Twin studies show vegan diet boosts heart health

Cardiometabolic consequences of omnivorous vs. vegan diets.


In a study with 22 pairs of identical twins, Stanford Medicine researchers discovered that switching to a vegan diet can make your heart healthier in just eight weeks. This is important because while eating less meat is good for the heart, it’s often hard to be sure because of other factors like genes and lifestyle. However, by studying identical twins who grew up in the same homes and had similar lifestyles, the researchers could focus specifically on the diet’s impact.

Christopher Gardner, Ph.D., the Rehnborg Farquhar Professor and a professor of medicine, said, “Not only did this study provide a groundbreaking way to assert that a vegan diet is healthier than the conventional omnivore diet, but the twins were also a riot to work with. They dressed the same, talked the same, and had a banter between them that you could have only if you spent an inordinate amount of time together.”

The research, published on Nov. 30 in JAMA Network Open, was led by senior author Gardner. The study’s first authors are Matthew Landry, PhD, who was previously a postdoctoral scholar at Stanford Prevention Research Center and is now at the University of California, Irvine, and Catherine Ward, PhD, a postdoctoral scholar at the center.

A registered dietitian, a “diet whisperer” by Gardner, was available throughout the study to provide advice and answer diet questions. Participants were interviewed about their eating habits and maintained a food log.

Forty-three participants successfully finished the study, showing that it’s practical to learn how to prepare a healthy diet in just four weeks, according to Gardner.

Gardner said, “Based on these results and thinking about longevity, most of us would benefit from a more plant-based diet.”

According to Gardner, vegans and, to some extent, omnivores made the fundamental changes for better heart health. They reduced saturated fats, boosted dietary fiber, and lost weight.

Gardner highlights the global influence, saying that while not everyone may adopt a vegan lifestyle, moving towards more plant-based choices can enhance health. He notes that a vegan diet may bring extra benefits like increased gut bacteria, reduced telomere loss, and slowing aging.

Gardner, primarily vegan for 40 years, suggests incorporating more plant-based foods into your diet. It doesn’t have to be strictly vegan; enjoying diverse vegan dishes like Indian masala, Asian stir-fry, or African lentil-based meals can be a positive starting point.

In conclusion, twin research strongly supports the idea that adopting a vegan diet can significantly improve cardiovascular health.

Journal reference:

  1. Matthew J. Landry, Catherine P. Ward et al., Cardiometabolic Effects of Omnivorous vs Vegan Diets in Identical Twins. JAMA Network Open. DOI: 10.1001/jamanetworkopen.2023.44457.


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