There are lots of ways in which adopting a vegan diet can improve your health, but there’s one way in which it can be incredibly detrimental. Vitamin B12 is crucial to a healthy, functioning body, but it isn't produced by plants. That means anyone on a strict vegan diet is at risk of deficiency.
To explain the risks of a B12 deficiency in plain English, we spoke to registered dietitian Jo Travers, author of The Low-Fad Diet and nutritional vlogger.
How important is vitamin B12?
Completely essential. It is involved with the formation of the coating of nerve cells. Deficiency of B12 results in macrocytic anaemia, which is when larger red blood cells aren’t fully developed.
What’s the recommended daily intake of B12? How is that supplied in an omnivore’s diet?
The recommendation in the UK is 1.5mcg per day for men and women over 19 years of age, although this is lower than other countries recommend. A daily dose of 3mcg is recommended for people following a plant-based diet because it is thought to be less well absorbed from fortified foods and supplements.
An egg has 0.6mcg, while 100g salmon has about 4.8mcg. As for more vegan-friendly foods, fortified breakfast cereal has roughly around 1mcg per 40g serving, and Marmite has 1mcg per 4g serving.
What are the symptoms of a B12 deficiency?
Symptoms include fatigue, tingling in the extremities and irregular heartbeat, as well as neurological symptoms such as memory loss and disorientation. It may even lead to dementia. Perhaps the worst thing about B12 deficiency is that the symptoms can be irreversible.
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Can you develop a deficiency over a month-long vegan or plant-based challenge like Veganuary?
It’s unlikely if you have been eating meat previously. Unlike the water-soluble vitamins, the body can store B12 for long periods in the liver.
Are vegetarians also potentially at risk of a B12 deficiency?
Yes, although less so because dairy and eggs contain B12.
How should vegans and vegetarians ensure they’re getting enough vitamin B12?
Vegans should definitely take a supplement, aiming for 3mcg a day.
