Omega-3 Fatty Acids
For a long time, people shunned fats and fatty foods believing that all fats are bad for you. But experts now agree that there are some fats that are not only good for you but are actually essential, such as omega-3 fatty acids.
To understand what omega-3 fatty acids are, it may be helpful to have a short lesson on dietary fats. There are two general types of fats: saturated and unsaturated. Saturated fats are typically found in animal products (like milk and butter) and are hard at room temperature. Since saturated fats have been linked to a higher risk for heart disease, people are advised to limit their consumption of these fats.
Omega-3 fatty acids are unsaturated fats. Unsaturated fats, which are liquid at room temperature, are found in vegetable oils, some animal products, nuts, seeds and soy and have a number of health benefits. It’s important to get these fats in your diet.
Two types of unsaturated fats are omega-3 and omega-6 fatty acids. Docasahexaenoic acid (we’ll call it DHA from here on in) and eicosapentaenoic acid (we’ll call that one EPA) are the two principal omega-3 fatty acids. In general, EPA and DHA are found from fatty fish and marine plants like algae and are often referred to as “fish oils.” The body can make some DHA and EPA from a third omega-3 fatty acid, alpha-linolenic acid (ALA) but the process is an inefficient one. As a result, it’s better to get EPA and DHA from the diet or a daily supplement.
DHA is particularly important for the health of our eyes, brain, heart and skin.
Omega-3s in the Diet
As mentioned above, the best source of omega-3 fatty acids is fish, particularly fatty varieties like salmon, mackerel, tuna, halibut, anchovies and sardines. It is also found in some fortified foods, like eggs and milk.
The United States’ Dietary Guidelines for Americans recommends that people consume two three-ounce servings of fatty fish per week. The European Food Safety Authority (EFSA) recommends 250 mg of EPA and DHA per day for adults as well as children aged two to 18 years. EFSA also recommends that infants over six months of age and small children under age two have a minimum intake of 100 mg of DHA per day.
Omega-3s and Brain and Eye Health
EPA and DHA are found in the walls surrounding our cells (known as cell membranes) and help keep those cell walls fluid and flexible. Because the eye membranes are among the most fluid and flexible membranes we have in our bodies, they contain a large amount of EPA and DHA. DHA is also thought to help the retina convert light into electrical signals.
DHA’s role in eye health starts very early. During pregnancy, DHA – and to a certain extent EPA – accumulate in the brain and the eyes of the fetus, especially during the last trimester of pregnancy, leading scientists to believe that DHA is important for brain development and visual acuity. The role was thought to be so important, in fact, that in the 1990s, DHA was added to infant formulas in Europe to better replicate what was in breast milk. DHA fortification of formula was permitted in the U.S. in 2001. More recently, EFSA recognized that maternal intake of an additional 200 mg/day above the recommended intake for adults contributed to the normal development of both the eyes of fetuses and breastfed infants.
Research indicates that children whose mothers had optimal intake of DHA during pregnancy and breast-feeding perform better in school than kids whose moms did not have adequate intake. In one study, the children of mothers with the lowest seafood intake had the biggest risk of poor behavior and lower scores in fine motor skills, communication and social development.1 DHA has also been associated with improved concentration and improvement in attention deficient disorder with hyperactivity-like symptoms.2,3
In adults, supplementation with omega-3 fatty acids has also been shown to improve memory and to slow cognitive decline in older adults. Research indicates that elderly people who eat fish or seafood at least once per week are at lower risk for developing dementia, including Alzheimer’s disease. Experts suggest that omega-3s improve blood flow to the brain and may help regenerate nerve cells. Omega-3 fatty acids may also be effective in mood disorders like depression and bi-polar disorder.
DHA has also been associated with dry eye syndrome (DES). DES is an uncomfortable condition in which there aren’t enough tears to lubricate and nourish the eye. It is caused by a number of factors – including age – and can also be a secondary effect of several diseases. In one study, a higher dietary intake of omega-3 fatty acids is associated with a decreased incidence of DES in women.4 Another study found that patients with Sjögrens syndrome, a cause of DES, had a lower intake of omega-3 acids.5
Like lutein, DHA and EPA are anti-inflammatory and may be helpful in preventing skin damage. Several studies have shown that supplementation with omega-3 fatty acids can minimize the redness that comes from exposure to UV radiation like that from the sun.6 Omega-3s fatty acids’ ability to protect the skin from UV exposure may also prevent the break down of collagen in the skin. Collagen is the tissue that gives skin its elasticity.
Another aspect of skin health where omega-3s appear to be effective is in wound healing. In two studies, supplementation with omega-3s improved the ability to heal blisters.7,8
Controlled clinical trials have consistently demonstrated that fish oil supplementation reduces overall death rates from heart disease. In particular, omega-3 fatty acids have been shown to reduce the risk of sudden cardiac death, a seemingly unexplained death due to the loss of heart function.9 Omega-3 fatty acids also decrease triglyceride levels, slow the growth of plaque in the arteries and lower blood pressure.10 A recent study demonstrated that omega-3 fatty acids reduce blood pressure as much as or more than other lifestyle factors like reducing sodium in the diet, restricting alcohol consumption and increasing exercise.11
A recent study found that those with the highest levels of omega-3 fatty acids in their blood had a lower risk of death, regardless of the cause, than those with the lowest levels. Life expectancy after age 65, was more than two years greater in those with high levels of omega-3s versus those with the lowest level. Another study compared patients who began taking an omega-3 supplement within three months of having a heart attack with those that did not. Those who took the supplements had a 22 percent lower death rate than those who didn’t take supplements.12
1 Lancet. 2007 Feb 17;369(9561):578-85
2 J Dev Behav Pediatr 2007 Apr; 28(2):82-91
3 J Atten Disord 2013 Nov 8
4 Miljanovic, Am J Clin Nutr. 2005. 82(4): 887-893
5 Cermak, et. al. European Journal of Clinical Nutrition (2003) 57, 328–334
6 Am J Clin Nutr May 2001 73(5):853-864
7 Wound Repair Regen 2008;16:337-345
8 Wound Repair Regen. 2011;19:189-200.
9 Global Organization for EPA+DHA Omega-3 Fatty Acids
10 American Heart Association
11 Am J Hypertens 2014 Mar 6
12 Clin Ther. 2013; 35: 40–51