Can switching to a plant-based diet reduce the risk of heart disease? | BHF

Replacing animal foods with plant-based foods may reduce the risk of heart disease and diabetes. We look behind the headlines and examine the claims.

Issued on January 15, 2024

Switching from meat and dairy to plant-based foods like whole grains, beans, nuts, olive oil, fruits and vegetables could significantly reduce the risk of cardiovascular diseases such as coronary heart disease and type 2 diabetes, according to a study published in BMC Medicine.

The German-based researchers reviewed 37 studies conducted up to March 2023. They only included studies that involved generally healthy participants who switched from animal-based to plant-based foods. Participants in each study were also followed over time to see if they developed cardiovascular disease or type 2 diabetes, or died from any cause during the study period.

The study found that replacing processed meats such as ham, bacon, burgers and sausages with nuts and legumes significantly improved risk: replacing daily processed meat with nuts or legumes reduced the risk of cardiovascular disease by 25%. Also, replacing daily processed meat with nuts reduced the risk of type 2 diabetes and death from all causes by 20%.

Additionally, substituting one egg per day with nuts was associated with a 17% lower risk of cardiovascular disease, and substituting either nuts or whole grains was associated with a 20% lower risk of type 2 diabetes.

There’s no clear evidence that replacing chicken, fish or shellfish with nuts or legumes reduces the risk of cardiovascular disease, but replacing chicken with whole grains was found to reduce the risk of type 2 diabetes by 13 percent.

What do researchers say?

The researchers concluded that switching from animal-based foods to plant-based foods was associated with positive effects on heart health and diabetes risk, noting that the associations were strongest when processed meat was replaced with nuts, legumes and whole grains.

Dr Sabrina Schlesinger, study leader at the German Diabetes Centre in Düsseldorf, said: “Many people start their day with eggs or fried foods for breakfast, but the results of this analysis show that it may be better to replace these foods with plant-based foods. There is also some evidence that people may benefit from replacing chicken with plant-based foods, but there was little evidence for replacing dairy products.”

In the paper, the authors call for more research to fill the gaps in our understanding. Although meat and dairy alternatives are very popular, no studies were available for the review. In the absence of studies on specific dairy products such as milk, yogurt, and cheese, the researchers had to treat dairy products as a group.

BHF verdict

We already know that to lower the risk of heart and circulatory disease, most people would benefit from eating less red and processed meat; this study backs that up. In the UK, government guidelines aim to limit red and processed meat to no more than 70g a day, the equivalent of three slices of ham, two slices of bacon, or one small beefburger. The guidelines also recommend choosing plant-based protein more often.

A balanced vegetarian or vegan diet is a healthy way to eat, but you don’t have to completely eliminate meat to reap the benefits. The traditional Mediterranean diet is associated with a reduced risk of heart and circulatory disease, and involves eating small amounts of meat and lots of plant-based proteins like lentils, nuts, seeds and fish.

If you want to reduce your intake of red and processed meats, start by adopting a vegetarian diet each week and/or substituting legumes for some of your red and processed meats. Our recipe finder has some great recipes to get you started.

How good was the study?

The researchers used two related methods: systematic review and meta-analysis. In a systematic review, multiple studies that address the same research question are grouped together and analyzed in a structured way. A meta-analysis is a statistical method used in a systematic review to combine the results of these studies. A high-quality systematic review is often more reliable than each study in isolation.

This was the first systematic review and meta-analysis to summarize the relationship between switching from animal-based foods to a plant-based diet and the risk of cardiovascular disease, type 2 diabetes, and death. One of the strengths of this study is that it used the “GRADE” methodology, a systematic approach to rating the certainty of results. This allowed the researchers to know how confident they should be in their findings.

But there were limitations. Because the study was observational, it’s impossible to know whether the food swaps directly translated into better heart or metabolic health. Although the researchers controlled for factors like physical activity, alcohol intake, and smoking, they may have missed other factors, called “confounders,” that contributed to the results.

How good was the media coverage?

The study was covered by media outlets including The Guardian, Daily Mail and the Mirror.

The Guardian’s headline was accurate: “Switching to plant-based foods may reduce risk of diabetes, heart disease, major study finds.” The article provided a balanced summary of the study, drawing attention to its main findings while also highlighting its weaknesses.

The Mirror’s headline was “Simple breakfast changes could drastically cut risk of heart attack” and the Daily Mail’s headline was “Don’t eat eggs on the way to work – have a handful of nuts instead: scientists say a simple breakfast change could significantly cut your risk of heart attack.”

Both headlines call attention to eggs as the main food of interest, noting that replacing processed meats had the greatest impact on heart health, risk of type 2 diabetes, and death from all causes. Additionally, while the headlines mention the risk of heart attack, the study focuses on the risk of heart disease and diabetes.

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