DHA (2001, 2012-13) and macular degeneration
Learn more about macular degeneration treatment and information.
These studies looked at omega-3 fatty acids, specifically DHA and its effect on protection against macular degeneration.
Eating fish, especially tuna fish, may protect against age-related macular degeneration (AMD) (considered in 2001 to be untreatable).
Over several years, investigators questioned study participants about their diets and calculated the types of fat and total fat they ate. Those who ate more fat overall increased their risk of AMD, while those who ate fish reduced their risk of developing the eye disease.
Diets containing saturated fats from animals and unsaturated fats from vegetables were associated with modest increases in the risk of developing AMD, although long-chain fats from fish, especially tuna fish, actually reduced the risk. A specific fish fat, called docosahexaenoic acid (DHA), may help protect and promote healthy retinal function.
DHA is concentrated in the retina of the eye and is modestly inversely related to AMD. The intake of fish, the food source of DHA, was also inversely related, with participants eating more fish having a lower rate of macular degeneration incidence.
Researchers: Cho, Eunyoung, et al.
Published: Prospective study of dietary fat and the risk of age-related macular degeneration, American Journal of Clinical Nutrition, 2001
Editor's note: tuna is high on the food chain and contains high levels of mercury. DHA is better from other fish sources such as wild-caught salmon and smaller oily fish such as sardines and herring which are low on the food chain.
It is well known that the proper functioning of the retina gets worse with age. A substance, known as A2E, a component of the toxic material lipofuscin, accumulates in retinal pigment cells. Researchers analyzed the effect of giving DHA (docosahexaenoic acid)supplementats to mice who had A2E in the cells of their retinas. This done of periods ranging from 1 to 18 months, and took into account the proportion of DHA versus fatty acids, and diets without DHA.
The scientists found that A2E accumulations were reduced, and was tied to better retina functioning for mice who already had retina degeneration, and slowed this limitation for mice with more advanced retina problems.
They concluded that DHA in the diet could have a broad preventative therapeutic effect.
Researchers: Blake Dornstauder, et al
Published: Investigations in Ophthalmology and Visual Science, April, 2012
A randomized and double-blind research study assessed the effectiveness of DHA in preventing advanced, or wet, macular degeneration in which additional blood vessels grow behind the macula, forcing distortion. Over a three year period 55 to 85 year old patients who had early lesions of wet macular degeneration were given 840mg daily DHA and 270mg daily EPA (eicosapentaenoic acid), or an olive oil placebo.
The scientists found that wet macular degeneration incidence was markedly reduced in the patients who received DHA over the period, and who also showed a continued high EPA plus DHA index during that time.
Researchers: E.H.Souied, C. Delcourt, et al.
Published: Oral docosahexaenoic acid in the prevention of exudative age-related macular degeneration: The Nutritional AMD Treatment 2 Study Ophthalmology February, 2013.