1. Vitamin B12
Meat
Did you know that not a single population in the history of the world has ever willingly adopted a vegan diet?
That’s because before the era of supplements, such a dietary shift would have started killing people within a few years.
The most well known vitamin that the body can’t produce and can only be gotten from animal foods, is Vitamin B12.
Vitamin B12 is a water-soluble vitamin that is involved in the function of every cell in the body. It is tightly involved in the formation of blood and the function of the brain.
Deficiency usually results in anemia, impaired brain function, symptoms of mental disorders and a smaller brain (1, 2, 3).
There is also evidence linking B12 deficiency to Alzheimer’s Disease, which is the most common cause of dementia in Western countries (4, 5).
The only good food sources of B12 are animal foods like meat, fish and eggs.
A deficiency is widespread among vegans and vegetarians, who avoid these foods. In one study, a whopping 92% of vegans and 47% of lacto-ovo vegetarians were deficient in this critical brain nutrient