Question

Vegetarian diets can provide high levels of antioxidants and a lipid profile that can help prevent coronary disease. However, there can be some associated problems. Blood samples were taken from a large group of volunteer subjects who were vegans (strict vegetarians: no animal products), lactovegetarians (vegetarians who eat dairy products), or omnivores (individuals with a normal, varied diet including meat). In each case, the volunteers had followed the diet for several years. The blood levels of both homocysteine and methylmalonate were elevated in the vegan group, somewhat lower in the lactovegetarian group, and much lower in the omnivore group. Choose the best explanation for the elevated blood levels of homocysteine and methylmalonate.1. Vitamin B12 (cobolamin) is missing from the vegan diet and very low in the lactovegetarian diet.2. Vitamin B9 (folic acid) is missing from the vegan diet and very low in the lactovegetarian diet.3. Vitamin B6 (pyridoxine) is missing from the vegan diet and very low in the lactovegetarian diet.4. Antioxidants in the both the vegan and lactovegetarian diets inhibit the formation of methionine from homocysteine

Answer 1

Answer: the best statement is 1 (Vitamin B12 (cobolamin) is missing from the vegan diet and very low in the lactovegetarian diet.)

Explanation:

Vitamin B12( cobalamin) is a water soluble vitamin that is essential in the formation of red blood cells. It also serves as a coenzyme in the metabolic reaction of the body. Such reaction includes:

- the remethylation of methionine from homocysteine which is catalyzed by methionine synthase and requires methylcobalamin.

The deficiency of vitamin B12 can lead to the following:

- elevated homocysteine ,

- an increase in methylmalonate

This is due to deficiencies in methionine synthase and methylmalonic acid mutase, respectively in individuals on vegan diet for several years.

Vegans are vegetarians that don't include diary or animal products in their meals. This predisposes them to lack of Vitamin B12. Dairy products provide some vitamin B12 in the lactovegetarian diet. Therefore statement 1 is the correct answer, thanks.