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• Posted May 16, 2024

Plant-Based Diets Lower Risk of Heart Trouble, Cancer and Death

Following a vegetarian or vegan diet might just buy you a longer, healthier life, a new review finds.

Staying away from meat was tied to a reduced risk of heart disease, cancer and early death, researchers reported in a study published Wednesday in the journal PLOS One.

After combing through nearly 50 studies on such diets that were published between 2000 and 2023, a clear pattern emerged: Both were linked to a lower risk of both cancer and heart disease linked to narrowed arteries. Notably, the diets seemed to reduce the risk of prostate cancer and gastrointestinal cancers like colon cancer. Vegetarian diets were also linked to a lower risk of dying from cardiovascular disease.

In addition, plant-based diets lowered the chances of obesity, inflammation and "bad" LDL cholesterol. 

"This research shows, in general, that a plant-based diet can be beneficial, and taking small steps in that direction can make a difference,"said review co-author Matthew Landry, an assistant professor of population health and disease prevention at the University of California, Irvine.

"You don't have to go completely vegan to see some of these benefits,"he told NBC News. "Even reducing a day or two per week of animal-based consumption can have benefits over time."

Still, Dr. Walter Willett, a professor of epidemiology and nutrition at the Harvard T.H. Chan School of Public Health, noted that not everyone who follows a plant-based diet eats the same healthy foods.

"A vegetarian diet could be based primarily on refined starches and sugar, which we see to be the worst dietary pattern,"Willett, who was not involved in the new research, told NBC News. 

A healthy plant-based diet, he said, should consist mostly of whole grains, fruits, vegetables, nuts, soy, beans and non-hydrogenated plant oils. 

Why does steering clear of meat translate into better health? 

While it may help prevent obesity, the benefits extend beyond that, Landry said. 

"Some of it is independent of weight. Even when weight is maintained or doesn't change, we still see reductions in some of these other clinical health outcomes, especially when it relates to cardiovascular disease,"he said.

One possible reason is that many fruits and vegetables are high in anti-inflammatory nutrients and antioxidants, which can lower plaque buildup in the arteries.

Plant-based diets also tend to be high in fiber, which helps lower bad cholesterol, Brie Turner-McGrievy, a professor of health promotion, education and behavior at the University of South Carolina, told NBC News. In 2014, she published a study that found plant-based diets lower risk factors for heart disease, stroke and type 2 diabetes. Her research was included in the new review.

"Soluble fiber that's found in things like beans and oats is really a powerful tool to help lower LDL cholesterol levels,"she said.

Another benefit of a plant-based diet may be rooted in the absence of meat, she added.

"It's just really hard to lower your saturated fat intake if you're consuming animal-based foods,"Turner-McGrievy said. "Cheese, for example, is the No. 1 source of saturated fat in the diet."

Processed meat products such as bacon or salami are also known to raise the risk of cancer, according to the World Health Organization. The agency considers red meat in general to be a "probable human carcinogen."

Despite the positive findings in the new review, the researchers stopped short of recommending plant-based diets for everyone. 

"During pregnancy, it's not recommended based on the data that we have to use a strict vegetarian diet,"review co-author Dr. Federica Guaraldi, an endocrinologist at the IRCCS Institute of Neurological Sciences of Bologna in Italy. 

The review authors also cautioned that plant-based diets might lead to vitamin B12 deficiencies, but Landry noted that can be addressed by taking a B12 supplement.  

"From my perspective as a dietitian, a healthy plant-based diet -- either vegetarian or vegan -- can really meet just about all your vitamin and mineral needs,"he said.

More information

Harvard Health has more on plant-based diets.

SOURCE: PLOS One, May 15, 2024; NBC News