Featured Stories

The Truth About Fish Oil

Heart disease, depression, diabetes, memory loss. Omega-3 fish oil has been touted as a panacea. But what does the science say?

Paul Greenberg
Aug 2, 2018 · 10 min read

recently learned from an eminent cardiologist that around half of all patients first report heart disease to their doctors by dropping dead. No conversation where the physician lays on a tender hand and whispers, “I’m a little worried about your triglycerides.” Just fibrillation followed by abrupt arrest. Boom. Finis.

To date, no one has succeeded at pinpointing the exact cause of sudden cardiac death. Is it a chemical imbalance in the body owing to years of bad dietary habits? Is it an electrical short circuit where the heart fails to get the right signals across misfiring cell membranes? No one quite knows. But a significant amount of medical researchers think it might have something to do with the omega-3 fatty acid.

What first drew me to the omega question was the same thing that draws most people to omega-3s. I was approaching 50. My blood pressure was higher, my heart rate elevated, my energy diminished. Cholesterol, the bad kind, flirted with requiring medication. When I indulged the late-night urge to troll the dark web of the supplement world, searching for some nonpharmaceutical way around all of these afflictions, standing at every turn was the omega-3.

A search for the phrase “omega-3s may” produced a bizarre panoply of speculations. Omega-3s may “help prevent coronary heart disease,” “increase brain volume,” “boost sperm competitiveness,” “build muscle in older adults,” “prevent some forms of depression,” “help lower risk of Type 2 diabetes.” Many hypotheses. Taken collectively, they promised no less than a cure for middle age itself.

But what was the omega-3? What did it actually do in the human body and in the natural world? Why was it always mentioned but never satisfactorily explained? These questions set me off on a global omega journey, from darkest Peru to farthest Antarctica, across the Mediterranean to the tippy-top of Norway, and on to the annual meeting of the omega-3 industry in the Canary Islands.

But just as I started making my way around the world, a raft of negative studies about omega-3s started hitting the presses. The New England Journal of Medicine, the Journal of the American Medical Association, and several others all seized on what they saw as an omega hoax. Most damning of all was a meta-analysis in the Journal of the American Medical Association that reviewed dozens of recent studies and concluded that omega-3 supplementation “was not associated with a lower risk of all-cause mortality, cardiac death, sudden death, myocardial infarction, or stroke based on relative and absolute measures of association.”

While omega-6 fatty acids are every bit as essential to the human body as omega-3s, the way we eat them today is out of sync.

That’s when I realized that I had to look much further than the supplements. I had to look at omega-3s in the context of all the other food we eat and the systems that produce those foods. That’s what brought me to the epic struggle between the world of omega-3 and the world of omega-6. The physician who would school me in this was a Greek clinician named Artemis Simopoulos, whose story was contained in an omega-3 history by the science writer Susan Allport called The Queen of Fats.

Simopoulos grew up in the midst of a panic about fat. After President Eisenhower suffered a heart attack in office and Ancel Keys published his Seven Countries Study that demonized saturated fat and cholesterol, Americans came to believe that all fat was bad. But Simopoulis took issue with this way of thinking, because it didn’t address the dynamic way certain fats acted in the human body. “I met Ancel Keys,” Simopoulos told me over a cup of murky, dark Greek coffee emblazoned with an illustration of the Parthenon. “Keys wasn’t a physician. He didn’t understand human metabolism. All Keys cared about was saturated fat.”

The overbearing presence of Keys and his cholesterol obsession bothered Simopoulos so much that she began an analysis of the traditional Mediterranean eating patterns. While teaching at the Mediterranean Agronomic Institute of Chania, she went back to some of the original Seven Countries Study data and made further analyses of what she thought was the true model for eating. Simopoulos found a marked difference — in particular, the presence of a succulent called purslane.

