In this final installment into DHA we should talk about DHA and your neurons. I’m sure it won’t be the last time I discuss it but for now we’ll leave it for a while. In the last 3 we talked about cardiovascular disease, cancer and arthritis. DHA has some interesting potential as being a useful agent for neurological health. Lets take a look and see what has been looked at.
Children with phenylketonuria have low protein intake and thus have low omega-3 intake. For fine motor skills it can be problematic because omega-3 is low and DHA is an important part of neurotransmission. In a study of children with PKU and controls who were supplied with fish oil, PKU children had improvement in motor skills where and controls did not. 1
DHA is important in fetal development and there appears to be a need for proper ratio of DHA and arachidonic acid (AA). This sounds much like the need for us adults to have a proper omega-3 to omega-6 ratio. Children who had higher levels of these in cord blood were deemed to have more “neurologic optimality”. 2 I think this was the way the researchers were trying to say that they were more neurologically developed at birth.
In a small study looking at patients with peroxisomal disorders (a disorder where the organelles in the cells are not functioning properly) researchers gave DHA ethyl ester because in these patients DHA is significantly reduced. After giving DHA liver function, vision and brain myelin images improved.3 Myelin is a sheet that covers nerves to produce action potentials which is an essential part of nerve transmission.
One the Alzheimers front, one study looking at patients with DHA levels found that patients with the lower levels of DHA had a 67% increased chance of developing alzheimers. They concluded that maintaining adequate levels of DHA is important, especially in the elderly. 4
In several studies of rodents (I know) use of DHA improved various outcomes including glial cell survival, decreased oxidative stress and improved function after injury. 5
In a review of epidemiological studies, low DHA intake is associated with pro-inflammatory conditions. Alzheimers, Parkinsons and severe depression also all show low levels of DHA. 6 Increasing intake in these at risk populations may be beneficial.
One extensive summary was done that looked at several studies and concluded that more studies are needed of longer duration and better quality. Many showed benefits, and many showed no benefit in various neurologic diseases. 7
Epidemiological studies don’t give us the whole picture though. It’s important to remember that because so many other factors may be at work. All we can really say from those is that there is an association. We know DHA is really important in brain function and we’re guessing that not enough DHA might be a problem with brain health.
Another potential problem with all of these studies, whether they’re looking at fish consumption, fish oil consumption or other forms of DHA is that they aren’t really looking at other parts of the diet. High levels of omega-6 fatty acids can decrease the conversion of ALA to EPA and DHA. Too much omega-6 is also proinflammatory so for a person who is consuming too much of it, no amount of omega 3 will do much to help the inflammation.
This situation is similar to others. Too much vitamin E has shown to be pro-inflammatory, at least when given as alpha tocopherol only. So if a person ingests regular amounts of alpha tocopherol for x, y or z, should he also ingest loads of vitamin C to counteract the oxidant effects of the alpha tocopherol? Probably better just to back off on it. I believe the same hold true for omega 6 fatty acids. Backing off is probably the better route to take than compensate with omega 3. This is why it will likely be impossible to do an adequate study. You have to control everything else that goes into a patient’s mouth.
Reducing soybean, corn, sunflower, safflower and other junk oils from a diet is actually a huge dietary change. Take a look at your labels in the pantry and just see what has those oils in it. I’m willing to bet if you have problems of any kind and eliminate those you might just start feeling better.
Disclaimer: All info on this website is for education purposes only. Any dietary or lifestyle changes that readers want to make should be done with the guidance of a competent medical practitioner. The author assumes no responsibility nor liability for the use or dissemination of this information. Anyone who chooses to apply this information for their own personal use does so at their own risk.
1. Koletzko, Berthold, et al. “Does dietary DHA improve neural function in children? Observations in phenylketonuria.” Prostaglandins, Leukotrienes and Essential Fatty Acids 81.2 (2009): 159-164.
2.Dijck-Brouwer, D. A., et al. “Lower fetal status of docosahexaenoic acid, arachidonic acid and essential fatty acids is associated with less favorable neonatal neurological condition.” Prostaglandins, leukotrienes and essential fatty acids 72.1 (2005): 21-28.
3. Martinez, Manuela, and Elida Vazquez. “MRI evidence that docosahexaenoic acid ethyl ester improves myelination in generalized peroxisomal disorders.” Neurology 51.1 (1998): 26-32.
4. Kyle, D. J., et al. “Low serum docosahexaenoic acid is a significant risk factor for Alzheimer’s dementia.” Lipids 34 (1999): S245-S245.
5.Michael-Titus, Adina T. “Omega-3 fatty acids and neurological injury.” Prostaglandins, Leukotrienes and Essential Fatty Acids 77.5 (2007): 295-300.
6.Orr, Sarah K., and Richard P. Bazinet. “The emerging role of docosahexaenoic acid in neuroinflammation.” Current opinion in investigational drugs (London, England: 2000) 9.7 (2008): 735-743.
7. MacLean, Catherine H., et al. “Effects of Omega‐3 Fatty Acids on Cognitive Function with Aging, Dementia, and Neurological Diseases: Summary.” (2005).