Causes of vitamin b12 deficiency

Vitamin B12 deficiency develops for one of three reasons: you do not eat enough B12, your stomach and gut cannot absorb it, or a medicine interferes with it.

Not eating enough. B12 is found almost entirely in animal-source foods - milk, curd, paneer, eggs, fish, meat and fortified products. Plants do not make B12, and no herb or traditional vegetarian preparation contains a reliable amount. This is why long-standing vegetarian and especially vegan diets are the single largest at-risk pattern in India. Exclusive breastfeeding by a B12-deficient mother can also leave an infant deficient.

Poor absorption. Even a good diet fails when absorption breaks down. Pernicious anaemia is an autoimmune condition where the stomach stops producing intrinsic factor, the protein B12 needs for uptake. Stomach or weight-loss surgery, chronic gastritis, coeliac disease and Crohn's disease all reduce absorption. Older adults often lose stomach acid with age, which frees less B12 from food.

Medicines. Metformin, used by millions with type 2 diabetes, gradually lowers B12 with long-term use. Proton-pump inhibitors and H2 blockers (omeprazole, pantoprazole, ranitidine-type antacids) taken for years do the same by cutting stomach acid. Regular heavy alcohol use damages both intake and absorption.

Who should suspect it: vegetarians and vegans, people over 60, anyone on metformin or daily antacids for years, people after stomach or intestinal surgery, and those with autoimmune disease in the family.

Ayurvedic view (interpretive): classical texts describe weakness, pallor and poor tissue nourishment under patterns like pandu and dhatu kshaya, which modern readers may map to deficiency states including B12 deficiency. This is a traditional interpretive framework, not a diagnosis, and evidence for it is limited. Ayurvedic care can be an adjunct for digestion and diet, never a substitute for testing and B12 replacement.

Remember: no plant food or herb supplies reliable B12. Vegetarians, vegans, elderly people, and anyone on metformin or long-term antacids should test rather than guess.