Thomas (not real name) was suffering from tingling and numbness in his hands and feet for some months. Later, he also developed weakness. Upon conducting a routine complete blood check, it was found that he had longer-than-usual red blood cells and low haemoglobin, suggestive of a vitamin B12 deficiency. His condition improved after taking a few doses of vitamin B12 injections. Vitamin B12, also known as cobalamin, is a vitamin very necessary for the human body to keep the brain and nervous system healthy. It helps in production of normal, healthy red blood cells. It is also needed for DNA synthesis in the body. It is useful for strengthening cells, bones, hair, and skin and is helpful for the eyes and mind. It helps to prevent macular degeneration. B12 helps to convert homocysteine (an amino acid) into other molecules, high levels of which otherwise increase risk of cardiac problems and stroke. While not a direct source of energy, vitamin B12 is vital to convert food into reusable energy. It is known to elevate mood and help correct depression. Memory is sharpened, with an adequate amount of vitamin B12. In adults, deficiency of vitamin B12 causes anaemia, spinal cord degeneration, weakness, and or paralysis of the limbs. Severe and or prolonged deficiency can cause irreversible neurological damage. Psychosis can occur in severe cases. Deficiency of vitamin B12 during pregnancy leads to birth defects in the new-born child, which can be prevented by ensuring that the body gets an adequate amount as needed. Neural tube defect is one where the neural tube that connects brain to spinal cord in a foetus does not close completely. If mild, there may be no symptoms, but in moderate to severe cases, it may cause bladder and or bowel dysfunction, paralysis, and even death. Deficiency of vitamin B12 causes anaemia, early fatigue and weakness. The tongue can become sore with ulcers in the mouth. It is a very much needed component, but the body does not procure its vitamin B12; hence, one has to depend on external sources for it. Daily requirement of vitamin B12 is 2.4 micrograms for an adult. For a breastfeeding mother, it is slightly more, about 2.8mg per day. B12 deficiency commonly occurs in elderly people due to poor intake. It can also be due to malabsorption, i.e., diseases where absorption of nutrients, including vitamin B12, is impaired; examples, post-gastric surgery and diseases of the intestines. Some drugs like metformin used for diabetes, proton pump inhibitors and H2 receptor antagonists used for acidity, flatulence, anti-cold medicines, all interfere with absorption, and or metabolism of vitamin B12, resulting in deficiency. Alcohol use also causes vitamin B12 deficiency. People taking a vegan diet strictly are also prone to develop vitamin B12 deficiency, because there are very few vegetable sources of vitamin B12, as compared to animal sources. Beef, ham, pork, lamb, poultry, fish, particularly haddock and tuna, eggs, are good sources of vitamin B12. For vegetarians, some nutritional yeast products, dairy products like milk, yoghurt, cheese, soya milk and other soya products, almond milk, fortified cereals, are dietary sources of vitamin B12. Certain types of mushrooms, like shitake, white button mushrooms, also contain vitamin B12, though in a small quantity. Similarly, almonds, pistachios, and walnuts also contain small amounts of vitamin B12. Deficiency of vitamin B12 is suspected on the basis of symptoms and can be confirmed by a simple laboratory test, measuring vitamin B12 levels in the blood. Mild deficiency of vitamin B12 can be corrected by dietary means. Otherwise, in moderate to severe cases, one may have to take weekly injections of vitamin B12, followed by tablets regularly daily. Supplements of vitamin B12 are useful for individuals prone to developing deficiency, like the elderly, those who have undergone abdominal surgery, using alcohol etc. Dr Rachna Pande is a specialist in internal medicine.
