We Smell Something Fishy: The Debate Over Fish Oil Rages On

It seems like every time we check the news, there's a new wonder supplement that comes along and claims to cure everything, from acne to bad taste in men. The claims are so out there that it’s hard to know if they could possibly be true, or to resist the allure of popping a pill and having all your problems solved.

One particular pill adored by celebrity dermatologists and nutritionists alike is fish oil. Rich in omegas, fish oil is constantly touted to be the cure for what ails you. But is this "magic pill" really all it's cracked up to be?

A recent study done in the Netherlands showed that tumors in mice became insensitive to chemotherapy after being given normal amounts of fish oil supplements. The authors of this study concluded that substances that are found in traditional fish oil supplements are similar to protective substances that the body itself secretes into the blood that are powerful enough to block the effect of chemotherapy, meaning fish oil is a no-go for cancer patients.

One can only deduce that fish oil supplements are pretty powerful stuff if they can protect your cells from something as intense as the toxic chemicals used to kill cancer cells and be responsible for curing acne and preventing heart disease and dementia. Seems too good to be true, right?

We asked two experts — Dr. Eleni Linos, dermatologist and assistant clinical professor at UCSF, and Dr. Eduaro Dolhun, founder of the Dolhun Clinic and the nonprofit Doctors Outreach Clinics — our most burning questions about this high-profile supplement. Read on to hear what they have to say about the great fish-oil debate.

Why is there so much debate about these supplements? Why does it seem like every time one study comes out saying one thing, something else comes along to prove it wrong? According to Dr. Dolhun, “We are stepping into one of the most difficult areas in medicine. Over the next 15 to 20 years, a lot of folks will be weighing in on the pros and cons and doing the research, but right now the most authoritative response is that we just don’t know yet. There is this search for a magic pill; what can I take that’s going to cure everything? But something like this just doesn’t exist.

Most diseases are an interplay between genetics and environment. If it’s not genetically coded — like the color of your eyes — then it’s environment, which includes everything you are exposed to. That means asbestos, that means alcohol, tobacco, stress. You’re trying to isolate one small factor among hundreds of thousands of factors and then use it to prevent complex diseases.”

Are there any dangers associated with fish oil? “The side effects are minimal,” says Dr. Dolhun, “but there is a risk of low-grade contaminated fish oil. Fish oils have been known to contain mercury and other heavy metals. Be smart if you are consuming fish oil and look at where it’s sourced. If you don’t consult with your doctor before beginning to take the supplements, make sure you tell him that you are taking them so he can keep an eye on your heavy metal levels.”

Dr. Linos agrees: “In general, there is nothing dangerous in fish oil, if you are careful about the source of supplements and make sure the brand regularly checks for heavy metals. The benefits of fish intake have been shown to outweigh the risks for many health outcomes." She also cautions that fish oil can have strong anti-coagulant properties, although this is usually not an issue for otherwise healthy young adults. It’s important to be careful and to check with your doctor to make sure that this effect won’t interfere with other medications you are taking.

Studies have shown that taking fish oil supplements over the course of several months can decrease your natural levels of vitamin E. Since vitamin E plays an important role in preventing UV-induced free radical damage to skin, especially in repairing sun damage, be sure that you add additional vitamin E into your diet in the form of almonds, raw seeds, and leafy greens like spinach and kale.

Are supplements more effective than just eating more oily fish? “There have been a lot of major studies done on supplements and, with very few exceptions, they just don’t end up being as effective as getting the nutrients from your diet,” says Dr. Linos. “These are big, randomized trials showing that they are not as effective. In general, it is probably better to have a balanced diet, and include fish in your regular diet, than rely on a pill.”

“Not all fish oils are created equal,” says Dr. Dolhun. “Are you really getting the fish oil they say you’re getting? There is only one FDA-regulated fish oil on the market, and it is really expensive. It’s like olive oil — the label can say that it’s hand pressed by little children in Rome, but at the end of the day you really have no idea what is in that bottle. The closer you can get to the live state, the better.”

Is fish oil really effective for treating acne? Most of the studies done on the connection between fish oil supplements and acne are still anecdotal, and involve only a small number (usually around five-10) of subjects. According to Dr. Linos, “In general, there is not a strong link between diet and acne. There are few high quality studies done on fish oil and acne, so we don’t have conclusive recommendations for acne specifically. However, fish oil is so beneficial for our general health and prevention of heart disease and stroke that there are many other important reasons to increase consumption.”

“We know that the components of fish oil play an important role in cellular growth, and that they cause an inflammatory response,” says Dr. Dolhun, “but by far the best anti-inflammatory — I mean there’s not even a close second — is regular exercise. Just the value of walking, swimming, or doing something physical every day is far greater than fish oil could ever be."

What about the supposed connection between the brain, memory, and fish oil?

A 2012 study done by UCLA Easton Center for Alzheimer's Disease Research found that participants with low levels of omega-3 fatty acids (also known as EPA or DHA) in their blood had slightly smaller brains and scored lower on memory and cognitive tests than people with higher blood levels of omega-3s. These results are part of long running study which has suggested intake of fatty fish like salmon and tuna can lower the risk of Alzheimer's disease and other causes of dementia.

However, the study doesn’t make it clear just how much fish or omega-3s the participants were consuming to get these results. According to Dr. Zaldy Tan, the study's lead author and a visiting associate professor in the geriatrics department of the University of California, Los Angeles, “There isn't a universally accepted target for the level of omega-3s in the blood."

"When it comes to brain function, the brain is made mostly of fat, so we know that there has to be some impact,” says Dr. Dolhun, “But we just don’t have the distinctive studies. Medicine is still learning.”

What about all the contradicting information out there about fish oil and heart health? “Societies with diets with more fish in them have lower rates of heart disease. That’s why researchers started looking at fish oil in the first place,” Dr. Dolhun says. The first studies on fish oil, done in the '80s, found a connection between omega-3s and improvements in levels of triglycerides — a type of fat in the blood that is associated with heart attacks. Subsequent studies found that omega-3s were shown to lower blood pressure and prevent heart rhythm abnormalities.

But all of this has been called into question by a recent, comprehensive study of nearly 70,000 people dating back to 1989 found that fish oil supplements just aren’t causing the results that people expected. "Omega-3 supplementation did not statistically significantly reduce all-cause mortality, sudden and cardiac death (heart attack), or stroke," says Dr. Moses Elisaf, the senior author of the study and a professor of internal medicine at the University of Ioannina Medical School, in Greece.

The results of this study have led scientists to speculate that fish oil doesn't provide the same benefits as omega-3s in their natural state. While the doses found in the pills are not really different in their composition, the super-concentrated form may not be absorbed by your body the same way that it would if you got a low, steady dose from eating foods rich in the same oils. “There is a lot of complexity in the oil," says Dr. Dolhun. "Whole sardines, with the bones in and everything, tend to be better for you. The more natural the source, the better.”

So, should a normal, healthy person be taking a daily fish oil supplement? “If you’re eating processed foods and Big Macs, and you’re not exercising, and you’re taking a fish oil pill — no, it’s not going to help,” says Dr. Dolhun. “Get out there, walk, socialize, work on your diet, and then fish oil might help. I am a big believer in fish oil and I do prescribe it to my patients, but only after making all these changes.”