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One set of identical twins compares vegan diets as part of Stanford study

Identical twins compare vegan diets to determine which one is better for cardiovascular health
Identical twins compare vegan diets to determine which one is better for cardiovascular health 02:07

PHILADELPHIA (CBS) -- A vegan diet improves cardiovascular health, according to unique new research.

In this research, identical twins were used to compare a vegan diet to one where you eat both plant and animal products to determine which one is better for your heart.

Rosalyn Moorhouse and Carolyn Sideco sacrificed their diets for research.

"My uniqueness is tethered to the fact there is someone else who is genetically the same as me," Moorhouse said.

They were one set of 22 identical twins who Stanford researchers studied for eight weeks, comparing vegan and omnivore diets. Carolyn was randomly selected as the vegan.

"It was challenging just as I had expected," Sideco said.

Both diets were healthy — full of vegetables, legumes, whole grains and no starches and refined sugars. The vegan diet had no animal products. The omnivore diet included chicken, fish, eggs, cheese and dairy.

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"They made really significant changes in a number of nutrients, a number of foods, even the omnivores," Twin study author Christopher Gardner said.

Researchers found vegan eaters saw the most improvement in their cardiovascular health.

"The LDL cholesterol dropped by 14 milligrams per deciliter, which was more than a 10% drop. They didn't have high insulin levels, to begin with, but they dropped in the vegan group and they lost a little bit of weight," Gardner said.

Carolyn and Rosalyn said both diets helped change their eating habits.

"I feel even more empowered to say of all these things I can choose, I'm going to choose the healthier option or the plant-forward option," Moorhouse said.

Doctors said even a nudge in the plant-based direction can improve health.

The twin study is now a Netflix documentary called "You Are What You Eat: A Twin Experiment."

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