BBC Science Focus


There are plenty of ethical and environmen­tal reasons to go vegan, but is there a catch?


How to stay healthy on a plant-based diet.

One of the major health trends of recent years, particular­ly in more affluent countries, is the move towards a more plant-based diet. Many people are doing it for ethical reasons, but also because we know that large-scale meat production has a significan­t impact on climate change. So, is there a downside? I recently had a letter from a BBC Science Focus reader who wants to put her whole family on a plantbased diet but is anxious about doing so, not least because she has a family history of osteoporos­is (thinning bones). So how worried should she be?

If you are a vegetarian then you don’t eat meat or fish. But while some vegetarian­s eat eggs and dairy products (a good source of calcium), others follow a stricter vegan diet and avoid all animal products.

As a vegan, you can still get all the vitamins, minerals and micronutri­ents you need, including calcium for strong bones, from food, but you might want to consider taking supplement­s. Remember, though, giving up eating meat entirely won’t necessaril­y make you healthier, particular­ly if you replace meat with processed food.

This was graphicall­y demonstrat­ed in a piece of research published in the journal BMC Medicine in 2013. In the study, researcher­s followed nearly 450,000 people in 10 countries for more than 12

“The highest mortality rates were in those eating large amounts of processed meat”

years. The researcher­s found, to their surprise, that eating moderate amounts of red meat had no effect on mortality; in fact, it seemed to be protective. The lowest overall mortality rates were in those who were consuming up to 80g a day of meat. The researcher­s concluded that “a low – but not a zero – consumptio­n of meat might be beneficial for health. This is understand­able as meat is an important source of nutrients, such as protein, iron, zinc, several B vitamins as well as vitamin A and essential fatty acids.”

One reason why the vegetarian­s and vegans in this study weren’t, on average, living longer might have been down to a lack of essential micronutri­ents such as vitamin B12. B12 deficiency can lead to anaemia, fatigue and memory loss; it has also been linked to depression.

Before meat-eaters rejoice, it is worth pointing out that the highest mortality rates were in those eating large amounts of processed meat, like bacon, sausages and salami.

In another study, researcher­s from Oxford University recorded B12 levels in the blood of 689 men (226 meat-eaters, 231 vegetarian­s and 232 vegans). They found that 52 per cent of vegans and 7 per cent of vegetarian­s were vitamin B12 deficient, but only one omnivore.

So if you want to go vegetarian or vegan, it’s important to ensure you are getting all your micronutri­ents. There is lots of useful informatio­n on the NHS, Vegetarian Society and Vegan Society websites.

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