What Is a DHA Supplement Good for, and Who Should or Should Not Take It?

DHA is an omega-3 fatty acid that your body uses for many functions. DHA supplements are generally good for everyone, but people taking medication that affects blood clotting, blood pressure, and other conditions should check with their doctor before taking DHA.

Docosahexaenoic acid (DHA) is a type of omega-3 fatty acid. Your body uses DHA for many functions, including cell growth and muscle activity. You have to get DHA from food because your body can't make enough on its own. This chemical is associated with many health benefits, and it is generally safe to take a DHA supplement. Read on to learn when you should. 

DHA has many benefits for your heart, brain, and other physical systems. Babies particularly need DHA, especially in their first six months of life, when their brains, eyes, and nervous systems are developing. 

DHA may also help manage the following conditions: 

Attention-deficit hyperactivity disorder (ADHD)

DHA is one of the most essential fatty acids for your brain and can help control symptoms of ADHD. It helps protect your brain and transmit information. If, on the other hand, your brain doesn't have enough omega-3 fatty acids, it can affect your brain in the following ways: 

• The protective sheath around brain cells or neurons degenerates.
• You have less serotonin, which can negatively affect your mood and mental activity.
• You have lower dopamine levels.
• You have fewer neural connections in your brain.
• You have a higher chance of experiencing low-grade brain inflammation.  

Heart disease

The omega-3 fatty acids found in fish may help prevent you from developing heart disease or help you manage existing heart disease. Specifically, DHA may: 

• Lower the triglycerides in your blood
• Reduce your blood pressure
• Lower your risk of developing blood clots
• Reduce the plaque buildup in your arteries

Rheumatoid arthritis 

Omega-3 fatty acids may help with some symptoms of rheumatoid arthritis, including morning stiffness, pain, and joint tenderness. This may reduce the need for anti-inflammatory medicines. 

Studies on DHA and other omega-3 fatty acids use a wide range of dosages, though most participants take between 1000 and 2500 mg of DHA and EPA combined. Always consult a doctor before starting to take any supplement: The following guidelines are general amounts.

Babies and very young children

Babies who are breastfeeding will get enough DHA as long as their mothers are. 

Children between the ages of four and eight

Children between the ages of four and eight can take 1000 to 1500 mg of DHA and EPA combined. Look for products that contain about twice as much EPA as DHA, though. Avoid products with only one or the other. Studies show that both are important. 

Older children

Children over the age of eight may be able to take a supplement that contains 2000 to 2500 mg of DHA and EPA combined. 

Adults

Adults can take up to 3000 to 4000 mg of combined DHA and EPA daily. You can also eat two to three servings of fatty fish per week, which is equivalent to about 1250 mg per day. 

Pregnant women

If you're pregnant, you should talk to your doctor about how much DHA you should take. Make sure you only use supplements formulated for pregnancy. 

Vegans or vegetarians

People who don't eat fish or animal products can take 200 mg of DHA from a serving of algae. 

Although DHA supplements are generally considered safe, there are some possible chemical interactions you should be aware of (both positive and negative): 

Drugs or herbs that reduce clotting

Taking DHA with anticoagulant or antiplatelet medicines, herbs, and supplements that reduce clotting may increase your risk of bleeding. 

Blood pressure medicine

If you take medicine, herbs, or supplements to reduce your blood pressure, taking DHA along with them may cause your blood pressure to drop too low. 

Vitamin E

People with low vitamin E levels should be cautious when using DHA supplements because they can lower your vitamin E levels. 

Medicine for diabetes

Since it's possible for DHA supplements to lower your blood sugar levels, they could increase the effectiveness of your diabetes medicine. 

Cyclosporine

Cyclosporine is often prescribed for people who have received organ transplants to help prevent transplant rejection. Omega-3 fatty acids may reduce some of the side effects of cyclosporine, but you should talk to your doctor before you add any herbs or supplements to the medicines you’ve been prescribed. 

Contraceptives

Birth control pills may reduce the effect of fish oil on lowering your triglycerides. 

Fish oil supplements have been associated with mild side effects, including: 

• Bad breath
• Fishy aftertaste
• Heartburn
• Nausea
• Diarrhea
• Rashes

Taking high doses of fish oil supplements may also increase your risk of bleeding or stroke. 

If you'd rather get DHA in your diet than take supplements, it is primarily found in fatty, cold-water fish such as: 

• Salmon
• Tuna, particularly bluefin tuna
• Sardines
• Shellfish
• Herring

Although the accumulation of mercury is sometimes a concern when you are eating fish, a few servings per week doesn't pose a hazard to healthy people and offers many benefits. However, pregnant women and those who are planning a pregnancy should avoid eating the following fish:

• King mackerel
• Swordfish
• Tilefish
• Shark
• White albacore tuna in excess of six ounces weekly