It’s well documented that vegans may find it difficult to obtain enough vitamin B12 from food and are at risk from deficiency. A lack of B12 can cause neurological damage and dementia, as well as anaemia and cardiovascular disease, so its certainly worth ensuring you are getting enough!
It may take some time for a deficiency to become apparent, as the vitamin is stored in the liver and only small amounts are needed each day. But, not everyone has a good storage amount to rely upon for even a short amount of time. The amount stored will depend upon the individuals diet history and their metabolism of the vitamin.
The metabolism of B12 is fairly complex. In animal food it is bound to protein and its metabolism relies on digestive enzymes, stomach acid and the production of Intrinsic Factor produced by the cells of the stomach. Any suboptimal workings can lead to inadequate absorption, even if intake has been sufficient. Hydrochloric acid levels and stomach function are affected by diet, stress, medicines, bacterial infection, age and low micronutrient content of our food.
How do we get B12 and is it worth worrying about even in the short term?
B12 is synthesiszed by bacteria that grow in the digestive systems of animals and studies show it IS present in the human colon. However absorption occurs in the ileum, the part of the intestine higher than the colon, and there are studies showing that the majority of B12 in the human stool is in an inactive form. There is also a theory and some evidence to support the possibility that vegetarian animals eating their feaces allows them to obtain B12 from plant foods. We do not do this! If we can’t rely on B12 being synthesised in our guts where can we get it from?
Good animal food sources are organ meats, salmon, tuna, sardines, trout, oysters, egg yolk and cheese. There is continued research into whether fermented plant foods are a source of B12 that is bioavailable to mammals. Studies performed on rats using Japaneese black tea is encouraging but to date there is NOT enough conclusive large scale relevant evidence to be relied upon.
B12 deficiency can lead to serious health problems. Given the lack of conclusive evidence re the availability of B12 produced in the human gut or the bioavalaibily from plant sources, it is prudent for vegans to ensure adequate intake through fortified foods or supplementation. Whether obtained from animal product, fortified foods or supplementation the source of B12 is always from micro-organisms.
Even if you are only partaking in Veganuary and then revert to eating animal products, it would be sensible to ensure you eat fortified foods and/or supplement during January. Deficiency has wide reaching and serious effects on the nervous system and cardiovascular system.
B12 is involved in myelin sheath formation; that’s the protective fatty substance that surrounds the axons of nerve cells. A damaged myelin sheath leads to slower nerve impulses so messages do not travel along the nerves as quickly. It is also involved in neurotransmitter production. Neurotransmitters are chemical messengers that carry messages across synapses; the gaps between neurons. B12 is needed in the production of acetylcholine that assists in memory and learning and melatonin that regulates sleep.
It is not difficult to see then how a deficiency can lead to neurological dysfunction, spinal cord degeneration, depression and mood disorders, cognitive decline, memory problems and insomnia. Supplementation has been shown to be effective for multiple sclerosis and Bell’s Palsy.
Vitamin B12 is important for the formation of red blood cells. It is what we call a methyl donor; it donates methyl groups needed for DNA synthesis. If DNA synthesis is impaired it results in defective DNA leading to oversized and poorly shaped red blood cells that do not function properly. The result is pernicious anaemia.
Vitamin B12 is needed for the proper functioning of the ‘homocysteine cycle’. Homocyscteine is a by-product of protein metabolism that is converted to methionine using B12. Elevated levels of homocysteine are associated with increased risk of heart disease and high levels are often one of the first indicators of a need for additional B12 before any neurological symptoms develop.
Foods fortified include some plant milks and some cereals. Supplements are readily available in tablet form or sublingual liquids for better absorption.