Review Question - QID 106633

Due to this patient's compulsion to over-boil her fruits and vegetables, she will destroy all of the vitamin C within these foods, as vitamin C is heat labile and water soluble. Ultimately, she may develop scurvy due to vitamin C deficiency.

Vitamin C is a water-soluble vitamin that plays many roles in the body. It functions as an antioxidant keeping iron in the absorbable Fe2+ state. It is a cofactor for dopamine beta hydroxylase, converting dopamine to norepinephrine, and is also a cofactor in the synthesis of collagen, aiding in the hydroxylation of proline and lysine. Fibroblasts use vitamin C as a co-factor for prolyl-4-hydroxylase and lysyl-hydroxylase in the conversion of procollagen to collagen, an essential step in wound healing. Vitamin C is sensitive to high temperatures, especially when it is boiled for long periods of time. Vitamin C deficiency can result in scurvy, which presents with swollen gums, bruising, anemia, and poor wound healing.

Wang and Still report on a case of scurvy in a 65-year-old male. He states that he had been abusing alcohol for the past several years and only ate cheese pizzas for his meals. He presented with spontaneous bruises on his legs without precipitating trauma as well as poor dentition. Blood serum analysis revealed that a below normal vitamin C level; he was treated simply with oral vitamin C for several days without any further complications.

Although taking large daily doses of vitamin C had been recommend by double Nobel-prize winner Linus Pauling, taking excessively large amounts can make this otherwise safe, water-soluble vitamin harmful to the kidneys. Mashour et al. report a case of a 31-year-old African American male taking up to 5,000 mg of vitamin C (over 50 times the recommended daily allowance) daily for a recent respiratory infection and continuing it even after he recovered. He presented with acute renal failure due to the accumulation of oxalic acid, the by-product of vitamin C metabolism. The patient discontinued the large doses of vitamin C and recovered within 2 weeks.

Illustration A demonstrates bleeding gums as seen in scurvy. Illustration B demonstrates the bruising and poor wounding healing in scurvy.

Incorrect Answers:
Answers 1,2,4,5: Vitamin C is a heat-labile vitamin that is destroyed with heating. It is commonly found in fruits and vegetables. Vitamins A, D, E, and K are heat-stable and fat-soluble vitamins that would not be lost or destroyed by boiling.