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Blood tests: A blood test can measure vitamin B12 levels, along with other markers such as homocysteine and methylmalonic acid, which may also indicate a deficiency. Imaging studies: If gastrointestinal cancer is suspected, imaging techniques like CT scans, MRIs, or endoscopy are used to identify tumors or other abnormalities in the digestive ...
The structure of vitamin B 12 was the first low-molecular weight natural product determined by x-ray analysis rather than by chemical degradation. Thus, while the structure of this novel type of complex biomolecule was established, its chemistry remained essentially unknown; exploration of this chemistry became one of the tasks of the vitamin's chemical synthesis.
Vitamin B 12 is the most chemically complex of all vitamins. [6] [2] [7] Only some archaea and bacteria can synthesize vitamin B 12. [8] Vitamin B 12 deficiency is a widespread condition that is particularly prevalent in populations with low or no consumption of animal foods. [9]
Humans can produce some vitamins from precursors they consume: for example, vitamin A is synthesized from beta carotene; and niacin is synthesized from the amino acid tryptophan. [54] Vitamin C can be synthesized by some species but not by others. Vitamin B 12 is the only vitamin or nutrient not available from plant sources.
An underlying disorder can have 2 main causes: Metabolic causes: Genetic defects in enzymes (e.g. kynureninase) involved in the kynurenine pathway of synthesis of niacin from tryptophan can lead to pellagra (niacin deficiency). [1] Lifestyle choices: Lifestyle choices and habits that increase vitamin needs, such as smoking or drinking alcohol. [2]
The Food and Drug Administration (FDA) has recently approved a blood test screening for colorectal cancer that has an over 83% success rate at detecting the presence of this form of cancer.
Normal MMA levels indicate folate deficiency and elevated MMA levels indicate vitamin B 12 deficiency. [98] Elevated MMA levels may also be due to the rare metabolic disorder combined malonic and methylmalonic aciduria (CMAMMA). [117] [118] Folate deficiency is treated with supplemental oral folic acid of 400 to 1000 μg per day.
Vitamin K is a family of structurally similar, fat-soluble vitamers found in foods and marketed as dietary supplements. [1] The human body requires vitamin K for post-synthesis modification of certain proteins that are required for blood coagulation ("K" from Danish koagulation, for "coagulation") or for controlling binding of calcium in bones and other tissues. [2]