Why tiny amounts of vitamin B12 matter more as we age - The Conversation

Berna Namoglu/Shutterstock Why tiny amounts of vitamin B12 matter more as we age Published: June 12, 2026 10.56am CEST https://theconversation.com/why-tiny-amounts-of-vitamin-b12-matter-more-as-we-age-282520 https://theconversation.com/why-tiny-amounts-of-vitamin-b12-matter-more-as-we-age-282520 Link copied Share article Share article Copy link Email Bluesky Facebook WhatsApp Messenger LinkedIn X (Twitter) Print article Two micrograms is an almost unimaginably small amount. It weighs less than a tiny fragment of a grain of table salt. Yet adults need only around this amount of vitamin B12 each day, depending on the guideline used, to support red blood cells, nerves and DNA production. In 2026, it is 100 years since George Minot and William Murphy reported that a liver-rich diet could treat pernicious anaemia, then a frequently fatal disease. Their work transformed medicine and eventually led scientists to identify vitamin B12 as the substance in liver that treated the disease. But the route to that breakthrough began with an unexpected clue from animal experiments. The American physician and pathologist George Whipple had shown that liver helped dogs recover from anaemia caused by blood loss. Blood-loss anaemia happens when the body loses red blood cells through bleeding. Pernicious anaemia is different: the problem is not bleeding, but poor absorption of vitamin B12. Even so, Whipple’s experiments pointed researchers towards liver as a source of a powerful blood-forming factor. Patients with pernicious anaemia who had been close to death often improved dramatically within weeks of eating liver-rich diets. The success of liver treatment eventually led scientists to isolate the deep red compound now known as vitamin B12, or cobalamin. Despite decades of research, vitamin B12 deficiency remains common, particularly among older adults, vegans, vegetarians and people with conditions that affect absorption. Some people do not consume enough B12 because it is naturally found mainly in foods from animals, including meat, fish, eggs and dairy products. Others struggle to absorb it properly. This becomes more common with age. Some older people produce less stomach acid, which is needed to release B12 from food. Others develop autoimmune gastritis, in which the immune system damages stomach cells involved in producing acid and intrinsic factor, the protein needed for vitamin B12 absorption. Weight-loss surgery and some medicines used for diabetes or acid reflux can also reduce absorption. The symptoms of deficiency can develop slowly and are often mistaken for normal ageing. People may feel exhausted, weak or short of breath. Some develop numbness or tingling in their hands and feet, poor balance, memory problems or what many describe as “brain fog”. These symptoms are not specific to B12 deficiency, so persistent tiredness, tingling or balance problems should be checked rather than assumed to be a simple vitamin problem. People at higher risk, including vegans, vegetarians, older adults and those taking medicines that affect stomach acid or diabetes treatment, may need testing or supplementation advice from a health professional.