The long-chain omega-3 fatty acid docosahexaenoic acid, or DHA, is abundant in human plasma and cell membranes. The highly concentrated presence in your body makes DHA a significant nutrient for adequate central nervous system functions. Specifically, DHA may play a role in reducing the risk of nerve damage associated with Alzheimer's disease, diabetic neuropathy and retinal nerve degeneration.
Nervous System Functions
Your nervous system is a complex network of connecting nerve processes that communicates information throughout your body. The central nervous system, or CNA, includes your brain and spinal cord, which transmits signals that regulate your thoughts, mood and emotions as well as movement, glandular and organ functions. The peripheral nervous system connects to the CNS and regulates voluntary, involuntary and sensory processes. A well functioning nervous system allows you to conduct normal daily activities with ease. However, damage to your nervous system can result in a host of complications including memory impairment, loss of feeling in your extremities or blindness.
Nerve Cell Protection
Within your body constant chemical reactions occur and your nerve cells, or neurons, are directly impacted by nutrients you get from food. Fat is a cell membrane insulator that plays a role in protecting your neurons from some of the chemical reactions that happen during nutrient metabolism. Oxidative damage resulting in free radicals, or harmful molecules, can damage neurons if you do not have enough protective compounds around the nerve cells. However, saturated fat in excess can also cause nerve cell damage. The omega-3 fatty acid DHA is polyunsaturated and has a neuroprotective effect, which surrounds neurons to prevent damaging molecules from infiltration that causes cell death.
DHA Sources and Intake
Oily fish or DHA enriched supplements supply your body with this nutrient because your body does not create DHA on its own. No standardized daily value is established for DHA. The U.S. Food and Nutrition Board set an adequate intake for alpha-linolenic acid, or ALA, in adults at 1.1 to 1.6 g per day. The ALA converts to DHA during metabolic processes. However, the Linus Pauling Institute notes that ALA may not efficiently convert to DHA and the best way to get this nutrient is from direct sources containing it like salmon, tuna or trout, at least twice a week.
DHA and Nerve Research
According to a 2003 study by researchers Thierry Coste et al, published in the "Diabetes Journals," DHA supplements given to diabetic study participants have a protective effect in preventing the development of neuropathy, nerve damage of the extremities. Retinal nerve damage, or macular degeneration, impacts 1 in 5 American adults over the age of 60, notes the Macular Degeneration Association. DHA concentrates in the photo receptors of the retina in your eyes and regular consumption of this nutrient can minimize your risk of retinal nerve damage as you age. DHA does not inhibit the progression of neuron damage in the brain associated with mild to moderate Alzheimer's disease, according to a 2010 study published in the "Journal of the American Medical Association." However, DHA may have protective effects if consumed in the early stages of the disease.
References
- Penn Medicine: Nervous System
- Linus Pauling Institute: Essential Fatty Acids
- National Institute on Aging; Alzheimer's Disease Fact Sheet; Feb. 2010
- Macular Degeneration Association; Lack of Omega 3 Fats Leads to Macular Degeneration; Emilia Klapp; April 20, 2011
- Diabetes Journals; Neuroprotective Effect of Docosahexaenoic Acid-Enriched Phospholipids in Experimental Diabetic Neuropathy; Thierry C. Coste et al; Oct. 2003
- Journal of the American Medical Association; Docosahexaenoic Acid Supplementation and Cognitive Decline in Alzheimer's Disease; Joseph F. Quinn, MD, et al; 2010
