A Plant-Based Diet Can Make You Younger, Says New Research

“You’re as young as you feel,” especially if you eat plants. New research from Stanford University, published in BMC Medicine, suggests that eating a plant-based diet for just eight weeks may help decrease biological age. In contrast, the same study found that eating an omnivorous diet for the same period does not appear to have the same effect. Here, we dive into the findings. But first, let’s take a look at what biological aging actually means. Spoiler: star signs and birthdays don’t count here.

What is meant by biological aging?

Biological age is different from chronological age. The latter is simply the number of years a person has lived, while the former refers to the true physiological condition of the body. Various biomarkers, including organ function, inflammatory markers, metabolic function, and DNA methylation determine biological age.

DNA methylation, the focus of the new Stanford findings, is a process that adds small chemical tags called methyl groups to the DNA. This process can turn genes on or off, affecting how cells function without changing the actual DNA sequence. It’s effectively a way to manage the instructions in our DNA by adding tiny chemical switches, and it’s essential for regulating genes involved in aging and disease.

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Can a plant-based diet reduce your biological age?

Many factors, including diet, influence DNA methylation. Certain nutrients, like folate, vitamin B12, and choline, as well as antioxidants, are crucial for the methylation process. Research suggests that a balanced diet that supports DNA methylation can help maintain healthy gene expression patterns and reduce the risk of chronic diseases like cancer.

The Stanford researchers, who followed 21 pairs of adult identical twins, monitored levels of DNA methylation from blood samples to determine biological age. The twins that ate a plant-based diet for eight weeks showed a decreased biological age, while the twins that ate an omnivorous diet for the same period did not.

Researchers also observed a decrease in the ages of the heart, hormone, liver, and inflammatory and metabolic systems of the plant-based participants. This is likely because a plant-based diet is often rich in whole foods, like nuts, beans, seeds, fruits, and vegetables. These foods are nutrient-dense, rich in antioxidants, and have anti-inflammatory benefits. 

However, the authors also noted that more research is needed, as the twins who ate a plant-based diet also lost more weight than the others, and this may also have been a factor in reducing biological age. 

RELATED: Eating More Plants Can Delay “Age Bursts” in Your 40s and 60s

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More findings from the Stanford twin study

The new research builds on previous findings from the Stanford study, which was initially published in 2023, and was also the focus of a 2024 Netflix documentary called You Are What You Eat: A Twin Experiment.

As well as looking at biological aging, researchers examined other factors, such as heart health and gut health. They noted that the twins who followed a plant-based diet had reduced levels of LDL cholesterol (a risk factor for heart disease) and more beneficial types of gut bacteria.

According to the study’s senior author Christopher Gardner, PhD, following identical twins was a “groundbreaking way to assert that a vegan diet is healthier than the conventional diet.”

“[The research] suggests that anyone who chooses a vegan diet can improve their long-term health in two months, with the most change seen in the first month,” he added.

Dan Buettner

A growing body of research supports a plant-based diet

This study isn’t alone. A growing body of research suggests that eating an abundance of plant-based whole foods is one of the healthiest ways to live. In the world’s five Blue Zones, which are areas where people live longer, healthier lives, plant-based foods are staples, while meat and dairy are eaten in limited amounts.

This contrasts with the US, where the Standard American Diet is high in red meat, ultra-processed foods, refined carbohydrates, and high-fat dairy products, contributing to an increased risk of chronic disease, including cancer, heart disease, and type 2 diabetes.

“Overall, the best thing we can do, longevity-wise, to add another six-to-10 years to life is to learn how to cook a whole-food, plant-based diet at home,” says Dan Buettner, an explorer and researcher who has extensively studied the Blue Zones.

Gardener agrees. “Based on these results and thinking about longevity, most of us would benefit from going to a more plant-based diet,” He said, speaking about the twin study.