Eating a plant-based diet has proven to be very good for your heart and health in general, as well as the planet. In fact, a recent study found that a young person can live another 13 years by eating more vegetables and legumes, in addition to whole grains, fruits and nuts.
Which makes the findings of a new analysis of the diets of nearly 400,000 UK adults published Monday in the journal Frontiers in Nutrition quite surprising: eating vegetables, especially cooked ones, does not reduce the risk of heart disease by over time.
“Our large study found no evidence of a protective effect of vegetable intake on the occurrence of CVD (cardiovascular disease),” said Qi Feng, an epidemiologist at the University of Oxford’s Nuffield Department of Population Health, in a statement.
The study pointed out that eating raw vegetables can protect against heart disease, cooked vegetables cannot. Any benefit disappeared when the researchers considered lifestyle factors such as physical activity, educational level, smoking, alcohol consumption, fruit intake, consumption of red and processed meat, and use of mineral and vitamin supplements.
“Instead, our analyzes show that the apparently protective effect of vegetable intake against CVD risk is most likely explained by bias. […] related to differences in socioeconomic status and lifestyle,” said Feng.
Experts urge caution
Don’t start celebrating just yet, vegetable haters. Experts in the UK and US quickly objected to the study’s conclusion.
“While this study showed that eating more vegetables was not associated with a lower risk of heart and circulatory disease, once other lifestyles and other factors were taken into account, this does not mean that we should stop eating vegetables,” he said. Victoria Taylor, senior nutritionist at the British Heart Foundation, in a statement.
“There is good experimental evidence that eating fiber-rich foods such as vegetables can help reduce weight and improve levels of risk factors known to cause heart disease. The present observational study cannot overcome this evidence and its conclusions can be debated as the authors may have over-adjusted for factors that explain the lower vegetable intake,” said Naveed Sattar, professor of cardiovascular and metabolic medicine at the University of Glasgow, in Scotland in a statement.
“The results are not surprising. Choosing a single component and assuming just adding it to the diet, for example vegetables, is likely not going to have the desired effect,” Alice Lichtenstein, director and senior scientist at Tufts University’s Cardiovascular Nutrition Laboratory, told Tufts University. CNN in an email.
“One thing that has become clear over the past decade is that we shouldn’t look at individual foods or nutrients, but at the whole dietary pattern,” said Lichtenstein, who is also a professor of Nutrition Science and Policy at Tufts University.
Just five tablespoons of vegetables
The study used data from the UK Biobank, a longitudinal study of nearly half a million UK adults designed to investigate how genetics and the environment contribute to many common diseases.
People were asked at the beginning of the study how many raw and cooked vegetables they ate, and then were followed for more than 10 years to see if they developed heart disease.
On average, people in the UK study reported eating around five tablespoons of vegetables a day – that’s just 71 grams. About 2.5 tablespoons were raw vegetables, the other three were cooked.
“That’s so little,” said Andrew Freeman, co-chair of the Nutrition and Lifestyle Working Group at the American College of Cardiology.
Dietary guidelines in the UK call for five servings of fruits and vegetables a day, with each serving being around 80 grams (1 cup), for a total of 5 cups a day.
In the United States, dietary guidelines are more specific, recommending that most adults eat at least 1.5 to 2 cups of fruit and 2 to 3 cups of vegetables a day as part of a healthy diet. Translating cups to tablespoons, a healthy vegetable intake would include up to 48 tablespoons of vegetables a day.
“That’s a ton of tablespoons,” Freeman said. “So the question is, if these people in the study were eating such a small amount of vegetables, what else are they eating and how much has that confounded these results?”
Gunter Kuhnle, professor of nutrition at the University of Reading in the UK, also pointed to the impact of alternative food choices.
“People who don’t eat vegetables need to eat something else — and when estimating the health effect of eating vegetables, it’s important to consider what they replace,” Kuhnle said in a statement.
“Replacing a sugary snack with carrot sticks is likely to improve health – and have a beneficial effect on CVD risk. That would not be the case when replacing a whole-grain snack with carrots,” he said.
What is the path for the audience that eats (and hates) vegetables?
“This is a very interesting study – but not one that should be used as a justification for stopping eating vegetables,” Kuhnle said.
“The best advice we can give people is to focus on their entire diet, what foods to prioritize and what to minimize,” Lichtenstein said. “Overall, I think the data still support the beneficial effects of a dietary pattern rich in fruits, vegetables, whole grains, legumes, fish, fat-free and low-fat dairy and relatively low in added sugar and salt.”
Source: CNN Brasil
