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The Importance of DHA For A Baby's Brain

Apr 15, 2017 BY Du La

Docosahexaenoic acid (DHA) is a long-chain polyunsaturated fatty acid (LCPUFA). It is described as an “essential” nutrient because our bodies do not produce it the way it produces a nutrient like vitamin D (which is produced with sun exposure).

“Essential” nutrients must be obtained through the diet, or in the case of breastfeeding infants, the mother’s diet.

DHA specifically (there are other LCPUFAs) is essential for the development of the human brain1 (the human brain is approximately 60% fat2, approximately 15% of which is DHA3) and retina of the eye2. The brain develops early in life at a rapid pace, reaching essential completion by ages five or six years2.

DHA is so closely related to brain development, that some hypothesize that the incorporation of fish (which is our primary source of dietary DHA) into the human diet in the Palaeolithic period (the period corresponding to dramatic increases in human brain size and tool use) was the driver of the evolution of human intelligence5.

The frontal lobes of the brain, which are particularly rich in DHA are associated with:

  • Planning3
  • Problem-solving3
  • Attention-maintenance3
  • Social, emotional and behavioural development3

Health and learning effects relevant to school-aged children associated with DHA deficiency include:

  • Learning and memory challenges3
  • Sub-normal IQ3
  • Dyslexia3
  • Dyspraxia3 (a movement and coordination disorder)
  • Attention-deficit hyperactivity disorder (ADHD)1
  • Depression1
  • Aggressive behaviour1

Importantly, not only has DHA deficiency been linked to health and learning challenges, but supplementation with DHA has been demonstrated to result in improvements in reading and behaviour (in otherwise healthy but under-performing school children)4.

Dietary Sources of DHA

As an “essential” nutrient, we must obtain DHA from our diet. DHA turnover in the brain is rapid1, meaning we require a steady dietary supply to maintain adequate levels.

Fatty fish (e.g., herring, salmon, sardines, mackerel, tuna) are the richest sources of DHA1 .

The concern some have over methyl mercury (a neurotoxin) consumption in the fat of fish is poorly founded. Methyl mercury is not fat-soluble, and as such, is not present in fish oils6. Further, methyl mercury present in fish is bound to an amino acid called cysteine, which decreases its toxicity by 90%6. To further reduce the risk posed by methyl mercury, one can restrict their fish consumption to non-predatory fish such as salmon and sardines (methyl mercury bio- accumulates as fish consume other fish)6.

An analysis of the health benefits associated with fish consumption matched against the potential health determents associated with other environmental toxins present in fish (dioxins, polychlorinated biphenyls) concluded “ "levels of dioxins and polychlorinated biphenyls in fish are low, and potential carcinogenic and other effects are outweighed by potential benefits of fish intake"6.

The US Institute of Medicine suggests pregnant women limit their consumption of higher methyl mercury-containing fish (e.g., tuna) to one meal per two weeks; and other fish (e.g., salmon, sardines) to two to three meals per week6.

Non-pregnant persons can eat one meal weekly, and two to three meals weekly respectively6. Based on available research, these are very conservative guidelines.

There exists a misconception that vegetarians and vegans can obtain adequate dietary DHA by eating foods rich in alpha-linolenic acids (ALA) such as flax seeds, soybeans, pumpkin seeds and  walnuts7. ALA is converted to DHA in the body, but in very small quantities. Research demonstrates that 9% or far less  (as little as 0.04%5) of ALA will ultimately be converted to DHA5. Further evidence exists that ALA supplementation in vegetarians resulted in no increases in DHA levels5.

Nutritional Supplementation with DHA

Fish oil supplements are the simplest means of supplementing with DHA (DHA amounts in particular supplements are listed on the label).

For vegetarians and vegans, algae-based DHA supplements are available, which resulted in DHA increases where ALA supplementation did not3.

What you need to know about DHA and your/your child’s  health

  • DHA is a very important nutrient for development of the human brain
  • Maintaining optimal DHA levels is of particular importance during pregnancy and in the first six years of life
  • DHA must be obtained from the diet, and on a regular basis
  • Three meals of  “low food chain fish” is a safe, and conservative recommendation for fish consumption
  • Most persons, but particularly vegetarians and vegans, especially if pregnant or breastfeeding should use a nutritional supplement supplying preformed DHA

References

  1. Horrocks LA1, Yeo YK. Health benefits of docosahexaenoic acid (DHA). Pharmacol Res. 1999 Sep;40(3):211-25.
  2. Chang CY1, Ke DSChen JY. Essential fatty acids and human brain. Acta Neurol Taiwan. 2009 Dec;18(4):231-41.
  3. Kuratko CN, Barrett EC, Nelson EB, Norman S. The Relationship of Docosahexaenoic Acid (DHA) with Learning and Behavior in Healthy Children: A Review. Nutrients. 2013 Jul; 5(7): 2777–2810.
  4. Richardson AJ, Burton JR, Sewell RP, Spreckelsen TF, Montgomery P. Docosahexaenoic Acid for Reading, Cognition and Behavior in Children Aged 7–9 Years: A Randomized, Controlled Trial (The DOLAB Study). PLoS ONE. 2012 Sep 6 [cited 2017 Apr 10]. doi.org/10.1371/journal.pone.0043909.
  5. Bradbury J. Docosahexaenoic Acid (DHA): An Ancient Nutrient for the Modern Human Brain. Nutrients. 2011 May; 3(5): 529–554.
  6. Jeejeebhoy KN. Benefits and Risks of a Fish Diet - Should We Be Eating More or Less? Nat Clin Pract Gastroenterol Hepatol. 2008;5(4):178-179. 
  1. University of Maryland Medical Center [Internet]. Alpha-linolenic acid. [cited 2017 Apr 10]. Available from: http://umm.edu/health/medical/altmed/supplement/alphalinolenic-acid.
Apr 15, 2017 BY Du La
2 Comments
Pranitha Kumari   •   April 24, 2017

Thanks for sharing valuable information.It is very useful for me and also useful for who wants more information. Health Tips

Reply
Rachel Molenda   •   April 24, 2017

Glad you enjoyed it Pranitha! :) Rachel - Joyous Health Team


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