DHA Benefits and Medical Effects

Omega-3’s are long-chain polyunsaturated essential fatty acids that are vital to human health. Its primary components are DHA and EPA. EPA (eicosapentaenoic acid) is believed to play a role in the prevention of cardiovascular disease, while DHA (docosahexaenoic acid) is the necessary for proper brain and nerve development. DHA is a important fat, making up about 30% of the structural fats in the gray matter of the brain and 97% of the omega-3’s in the brain. The omega-3 fatty acids content of the newborn’s brain is multiplied by 3 to 5 times during the last 3 months of gestation and then increases again by the same level during the first 3 months of life.

DHA Benefits

DHA (docosahexaenoic acid) is one of the most common fatty acids in the brain. It is a important structural fat in the brain and retina accounting for up to 97 percent of the omega-3 fatty acids in the brain and up to 93 percent of the omega-3 fatty acids in the retina. DHA is also, an vital structural component of heart tissue and naturally found in breastmilk. DHA has a favorable effect on diseases such as arthritis, some cancers, hypertension, thrombosis, atherosclerosis, myocardial infarction, diabetes mellitus, and depression. DHA deficiencies are associated with attention deficit hyperactivity disorder, unipolar depression, adrenoleukodystrophy, phenylketonuria, and cystic fibrosis. Reduction in omega-3 fatty acid DHA in the brain are associated with cognitive decline during aging and with onset of sporadic Alzheimer’s disease. DHA builds cell membranes in the brain and protects against macular degeneration and colon cancer and relieves inflammatory bowel disease and autoimmune conditions such as lupus.and rheumatoid arthritis. Whereas EPA is the inhibitor of the enzyme delta-5-desaturase (D5D) that produces arachidonic acid (AA), DHA is an inhibitor of other key enzyme delta-6-desaturase (D6D) that produces the first metabolite from linoleic acid known as gamma linolenic acid.


It’s essential that pregnant women take in enough Omega-3 and that children in early infancy take in  Omega-3. In the last  three months of pregnancy, the need for omega 3 fatty acids is increased significantly, as this is the stage for brain development in the baby and DHA fatty acids are required. Omega-3 are even more vital during the third trimester, an important time period for fetal brain development. omega-3 fatty acids are also used after birth to make breast milk. A Danish study showed that women with  omega-3 fatty acids intake during pregnancy give birth to babies with normal birth weights and are less prone to giving birth prematurely. DHA is necessary for brain and eye development throughout the life stages. However is especially important during the first 2 years of life and early childhood. Between birth and 5 years of age, the  rain increases almost 3.5 times in mass. During this time it is important hat children consume enough levels of DHA in their diet to support this period of rapid brain and eye growth and development.

Eye Health

The brain, retina and other neural tissues are especially rich in LC-PUFA (long-chain polyunsaturated fatty acids). Omega-3 fatty acid DHA comprises approximately 60% of the rod outer segments of the eyes. The retina develops rapidly during the  recent months of pregnancy and the first 6 months of infancy. According to an analysis of several studies performed by scientists at “Harvard School of Public Health” and reported in the journal “Pediatrics“, the researchers found that healthy pre-term infants who were fed DHA-supplementation formula demonstrated significantly better visual acuity at 2 and 4 months of age, compared with similar pre-term infants who were fed formula that did not include the omega-3 supplementation.

New findings showed  that higher intake of omega-3 fatty acid DHA  is associated with lower risk for progression to DHAadvanced age-related macular degeneration. A 2009 National Eye Institute study that used data obtained from the Age-Related Eye Disease Study found individuals who reported the highest level of omega-3 fatty acids in their diet were 30 % lower probably than their peers to develop macular degeneration during a 12-year period. Findings of several studies, including one reported in the Feb 2001 edition of the American Journal of Clinical Nutrition indicate that eating high amounts of omega-3 fatty acids may help promote macular health. Researches also show that omega-3 fatty acids can help lessen dry eye syndrome, a chronic eye disease caused by a reduce in tear production or increase in tear evaporation.


Researchers, (the University of  Kuopia, and at Harvard Medical School) examined at the incidence of silent brain damage in approximately 3,500 people age 65 or older. Eating tuna or other non-fried fish was associated with a 25 percent less risk of these abnormalities, which are linked to higher rates of stroke and cognitive decline.

