FNDH 400 Exam 4

What is the difference between folic acid and folate? - correct answer -Folate is a B vitamin that exists in either reduced form which is (folate) or its oxidized from (folic acid) -Folic acid refers to the synthetic form -Folate refers to the natural form -Folic acid is better absorbed because it is more bioavailable than folate -folic acid is more stable, folate can be destroyed by heat, oxidation and light What is the cofactor form of folate? - correct answer tetrahydrogolate (THF) Why does the US fortify foods with folic acid - correct answer The neural tube closes quickly after conception (21-28 days) so females need to be consuming folic acid very early in their pregnancy to decrease the risk of neural tube defects. In addition 50% of pregnancies are unplanned so many women might not know they're pregnant during the period when folic acid needs to be consumed Women of reproductive age pretty much need to be consuming folic acid all the time to decrease rick of neural tube defects They choose to fortify grains so that it was in the food supply rather than relying on all women of reproductive age to take supplements (which some might not be able to afford) What is megaloblastic anemia and why do folate and vitamin B12 deficiencies lead to this condition? - correct answer Megaloblastic anemia is the same type of anemia that occurs in folate deficiency that is characterized by few enlarged immature red blood cells, but in vitamin B12 deficiency this can occur because there is not enough cobalamin to convert 5-methyl THF to THF. THF is not available for normal DNA synthesis and the red blood cells do not divide correctly What is vitamin B12's specific name? - correct answer Cobalamin Why is B12 deficiency an issue for vegans and why are most reliable sources of B12 animal based foods? - correct answer Animals consume microorganisms in soil or bacteria that produce vitamin B12 Fermented soy products are not a reliable source of B12 Plants and animals do not synthesize B12 Spirulina contains a pseudo-vitamin B12 that is not bioavailable What is Pernicious anemia? - correct answer a condition of inadequate intrinsic factor production that causes poor vitamin B12 absorption Common in people over the age of 50 What is Atrophic gastritis? - correct answer In people over the age of 50 it is a chronic inflammatory condition that leads to teh loss of glands in the stomach the loss of glands leads to decreased intrinsic factor production How can folate/folic acid mask a vitamin B12 deficiency and why could this be problematic? - correct answer If high levels of folate or folic acid is given during vitamin B12 deficiency, it can correct this anemia. This is referred to as masking because it does not rectify the deficiency but it "cures" the symptoms. This is problematic because it does not correct the more serious neurological problems that can result from vitamin B12 deficiency Why is vitamin D conditionally essential? - correct answer it is unique because it is part vitamin part hormone its considered part hormone for 2 reasons (1) we can synthesize it (2) it has hormone like functions Although the amount which is synthesized is often not enough to meet our needs thus we need to consume vitamin D under certain circumstances How is vitamin D3 synthesized, activated and transported including the circulating form and the active form - correct answer Vitamin D3 is synthesized from cholesterol In the skin cholesterol is converted to 7-dehydrocholesterol. In the presence of UV-B light, 7-dehydrocholesterol is converted to vitamin D3 Synthesized vitamin D will combine with vitamin D-bonding protein (DBP) to be transported to the liver. Dietary D2 and D3 is transported to teh liver via chylomicrons and then taken up in chylomicron remnants. Once in the liver, the enzyme 25-hydroxylase (25-OHase) adds a hydroxyl group at the 25th carbon forming 25-hydroxy vitamin D (25(OH)D, calcidiol) this is the circulating form of vitamin D The active form of vitamin D is formed with the addition of another hydroxyl group by the enzyme 1alpha-hydroxylase in the kidney forming 1,25 hydroxy vitamin D (1,25(OH)2D) What are the differences between D2 and D3 including structural, sources, and effectiveness - correct answer Vitamin D2 and D3 were once thought to be equivalent forms of vitamin D but research has found that D3 supplementation increases 25(OH)D concentrations more than D2 supplementation D2 is primarily found in plants and yeast, it also contains an extra double bond in its tail D3 is mainly made by animals Why is milk fortification what vitamin D potentially problematic for ethnicities such as African Americans - correct answer It can be a problem for people with lactose intolerance which is shown to occur greatly with people who have darker skin, meaning they have an increased risk of vitamin D deficiency because they require greater sun exposure to synthesize adequate amounts of vitamin D3