Vitamin C & B1
Casimir Funk (1912) said that scurvy occurs due to lack of anti-scurvy vitamine. Albert Szent-Gyorgyi isolated hexuronic acid (a 6-carbon compound) later renamed as ascorbic acid, awarded noble prize in 1937. Vitamin C is involved in synthesis of collagen (tough fibrous protein, provides structure of connective tissue such as skin/arteries/bones/teeth, along with keratin give elasticity to skin). Peoples eat white rice, lacks thiamine & results in Beriberi, first synthesized in 1936, easily destroyed by heat.