DHA and Omega-3 Fatty Acids
The term healthy fat may sound too good to be true, but that’s exactly what docosahexaenoic acid (DHA) and other omega-3 fatty acids are. They are monounsaturated, which means they are room temperature – think oil instead of butter. (The other healthy fats are polyunsaturated fats, such as olive oil).
DHA is a long-chain omega-3 that is naturally present in fatty fish such as mackerel, salmon, sardines, trout, and tuna. In the human body, DHA is found primarily in the brain and eyes, and it is important for development of these organs. Adults with the highest levels of DHA are up to 47 percent less likely to develop dementia than those with lower levels of the substance, according to studies, and the fatty acids also help the development of visual and cognitive abilities in infants.
Another type of long-chain omega-3, eicosapentaenoic acid (EPA), also has numerous health benefits. Together, DHA and EPA have been shown to lower the LDL (“bad”) cholesterol level, heart rate, and blood pressure and boost HDL (“good”) cholesterol. Studies show that about 500 milligrams a day of DHA and EPA – the amount you’d get from eating about 8 ounces of fatty fish a week – is enough to produce benefits in an adult.
The American Heart Association recommends that all adults eat fish at least twice a week. And for fetal and infant brain and tissue development, the European Commission advises that all pregnant and breastfeeding women consume an average of at least 200 milligrams of DHA a day. (Guidelines and expert recommendations in the United States have flip-flopped in recent years because of concerns over mercury poisoning during pregnancy. According to the Food and Drug Administration, pregnant women should not eat king mackerel, shark, swordfish, or tilefish and should limit albacore tuna to 6 ounces a week). For those who choose not to eat fish, both fish oil and algal oil supplements are good sources of DHA. Certain foods and beverages are also now available in omega-3 fortified versions.
1. A shorter-chain omega-3 called alpha-linolenic acid (ALA) is found in plant foods such as flaxseeds, walnuts, and canola oil. The human body can covert ALA into DHA in very small amounts, but it’s important to consume both kinds directly.
2. A 2008 study found that farmed tilapia, a popular fish in the United States, has low levels of omega-3s, and high levels of unhealthy omega-6 fatty acids because of inexpensive, unhealthy food the fish have been fed.
3. Breast milk contains DHA and is the preferred source for infant nutrition. Babies who are not breasted should receive a formula containing DHA and arachidonic acid, another healthy fat.