Written by: Kevin Cann
One of the major differences in our diet compared to the diet of our Paleolithic ancestors, as outlined by Dr. Cordain in his article titled Origins and Evolutions of the Western Diet: Health Implications for the 21st Century, was the difference in fatty acid consumption. Our Paleolithic ancestors consumed omega 3 and omega 6 fatty acids in an even ratio (http://ajcn.nutrition.org/content/81/2/341.full ). Today we consume anywhere between 15:1 to 30:1 in favor of omega 6 fatty acids.
This is largely caused by the cheap manufacturing of industrial seed oils and the fear of saturated fats. Both omega 3 and omega 6 fatty acids are polyunsaturated fats (PUFA) and the USDA recommends that 70% of our fat calories come from these PUFAs. I wrote about the dangers of too much PUFA in the diet in a previous article, http://breakingmuscle.com/nutrition/why-simply-adding-fish-oil-doesn-t-work . What I would like to discuss today is the role these fatty acids play in our mental well-being.
Omega 3 fatty acids play a critical role in cognitive development as a child, specifically the long chain omega 3 fats DHA and EPA. DHA and EPA also play a critical role in us maintaining that cognitive awareness as we age. Studies have linked low levels of omega 3 fatty acids to schizophrenia, bipolar disorder, Huntington’s disease, obsessive compulsive disorder, and ADHD (http://www.sciencedaily.com/releases/2009/12/091216130718.htm ).
DHA seems to be the fat that plays the biggest role in cognitive development while EPA plays a larger role in helping us control our mood. Together meta-analysis has shown that they can positively contribute to aiding major depressive disorder and bipolar disorder with promising results for schizophrenia and borderline personality disorder. They have also been shown to mark improvements in ADHD, autism, dyslexia, and aggression as well as lower inflammatory markers (http://www.ncbi.nlm.nih.gov/pubmed/18072818 ). Omega 3 fatty acid supplementation has even been shown to increase cognitive skills in healthy individuals (http://www.ncbi.nlm.nih.gov/pubmed/16269019 ).
Omega 3 fatty acids are anti-inflammatory while omega 6 fatty acids are inflammatory. Researchers in Israel looked at the omega 6 and omega 3 fatty acid levels of rats to determine the role of omega 3 fats and depression. What they found was fascinating. They discovered that the depressed rats all had higher levels of omega 6 fatty acids and omega 3 fatty acids were similar for the two groups (http://www.sciencedaily.com/releases/2005/05/050525161319.htm ). This study is suggesting that high intake of omega 6 fats alone may be leading to depression regardless of how much fatty fish or fish oil pills you take.
Human studies have shown similar results. In a study performed on 43 adults researchers looked at blood samples to report inflammatory markers as well as omega 6 to omega 3 ratios. The higher the omega 6 ratios the higher the inflammation and depressive symptoms. In fact, the study included 6 patients with major depressive disorder and all 6 had higher omega 6 to omega 3 ratios when compared to the rest of the group (http://www.ncbi.nlm.nih.gov/pubmed/17401057 ).
That study looked at inflammation and depression and showed how one effects the other. Inflammation causes depression and depression increases inflammation. During the inflammation process our body makes protein messengers called cytokines. These cytokines relay important information to the cells of the brain and body. One in particular, interleukin 6 (IL-6) plays a major role in depression. IL-6 can cross the blood brain barrier and wreak havoc on neurons.
Studies have consistently found elevated levels of IL-6 in depressed patients. One theory suggests that traumatic stress brings about a rise in inflammation, which in turn causes elevated IL-6 levels, which then down regulates our mood (http://www.ncbi.nlm.nih.gov/pubmed/19359044 ). Another theory lies in our food intake. Studies have shown that partially hydrogenated vegetable oils (PHVO) are associated with higher intakes of inflammatory markers such as IL-6 and TNF-alpha (http://www.ncbi.nlm.nih.gov/pubmed/18842776 ).
TNF-alpha is another inflammatory marker that may have a critical role in depression. TNF-alpha is another cytokine just like IL-6. Studies have shown that TNF-alpha can induce depressive like symptoms even without malaise (http://www.ncbi.nlm.nih.gov/pubmed/16458261 ). The good news is that these inflammatory markers decrease as EPA increases (http://www.ncbi.nlm.nih.gov/pubmed/8604658 ). Like my previous article stated, you cannot just throw omega 3 fatty acids on top of omega 6 fatty acids and hope everything will change. Limit omega 6 fatty acid consumption and get a pound of fresh water fatty fish per week. If that is not possible 2g of EPA/DHA per day from fish oil supplementation is ok.
We talk about the modern diet being a major cause to obesity, diabetes, and cancer. We can throw depression and other mood disorders onto this list as well. One major difference between the diets of our ancestors and the diets today are ratios of omega 3 to omega 6 intake. Eat less processed foods as most are high in omega 6 fatty acids, eat more real foods that come from the earth, and get some fish in there a couple of times a week. Balance diet with social relationships, sleep, stress, and vitamin D and I assure you those negative feelings will get better.