Research on DHA: Know the Facts
The omega-3 fatty acid docosahexaenoic acid (DHA) is known for its importance for healthy brain function and cardio-protection. Ongoing research continues to substantiate these claims and find additional benefits of DHA supplementation.
Just this past year, scientists attributed the following benefits to DHA:
Proper response to sensory stimuli: A new study published in the journal Behavioral Neuroscience examined the relationship between omega-3 fatty acid intake and the nervous system’s ability to handle sensory input – a function called sensorimotor gating (Fedorova). Mice were fed diets containing either ALA only or ALA + EPA + DHA. The mice were evaluated on their responses to a loud noise following a soft tone – in normal sensorimotor gating, the soft tone acts as a warning so that the animal is not startled by the loud noise. The mice fed ALA + EPA + DHA had a 12% increase in brain DHA content and displayed improved sensorimotor gating – they responded more calmly to the loud noise.1 Inadequate sensorimotor gating is central to human disorders like schizophrenia and ADHD – children with ADHD have reduced DHA levels2, and DHA has been shown to improve the symptoms of ADHD.3
Cognitive development in infants
DHA makes up 90% of the omega-3 fatty acid content of the brain, and is a major component of brain cell membranes. Since DHA is crucial during development of the brain, adequate DHA intake is important for pregnant and nursing women. Previous studies documenting improved cognitive skills in breastfed infants have attributed this to the DHA content of breast milk. A new study has confirmed these observations. Infants were fed formula with or without supplemental DHA – when they reached 9 months of age, the babies given DHA scored higher on a problem solving test.4
Keeping arteries clear: The oxidized form of LDL cholesterol contributes to the formation of atherosclerotic plaque. DHA supplementation in healthy, middle-aged men had antioxidant effects on LDL.5
Men who took DHA supplements for 6-12 weeks decreased the concentrations of several inflammatory markers in their blood by approximately 20%.6-7
DHA and EPA induced programmed cell death in colon cancer cells8 and prostate cancer cells9, and DHA supplementation reduced tumor size in a mouse model of cancer.10
Slowing the aging process:
It had already been shown that heart disease patients with higher intakes of DHA and EPA survived longer. A new study has found that higher intake of these
omega-3 fatty acids was associated with slower rate of telomere shortening, which is a DNA-level sign of aging.11
1.American Psychological Association (2009, December 19). New study links DHA type of omega-3 to better nervous-system function. http://www.sciencedaily.com/releases/2009/12/091216130718.htm Fedorova I et al. Deficit in prepulse inhibition in mice caused by dietary n-3 fatty acid deficiency. Behav Neurosci. 2009 Dec;123(6):1218-25.
2. Colter AL et al. Fatty acid status and behavioural symptoms of attention deficit hyperactivity disorder in adolescents: a case-control study. Nutr J. 2008 Feb 14;7:8.
3. Richardson AJ, Puri BK. A randomized double-blind, placebo-controlled study of the effects of supplementation with highly unsaturated fatty acids on ADHD-related symptoms in children with specific learning difficulties. Prog Neuropsychopharmacol Biol Psychiatry 2002;26(2):233-239.
4. Society for Research in Child Development (2009, September 17). Supplementing Babies’ Formula With DHA Boosts Cognitive Development, Study Finds. ScienceDaily. Retrieved December 21, 2009, from http://www.sciencedaily.com/releases/2009/09/090915100945.htm
5. Calzada C et al. Subgram daily supplementation with docosahexaenoic acid protects low-density lipoproteins from oxidation in healthy men. Atherosclerosis. 2009 Aug 3. [Epub ahead of print] 6. Kelley DS et al. DHA supplementation decreases serum C-reactive protein and other markers of inflammation in hypertriglyceridemic men. J Nutr. 2009 Mar;139(3):495-501. Epub 2009 Jan 21.
7. Bloomer RJ et al. Effect of eicosapentaenoic and docosahexaenoic acid on resting and exercise-induced inflammatory and oxidative stress biomarkers: a randomized, placebo controlled, cross-over study. Lipids in Health and Disease 2009, 8:36
8. Giros A et al. Regulation of colorectal cancer cell apoptosis by the n-3 polyunsaturated fatty acids Docosahexaenoic and Eicosapentaenoic. Cancer Prev Res (Phila Pa). 2009 Aug;2(8):732-42. Epub 2009 Jul 28.
9. Anderson BM et al. Are all n-3 polyunsaturated fatty acids created equal? Lipids in Health and Disease 2009
10. El-Mesery M et al. Chemopreventive and renal protective effects for docosahexaenoic acid (DHA): implications of CRP and lipid peroxides. Cell Div. 2009 Apr 2;4:6.
11. Farzaneh-Far R et al. Association of Marine Omega-3 Fatty Acid Levels With Telomeric Aging in Patients With Coronary Heart DiseaseJAMA. 2010;303(3):250-257.
12. Myers RA Worm B. Rapid worldwide depletion of predatory fish communities. Nature 423, 280-283 (15 May 2003)
13. Jenkins D et al. Are dietary recommendations for the use of fish oils sustainable? CMAJ 180 (6): 633. (2009)