Eating Broccoli May Help Seniors Protect their Eyesight
~ June 2006 No.206 ~
The results have only been demonstrated in the lab, but it may be that broccoli contains a powerful ingredient that can prevent the occurrence of a chronic eye disease. As we age, the eye is less capable of removing oxidants. It is the long term action of oxidants that lead to age-related macular degeneration or AMD. As many as 30 million people are believed to suffer from AMD to-day.
AMD results in the loss of central vision – you can see things clearly on the edges of your vision, but the centre is clouded or, at worst, completely opaque. There are two forms of AMD – the dry and the wet form. The dry form of AMD accounts for approximately 90% of cases. Dry AMD is slow to develop and causes the deposition of a yellow substance called drusen that appears on the retina. It is the drusen that clouds the vision. Partial vision is also lost due to the wet form of AMD. In this case, new small blood vessels form in the eye, rupture and bleed under the retina. In contrast to the dry form, the wet form can cause rapid and drastic loss of central vision. The leaking blood vessels that cause wet AMD can sometimes be treated using lasers.
Broccoli contains sulforaphane, an isothiocynate that has been shown in the past to modify the metabolism of some carcinogens. US researchers have shown that sulforaphane can also provide a boost to the body’s Phase 2 enzyme antioxidant system that is important in the detoxification of oxidants. The Phase 2 enzyme system does not involve small individual antioxidant molecules like vitamin C, vitamin E or lycopene. These well known antioxidants react with one oxidant at a time and then are no longer active. Sulforaphane appears to stimulate the body’s internal antioxidant system. Incubating sulforaphane with retinal pigment epithelial cells increased the life of the cells when they were exposed to ultra-violet light and a photo-toxin. Data showed that it was an increase in components of the Phase 2 enzyme system that led to the protection of the eye cells.
The experiments have only been done in the lab on cells, but the results could lead to new ways to stimulate the body’s natural protective mechanisms and help protect us against the harmful effects of oxidants in the eye or elsewhere in the body. Eating broccoli regularly may be an essential part of this new approach to health.
Chemical Structure of Sulforaphane
Induction of phase 2 genes by sulforaphane protects retinal pigment epithelial cells against photooxidative damage
Proc Natl Acad Sci USA 13: 10446-51.