Omega-3 fatty acid DHA is also necessary for maintenance of normal brain function in adults. It is a component of several prominent phospholipids in the brain, with the highest levels of DHA being found in phosphatidyl-serine and phosphatidylethanolamine. Docosahexaenoic acid is taken up by the brain in preference to other fatty acids. DHA which reduces oxidative stress and enhances synaptic plasticity and learning and memory is the most abundant omega-3 in cell membranes in the brain. Omega 3 fatty acids concentrations influence the production of neurotrophic factors, which regulate the growth of new brain cells.

Experts believe the omega-3 DHA is preventive against Alzheimer’s and dementia. Individuals with Alzheimer’s have important lower levels of omega-3 fatty acid DHA in the neurons of their hippocampus, an area of the brain severely affected in the disease. This region is critical to creating recent memories. In a study  reported in 1991 in Lipids, a group of Swedish researchers found that levels of omega-3 fatty acid DHA were lower in brain samples of individuals with Alzheimer’s disease compared to healthy geriatric patients. In the Farmingham Heart Study, people with the maximum levels of  DHA experienced a 47 % decrease in risk of dementia and a 39% decrease in the risk of Alzheimer’s disease. Scientists have pinpointed the mechanism behind omega-3 fatty acids and vitamin D3 ability to increase the immune system’s capability to clear the brain of amyloid plaques that are associated with Alzheimer’s disease. In a  preliminary study reported in the February edition of the “Journal of Alzheimer’s Disease”, the researchers identified key genes and signaling networks regulated by vitamin D3 and the DHA that may help control inflammation and improve plaque clearance. “Our new study sheds further light on a possible role for nutritional substances such as vitamin D3 and omega-3 in boosting immunity to help fight Alzheimer’s,” explained Dr. Milan Fiala, at the David Geffen School of Medicine at UCLA.  Vitamin D, omega-3 may help clear amyloid.


Omega-3 fatty acid DHA seems to reduce inflammation in the body by suppressing a certain enzyme (COX-2) and inflammatory chemicals such as IL-1 (interleukin-1) and TNF (tumor necrosis factor). New researches  show that DHA has a significant inhibitory activity on the expression of cytokines in endothelial cells, which suppress the inflammatory process and may inhibit the progression of atherosclerosis. In a experiment that used human blood samples, DHA+EPA intake changed the expression of 1040 genes and resulted in a reduced expression of genes involved in inflammatory and atherogenesis-related pathways, such as nuclear transcription factorkB signaling, eicosanoid synthesis, scavenger receptor activity, adipogenesis, and hypoxia signaling.

Increased blood levels of omega-3 fatty acids are associated with lower levels of compounds linked to inflammation and heart illness. A study by Professor Manohar Garg from the “University of Newcastle” found that increased blood levels of the omega-3 fatty acids DHA  and EPA were associated with decreased levels of C-reactive protein. A recent study examined the association between omega-3 fatty acids and risk factors for different chronic diseases. The findings demonstrated  that increased levels of DHA and EPA were associated with reduced levels of several disease biomarkers. The researchers showed that increased RBC levels of DHA and EPA correlated with reduced levels of triglycerides and  C-reactive protein (CRP).


Serotonin and dopamine, which are receptors and neurotransmitters in the brain, are composed of omega-3 fatty acid DHA. The human brain is composed of over 60 percent fat and its primary fat is DHA. A healthy brain contains more than 20 g of omega-3 fatty acid DHA; and  is an vital component of neuronal membranes. The main function of brain cells is to transmit neurotransmitters. When brain cells fail to transmit these chemicals (such as serotonin) effectively, the sequel can be of psychiatric disease, including depression. Omega-3 fatty acids may improve brain function by making brain cell membranes more fluid.

