Our body needs vitamins to function. Vitamins play a crucial role in the absorption of nutrients and the functioning of vital organs. Unlike many other animals, strangely, the human body has evolved without the capacity to make vitamins internally and therefore needs to ingest them regularly. These vitamins are usually available from the meat, milk, eggs, fruits and vegetables that we need. Eating fruits and vegetables regularly is essential.
Vitamin B12 is water soluble and vitamin D is fat soluble. Vitamin B12 is required for cell division, red blood cell production and the functioning of your nerves. Vitamin B12 is found in most animal products (e.g. meat, liver, fish, eggs, and milk) and some yeasts and seaweed, but not in plant-foods.It is also made by bacteria in the large intestine using the mineral, cobalt, that we get from foods. Vegans often are deficient in Vitamin B12.
Vitamin D is required for the uptake of calcium which is required for the development of teeth and bones. It also helps develop your immune system. Vitamin D can only be ingested through the foods we eat. Sources include eggs, milk, yogurt and fortified foods.
People of south Asian descent, in particular, seem to have a tendency to be deficient in vitamin B12 and D. The consequences of being deficient can include muscle atrophy, vision loss, nerve problems, depression, memory loss. It is important to have yourself tested since the symptoms are not obvious and take time to manifest.