VITAMIN B2

Vitamin B2, also called riboflavin, is a water-soluble vitamin present in most animal and plant tissues. It is one of the essential B vitamins, known to help support adrenal function, help calm and maintain a healthy nervous system, and facilitate key metabolic processes, including helping to turn food into energy. It is necessary for energy production and normal cell function and growth. It is also crucial in helping other B vitamins undergo the chemical changes that make them useful.

Emerging research shows that riboflavin can act as an antioxidant, potentially helping to prevent cancer and prohibit cholesterol buildup by controlling the proliferation of harmful molecules known as free radicals.. Keep in mind that riboflavin is easily destroyed by exposure to light.The recommended amount of 50 mg as part of a B-50 complex in a daily multivitamin is advised.
Riboflavin is not toxic when taken orally, as its low solubility keeps it from being absorbed in dangerous amounts from the gut [2]. Although toxic doses can be administered by injection[2], any excess at nutritionally relevant doses is excreted in the urine[3], imparting a bright yellow color when in large quantities

Riboflavin deficiency
Further information: Ariboflavinosis
Riboflavin is continuously excreted in the urine of healthy individuals[1], making deficiency relatively common when dietary intake is insufficient. However, Riboflavin deficiency is always accompanied by deficiency of other vitamins[1].
A deficiency of riboflavin can be primary - due to not getting enough of the vitamin from the diet - or secondary, which may be a result of conditions that affect absorption in the intestine, the body not being able to use the vitamin, or an increase in the excretion of the vitamin from the body..
In humans, signs and symptoms of riboflavin deficiency (ariboflavinosis) include cracked and red lips, inflammation of the lining of mouth and tongue, mouth ulcers, cracks at the corners of the mouth (angular cheilitis), and a sore throat. A deficiency may also cause dry and scaling skin, fluid in the mucous membranes, and iron-deficiency anemia. The eyes may also become bloodshot, itchy, watery and sensitive to bright light.

Sources:
Riboflavin is found naturally in asparagus, okra, chard, cottage cheese, milk, yogurt, meat, eggs, buckwheat and fish, each of which contain at least 0.1 mg of the vitamin per 3-10.5 oz (85-300 gram) serving[citation