More intake of omega-3 fatty acid DHA and EPA is linked with increased gray matter volume in brain regions controlling depression and mood. Dr. Sarah M. Conklin explained a study showing that the amount of omega-3 fatty acid consumed in the diet may cause positive anatomical changes in areas of the brain that regulate emotion. Fifty-five healthy adults had MRI scans to determine the volume of gray matter in specific brain regions. The more the intake of omega-3 fatty acids, the larger was the volume of gray matter in the anterior cingulate cortex, a brain area controlling emotion and mood and implicated in depression. “We were able to show that individuals who consumed more omega-3 fatty acids in their diets had more gray matter volume in areas of the brain important for regulating mood,” Dr. Conklin says. Dr. Andrew Stoll, has done some of studies using omega-3 fatty acids in depression and bi-polar disorder. Dr. Stoll showed that  omega-3 fatty acids may inhibit neuronal signal transduction pathways in a manner similar to that of lithium.

In a 2006 study reported in the January edition of “Acta Psychiatrica Scandinavica”, 16 new mothers with postpartum depression took 0.5 to 2.8 g of EPA/DHA daily for 8 weeks. Depression scores decreased approximately 50% in all groups. When 20 menopausal women with major depression took 2 grams of  DHA and EPA daily for 8 weeks, 70% found their mood developed, and 45% found their depression went into remission. Mean scores on the Montgomery-Asberg Depression Rating Scale dropped from 24.2 to 10.7. In a study conducted in 2011,  medical students who took a daily omega-3 supplement containing 348 milligrams DHA and 2,085 milligrams of EPA for 12 weeks had a 20 percent decrease in anxiety compared with students who took a placebo. A multi-center study in the USA showed that supplement with 900 milligrams of  DHA/day was associated with developed earning and memory function in adults whose cognitive performance had declined.


Data from the MRFIT study have indicated that increasing intakes of EPA+DHA up to 700 mg/day are associated with overall reductions in all-cause as well as coronary disease-related mortality. Omega-3 fatty acids inhibit the production of thromboxane A2 and inflammatory cytokines. Both of these changes tend to reduce the tendency of blood to clot, which should the risk of a fatal heart attack. According to researches involving patients suffering from cardiovascular such as myocardial infarction and rhythm disorders, omega-3 fatty acids were responsible for decreasing  mortality by 20% to 56%.  Omega-3 fatty acid DHA has been shown to lower triglyceride. This can decrease the risk of heart disease. New findings show that taking 3 grams daily of pure omega-3 fatty acid DHA produce a 30-40% more decrease in triglyceride levels in plasma than a corresponding amount of EPA.


EPA and DHA induced programmed cell death in colon cancer cells and prostate cancer cells, and omega-3 fatty acid DHA supplementation decreased tumor size in a mouse model of cancer. A study in the European Journal of Cancer Prevention suggests a decreased risk in breast and colorectal cancer with increased DHA and EPA intake. Preliminary studies suggest that taking omega-3 daily may help slow the progression of colon cancer in people with early stages of the disease. Researchers at Vanderbilt University Medical Center have found that eating omega-3 fatty acids regularly can result in prevention of colon polyp formation.

DHA Food Sources List

DHA is present in salmon, tuna, mackerel, trout, halibut, sardines, and herring. Algae usually provides just DHA.


The American Heart Association recommends consuming 1–3 g per day of DHA and EPA. Several studies documenting the positive effects of omega-3s have been conducted with supplemental daily dosages between 2 to 5 gr of DHA and EPA, more than could get in 2 servings of fish a week. The European Perilip Group of clinicians and experts in omega-3 research, currently recommend  minimum 200 milligrams of omega-3 fatty acid DHA per day during pregnancy and lactation. 300mg/day of omega-3 fatty acid DHA for pregnant and lactating women was the recommendation by a workshop sponsored by the National Institutes of  Health and International Society for the Study of Fatty Acids and Lipids. A dose of 2-4 g of DHA+EPA per day  may lower very high triglycerides by 20 % to 50 %. 800 mg DHA and 1,600 mg EPA/day in adults provides an development in sustained attention, reduces errors in attention tests and provides developments in reaction times measured by electromyography. A new study of healthy older adults with mild memory problems found that supplement with 900 milligrams  of  DHA daily developed their memory. (Oily fish can include high levels of toxic pesticides, dioxins, PCB’s, or heavy metals such as mercury and lead. Therefore, choose just brands of fish oil that are molecularly distilled or otherwise guaranteed to be free of toxic contaminants).

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