Here’s How Vitamin B12 Supplements Could Be Deadly

Vitamin B12 is a water-soluble vitamin essential to brain and nervous system functions, which has a role to play in cell metabolism and red blood cell multiplication. The natural sources of the vitamin are non-vegetarian food and non-plant-based foods such as fish, milk, eggs and poultry, among others. For vegetarians, fortified breakfast cereals have high vitamin B12 concentration. 

Vitamin B12 deficiency can manifest as depression, disorientation, fatigue, loss of appetite, weight loss and potential damage to the brain and nervous system. Sometimes when the deficiency occurs, supplements are recommended. However, people tend to take high dosages without a doctor's supervision.

Even healthy adults have problems with absorption and food is the best source of vitamin B12. In fact, too much vitamin B12 concentration could result in health complications, as per a recent study. 

The study published this January in the journal JAMA Network Open analyzed the vitamin’s effect on mortality rates. Previous studies had found that excessive vitamin B12 concentration impacted the elderly negatively, increasing their mortality rates.

Researchers at the University of Groningen in the Netherlands examined data of participants from the longitudinal cohort Prevention of Renal and Vascular End-stage Disease Study (PREVEND) because it had a wide age range of participants. Exactly 5,571 healthy Dutch men and women with a mean age of 54 who did not take supplements were assessed. The average follow-up period was eight years, between 2001 and 2011.  

Without canceling out influencing factors such as diabetes, cancer, cardiovascular diseases, liver and kidney functions and substance abuse, it appeared that low blood plasma concentration levels of vitamin B12 increased mortality rates. On the contrary, when the factors were taken into account, the opposite effect was observed. So much so that the death rates were nearly twice as high among people who had more vitamin B12

“High amounts of vitamin B12 are often taken without a medical indication,” Dr. Stephan J.L. Bakker, senior author and a professor of internal medicine at the University Medical Center Groningen, said. “It might change the gut microbiota in ways that could be harmful — no one really knows,”

“These findings suggest that higher levels of plasma concentrations of vitamin B12 were associated with increased risk of all-cause mortality after adjusting for age, sex, renal function, and other clinical and laboratory variables. The mechanisms underlying this association remain to be established,” the researchers concluded in their paper. 

“Further investigation is needed to unravel the complexity of 1-carbon metabolism in different mortality causes, such as cardiometabolic disease and cancer,” the researchers added. 

Supplements A glass filled with various supplements. Pixabay