A diet very high in omega-6 fat makes matters worse; your body makes even less DHA fat. We need enough DHA fat to ensure optimum health. The high level of omega-6 fat competes for the enzymes involved in fatty acid desaturation (conversion to longer-chain fats) and interferes with the conversion of alpha-linolenic acid (omega-3) to EPA and DHA. Therefore, our high fat intake contributes to our DHA fat deficiency.
Our modern diet, full of vegetable oils and animal products, is very high in omega-6 fat and very low in omega-3 fat; the higher the omega-6 to omega-3 ratio, the higher the risk of heart disease, diabetes, and inflammatory illnesses.2
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2. Simopoulos, A. P. 1999. Essential fatty acids in health and chronic disease. Am. J. Clin. Nutr. 70 (3): 560–69.