Vitamin B12Nutritional functions and dietVitamin B12, also known as cobalamin, has a few key functions. Vitamin B12 is a water-soluble vitamin and a coenzyme for a critical methyl transfer reaction which is an essential biochemical reaction in the metabolism of fats and proteins. Vitamin B12 contributes not only to metabolism, but also to red blood cell formation, neurological functions and DNA synthesis (The Standing Committee, 1998, p.307). Unlike most B vitamins, vitamin B12 is only found in animal products. Since vitamin B12 is bound to proteins found in foods, the richest sources come from shellfish, organ meats, some game meats, and then some types of fish (The Standing Committee, 1998, p. 343) . Most of our vitamin B12 consumption in the United States comes from a mixed food category. For example, sandwiches containing meat, fish, or poultry as the main ingredient make up the bulk of our vitamin B12 intake in the United States. Other categories that make up the majority of our vitamin B12 intake are milk and dairy products as well as beef products. Since vitamin B12 comes only from animal products, there is another common consumption category, this category is known as the fortified category. Products fortified with vitamin B12 are fortified with the synthetic version and these products include foods such as breakfast cereals (The Standing Committee, 1998, p.343). age 50, as many people over 50 begin to lose the ability to absorb vitamin B12 from food due to reduced stomach acid. Another group at risk of developing a deficiency is people who follow a vegan or vegetarian diet. Since vegans or vegetarians do not... middle of paper ....... Infants do not have a set RDA, but they follow an Adequate Intake (AI). These recommendations are a set of vitamin B12 values ​​that have been observed in infants fed primarily breast milk (The Standing Committee, 1998, p. 322). The recommendations for older adults were established based on the assumption that since 10 to 30 percent of older adults have gastritis with low stomach acid secretion, then they may have low bioavailability of vitamin B12 from food. Therefore, given the high prevalence of this condition, the EAR recommendations would be higher than 2.0 micrograms (The Standing Committee, 1998, p. 338). There is insufficient data on recommendations for infants and the elderly. Some questions that might arise that might influence the DRI parameters Experimental papers published after 1998 The first experimental paper I found and published after the DRI report was a study