Everything you need to know about DHA and your health

Docosahexaenoic acid (DHA) is the longest and most unsaturated of the omega-3 fatty acids. DHA is one of the most abundant fatty acids in the brain. Although DHA can be consumed directly by eating certain kinds of fish such as salmon, mackerel and sardines, it can also be produced in the body. This process requires the conversion of alpha linolenic acid (ALA), which is also known as omega-3, to eicosapentaenoic acid (EPA). In the next step of the metabolic process, EPA is converted into DHA. Alpha-linoleic acid is also found in flaxseed oil (5).

In combination with eicosapentaenoic acid (EPA), DHA is used for a variety of conditions, including the prevention and reversal of heart disease, hyperlipidemia, and hypertension. One study found that DHA lowered cholesterol in the body as well as improved the elasticity of the arteries (4). Other research has focused on DHA’s ability to lower blood pressure (1).

DHA is essential for the proper growth of the brain, eyes and nervous system of the infants. Studies suggest infants given supplemental DHA in infant formulas and in breast milk score significantly higher in mental development studies (5).

Recent research has focused on DHA’s ability to improve cognitive function, reduce the incidence of neuropsychological disorders, reduce the incidence of breast cancer, and help prevent inflammation in the brain.

A study published in the May 2007 edition of the Journal of Neurochemistry examined DHA’s effect on neuroinflammation, which is a hallmark of all central nervous system (CNS) diseases. The researchers noted that DHA may help to reduce neuroinflammation, therefore may decrease the risk of developing CNS diseases as well as assisting in the repair of damaged brain neurons (2).

Another study found that DHA supplementation could improve the cognitive dysfunction due to organic brain damages or aging. Researchers examined whether ARA and DHA have beneficial effects in amnesic patients. 21 of the subjects had mild cognitive dysfunction, 10 had organic brain lesions, and 8 had Alzheimer's disease. The results suggested that ARA and DHA supplementation might improve the cognitive dysfunction due to organic brain damages or aging (3).

Other research has also examined treating neuropsychological disorders (depression and schizophrenia) with DHA. A recent review from Deakin University in Victoria, Australia, concluded that: “it is clear from the literature that DHA is involved in a variety of processes in neural cells and that its role is far more complex than simply influencing cell membrane properties” (6). Some epidemiological, experimental and clinical data have noted that polyunsaturated fatty acids such as DHA could play a role in the pathogenesis and/or the treatment of depression.

It is clear from the research presented that DHA and other omega-3 fatty acids are essential for good health and the prevention of disease, yet many Americans are deficient in DHA due to our over processed diets and low intake of flaxseed oil and oily fish. Contact your doctor of nutritionist to determine the amount you should include in your diet.

References

1. Arterburn et al. (2000). A combined subchronic (90-day) toxicity and neurotoxicity study of a single-cell source of docosahexaenoic acid triglyceride (DHASCO oil). Food Chem Toxicol; 38(1):35-49.
2. Farooqui AA, Horrocks LA, Farooqui T (2007). Modulation of inflammation in brain: a matter of fat. Journal of Neurochemistry; 101(3): 577-99.
3. Kotani et al. (2006). Dietary supplementation of arachidonic and docosahexaenoic acids improves cognitive dysfunction. Neurosci Res; 56(2): 159-64.
4. Nestel P, Shige H, Pomeroy S, Cehun M, Abbey M, Raederstorff D (2002). The n-3 fatty acids eicosapentaenoic acid and docosahexaenoic acid increase systemic arterial compliance in humans. American Journal of Clinical Nutrition.;76(2):326-330.
5. NHI OnDemand; 2000-2007 (online). Global Information Hub on Integrated Medicine. Available from http://content.nhiondemand.com [Cited Aug.28, 2007].
6. Sinclair et al. (2007). Omega 3 fatty acids and the brain: a review of studies in depression. Asia Pac J Clin Nutr; 16 Suppl 1:391-7.