‘It is a worry’: The truth about veganism and bone health
Vegan diets are one of the fastest growing consumer trends. According to the Vegan Society, 600,000 people in the UK currently choose to cut out dairy, meat and fish, making up 1.16 per cent of the population in 2019.
But could a vegan diet, which is often thought of as a healthier and more ethical lifestyle choice, be more damaging than we think? That was the result of a new study undertaken by Oxford University, which found that vegans are 43 per cent more likely to suffer from a bone fracture anywhere – particularly in the leg, vertebrae and collar bone – due to lower calcium and protein intakes. The study, which tracked more than 50,000 British people with an average age of 50 over two decades, also found that giving up meat can weaken bones and even trigger osteoporosis. It’s thought that women are most vulnerable to such injuries because their bones naturally lose strength after the menopause, as levels of oestrogen drop.
According to Dr Tammy Tong, an Oxford University nutritional epidemiologist and lead author of the study, the biggest differences were for hip fractures, where the risk in vegans was 2.3 times higher than in people who ate meat – equivalent to 15 more cases per 1,000 people over 10 years. Indeed, this is the most common serious injury in older people: there are more than 76,000 cases a year, costing the NHS £1 billion annually.
The study adds to a growing body of research on the links between veganism and bone health. Earlier studies have shown that vegans have lower bone mineral density and fracture rates nearly a third higher than the general population. This is down to deficiencies; by cutting out meat, fish and dairy, vegan diets lack protein, calcium and vitamin D3, all of which function to keep our bones healthy.
Our bones are made up of a mineral that contains calcium, so getting enough of it in our diet is crucial for the physical structure of the bone, says Professor Ian Givens, a nutritionist at the University of Reading. He explains that if you don't have enough calcium in your diet, your body will take calcium out to ensure normal cell function: this leads to weaker bones, and an increase in fractures.
It's true that vegetables rich in calcium like kale and broccoli can protect bones, but many vegans don’t meet their calcium requirements, leading to the increase in fractures. Plant-based calcium can also be harder for the body to absorb, so supplements or plenty of fortified foods is recommended.
While vitamin D still isn’t well understood, experts agree that it’s crucial for keeping bones and teeth healthy because it increases the absorption of calcium in the intestines. In recent months, lower levels of vitamin have also been linked with a higher chance of developing Covid. “There is also some evidence to show that vitamin B12 deficiency, which traditionally hasn’t been important in terms of bone health, stimulates bone resorption, which leaves you with weakened bones,” adds Prof Givens.
Vegan diets may be more risky for teenagers, adds Prof Givens. This is because the maximum period of bone mineralisation and development is during adolescence between the ages of 11 and 18. “If you don’t get bone mineralisation correct in that period, you end up with a lower peak bone mass. As you progress into later life, you have an increased risk of weaker bones,” he says.
Given adds that this is particularly present in young adolescent girls: statistics released in 2015 showed that nine out of 10 teenage girls, and seven out of 10 teenage boys do not get enough calcium in their diet. “That is a worry, because it’s in that period when bone mineralisation is at its optimum. The end outcome of this would be a higher chance of developing osteoporosis."
However, much of the research around a vegan diet is conflicting, with a lot of evidence pointing to the health benefits of ditching meat, dairy and eggs. These include a healthy decrease in cholesterol, blood pressure and heart disease, to name just a few. One British study published in the BMJ Open Diabetes Research and Care even showed that a plant-based vegan diet could help people with type 2 diabetes manage weight and blood sugar levels. Other studies have linked veganism to weight loss: Beyonce famously went vegan in 2018 to slim down her figure in time for Coachella.
“It's true that both vegetarian and vegan diets tend to have lower BMI and cardiovascular mortality tends to be a bit lower too,” says Given.
Indeed, several high profile athletes have opted to follow a vegan diet in recent years. These include the tennis player Venus Williams, who adopted a raw vegan diet to manage the symptoms of Sjögren’s syndrome, Formula One driver Lewis Hamilton and boxer David Haye. Speaking about her decision to follow a vegan diet in Health magazine, Williams said: "I was diagnosed with an autoimmune disease, and I wanted to maintain my performance on the court. Once I started, I fell in love with the concept of fuelling your body in the best way possible [through raw, vegan food]. Not only does it help me on the court, but I feel like I’m doing the right thing for me."
Dr Shireen Kassam, a consultant haematologist, maintains that calcium, potassium, magnesium, folate, vitamin K and vitamin D (from sunlight) can all be obtained from a healthy plant-based diet. “If vegans are consuming at least 525mg per day of calcium (the UK recommended daily intake for adults is 700mg), eating plenty of fruits and vegetables, and reducing animal sources of protein, dairy consumption is not necessary for bone health,” he says.
As Prof Given sees it, anyone embarking on a vegan diet should be aware of the possibility of these deficiencies, and prepare by looking for alternate sources: "Leafy vegetables are a classic source of calcium and vitamin D. You can also buy calcium supplements, and bread that's fortified with calcium to help balance out your diet," he says.
