By Clare Oliver-Williams, Cambridge University
According to the Vegan Society, around half a million Britons are now vegan. In the US, the number of American vegans has increased by 300% over the past 15 years.
There are many reasons why people can choose a vegan diet, such as: B. animal welfare, sustainability or weight loss. Another reason that is often touted is that vegan nutrition is good for your heart and can not only prevent heart disease, but even reverse it.
However, as our most recent review found, this is not necessarily the case. In fact, we've found that there is currently little evidence that a vegan diet can protect the heart or reverse heart disease.
The good and the bad
This does not mean that vegan diets have no benefits. Large amounts of whole grains in addition to fruits and vegetables mean that vegans consume more fiber than omnivores (people who eat meat products in addition to fruits and vegetables). And research shows that people who eat high-fiber diets are less likely to suffer from heart disease.
Eating lots of fruits and vegetables also means consuming lots of phytonutrients, which are natural chemicals found in plants. Some research suggests that these have inflammatory and antioxidant properties that can help prevent damage to cells in the body. Since vegans eat more fruits and vegetables on average, they should benefit more from them.
And a vegan diet is linked to a number of other health benefits that should benefit heart health, including lower weight, lower blood pressure, and lower cholesterol.
However, a vegan diet can easily become deficient in vital nutrients if not carefully composed. For example, vegan diets may contain lower amounts of certain omega-3 fatty acids that are easy to find in seafood. This can mean vegans are not getting the heart benefits of omega-3 fatty acids, such as: B. lower blood pressure and a lower risk of heart attacks.
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Some minerals and vitamins are harder to get even for vegans without supplements. Vegans have lower levels of selenium, iodine, and vitamin B12 than non-vegans, which can be detrimental to their heart health. Low levels of these minerals and vitamins can also lead to thyroid problems, muscle disorders, and anemia.
Our team wanted to know whether a vegan diet really lowers the risk of heart attacks or strokes. To do this, we had to go through all of the current evidence that investigated this. This would allow us to develop a conclusion based on all current data.
Although veganism is growing in popularity, vegans still make up a small portion of the population. As a result, few studies have looked at the effects of a vegan diet of any length on heart health. We could only find three – although they were large studies overall, with data on more than 73,000 people combined and more than 7,000 vegans.
None of the studies found that vegans were protected from heart disease, heart attacks, or strokes compared to omnivores. Unfortunately, there was even an indication that vegans might be more likely to have an ischemic stroke caused by a blood clot in the brain. However, it is uncertain whether the vegan diet itself actually increased the risk of this type of stroke, or whether it was just a fluke.
Our study also looked at whether a vegan diet could benefit people who already had heart disease. One study showed that veganism can be beneficial and potentially stop or reverse heart disease. The researchers found that people who started a vegan diet and stayed on it for more than three years were six times less likely to have another serious heart problem or stroke than those who started a vegan diet but didn't continue it. This is just one in 177 vegans compared to 13 in 21 non-vegans who got sick again. However, since it is a relatively small sample, ideally we would want a much larger study to check this out.
The other two studies showed no benefit or reversal of heart disease in people who started a vegan diet. However, participants in these studies only followed a vegan diet for two or six months – which makes it difficult to see any real long-term effects. However, one of the benefits of a six-month vegan diet was that participants had lower cholesterol levels and lost more weight than those on the omnivorous diet.
Overall, our review found that there is no evidence to support claims that veganism is good for your heart. This is partly because there are few studies – and only 361 people in the studies we examined became vegans after developing heart disease. Participants in two of the studies were only vegan for less than six months, which may not be long enough to see a major impact on heart disease.
But veganism can have other health benefits as well. Vegans have been found to have healthier weights and lower blood sugar levels than those who consume meat and dairy products. They are also less likely to develop cancer, high blood pressure, and diabetes. But its impact on heart disease, the leading killer in the world, really needs to be better understood.
Clare Oliver-Williams, Research Associate, Cambridge University
This article is republished by The Conversation under a Creative Commons license. Read the original article.
Top pic: Some people turn to a vegan diet in the hopes that it will benefit their heart health. let design / Shutterstock