Vegan diet helps improve heart health in just weeks, study suggests

For this study, researchers recruited 22 pairs of identical twins, with one twin asked to follow a vegan diet and the other an omnivore diet.

“Studying nutrition in humans is always complicated by humans being different in so many ways — different exercise habits, sleep patterns, (and) stress levels,” Dr. Christopher D. Gardner, Ph.D., a nutrition scientist at the Stanford Prevention Research Center in the Department of Medicine in the School of Medicine at Stanford University, and senior author of this study explained to Medical News Today. “In a ‘randomized trial’ — the gold standard of human research — those different factors are assumed to be equally distributed between study groups due to the randomization. But there are always some factors that are not equally distributed.”

“The idea of working with identical twins was fascinating to us,” Dr. Gardner continued. “When randomizing identical twins to two study arms, the genetics are perfectly matched, and likely many other factors are matched because these pairs were raised in the same families, lived in the same neighborhoods, and many other similarities. In fact, it was quite entertaining how much these adult identical twins looked alike, dressed alike, (and) talked alike.”

Over a two-month period, the 44 study participants followed either a vegan diet that was entirely plant-based with no meat or animal products or an omnivore diet that included meat and other animal-sourced foods like eggs and dairy.

Both diets reportedly included vegetables, legumes, fruits, and whole grains while limiting added sugars and refined grains.

Some of the vegan diet meals included:

• Strawberry almond oatmeal
• Tofu scramble with Beyond breakfast sausage
• Coconut curry spinach and chickpeas with quinoa
• Black bean bowl with tofu
• Lentils and herb-roasted potatoes with remoulade sauce
• Harissa chickpeas with sumac carrots and broccoli
• Tofu with coconut curry brown rice

Some examples of the omnivore diet meals participants ate include:

• Egg whites with turkey bacon and Brussels sprouts
• Chicken fajita scramble with zucchini, squash and tomatoes
• Sunny side egg with asparagus and tomato
• Honey dijon steak with vegetables and rice
• BBQ chicken with broccoli and quinoa

During the first four weeks of the study, all participants received 21 delivered meals per week from a meal service that followed their specified diet.

For the last four weeks, study participants were required to make their own meals. They also had access to an on-call registered dietician to answer questions and offer suggestions.

As 43 of the 44 participants completed the full study, researchers believe that shows it is realistic to be able to learn how to make healthy meals in four weeks.

“As expected, from baseline to the end of four weeks the participants reported eating better in many ways. What was very satisfying was our analysis of any differences between phase #1 and phase #2 — there were hardly any differences. Almost all of the changes they made during food delivery were maintained when they were on their own.”

– Dr. Gardner

At three points during the study — at the beginning, halfway through, and at the completion of two months — researchers weighed the study participants and drew blood.

At baseline, the average LDL cholesterol level for those following the vegan diet was 110.7 mg/dL and 118.5 mg/dL for the omnivore participants. Those levels dropped to 95.5 for vegans and 116.1 for omnivores by the end of the study.

Scientists also found study participants following the vegan diet had about a 20% decrease in fasting insulin levels and lost an average of 4.2 lbs more than those following the omnivore diet.

“To be honest, I was a bit surprised the differences were as large as they were for the LDL-cholesterol and the insulin. We recruited generally healthy participants, without much room for improvement. And … the omnivore diet was designed to be healthy.

The participants randomized to that diet actually increased vegetables and whole grains, and decreased added sugars and refined grains, compared to their pre-study diet. That also likely minimized the opportunity to observe a difference.”

– Dr. Gardner

“And yet we still observed statistically significant beneficial changes for the vegan group relative to their identical siblings on the omnivore diet,” he added. “The clinical pearl here is that this study supports how quickly changes to a more plant-based diet can lead to rapid improvements in cardiometabolic risk factors.”

While not everyone may want to go vegan, medical experts agree that even slight changes to a diet can positively impact cardiovascular health.

Dr. Cheng-Han Chen, a board certified interventional cardiologist and medical director of the Structural Heart Program at MemorialCare Saddleback Medical Center in Laguna Hills, CA, told MNT the vegan diet is rich in a lot of foods considered “heart healthy” and associated with decreased risk of heart disease, such as fruits, vegetables, nuts, legumes, and whole grains.

Dr. Chen noted:

“[E]ven if you don’t follow a strict vegan diet, a lot of these studies have shown us that as long as we can increase our intake of those types of foods, then we should be able to make substantial improvements in our heart health.”

Monique Richard, a registered dietitian nutritionist, owner of Nutrition-In-Sight, and national media spokesperson for the Academy of Nutrition Dietetics, agreed.

“A vegan dietary pattern may not be appropriate, desirable, feasible, or accessible to everyone, but focusing on adding more variety of plants is usually very beneficial and applicable to the majority of individuals,” Richard told MNT.

According to Richard, only a very small percentage of Americans meet the recommended five to eight servings of fruits and vegetables daily.

“If you fall within that category maybe try adding just one more serving — one serving = 1/2 cup cooked or one cup raw — of vegetables and one more serving of fruit — with no added sugar — per day to what you are, or are not, already having,” she continued. “The additional vitamins, minerals and nutrients are what your body needs and benefits from.”

Richard also suggested trying a new vegan recipe each month or learning a new cooking skill to enhance the flavors of plant proteins like beans and legumes.

“All the small efforts can add up to significant changes,” she added. “If you’re not sure where to start to improve your cardiovascular health or what to tackle first, partnering with a registered dietitian nutritionist can be a great first step.”