Omega-3 and omega-6 are types of essential fatty acids. Omega-3 fish oil is used for a variety of health benefits and is associated with stabilizing mood and improving other brain functions. Omega-6 is better known for its health risks rather than its benefits. The problem is one of proportion. Humans function optimally with an intake of 3:1 omega-6 to omega-3 fatty acids. However, as the University of Maryland Medical Center website explains, most people take in 14 to 25 times more omega-6 than is needed. The imbalance can produce functional problems of the brain.
Omega-6 and Depression
Researchers reporting in the June 2005 issue of the "Journal of Lipid Research" noted that many studies have linked omega-3 fatty acid deficiency to depression. To test the validity of the link, the researchers analyzed the fatty-acid composition of the brains of rats that were bred to have depressed behaviors. These rats returned to normal behavior when treated with anti-depressants. They then analyzed the fatty-acid composition of the brains of normal rats. The scientists found that both sets of rats had the same levels of omega-3 fatty acids; however, the depressed rats had much higher levels of omega-6 fatty acids.
Omega-6 and the Potential for Mental Illness
Dutch researchers reporting in the September 2006 edition of "Pediatric Research" cautioned that omega-6 overload in the diet of pregnant women may be linked to fetal brain development problems that manifest later as mental illness. The researchers demonstrated that the imbalance of omega-6 to omega-3 fatty acids in the mothers' diets transferred to the developing fetuses by measuring the content in the umbilical cords. The infants were tested at age 18 months, and those whose umbilical cords had contained the highest omega-6 concentrations scored lowest on neurological tests.
Mental Health as a Function of Omega Content
Researchers reporting in the July 2007 issue of "Psychiatry Research" recognized that a relative deficiency of omega-3s and high tissue levels of omega-6s are both associated with depression and anti-social behavior. They tested these findings in a group of 105 healthy adults. First they measured the fasting blood levels of these two fatty acids in the subjects. Participants then completed a series of tests gauging depression, personality, impulsiveness, hostility and anger. Another battery of tests measured basic brain functions including intelligence, short-term memory and delayed memory.
The Findings
The researchers found that a higher omega-6 to omega-3 ratio was associated with lower intelligence and with poor performance on tests of logical memory recall and visual reproduction recall. Further, higher levels of omega-6 were associated with greater odds of having mild-to-moderate depression. High levels were also associated with less control over both motor and emotional impulsivity. Higher levels of omega-3 were associated with less impulsivity, hostility, anger and cynicism. The authors concluded that fatty acid status is associated with variability in personality and self-control.
References
- University of Maryland Medical Center: Omega-6 Fatty Acids
- "Journal of Lipid Research"; Increased Arachidonic Acid Concentration in the Brain of Flinders Sensitive Line Rats, an Animal Model of Depression; Pnina Green et al.; June 2005
- "Pediatric Research"; Neurologic Condition of Healthy Term Infants at 18 Months: Positive Association with Venous Umbilical DHA Status and Negative Association with Umbilical Trans-fatty Acids; Hylco Bouwstra et al.; September 2006
- "Psychiatry Research"; Serum Omega-3 Fatty Acids Are Associated with Variation in Mood, Personality and Behavior in Hypercholesterolemic Community Volunteers; Sarah Conklin et al.; July 2007
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