Vitamin Btwelve (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 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.
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?
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).
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 sitios de citas polÃticas of MMA is a sign that cellular B12 supplies are too low. ,