Vitamin B12: the vanishing vitamin

B12 is mostly found in animal foods like meat, eggs and fish. Yet one of the richest sources is tempeh, a traditional Indonesian food made from fermented soy beans. This is because vitamin B12 is produced by bacteria.

A 100g serving of traditional tempeh can contain up to 15 micrograms of B12 – much higher than most meat products.

When tempeh was introduced to the US in the 1970’s, it was made by small cottage industries. These still contained about 4mcg of B12 per serving – double the daily recommended allowance of just 2mcg.

Today, US tempeh is made mainly in big factories with high standards of hygiene. Most of this has zero B12, unless the manufacturer puts it back in.

The same as happened with modern miso, soy sauce, yoghurt, pickles, beer and other fermented foods. Even meat products nowadays have low levels of B12, because farm animals are regularly given antibiotics, which kill bacteria. We need very little of this rare vitamin. Our liver can store about five year’s supply. But deficiency ca cause weakness, anemia and fatigue as well as nervous, mental and emotional disturbances, and brain damage.

You need not worry about vitamin B12 deficiency if you eat a bit of fish, meat or eggs. But too much meat in the diet can block the body’s absorption of B12.

UPDATE: I wrote back in the 1990s that vegans or pure vegetarians can get enough B12 from eating fermented foods that have been produced naturally, under not-so-hygienic conditions. That is, from eating bacteria!

However, I have since learned that fermented foods like tempeh are NOT reliable sources of this vitamin for vegans, because such foods contain mainly the inactive form of Vitamin B12, also known as B12 analogs. In its inactive form, B12 analogs are believed to be not well absorbed by the body and they might even interfere with the body's absorption of "active" B12 from other sources.

But why is this so? Again is it because modern fermented foods are produced under too hygienic conditions? Or is it that even not-so-hygienic tempeh etc also contain mainly B12 analogs, with very little active B12? I don't know the answer...

Because of this, vegans are advised to take either B12 supplements, or foods that have been specially fortified with Vitamin B12. I disagree with this approach. To me, having to take supplements or artificially fortified foods only goes to show that a vegan or pure vegetarian diet is both unnatural and unhealthy.

On the one hand, it is healthy to eat PLENTY of vegetables and other plant foods like grains, beans, seeds, nuts and fruits. However, there are serious doubts about the wisdom and health benefits of eating ONLY plant foods.

The need for Vitamin B12 is one compelling reason for not being too pure - both pure as a vegetarian as well as pure in terms of cleanliness. Some bacteria - and flexibility in dietary ideology - will do you good.