According to most doctors and nutritionists, eating five portions of fruits and vegetables daily is considered sufficient for good health, but a recent study, reported in the International Journal of Epidemiology, posits that the greatest benefits come from eating 10 portions a day.
An analysis of 95 studies assessing the health benefits of fruit and vegetable consumption have led researchers to believe that eating 800 grams (around 10 portions of 80 grams) of fruits and vegetables daily was associated with the lowest risk of disease and premature death.
One portion of fruits of vegetables was defined as 80 grams – the equivalent to a small banana, pear, or apple, or three heaped tablespoons of cooked vegetables, such as peas, broccoli, or cauliflower.
The study, undertaken by Lead author Dr. Dagfinn Aune, of the School of Public Health at Imperial College London in the United Kingdom, and colleagues, took into consideration 95 studies that involved almost 2 million participants and around 43,000 cases of heart disease, 47,000 cases of stroke, 81,000 cases of cardiovascular disease (CVD), and 94,000 deaths.
Current guidelines recommend that adults should aim to eat around five cups of fruits and vegetables daily – two cups of fruits and three cups of vegetables – to help reduce the risk of heart disease, stroke, cancer, and other chronic diseases. Apples, pears, green leafy vegetables, and cruciferous vegetables were found to be among the most beneficial for health.
Dr. Aune and colleagues set out to determine how many fruits and vegetables need to be consumed for maximum protection against disease and early death. The team analysed the fruit and vegetable intake of each participant, looking specifically at how much they consumed daily and the specific fruits and vegetables consumed, and then calculated the association between fruit and vegetable intake and the risks of heart disease, stroke, CVD, cancer, and premature death.
The team found that participants who ate just 200 grams of fruits and vegetables a day, compared with no fruit and vegetable consumption, saw definite health benefits including an 18% reduced risk of stroke, a 16 % reduced risk of heart disease, a 13% lower risk of CVD, a 4 % reduced risk of cancer, and a 15% lower risk of premature death.
Compared with subjects who consumed no fruits and vegetables, those who ate up to 800 grams – or 10 portions – each day were found to have a 33% lower risk of stroke, a 28% reduced risk of CVD, a 24 % lower risk of heart disease, a 13% decrease in cancer risk, and a 31 % reduction in premature death.
According to the research, eating 10 portions of fruits and vegetables daily could prevent around 7.8 million premature deaths across the globe annually.
Which Fruits & Vegetables are Best?
The team found that apples, pears, citrus fruits, green leafy vegetables (such as chicory and spinach), and cruciferous vegetables (such as cabbage and broccoli) were best for reducing the risk of stroke, CVD, heart disease, and premature death.
The greatest reduction in cancer risk was associated with intake of green vegetables (such as green beans), yellow vegetables (such as peppers and carrots), and cruciferous vegetables.
Consumption of raw and cooked vegetables was associated with reduced risk of premature death, but the team did not have enough data to determine which specific fruits and vegetables reduced this risk.
According to the team, fruits and vegetables have been linked to lower cholesterol and improved blood vessel and immune system function.
“This may be due to the complex network of nutrients they hold,” notes Dr. Aune. “For instance, they contain many antioxidants, which may reduce DNA damage, and lead to a reduction in cancer risk.”
Overall, the researchers believe their findings highlight the importance of fruits and vegetables as part of a healthful diet.
“We need further research into the effects of specific types of fruits and vegetables and preparation methods of fruit and vegetables. We also need more research on the relationship between fruit and vegetable intake with causes of death other than cancer and cardiovascular disease.
However, it is clear from this work that a high intake of fruit and vegetables hold tremendous health benefits, and we should try to increase their intake in our diet.” said Dr. Dagfinn Aune