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Explainer
Plant-Based Diets Boast Many Health Claims, but What Does the Science Show?
Health•11 min read
Reported
A new study published in BMC Medicine finds even small plant-based swaps can lower risk of heart disease and death.
Words by Grace Hussain
Heart disease is responsible for 1 in 5 deaths in the United States, according to the CDC. That works out to as many as 695,000 people in 2021. The costs add up too: $239.9 billion per year to the healthcare system. And these impacts aren’t equally distributed either, as Black Americans were 30 percent more likely to die from heart failure than white Americans in 2018. Given these staggering costs, researchers are intently focused on solutions, chief among them changes to the way we eat.
Now, a new study published in the journal BMC Medicine looked at 37 studies testing the health impacts of replacing a serving of meat or dairy products with plant-based foods, and found small plant-based shifts reduced the risk of death, cardiovascular disease, type 2 diabetes and heart disease.
Instead of evaluating a complete dietary overhaul like going entirely vegan, the researchers focused on swapping just one serving of animal products per day. For example, choosing a handful of nuts instead of a 50 gram serving of processed meats reduced the risk of coronary heart disease by 13 percent and the risk of all types of cardiovascular disease by 27 percent. Opting for legumes or whole grains instead of processed meats provides similar results.
One of the easiest and most intuitive swaps, cooking with olive oil instead of butter, was also associated with some of the biggest benefits. Not only did making the change reduce the risk of cardiovascular disease overall, but it also reduced the risk of type 2 diabetes and death from any cause.
This latest research lines up with plenty of studies that came before it. Earlier this year a meta-analysis found that swapping at least some meat with plant based substitutes resulted in lower cholesterol. Even a decade ago medical professionals were recommending plant based diets as an affordable and effective way to “improve health outcomes.”
Yet not every nutrition scientist agrees, pointing to how unreliable the observational studies in dietary research tend to be. When it comes to nutrition, research ethics prevent scientists from randomly assigning a dietary pattern, so instead they ask study participants what they eat and then look at health outcomes. As you might imagine, there are several weaknesses with this approach. Some people inclined toward a specific diet may just be genetically different from those inclined toward different eating habits. Plus, humans can be unreliable witnesses, especially to their own experience.
As the study authors note, replacing meat and dairy with plant-based options offers more than personal health benefits, These swaps benefit the environment and biodiversity.
Another recent analysis found emissions equivalent to almost the entire aviation industry would be saved if top consuming countries — including those in North and South America and Europe — replaced a third of the animal products they consume with plant-based ones. Other benefits include freeing up an area of land roughly the size of India and saving 7.5 million Olympic pools worth of water.
By far the worst environmental offender on your plate is beef. Each day, beef cattle belch around 500 liters of methane, a greenhouse gas with 80 times more heating power than carbon dioxide. To make matters worse, cattle ranching is the leading driver of deforestation in the Amazon rainforest, destroying habitat relied upon by the thousands of species who call the rainforest home.
Even though the researchers reviewed over 1200 articles, they included only 37 in the study, with some findings based on analysis of just two studies. As a result, the researchers called for more studies based on small swaps.
Yet even with the limitations, the researchers note that “a shift in diet from a high consumption of animal-based foods, especially red and processed meat, to plant-based foods is associated with a lower risk of all-cause mortality” and cardiovascular disease. More evidence that a shift to a plant-rich diet is good for personal and planetary health.