For plants, carotenoid pigments and chlorophyll have different and complementary absorption bands, which can increase the utilization of light energy. Other pigments (except chlorophyll a) can also be called antenna pigments, which can transfer photon energy to chlorophyll a (only it can) for energy conversion, and convert light energy into active chemical energy.

For people, carotene and lutein in carotenoids have antioxidant and anti-aging effects, and B-carotene is converted into vitamin A in human body. Moreover, astaxanthin, the strongest natural reducing agent (with the best antioxidant effect), is also a carotene in red algae.

Chlorophyll also has antioxidant function, and the structure of chlorophyll is very similar to that of hemoglobin in human body (it is porphyrin organic matter, magnesium ion is in the middle of chlorophyll porphyrin ring, and iron ion is in the middle of human hemoglobin). Eating more chlorophyll can replenish blood.

So the function of plant natural pigment is very important.