Evidence suggests that dietary intake of EPA and DHA is associated with a decreased risk for certain neuropsychiatric disorders – particularly Attention Deficit (Hyperactivity) Disorder (ADD/ADHD), Alzheimer’s Disease (AD) and Depression. AD is the most common form of dementia and is characterized by the presence of senile plaques in the brain that affect cognitive processes, including memory, reasoning and judgment. AD appears to be an inflammatory disease, based on evidence that the AD brain is under intense oxidative stress.
Although preliminary, omega-3 fatty acids have shown considerable promise in reducing risk of AD. In one such study, the association between DHA levels in the blood and dementia in 899 men and women (average age 76) was examined. The participants, who were free of dementia at the start of the study, provided blood samples and underwent neuropsychological testing. After an average of nine years of follow-up, the researchers documented 99 cases of dementia, including 71 with AD. Men and women who consumed the highest level of DHA over the nine years, had a 47 % lower risk of developing dementia and 39 per cent lower risk of developing AD than those consuming lower DHA levels.
Low levels of dietary EPA and DHA have also been linked to the severity of depression64. For example, the regular use of cod liver oil has been correlated with lower levels of depressive symptoms in the general population. The prevalence of depressive symptoms among those who used cod liver oil daily was 2.5% versus 3.8% in the rest of the population. A comprehensive analysis of the literature in this area revealed a protective effect of DHA and EPA in mood disorders, particularly in depression.
In humans, omega 3 fatty acids reportedly play a role in the etiology of attention-deficit hyperactivity disorder (ADHD) and aggression. Children and adults with ADHD have been found to have significantly lower levels of blood DHA. A sample of 35 young adult college students with clinically diagnosed ADHD has recently been studied in comparison with a matched group of 112 students without ADHD. Significant inverse relationships were found between blood cell DHA levels and inattention and hyperactivity, suggesting that lower DHA status was associated with more severe behavioral symptoms.
Kelley Fitzpatrick
Director of Health & Nutrition
Flax Canada
