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Earlier this week, a new study came out that found that women who take fish oil in the last three months of pregnancy may actually lower their child’s risk of developing asthma. Of course, as with most studies, further research is needed to truly understand the scope of these findings. But the news added to that nagging sense that I should listen to all of the people in my life who won’t shut up about taking fish oil as a cure for literally everything. I decided to consult with some experts.

What is fish oil? First of all, it’s not, as I had imagined, the gross oil at the bottom of a pan when you’re frying a fish. Instead, we’re talking about the omega-3 fatty acids that are found in cold-water fish like mackerel, salmon, sardines, and halibut. The omega-3 fatty acids found in fish oil are also known as “essential fatty acids,” nutritionist Andrea Moss of Moss Wellness tells me.

Why are these fatty acids so “essential”? Our bodies get most of the fats we need to survive through our diets — except for essential fatty acids like omega-3s. These fatty acids improve oxygen uptake and circulation, and aid in the formation of cell walls. Without them, we’re at risk of liver and kidney problems, diminished immune capacity, depression, and a host of other medical problems, according to the Physician’s Committee for Responsible Medicine. That’s why these fatty acids are so vital. “We refer to these as essential fatty acids because the body can’t actually make its supply on its own,” Moss explains. “So what that means is, we actually need to consume omega-3 fatty acids.”

What are the benefits of fish oil? According to registered dietitian and nutritionist Amy Shapiro of Real Nutrition NYC, many benefits of fish oil are still being researched, but plenty are already known. For one, fish oil can keep your triglycerides low and potentially prevent strokes and heart attacks by helping those muscles and systems function better. Fish oil also helps reduce inflammation, which is great for people suffering from joint pain and arthritis. It’s also believed to help with anxiety, depression, and ADHD, and on top of that, it can help with dry skin or eczema, since it’s a great source to keep the skin moist and fresh. Fish oil is also thought to help boost a woman’s fertility. In fact, Moss says she took it herself when she was trying to get pregnant.

So, how do I even take it? You can get fish oil in many forms. Of course, the ideal way is to eat cold-water fatty fish two or three times a week to obtain the benefits right from the source. But that’s not realistic for many of us, so Shapiro recommends people take a “well-researched” fish-oil supplement. She suggests people go to ConsumerLab.com to see which supplements are the purest, and then either take omega-3 fatty acids or cod-liver oil as an actual oil you add to smoothies or food, or just take it as a capsule.

But I’m vegan or vegetarian. Never fear; people who adhere to plant-based diets are able to get omega-3 fatty acids from sources other than fish oil. You can take a vegan supplement, or you can try to incorporate flaxseed, chia seeds, or walnuts into your diet. The body breaks down omega-3s from plant-based sources a bit differently, though, Moss warns, so while she recommends taking fish oil if you can, she understands the importance of making the choice that feels ethically, morally, and intuitively right for you.

Who shouldn’t take fish oil? As with any supplement, people need to make sure that fish oil is right for them before taking it. Everyone should consult with their doctor if they have any personal health concerns, Moss notes. And, because fish oil is a natural blood thinner, the nutritionist cautions that people with medical issues or who are about to go in for surgery shouldn’t take it. Also, fish oil is generally considered to be safe to take during pregnancy, but pregnant women should definitely consult with their doctors before taking it.

What should I look out for? One thing to note about fish oil is that, as we learned from Jeremy Piven, fish contain mercury. So, when you’re buying fish oil, make sure the supplement you’re taking is purified, mercury-free, and doesn’t contain any heavy metals.