Lactic acidosis is caused due to deficiency of which vitamin?

Acute thiamine deficiency causes lactic acidosis. The lack of thiamine, which is needed to conve pyruvate to acetyl Co, causes pyruvate to be conveed into lactic acid; the lactic acid then accumulates, causing acidosis. Acute beriberi due to thiamine deficiency is associated with anorexia, vomiting, lactic acidosis, altered hea rate, and cardiomegaly. Acute beriberi mostly seen in infants. In combination with proteins, riboflavin coenzymes, like flavin mononucleotide and flavin adenine dinucleotide, function in various dehydrogenation reactions. Deficiency of riboflavin causes cheilosis, glossitis, inflammation of cornea, bloodshot eyes, dimness of vision, photophobia, itching, burning, and dryness of eyes and redness of conjunctiva. Niacin is required for the synthesis of the active forms of vitamin B3, NAD+, and NADP+. Both NAD and NADP function as cofactors for numerous dehydreogenases, e.g. lactate and malate dehydrogenases. Deficiency of niacin causes pellagra characterized by glossitis of the tongue, dermatitis, depression, dementia and diarrhoea. Pantothenic acid is a component of coenzyme A and is required for the synthesis of phosphopantotheine of fatty acid synthases complex. Deficiency causes paraesthesia of extremities, abdominal cramps, restlessness and fatigue in humans. Ref: Advanced Nutrition and Human Metabolism By Sareen Annora Stepnick Gropper, Jack L. Smith, James L. Groff, 2009, Page 327; Harper's Illustrated Biochemistry, 26th Edition, Page 136, 140, 488