Zeaxanthin

Consumption of vegetables and fruits has long been associated with reduced rates of heart disease and some cancers. Because zeaxanthin is a major component of some plant foods known to be among the most protective, its antioxidant effects are thought to play a major part in preventing these conditions. In animal and human studies, zeaxanthin has been investigated for possible effects against atherosclerosis (hardening of the arteries). However, results from several human studies conflict with each other. While some seem to show that high zeaxanthin levels correlate with lower risk of atherosclerosis, other studies find little or no anti-atherosclerotic effect from zeaxanthin. While generally positive, results from studies of zeaxanthin in cancer are mixed, too. For cancer prevention, zeaxanthin is believed to increase the death rate of cancer cells. At the same time, it may decrease the growth of blood vessels that supply cancerous tumors. In laboratory studies, zeaxanthin has also appeared to change the ways that DNA repairs itself. Zeaxanthin has shown some effectiveness in studies of breast, colon, lung, and ovarian cancers in humans. Additionally, in laboratory mice, oral doses of zeaxanthin reduced the extent of skin damage from exposure to ultraviolet light. A possible protective effect from skin cancer may result. However, in an observational study of over 1,000 individuals in China, high blood levels of zeaxanthin seemed to be related to a slightly increased risk of having stomach cancer. The use of zeaxanthin in both heart disease and cancer needs more study.