Vitamin B_{a dozen} (cobalamin) is receiving much attention these days. Vitamin B₁₂ is one of the B vitamins implicated in brain and heart health, and it is one of the vitamins most likely to be deficient in the diets of vegetarians and vegans.

The consequences of vitamin B₁₂ deficiency are profound. During pregnancy, a deficiency of B₁₂ increases the risk of preeclampsia, a serious pregnancy complication characterized rencontres excitées avec papa-gâteau by high blood pressure and organ damage. A prenatal deficiency of B₁₂ and/or folate (vitamin B₉) also increases the infant’s risk of neural tube defects (defects of the brain and spine, such as spina bifida). In adults, B₁₂ deficiency increases the risk of peripheral neuropathy, depression, osteoporosis, Alzheimer’s disease, heart disease, and stroke. ,, Sadly, B₁₂ deficiency may even negate the cardiovascular benefits of a vegetarian diet.

Nutritional B12 is located in high quantities simply in animal items.

Vitamin B₁₂ is found in significant quantities only in animal foods. It is synthesized by microbes, including the bacteria that live in the rumens (first stomachs) of cows. This explains why B₁₂ is found in significant amounts in meat and dairy products. Fish acquire vitamin B₁₂ by consuming phytoplankton, which have a symbiotic relationship with bacteria that produce B₁₂. Plants, on the other hand, do not make B₁₂ and do not require it for growth. This simple fact of nature makes B₁₂ a nutrient of concern for vegetarians and especially for vegans, who avoid consuming meat, dairy products, or fish.

As more people turn to plant-based diets for many reasons, including overall health, nutritionists are raising the alarm about the risks of B₁₂ deficiency. “Of all the micronutrients, B₁₂ is the one we’re most concerned about,” says Thomas Sanders, professor emeritus of nutrition at King’s College London. “I’m concerned many people think B₁₂ deficiency is a myth.”

Indeed, some vegan advocates believe that plant foods can provide all the nutrients necessary for optimal health. We’ve even heard stories like “You can get enough B₁₂ from the soil on your vegetables if you don’t wash them,” and, “You don’t need to supplement with vitamin B₁₂, as you can get enough through the bacteria in your mouth.”

So, what’s the real status of B₁₂ in vegetarians and vegans, and how can you ensure adequate intake of this nutrient if your diet emphasizes plants rather than animal foods?

This new vegetarian risk to have B12 deficit

Despite the many benefits of vegetarian and vegan diets, individuals who follow such diets – whether in the UK, US, Europe, India, China, or Australia – tend to suffer from insufficient dietary B₁₂ intakes. ,,,,,

Without adequate dietary or supplemental B₁₂, signs of deficiency gradually appear. These may include fatigue, weakness, constipation, problems with balance, mental fogginess, tingling and numbness in the hands and feet, depression, and megaloblastic anemia (the formation of large and structurally abnormal red blood cells).

A working B12 insufficiency can happen in the presence out-of normal serum profile.

Since the neurological symptoms of deficiency are fairly nonspecific, vitamin B₁₂ deficiency is often overlooked in clinical practice. Many physicians do not think of testing for nutrient deficiencies, or they in B₁₂ level is a good marker of B₁₂ status. However, studies have shown that a functional B₁₂ deficiency can occur in the presence of normal serum levels. ,,,

The most accurate in (the biologically active form of vitamin B₁₂ in the blood) and/or methylmalonic acid (MMA), a substance produced in very small amounts during cellular metabolism. Vitamin B₁₂ is needed for the metabolism of MMA, so a buildup of MMA is a sign that cellular B₁₂ supplies are too low. ,