Experts warn against vegan diets - half of plant-based eaters at risk of muscle wastage, study suggests
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Half of vegans are deprived of vital nutrients risking problems like muscle wastage, scientists suggest.
Experts, who analysed the diet of almost 200 long term vegans in New Zealand, found about 50 per cent were deficient in two specific amino acids— the building blocks of protein — called lysine and leucine.
These essential nutrients — found in abundance in animal proteins like meat and eggs — are key to building and maintaining muscles and other bodily functions like turning fat into energy.
Worryingly, these deficiencies occurred despite the majority of the participating vegans, three in four, meeting the recommended dietary plant protein intake guidance from health chiefs.
Scientists, from Massey University, said while the vegans were, on paper, eating enough protein their bodies weren't digesting sufficient amounts of lysine and leucine.
This is because only a limited fraction of the already lower levels of these amino acids found in plant foods were actually being absorbed by the body with the rest merely being excreted.
Lead author of the study Patricia Soh said the results showed some of the potential hazards of going vegan.
'Vegan diets are the most restrictive form of plant-based eating, relying entirely on plant sources for all nutrients,' she said.
Vegan diets which forbid the consumption of animal products and instead opt for fruits, vegetables, nuts, legumes and seeds, have grown in popularity in Britain (stock image)
'Prolonged deficiencies in these essential nutrients can negatively the body functions, including muscle mass maintenance.'
She added that these dangers would be heightened among vulnerable vegans, like elderly people.
While plant foods, like beans, peas as well as nuts and seeds, do contain lysine and leucine, this is at lower levels than the equivalent amount of animal protein.
Switching to a completely plant-based diet could leave you tired or breaking out in acne dieticians have warned.
Not eating or drinking animal products could leave you missing out on key vitamins like B12 as well as proteins.
A lack of vitamin B12, which is in found milk and eggs, can lead to fatigue or tiredness and negatively impact your mental health.
Vitamin D is another nutrient found mainly in animal products, like oily fish, that those on vegan diets can be deficient in.
A vitamin D deficiency can lead to issues with bone development and cause pain.
Not getting enough protein, which we get from dairy products, fish, eggs and meat can stunt growth in children and also lead to acne breakouts.
A lack of iron, found in red meat and liver, can lead to anaemia, causing people to feel tired and have heart palpitations.
Iodine, mainly found in seafood, is another nutrient known to be lacking in vegan diets and is important in maintaining a health metabolism.
Plant-based diets can include all of these mentioned nutrients but people need to carefully manage what they eat, or take supplements, to ensure they get enough.
This is especially true if people are switching to a vegan diet after primarily getting these nutrients from animal products.
But another risk is the false perception that vegan products are inherently healthier than non-vegan options.
A MailOnline analysis of meat-free vegan alternative foods found a significant number contained more salt, sugar and fat than the product they were meant to replace.
Ms Soh, said more research was needed on how to boost intake of lysine and leucine among vegans.
'Including legumes, nuts and seeds are valuable to support overall protein intake and increase lysine and leucine quantities in a vegan diet,' she said.
However, other experts have said the studies' limitations need to be taken into context.
Professor Tom Sanders, an expert in nutrition and dietetics at King’s College London, said some issues included the fact no omnivore group was included in the analysis for comparison.
He highlighted another limitation was that study didn't consider the role of bacteria in the gut that can help produce lysine.
In the study, published in PLOS One, researchers analysed food diaries kept by 193 long-term vegans over four days.
They then took the food and drink recorded and used models to calculate how much amino acids were consumed and then how much would be extracted and lost via the digestion.
Scientists found 80 per cent of men and 73 per cent of women got enough overall protein from their diet.
However, when digestion was accounted for the proportion who were specifically got enough lysine and leucine fell to about half.
The authors set a level of 59mg of leucine and 45mg per gram of protein consumed based on American and New Zealand dietary recommendations.
Studies involving food diaries face limitations because they rely on people correctly reporting what they have eaten and in what amounts.
Such food diaries can also represent a snapshot in time and may not necessarily reflect a participant's regular diet.
Nutritionists have previously warned that going vegan could come with a range of health consequences.
These include a lack of vitamin B12, which is in found milk and eggs, which can lead to fatigue or tiredness and negatively impact your mental health.
Vitamin D is another nutrient found mainly in animal products, like oily fish, that those on vegan diets can be deficient in.
A vitamin D deficiency can lead to issues with bone development and cause pain.
A lack of iron, found in red meat and liver, can also lead to anaemia, causing people to feel tired and have heart palpitations.
Iodine, mainly found in seafood, is another nutrient known to be lacking in vegan diets and is important in maintaining a health metabolism.
Plant-based diets can include all of these mentioned nutrients, but people need to carefully manage what they eat, or take supplements, to ensure they get enough.
As of 2024, there are an estimated 2.5million vegans in the UK, about 3.6 per cent of the population.
Daily Mail
