B-complex vitamins

B complex vitamins (together with a brief description) are as follows:

B1 – thiamine (sometimes also referred to as aneurine)

B2 (G) – riboflavin (also ovoflavin, lactoflavin)

sources: yeast, liver, kidney, meat, eggs, milk, to a lesser extent leafy vegetables, almonds, mushrooms
function: macronutrient metabolism, healthy skin, eyes, hair
deficiency: angular cheilitis
RDI: about 1,8 mg

B3 (PP) – niacin (also nicotinic acid, nicotinamide, pellagra-preventing (PP) factor)

sources: many different vegetable and animal foods (mainly meat, fish, whole grain cereals …)
function: macronutrient metabolism, lowers blood cholesterol
deficiency: pellagra
RDI: about 19 mg

B5 – pantothenic acid

sources: almost all food
function: carbohydrate and fat metabolism, synthesis of several important substances
deficiency: very rare, may be manifested by exhaustion, apathy
RDI: about 5mg

B6 – pyridoxine (plus pyridoxal and pyridoxamine)

sources: meat, bananas, whole grain cereals, yeast, eggs, leafy vegetables
function: metabolism (amino acids, fats, glucose), synthesis of histamine and hemoglobin
deficiency: sleepiness, apathy
RDI: about 2mg

B7 (H) – biotin

B9 (M) – folate (folic acid)

sources: leafy vegetables, yeast, legumes, meat (especially liver), other vegetables, fruits, nuts
function: blood formation, DNA and RNA synthesis, cell division
deficiency: anemia, fatigue
RDI: about 400 µg

B12 – cobalamin (cyanocobalamin)

sources: animal souces as meat, liver, eggs, milk, plant sources are insufficient
function: blood formation, fat and protein metabolism, nervous system
deficiency: anemia, nutrient absorption disorder in the intestine, fatigue, neuropathy
RDI: about 3-5µg

There are more substances falling under the B class (eg B4, B8, B10, B11, etc.), only relevant vitamins for humans have been described in the list.