Impairs cell oxidation and results in a set of symptoms called ariboflavinosis. Specifically, these are lesions affecting the mouth, lips, eyes, skin, and genitalia. These lesions appear as fissures or cracks radiating from the corners of the mouth onto the skin. The first signs of deficiency may be a burning feeling in the eyes. They may feel gritty, and they become bloodshot and water readily.
Cataracts occur in severe deficiencies.
Extreme nervousness, general weakness, lethargy, and other signs usually associated with deficiencies of other B vitamins. It is thought to be involved in the metabolism of protein, carbohydrates, and fats. The most serious manifestation of B 12 deficiency is pernicious anemia , so called because it once was invariably fatal. Pernicious anemia leads to a general muscular weakness and signs of deterioration of the central nervous system. Skin pallor, heart palpitations, and eventually more severe heart disturbances are also symptoms, as are a sore, red, inflamed-looking tongue which eventually becomes smooth and glazed.