OXFORD, United Kingdom — It turns out mom was wrong, vegetables aren’t keeping you healthy — at least when it comes to heart disease. A new study reveals that the number of vegetables a person eats each day has little to no impact on their risk for cardiovascular disease.
An international team from the United Kingdom and China examined nearly 400,000 people, studying the link between consuming cooked and raw vegetables and their risk for heart problems. After accounting for socio-economic and lifestyle factors which can influence the impact a person’s diet has on their health, the team found there was little evidence eating more vegetables keeps the heart healthy.
What about a balanced diet?
Scientists still maintain that eating a balanced and healthy diet is the right thing to do. Studies show healthy eating can limit the risk of developing many diseases, including cancer and diabetes.
Before this study, scientists believed that nutrients in vegetables, such as carotenoids and alpha-tocopherol, played some role in protecting against cardiovascular disease. However, the evidence proving this has been inconsistent.
To solve this puzzle, the team used data from the UK Biobank, a database tracking the health and dieting habits of half a million people across Britain. From this group, researchers looked at the diet, lifestyle, medical, and reproductive history of 399,586 participants who enrolled between 2006 and 2010. Overall, 4.5 percent of these people went on to develop heart disease.
Specifically, study authors examined the amount of uncooked and cooked vegetables each person ate daily, and then compared it to their risk of death or hospitalization from a heart attack, stroke, or heart failure.
Does your lifestyle wipe away the benefits of eating vegetables?
The team found, on average, participants ate five tablespoons of total vegetables each day — 2.3 tablespoons of raw vegetables and 2.8 of cooked vegetables. On the surface, this appeared to be a good thing for the people eating all their veggies.
Results show the risk of CVD dropped by 15 percent among people eating the largest number of vegetables each day. However, that benefit disappeared when scientists factored in each person’s socio-economic, nutritional, and health or medicine-related information.
After controlling for each person’s unique lifestyle, the power of eating vegetables on heart disease risk fell by over 80 percent. The team believes if they can control for even more “residual confounding” factors, that benefit would disappear completely.
“Our large study did not find evidence for a protective effect of vegetable intake on the occurrence of CVD. Instead, our analyses show that the seemingly protective effect of vegetable intake against CVD risk is very likely to be accounted for by bias from residual confounding factors, related to differences in socioeconomic situation and lifestyle,” says lead author Dr. Qi Feng, a researcher at the Nuffield Department of Population Health at the University of Oxford, in a media release.
“This is an important study with implications for understanding the dietary causes of CVD and the burden of CVD normally attributed to low vegetable intake. However, eating a balanced diet and maintaining a healthy weight remains an important part of maintaining good health and reducing risk of major diseases, including some cancers. It is widely recommended that at least five portions of a variety of fruits and vegetables should be eaten every day,” adds co-author Dr. Ben Lacey.
The findings appear in the journal Frontiers in Nutrition.