Fish oil, omega-3
A class of fatty acids found in fish oils, especially from salmon and other cold-water fish, that acts to lower the levels of cholesterol and LDL (low-density lipoproteins) in the blood.
(LDL cholesterol is the 'bad' cholesterol.) Omega-3 fish oil is therefore thought to be a neutraceutical, a food that provides health benefits.
Eating fish has been reported to protect against late age-related macular degeneration, a common eye disease.
The maximum benefit appears to be from eating fish once a week.
(In technical terms, omega-3 fatty acids have a double bond three carbons from the methyl moiety.)