Docosahexaenoic Acid: Function & Diseases

Docosahexaenoic acid, like the other two omega-3 fatty acids alpha-linolenic acid (ALA) and eicosapentaenoic acid (EPA), plays an important role in keeping the body healthy. However, the proper ratio of omega-3 to omega-6 fatty acids should be considered when consuming the important fatty acid.

What is docosahexaenoic acid?

Docosahexaenoic acid – known as DHA for short – is one of the vital omega-3 fatty acids. The slightly yellowish liquid has the molecular formula C22H32O2. The long-chain, polyunsaturated fatty acid is an important building block in the cell walls of the brain, nerves and retina. DHA is produced by photosynthesis in tiny microalgae (spirulina), which in turn are consumed by creatures higher up the food chain. The higher up the food chain the creature is, the more DHA it has in its body. Fatty sea fish such as Atlantic herring, salmon, mackerel, sardines and tuna have a lot of DHA and EPA. People who want to avoid consuming fish can get the daily amount of DHA they need from alpha-linolenic acid-containing plant foods (canola oil, flax oil, flaxseeds, walnuts, etc.). However, alpha-linolenic acid can only synthesize about 2 to 5% of the daily required amount of DHA. Since the three omega-3 fatty acids ALA, EPA and DHA compete with the omega-6 fatty acid linoleic acid, an undersupply of EPA and DHA can quickly occur. The body of newborns can produce more docosahexaenoic acid than that of adults. To promote DHA formation, the health-conscious individual should ensure an adequate intake of vitamins C, E and B vitamins.

Function, effects, and roles

Docosahexaenoic acid dilates blood vessels and therefore has a blood pressure lowering effect. Due to the improved flow properties of the blood, organs and tissues are better supplied with oxygen. DHA eliminates arrhythmias and thus improves existing cardiac arrhythmias. If taken in sufficient quantities, it lowers high cholesterol levels and thus prevents heart attacks, arteriosclerosis and strokes. Because it prevents platelets from sticking together, it also reduces the risk of thrombosis. In addition, docosahexaenoic acid makes cell membranes elastic. It also has an immune system-promoting effect: docosanoids are synthesized from the fatty acid, tissue hormones that curb inflammatory processes in the brain and nerves. In rheumatic diseases such as arthritis, Crohn’s disease, ulcerative colitis and skin diseases such as psoriasis, it has an anti-inflammatory effect: it increases the level of eicosapentaenoic acid in the blood and thus reduces the formation of arachidonic acid, which has an inflammatory effect. As recently discovered, the polyunsaturated fatty acid DHA can even stop the growth of prostate cancer cells. Patients with the inflammatory chronic bowel diseases Crohn’s disease and ulcerative colitis should consume up to 5 g of omega-3 fatty acids daily. A sufficient amount of docosahexaenoic acid in the body keeps the brain and nerves functioning properly: The cell membranes located there play an important role in the development of dementia and Alzheimer’s disease and can positively influence the course of the disease if degenerative disease is already present. By keeping the membranes elastic, DHA reduces the production of pathogenic amyloid beta, a substance responsible for the amyloid plaques typical of Alzheimer’s disease in the brain and for the development of oxidative stress. As animal studies showed, docosahexaenoic acid dramatically increases the production of LR11 protein, which inhibits the formation of amyloid plaques.

Formation, occurrence, properties, and optimal levels

DHA is produced in the liver and is found in the brain and especially in nerve cell membranes: 97% of the fatty acids present in the brain are composed of DHA. It is also integrated in the photoreceptors of the retina (retina of the eye). It accounts for 93 percent of the fatty acids found there. In addition, docosahexaenoic acid is formed in large quantities in the mammary glands of nursing mothers. The infant receives this polyunsaturated fatty acid, which is important for the development of brain function, nerves and vision, through its mother’s milk. This is because the liver is not yet able to meet the increased demand. The female body can build up DHA better than the male body because of its higher estrogen level.DHA, which is not available to the body in bio-available form (fish meal or fish oil/krill oil capsules), is produced from alpha-linolenic acid. First, the fatty acid EPA, which is also important for maintaining metabolism, is produced. The enzymes delta 5 and delta 6 desaturase are necessary for this. To be able to produce them in sufficient quantities, the body needs vitamin B6, calcium, biotin, magnesium and zinc.

Diseases and disorders

Undersupply and also oversupply of docosahexaenoic acid have a detrimental effect on health. To prevent DHA deficiency, the German Nutrition Society (DGE) recommends consuming a maximum of 3 g of EPA and DHA in pure form daily (at least 100 g of fish 2 to 3 times a week or the corresponding number of fish oil capsules daily). For optimal supply, fish can also be consumed in frozen or canned form. Users who live vegan require at least 1200 mg of ALA-containing products daily. Since the average European hardly ever consumes these amounts, dietary supplementation with fish oil or algae oil capsules (for vegans) is recommended. The latter contain the appropriate dose of ALA. The EU Expert Commission advises pregnant and breastfeeding women to supplement their daily DHA consumption with an additional 200 mg. It is recommended that infants also be given DHA supplements during the first two years of life. However, users should pay attention to the optimal ratio of omega-6 to omega-3 fatty acids in their DHA intake, because if too much omega-6 is present in the body, less omega-3/DHA is produced. The German Nutrition Society (DGE) recommends a ratio of 5:1. In addition, he should take into account factors limiting DHA metabolism in the body, such as stress, lack of vitamins and trace elements, increased age, diseases such as diabetes mellitus, alcohol dependence, high cholesterol, viral infections, liver disease and chronic fat indigestion. Symptoms of DHA deficiency include tremors, impaired vision, muscle weakness, poor wound healing, decreased learning ability, and in infants, impaired growth and vision. Severe oversupply of docosahexaenoic acid increases the tendency to bleed, decreases the responsiveness of the immune system, and increases LDL cholesterol levels.