Dietary fat plays an important role in the absorption of ingested vitamin A. Dietary
vitamin A is digested in mixed micelles and absorbed with fat. There are indications that
increasing the level of fat in a low fat diet can improve retinol and carotene absorption.
Particularly for optimal carotenoid absorption, dietary fat must be consumed alongside
these provitamin A compounds.
The matrix of the food affects the ability of carotenoids to be released from food
and therefore affects intestinal absorption. For example, the rise in serum b–carotene
concentration has been observed to be significantly less when individuals consumed
carrots than when they received the same amount of the vitamin of b–carotene
supplement. The processing of food also greatly affects the absorption of carotenoids.
For instance, the absorption of carotene from sliced carrots was much lower than from
homogenised carrot. Cooking of carrot and spinach also greatly improved absorption.
Malabsorption of vitamin A can occur with diarrhea and intestinal infections such
as in gastroenteritis and respiratory infections. Malabsorption of the vitamin is also
associated with intestinal parasitism.