Highlights:
- Vitamin B12 supplements may have neurological benefits in people who are deficient in vitamin B12.
- Some researchers are studying the supplement for other benefits, such as sleep, but the evidence is uncertain.
Experts say vitamin B12 supplementation may help some people with a deficiency, but there is no conclusive evidence in the general population.
Vitamin B12 is required for DNA synthesis, healthy red blood cell formation, central nervous system function, myelination, and development. Carol J. Haggans, M.A., R.D. “It’s a big step forward for the NIH Office of Dietary Supplements,” said Helio, a science and health communications consultant.
“Vitamin B12 is only found in animal foods such as fish, meat, poultry, eggs, and dairy products,” Hagans says. “Thus, people who follow a vegan diet should get their vitamin B12 from fortified foods, such as many breakfast cereals and fortified nutritional yeast, or from dietary supplements.”
For men and most women, the Recommended Dietary Allowance (RDA) for vitamin B12 is 2.4 μg per day. During pregnancy it increases to 2.6 μg per day, and during lactation it increases again to 2.8 μg per day.
“Vitamin B12 supplementation is primarily used to cure vitamin B12 deficiency. Vitamin B12 deficiency can cause megaloblastic anemia and neurological changes such as numbness and tingling in the hands and feet. ” Hagans said. “In addition, vitamin B12 deficiency also affects patients with pernicious anemia. Pernicious anemia is an autoimmune disease that causes a deficiency of intrinsic factor, leading to malabsorption of vitamin B12, or vitamin B12 deficiency. Patients are often treated with intramuscular vitamin B12 injections to avoid any obstacles that interfere with oral vitamin B12 absorption.”
Hagans said patients who follow a vegan diet are often older, have had surgery or have medical conditions that make them more susceptible to deficiencies.
“Many older people, especially those with atrophic gastritis, have difficulty absorbing vitamin B12, so people over 50 should get most of their vitamin B12 from fortified foods and dietary supplements,” says Hagans. says. “These forms are more easily absorbed than vitamin B12 in food.”
Summary of evidence
The evidence regarding the benefits of vitamin B12 supplements is largely mixed.
A review of 35 studies in 2020 found that there is no evidence that vitamin B12 has a positive effect on symptoms of depression. However, researchers report that low levels of vitamin B12 in the body increase the risk of developing depression, and therefore early vitamin B12 supplementation can delay the onset of depression and increase the effectiveness of antidepressants. concluded that it is possible.
Other studies are less clear.
A systematic review, meta-analysis, and meta-regression analysis of 16 randomized controlled trials conducted in 2021 also found no evidence that vitamin B12 supplements had any effect on cognitive outcomes or measures of depression in patients without advanced neurological disease.
Furthermore, a community-based, double-blind, randomized, placebo-controlled trial conducted in Nepal in 2023 found that supplementation improved vitamin B12 status but had no effect on infant neurodevelopment or growth. The researchers therefore concluded that there is no evidence to support routine vitamin B12 supplementation during pregnancy.
Additionally, a 2021 randomized controlled trial in Nepal of 600 people evaluated the effects of vitamin B12 supplements on sleep. Researchers found that vitamin B12 supplementation had no effect on sleep in infants and other high-risk subgroups. There was no effect on total sleep time, wakefulness after sleep onset, or nighttime sleep time.
For more information
Hagans said that unlike other supplements, there is no tolerable upper intake level for vitamin B12, so “it is considered safe at all doses.”
“Vitamin B12 is bound to proteins in food and must be released by the action of hydrochloric acid and gastric proteases in the stomach before it can be absorbed,” Hagans says. “Vitamin B12 then binds to intrinsic factor, a transport and delivery binding protein, and the resulting complex is absorbed in the small intestine. If this process is interrupted, deficiency can occur even when people are consuming enough vitamin B12.”
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Editor’s note: Healio highlights the clinical value of various supplements. Check out the other articles in the series here:
