Carotenoids, writes Dr Lyndsey Greig, which were first isolated from and named after carrots, are a class of compounds including beta-carotene, lutein, lycopene and zeaxanthin.
Their potential health benefits have been widely documented, including antioxidant properties, and pro-vitamin activity. And recently, carotenoids have been among several substances linked to improved eye-health.
Age-related macular degeneration (AMD) is one of the world's biggest causes of blindness in the elderly. It affects the macula, a small portion of the retina whose health is essential for 20/20 vision. Like another serious eye-disease, retinitis pigmentosa, it results in the deterioration of the photoreceptor activity of the eye, meaning that the brain cannot correctly interpret incoming light.
As yet, there is no known cure, and existing treatments are notoriously ineffective. However, more effective treatments may be in sight thanks to recent and continuing research into the factors associated with a reduced risk of AMD.
Tentative conclusions drawn from the first exploratory investigations do appear to equate an increased lutein intake with a reduced risk of AMD.
And although it does not represent hope for a complete cure, it seems realistic to expect that progress of the condition may be arrested in those already suffering, or prevented entirely in those at high risk of developing it.
Although the National Eye Institute is cautious in endorsing these results, nutritionists have set a provisional daily lutein intake of 6 mg as likely to be beneficial for the eyes.
Unfortunately, however, it is difficult, although not impossible, to obtain this much lutein from diet alone.
But for those at high risk of developing AMD, lutein supplements may be the answer.
Increased lutein intake is not the only factor related to a reduced risk of developing AMD.
With the populations of Western nations growing older, research in this area attracts ever greater interest, and several different groups have recently released preliminary findings.
Among the suggestions is that certain types of fat may be implicated in the incidence of AMD, and that a diet high in Omega-3 fatty acids and low in linoleic acid could help prevent it.
Another recent study looked at the effect of a combination of antioxidants vitamin C, vitamin E, beta-carotene and zinc on patients with intermediate AMD, or advanced AMD in one eye only.
Again, there is evidence that this does slow the progression of the disease, but work towards a complete cure for AMD is also ongoing.
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