Interactions of lutein with other agents (micronutrients, foods):
Interactions between carotenoids
Metabolic studies found that when high doses of beta-carotene were absorbed, they competed with lutein and lycopene when ingested within a meal. However, in long-term clinical studies, consumption of high doses of beta-carotene had no adverse effect on serum carotenoid levels.
Dietary supplements versus food
In general, purified carotenoids in oil-in dietary supplements-have higher bioavailability than carotenoids from foods. In particular, One study shows that the bioavailability of lutein in spinach – versus bioavailability from purified lutein in oil – in a dietary supplement – is only 67%.
The relatively low bioavailability of carotenoids from foods is partly due to the fact that they are tightly bound to the proteins of the plant matrix. Carotenoids from green leafy vegetables are associated with chloroplasts, while those from red fruits are associated with chromoplasts. Fine crushing, homogenization and cooking destroy the plant matrix and thus increase the bioavailability of carotenoids.
The human body can absorb carotenoids through the intestine only if fat is present at the same time. However, a small amount of fat, as little as 3-5 g of fat in a meal, is sufficient to ensure absorption of carotenoids.
Margarine with vegetable sterol
Some studies show that regular use of margarine with vegetable sterol can result in a 10-20% decrease in serum carotenoid levels. However, with the additional intake of carotenoids from fruits or vegetables, this deficiency could be compensated.
Fat substitute olestra (sucrose polyester)
One study showed that daily consumption of 18 g of the fat substitute Olestra resulted in a 27% decrease in serum carotenoid levels after three weeks. In people who consumed only 2 g of Olestra daily, another study demonstrated that serum carotenoid levels decreased by 15%.
