Reviewed By: Steven D. Ehrlich, NMD
Review Date: 8/5/2015

Overview

Omega-6 fatty acids are essential fatty acids. They are necessary for human health, but the body cannot make them. You have to get them through food. Along with omega-3 fatty acids, omega-6 fatty acids play a crucial role in brain function, and normal growth and development. As a type of polyunsaturated fatty acid (PUFA), omega-6s help stimulate skin and hair growth, maintain bone health, regulate metabolism, and maintain the reproductive system.

A healthy diet contains a balance of omega-3 and omega-6 fatty acids. Omega-3 fatty acids help reduce inflammation, and some omega-6 fatty acids tend to promote inflammation. In fact, some studies suggest that elevated intakes of omega-6 fatty acids may play a role in complex regional pain syndrome. The typical American diet tends to contain 14 to 25 times more omega-6 fatty acids than omega-3 fatty acids.

The Mediterranean diet, on the other hand, has a healthier balance between omega-3 and omega-6 fatty acids. Studies show that people who follow a Mediterranean-style diet are less likely to develop heart disease. The Mediterranean diet does not include much meat (which is high in omega-6 fatty acids, though grass fed beef has a more favorable omega-3 to omega-6 fatty acid ratio), and emphasizes foods rich in omega-3 fatty acids, including whole grains, fresh fruits and vegetables, fish, olive oil, garlic, as well as moderate wine consumption.

There are several different types of omega-6 fatty acids, and not all promote inflammation. Most omega-6 fatty acids in the diet come from vegetable oils, such as linoleic acid (LA), not to be confused with alpha-linolenic acid (ALA), which is an omega-3 fatty acid. Linoleic acid is converted to gamma-linolenic acid (GLA) in the body. It can then break down further to arachidonic acid (AA). GLA is found in several plant-based oils, including evening primrose oil (EPO), borage oil, and black currant seed oil.

GLA may actually reduce inflammation. Much of the GLA taken as a supplement is converted to a substance called DGLA that fights inflammation. Having enough of certain nutrients in the body (including magnesium, zinc, and vitamins C, B3, and B6) helps promote the conversion of GLA to DGLA.

Uses

Omega-6 fatty acids may be useful for the following health conditions:

Diabetic neuropathy

Some studies show that taking gamma linolenic acid (GLA) for 6 months or more may reduce symptoms of nerve pain in people with diabetic neuropathy. People who have good blood sugar control may find GLA more effective than those with poor blood sugar control.

Rheumatoid arthritis (RA)

Studies are mixed as to whether evening primrose oil (EPO) helps reduce symptoms of RA. Preliminary evidence suggests EPO may reduce pain, swelling, and morning stiffness, but other studies have found no effect. When using GLA for symptoms of arthritis, it may take 1 to 3 months for benefits to appear. It is unlikely that EPO would help stop progression of the disease. So joint damage would still occur.

Allergies

Omega-6 fatty acids from food or supplements, such as GLA from EPO or other sources, have a longstanding history of folk use for allergies. Women who are prone to allergies appear to have lower levels of GLA in breast milk and blood. However, there is no good scientific evidence that taking GLA helps reduce allergy symptoms. Well-conducted research studies are needed.

Before you try GLA for allergies, work with your doctor to determine if it is safe for you. Then follow your allergy symptoms closely for any signs of improvement.

Attention deficit/hyperactivity disorder (ADHD)

Clinical studies suggest that children with ADHD have lower levels of EFAs, both omega-6s and omega-3s. EFAs are important to normal brain and behavioral function. Some studies indicate that taking fish oil (containing omega-3 fatty acids) may help reduce ADHD symptoms, though the studies have not been well designed. Most studies that used EPO have found it was no better than placebo at reducing symptoms.

Breast cancer

One study found that women with breast cancer who took GLA had a better response to tamoxifen (a drug used to treat estrogen-sensitive breast cancer) than those who took only tamoxifen. Other studies suggest that GLA inhibits tumor activity among breast cancer cell lines. There is some research suggesting that a diet rich in omega-6 fatty acids may promote breast cancer development. DO NOT add fatty acid supplements, or any supplements, to your breast cancer treatment regimen without your doctor's approval.

Eczema

Evidence is mixed as to whether EPO can help reduce symptoms of eczema. Preliminary studies showed some benefit, but they were not well designed. Later studies that examined people who took EPO for 16 to 24 weeks found no improvement in symptoms. If you want to try EPO, talk to your doctor about whether it is safe for you.

High blood pressure (hypertension)

Preliminary evidence suggests that GLA may help reduce high blood pressure, either alone or in combination with omega-3 fatty acids found in fish oil, namely eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). In one study, men with borderline high blood pressure who took 6g of blackcurrant oil had a reduction in diastolic blood pressure compared to those who took placebo.

Another study examined people with intermittent claudication, which is pain in the legs while walking that is caused by blockages in the blood vessels. Those who took GLA combined with EPA had a reduction in systolic blood pressure compared to those who took placebo.

More research is needed to see whether GLA is truly effective for hypertension.