what defines optimal daily intake of fruits and vegetables such as the recommended amount, and which foods to include and avoid... Our analysis in the two cohorts of U.S. men and women yielded results similar to those from 26 cohorts around the world, which supports the biological plausibility of our findings and suggests these findings can be applied to broader populations."

In the paper, more than 100,000 adults were studied for a period of up to 30 years. Data was collected every two to four years, including detailed dietary information on fruit and vegetable intake along with information on disease and death. In addition to this core group, the study also involved a meta-analysis of other studies. Overall, data was collected from 26 independent studies, 1.9 million participants, and 29 countries and territories around the world. In order to give a true global picture, data was analysed from North and South America, Europe, Asia, Africa, and Australia.

The study revealed a number of key findings, some of which were more obvious than others. Eating roughly two servings of fruits and three servings of vegetables was associated with the greatest longevity, although eating any more than this amount was not associated with any additional benefit. People who met the recommendation had a 13% lower risk of death from all causes, a 12% lower risk of death from cardiovascular disease, a 10% lower risk of death from cancer, and a 35% lower risk of death from respiratory disease.

Not all produce offered the same benefits, however, with potatoes, juices, and starchy vegetables like peas and corn not associated with any reduction in death or disease numbers. Green leafy vegetables were the most beneficial, including spinach, lettuce, and kale. Benefits were also noted in many other fruit and vegetables, including those rich in beta carotene and vitamin C. While not as good as leafy greens, citrus fruits, berries, and carrots all had a positive impact. While the study did not show a direct cause-and-effect relationship between fruit and veg consumption and long life, it did highlight key similarities among the entire global population.