R&D: EPA, DHA and Cognitive Health -- June 2008
Although the only health claim allowed by the FDA for eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) is for heart health, there are other benefits of these polyunsaturated fatty acids, especially in the area of cognitive health. After consumption, EPA and DHA are both distributed to every cell in the body, where they are involved in numerous processes. In the brain, they are known to modulate membrane properties such as elasticity, thickness and fluidity. They also modulate signaling cascades, gene expression, and immunity and inflammation through gene regulation.
One company looking into the cognitive role of EPA and DHA and how they relate to dietary intake is Hormel Foods Corporation. Dr. Chet Rao, sales and marketing manager for Hormel Specialty Products, explains that DHA is the most prominent fatty acid in the brain, retina and spermatozoa, and is necessary for vision, cognition and sperm motility. It is especially rich in the neurons and synapses of the cerebral cortex, where it occupies the number-two position of the membrane phospholipids. Rao explains that, among the mechanisms that explain their importance in the brain, “the entrance of DHA into the brain could correct DHA deficiency in membrane phospholipids in the cerebral cortex in patients with Alzheimer’s disease, and EPA would counter the pro-inflammatory action of arachidonic acid, which is a precursor of cytokine and pro-inflammatory eicosanoids that may be associated with greater cognitive decline. The association of palmitic acid in the plasma cholesterol esters and phospholipids is of interest. This 16-carbon saturate is associated with thrombosis and the elevation of plasma LDL cholesterol that can lead to atherosclerotic obstruction. Both of these conditions could increase the tendency to develop dementia. Thus, EPA and DHA work synergistically to counter cognitive function decline with different mechanisms.” For instance, in a recent report from the Framingham Heart Study, people with high levels of phosphatidylcholine DHA had a significantly lower (47%) risk of developing all-cause dementia than those who had low levels (Scharfer, et al., 2006).
Although the research on DHA and EPA is strong, there is still confusion about the extent of conversion of parent polyunsaturated fatty acids--in the case of EPA and DHA, alpha-linolenic acid (ALA). Theoretically, humans have the necessary enzymes to convert ALA to the EPA and DHA; however, a recent review argues that in vivo studies in people show that asymptotically equal to 5% of ALA is converted to EPA, and <0.5% of ALA is converted to DHA. In fact, by supplementing large amounts of ALA to the diet, it has been shown that there is a negligible effect of plasma DHA (Plourde and Cunnane, 2007).
Hormel has allowed the research on fish oils to help guide the company in developing proprietary dietary supplements and ingredients, under the brand Eterna®. These are low in the odorous and flavor components that are typically associated with fish, yet contain very high oxidative stability for longer shelflife. Hormel claims their patented formulations also provide synergistic effects of ultra-low cholesterol omega-3 fish oils and free plant sterols to provide a natural way to lower bad cholesterols and are used to develop application-specific ingredients. The main options for bioactive components are Eterna for Heart Healthy and Active Lifestyle, with high EPA and DHA levels for the combined effects of both EPA and DHA, and Eterna for Mental Well Being, with high levels of DHA. NS
--Kerry Hughes, Contributing Editor
For more information:
Hormel Specialty Products * Austin, Minn.
Dr. Chet Rao * 507-434-6891
email@example.com * www.hormelingredients.com
Plourde M and Cunnane SC. 2007. Extremely limited synthesis of long-chain polyunsaturates in adults: implications for their dietary essentiality and use as supplements. Appl Physiol Nutr Metab. 32:619-34.