Folate (Vitamin B9) deficiency
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Folate (Vitamin B9) deficiency
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Folate (Vitamin B9) deficiency
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Which of the following sets of red blood cell characteristics is most likely to be seen in this patient?
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Alcoholism p. 595
folate deficiency p. 428
Hemolytic anemia p. 429
folate deficiency and p. 428
Homocysteine
folate deficiency p. 428
Methotrexate p. 446
folate deficiency p. 428
Phenytoin
folate deficiency caused by p. 428
Pregnancy p. 657
folate deficiency caused by p. 428
Trimethoprim
folate deficiency with p. 428
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Folate deficiency is a clinical condition that occurs because of low level of folate or folic acid in the body. This can lead to a variety of problems ranging from anemia in individuals from all age groups to neural tube malformation in fetuses.
Folate, also known as vitamin B9, mainly comes from eating leafy greens and citrus fruits like oranges and lemons and, nowadays, many countries fortify foods like grains and cereals with folate.
Now, folic acid present in these food items is generally in polyglutamate form, which are basically chains of an amino acid called glutamic acid.
Because of the carboxyl group present in its structure, the chain is negatively charged making it polar and soluble in water, which is a polar molecule but not soluble in lipids which are nonpolar molecules.
So the polyglutamate residues of folic acid are almost non-absorbable from the GI tract, where all the cells are surfaced with lipid cell membranes.
So, to make them absorbable, when polyglutamate residues reach a portion of the small intestine called the jejunum, special enzymes present at the jejunal mucosa cut down the polyglutamate residues into monoglutamate.
Monoglutamate is smaller, and is less negatively charged, so these monoglutamate residues of folic acids can pass through the cell membrane and enter the jejunal cells, where they are converted into tetrahydrofolic acid or in short THF by the enzyme tetrahydrofolate reductase.
These THFs then get methylated into a more stable form called methyl-THF. Once formed, the methyl-THF then leaves the jejunal cell and enters the bloodstream.
Some of it goes to the liver and get stored for a short period of 2-3 months, while most of it is used up for metabolic activity inside various cells around the body.
Summary
Folate (vitamin B9) is a water-soluble vitamin that is mainly found in leafy green vegetables and fruits. It is important for the development of new cells, and it helps to form red blood cells. A folate deficiency can lead to anemia, and it can also increase the risk of neural tube defects in newborn babies. Symptoms of a folate deficiency can include fatigue, shortness of breath, and a pale complexion.
Sources
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- "Hyperhomocysteinemia in chronic alcoholism: correlation with folate, vitamin B(-1)2, and vitamin B-6 status" The American Journal of Clinical Nutrition (1996)
- "Neurologic Manifestations of Nutritional Disorders" Aminoff's Neurology and General Medicine (2014)
- "Neural tube defects: Different types and brief review of neurulation process and its clinical implication" Journal of Family Medicine and Primary Care (2021)
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