The most difficult vitamins riddles

Nicotinic acid, better known as niacin or vitamin B3, has nothing in common with tobacco. Chronic lack of niacin leads to pellagra, a vitamin deficiency disease.

A branched-chain amino acid (BCAA) is an amino acid having aliphatic side-chains with a branch. Among the proteinogenic amino acids, there are three BCAAs: leucine, isoleucine and valine. They are among the nine essential amino acids for humans, accounting for 35% of the essential amino acids in muscle proteins and 40% of the preformed amino acids required by mammals.

Rose hips are particularly high in vitamin C, one of the richest plant sources available.

Beriberi is a sickness caused by extreme deficiency of vitamin B1, thiamine. White rice is generally a poor source of vitamins, and completely lacks thiamine. The sickness became common in Asia in 1800s with the increased processing of rice.

Pellagra is a disease caused by a lack of niacin (vitamin B3). Symptoms include inflamed skin, diarrhea, dementia, and sores in the mouth. Areas of the skin exposed to either sunlight or friction are typically affected first. Over time, affected skin may become darker, stiff, begin to peel, or bleed.

Vitamins are classified as either fat soluble (vitamins A, D, E and K) or water soluble (vitamins B and C).

Vitamin D is synthesized from cholesterol in the skin with the help of the natural ultraviolet wavelength of sunlight. Supplementation of vitamin D is recommended only for sun-deprived people (eg. elderly or living in the Far North).

By convention, there are vitamins A, B, C, D, E and K. Flavonoids were referred to as Vitamin P from the mid-1930-s to early 50s, and this name is still sometimes used.