Which dietary change is most likely to increase usable vitamin A intake for someone who currently eats mostly raw spinach (plant source) and little dietary fat?

• A. Add a small amount of dietary fat (e.g., olive oil) to the spinach salad and/or include some animal source of preformed retinol (e.g., a small serving of liver or egg yolk) to increase absorption and provide preformed vitamin A.
• B. Boil the spinach for a very long time to remove water and concentrate beta-carotene, which will always increase its bioavailability regardless of fat presence or whether the source is plant- or animal-based.
• C. Consume more citrus fruit with the spinach since vitamin C will enzymatically convert beta-carotene to retinol in the stomach and therefore boost vitamin A status more than adding dietary fat would.
• D. Increase the volume of raw spinach tenfold without changing fat intake because provitamin conversion efficiency is linear and unaffected by dietary fat or preformed sources; therefore sheer quantity is the only way to raise usable vitamin A.

Answer: (A)