Nutrition / Food

Here’s What Fish Oil Can and Can’t Do for You

Looking to add more unsaturated fat to your diet? Fish oil supplements can help.

If you’re trying to increase the amount of Omega-3 fats in your diet, you might turn to fish oil supplements for a quick fix. Fish oil—usually composed of salmon, mackerel, and sardines—is popular for multiple reasons. It can improve heart health, boost your brain, ease anxiety, decrease inflammation throughout your body, and more.

“Fish oil is the fat from fish,” says New York-based Dietitian Stephanie Bostic. “It’s composed of a variety of types of fats, including docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). The fat content of different fish oils varies based on the production method and source. They can have as many as 30 or more different kinds of fats!”

Our experts explain all the pros and cons of taking fish oil so that you know exactly how these supplements impact your nutritional goals.

Fish oil is good for heart health.

According to Registered Dietitian Vanessa Rissetto, the Omega-3 fatty acids in fish oil can help lower blood pressure and cholesterol. Studies say that it increases HDL levels, known as the “good” form of cholesterol, but doesn’t necessarily reduce levels of LDL, or “bad” cholesterol. Fish oil also can lower your triglycerides, or the fat in your blood. While more research is needed, studies also show that small amounts of fish oil can reduce blood pressure, prevent plaque from forming within your arteries, and even lower your risk of heart attack.

It can promote healthy brain function—for adults and babies alike.

Since nearly 60 percent of your brain is made up of fat, Omega-3s are essential for healthy brain function. “The fatty acids EPA and DHA have been associated with improved health outcomes, including cognitive health, mental health, and improved markers related to cardiovascular health,” says Bostic. “Babies whose mothers have higher EPA and DHA intake during pregnancy show improved vision and brain development.”

Taking fish oil may improve your mental health.

Even though supplements lack a high enough concentration of Omega-3s in comparison to other fats, Rissetto says that studies have shown that fish oil can lead to a reduction in ADHD symptoms, as well as a decrease in depression. In larger doses, fish oil may ease anxiety, help with mood regulation, and minimize or prevent symptoms related to psychotic disorders.

Fish oil may decrease allergies and skin issues.

Regularly eating fish or taking Omega-3 supplements can help decrease food allergies, as well as skin issues, like eczema, dermatitis, and psoriasis, notes Rebecca Park, a registered nurse in New York City and founder of a natural health website. For example, a 2013 study in the American Journal of Clinical Nutrition found that children who ate fish at least twice a month in their first year of life were 75 percent less likely to develop seasonal or food allergies.

Fish oil supplements benefit your vision.

“Omega-3, in particular, is especially beneficial for eye health,” says Park. “You can’t stop the degeneration of your eyesight. But you can change certain lifestyle and diet habits to slow down the process. Foods that are rich in vitamins, minerals, and antioxidants are good for the eyes. Vitamin A, Vitamin C, Omega-3, lutein, and zeaxanthin are especially beneficial for eye health.”

People who don’t get enough Omega-3s have a higher risk of eye disease, and while eating fish can prevent age-related macular degeneration, fish oil supplementation may not make much of a difference.

It decreases inflammation.

Chronic inflammation contributes to all sorts of diseases and illnesses, including cancer, and research indicates that fish oil can help treat inflammation throughout the body. In general, a diet low in Omega-3 fatty acids increases your risk of inflammation, and fish oil supplementation can specifically lower the amount of inflammation in your liver, plus reduce joint pain.

Are there any drawbacks?

Overall, Rissetto says that there are very few drawbacks to fish oil supplementation, though some can cause gastrointestinal issues. Bostic adds that anyone with a fish allergy should avoid it. Plus, people who take blood thinners, along with pregnant or nursing mothers, should discuss fish oil supplements with their health care provider first. Some small studies show additional side effects, such as increased blood sugar levels, nosebleeds, and acid reflux.

“For most healthy people, eating fish is the safest way to ensure that you receive those nutrients,” says Bostic. “Two servings a week of fatty fish, like salmon or tuna, provides sufficient levels of EPA and DHA to provide health benefits.” Other foods rich in Omega-3, according to Park, include mackerel, salmon, walnuts, chia seeds, herring, flaxseeds, tuna, white fish, sardines, hemp seeds, anchovies, egg yolk, and chia seeds.

“One thing to note is that you don’t want to overdo it,” says Aaptiv Trainer Jaime McFaden. “If you take too much, you could have some adverse side effects, like diarrhea. If you are taking supplements, you also want to be cautious of where they are coming from. The FDA doesn’t regulate every brand of supplement. So, be careful and ask your doctor what is the best choice for you. It can be confusing in the U.S. because there are so many options for fish. You can pick farm or wild, with or without dyes, etc. In some cases, it is safer to take a supplement if you don’t know where your fish is coming from. Personally, I try to get my fish oils from fish and other natural sources and use supplements when I notice [that] I am not getting enough.”

Food Nutrition


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