Several clinical studies suggest that EPA / DHA lower blood pressure in people with hypertension. An analysis of 17 clinical studies using fish oil supplements found that taking 3 or more grams of fish oil daily may reduce blood pressure in people with untreated hypertension.

Diabetes

People with diabetes often have high triglyceride and low HDL levels. EPA / DHA can help lower triglycerides and apoproteins (markers of diabetes), and raise HDL. Also, some people with type 2 diabetes may have slight increases in fasting blood sugar when taking EPA / DHA

Rheumatoid arthritis

Most clinical studies examining EPA / DHA supplements for arthritis have focused on rheumatoid arthritis (RA), an autoimmune disease that causes inflammation in the joints. A number of small studies have found that EPA / DHA helps reduce symptoms of RA, including joint pain and morning stiffness. One study suggests that people with RA who take EPA / DHA may be able to lower their dose of non-steroidal anti-inflammatory drugs (NSAIDs). However, unlike prescription medications, fish oil does not appear to slow progression of RA, only to treat the symptoms. Joint damage still occurs.

Laboratory studies suggest that diets rich in DHA / EPA (omega-3 fatty acids) and low in the inflammatory omega-6 fatty acids, may help people with osteoarthritis, although more study is needed.

An analysis of 17 randomized, controlled clinical trials looked at the pain relieving effects of EPA / DHA omega-3 fatty acid supplements in people with RA or joint pain caused by inflammatory bowel disease (IBS) and painful menstruation (dysmenorrhea). The results suggest that DHA / EPA omega-3 fatty acids, along with conventional therapies such as NSAIDs, may help relieve joint pain associated with these conditions.

Systemic lupus erythematosus (SLE)

Several small studies suggest that EPA and fish oil may help reduce symptoms of lupus, an autoimmune condition characterized by fatigue and joint pain. However, two small studies found fish oil had no effect on lupus nephritis (kidney disease caused by lupus, a frequent complication of the disease).

Osteoporosis

Some studies suggest that omega-3 fatty acids may help increase levels of calcium in the body and improve bone strength, although not all results were positive. Some studies also suggest that people who don' t get enough of some essential fatty acids (particularly EPA and gamma-linolenic acid [GLA], an omega-6 fatty acid) are more likely to have bone loss than those with normal levels of these fatty acids. In a study of women over 65 with osteoporosis, those who took EPA and GLA supplements had less bone loss over 3 years than those who took placebo. Many of these women also experienced an increase in bone density.

Depression

Studies have found mixed results as to whether taking EPA /DHA omega-3 fatty acids can help depression symptoms. Several studies have found that people who took omega-3 fatty acids in addition to prescription antidepressants had a greater improvement in symptoms than those who took antidepressants alone. However, other studies have found no benefit.

Studies are also mixed on whether omega-3 fatty acids alone have any effect on depression. Depression is a serious illness and you should not try to treat it on your own. See a doctor for help.0.

Skin disorders

In one clinical study, 13 people with sun sensitivity known as photo dermatitis showed less sensitivity to UV rays after taking fish oil supplements. However, topical sunscreens are much better at protecting the skin from damaging effects of the sun than EPA / DHA omega-3 fatty acids. In another study of 40 people with psoriasis, those who took EPA with their prescription medications did better than those treated with the medications alone. However, a larger study of people with psoriasis found no benefit from fish oil.

Inflammatory bowel disease (IBD)

Results are mixed as to whether omega-3 fatty acids can help reduce symptoms of Crohn' s disease and ulcerative colitis, the two types of IBD. Some studies suggest that omega-3 fatty acids may help when added to medication, such as sulfasalazine (a standard medication for IBD). Others find no effect. More studies are needed. Fish oil supplements can cause side effects that are similar to symptoms of IBD (such as flatulence, belching, bloating, and diarrhea).

Asthma

Studies examining omega-3 fatty acids for asthma are mixed. In one small, well-designed clinical study of 29 children with asthma, those who took fish oil supplements rich in EPA and DHA for 10 months reduced their symptoms compared to children who took placebo. However, most studies have shown no effect.

Macular Degeneration

A questionnaire given to more than 3,000 people over the age of 49 found that those who ate more fish were less likely to have macular degeneration (a serious age-related eye condition that can progress to blindness) than those who ate less fish. Similarly, a clinical study comparing 350 people with macular degeneration to 500 without the eye disease found that those with a healthy dietary balance of omega-3 and omega-6 fatty acids and more fish in their diets were less likely to have macular degeneration.

Menstrual pain

In one study of 42 women, they had less menstrual pain when they took fish oil supplements than when they took placebo.

Coloncancer

Eating foods rich in omega-3 fatty acids seems to reduce the risk of colorectal cancer. For example, Eskimos, who tend to have a high-fat diet but eat significant amounts of fish rich in omega-3 fatty acids, have a low rate of colorectal cancer. Animal studies and laboratory studies have found that omega-3 fatty acids prevent worsening of colon cancer. Preliminary studies suggest that taking fish oil daily may help slow the progression of colon cancer in people with early stages of the disease. If you have colorectal cancer, ask your doctor before taking any supplements.

Breast cancer

Although not all experts agree, women who eat foods rich in EPA / DHA omega-3 fatty acids over many years may be less likely to develop breast cancer. More research is needed to understand the effect that omega-3 fatty acids may have on the prevention of breast cancer.

Prostate cancer

Population based studies of groups of men suggest that a low-fat diet including omega-3 fatty acids from fish or fish oil help prevent the development of prostate cancer.