Daijiworld Media Network - Mumbai

Mumbai, May 13: Vitamin B12, also known as cobalamin, is an essential nutrient that plays a key role in maintaining overall health. It is widely recommended as part of a balanced diet, but recent research has highlighted that both deficiency and excess levels may have complex health implications.

B12 is vital for the production of red blood cells, proper functioning of the nervous system, and DNA synthesis and repair. It is naturally found in animal-based foods such as meat, fish, eggs, milk and dairy products, and is also added to fortified cereals and bakery products.

While most individuals obtain sufficient vitamin B12 through a regular diet, deficiency is commonly seen among vegans, elderly people, and those with digestive or absorption disorders, often requiring supplementation.

Researchers say vitamin B12 is essential for proper DNA replication in cells. Inadequate levels can lead to errors in DNA copying, which over time may increase the risk of certain diseases, including some cancers such as colon cancer.

However, emerging studies have also raised questions about whether unusually high levels of vitamin B12 in the body may be associated with increased cancer risk.

A 2025 study from Vietnam indicated a “U-shaped” relationship between B12 intake and cancer risk, suggesting that both low and high levels could be linked to health concerns. However, experts caution that such findings show only association and do not establish direct causation.

Research on high-dose vitamin B supplements has not shown strong evidence that they reduce overall cancer risk or mortality. Some studies have suggested limited, cancer-specific effects, but results remain inconsistent.

In certain observational studies, long-term high-dose use of vitamins B6 and B12 has been loosely associated with a slightly higher risk of lung cancer in specific groups, though no direct cause-and-effect relationship has been confirmed.

Medical experts also note that elevated vitamin B12 levels in some cancer patients are often not the cause of the disease, but rather a consequence of underlying health conditions.

Studies published in recent years suggest that liver dysfunction and tumour-related changes in protein levels may lead to higher readings in blood tests, even when the body is not actually receiving excess usable vitamin B12.

Because of this, unusually high B12 levels in blood tests may sometimes act as a marker for underlying illness rather than a risk factor itself.

For most individuals, vitamin B12 obtained through food sources or standard supplementation is safe and essential. Excess intake from natural diets is rare, and deficiency remains a more common health concern worldwide.

Experts, however, advise against unnecessary long-term high-dose supplementation without medical supervision, especially when blood tests show persistently elevated levels without clear explanation.

Health experts emphasize that no single vitamin can prevent or cause cancer on its own. Maintaining overall health depends more on balanced nutrition, regular exercise, avoidance of smoking, and routine medical check-ups.

Researchers conclude that vitamin B12 intake should be adequate but balanced — ensuring enough to meet the body’s needs, without resorting to excessive supplementation unless medically advised.