Purslane is a plant that grows wild throughout the rough terrain of the Greek islands and coastal headlands. Simopoulos noticed it one day in the 1970s while observing the eating habits of chickens at her family’s country home. Almost to a bird, she noticed, they ate purslane. How, Simopoulos wondered, would this be reflected in the chemical composition of chickens and eggs?

Back in the lipid lab at the National Institutes of Health, she and Norman Salem, PhD, did a profile of Greek eggs and the eggs produced by grain-fed chickens in the United States. The lipid analysis was surprising. The Greek egg had a ratio of omega-6 to omega-3 fatty acids close to one-to-one. The U.S. egg showed an omega-6 to omega-3 ratio of 20-to-one. Simopoulos realized this imbalance appeared everywhere in the U.S. diet. Notably off-kilter were the cooking oils in which Americans drowned their food. Corn oil: 66-to-one. Soy, the most prevalent oil of all: 12-to-one. Taken collectively, this imbalance amounted to what one clinician at the National Institutes of Health told me was “the largest single change to the American diet in the last hundred years.”

Simopoulos believed this was a critical dietary mistake, primarily because excessive omega-6 leads the body in negative directions with regard to inflammation. Inflammation is one of the chief ways the body prepares to defend itself against microbial attack. It begins when capillaries dilate, opening a gateway for white blood cells to launch a counterattack against bacteria and viruses.

The problems with inflammation begin when it doesn’t subside. Extended periods of inflammation put pressure on nerves and possibly stimulate pain receptors in affected areas. Inflammation has been implicated in cardiovascular disease, dementia, cancer, Type II diabetes, and arthritis. The fact that Mediterranean people have generally lower rates of all these diseases implied that the Mediterranean eating pattern somehow addressed inflammation.

This is where omega-6 fatty acids come in. These include arachidonic acid, which is a precursor for compounds called prostaglandins that in some reactions can be inflammatory. Prior to beginning her own investigations, Simopoulos had been following the work of William Lands and other biochemists who had looked into the ways that omega-6s are processed in human cells.

Omega-3s and omega-6s are both essential fatty acids that our bodies need to function and that we must get from our diet. That said, they can lead cells in markedly different chemical directions — so different that Lands describes them as Cain and Abel, brothers but inherently competitive.

This makes sense if you consider what omega-3s and omega-6s do in nature. Omega-3s work in the body of fish to increase flexibility and speed up the transfer of energy across cell membranes. That’s why they are so present in cold-water fish such as salmon and mackerel. But the purpose of omega-6s in ecological metabolics seems more key to storing energy rather than spending it. It is for this reason that seed crops like corn and soy are so rich in omega-6 fatty acids.

For physicians like Simopoulos, the imbalance between omega-6 and omega-3 seemed a plausible cause for many Western diseases. Fat was responsible, just not in the ways Keys had proposed. Instead, fats were reactive, and different fats reacted in different ways. This revelation led Simopoulos to reconstruct what ancient Mediterranean people ate. Her conclusion was that like the chicken she’d observed plucking purslane, early Mediterranean humans would have eaten a combination of wild field greens high in short-chain fatty acids, seafood with long-chain omega-3s, browsing wild game, monounsaturated olive oil, and only a smattering of grains. All of this would have resulted in an ancient Mediterranean diet that had a ratio of about one-to-one.

So, while omega-6s are every bit as essential to the human body as omega-3s, the way we eat them today is out of sync with the foods with which we evolved. A 2016 recent study in the British Journal of Nutrition found that organic meat and dairy, which is typically fed more grass than conventional livestock, had an omega-3 level 50 percent higher than grain-fed animals.

But Americans don’t eat that way. Our diet is heavily skewed toward the omega-6. We eat animals that eat primarily corn and soy—crops that we subsidize to the tune of more than $15 billion annually. We eat processed potato and wheat products drowning in soy oil. We favor desserts soaked in high fructose corn syrup. In all, we consume some 200 pounds of land food meat annually compared with less than 15 pounds of seafood. And no wonder—all federal seafood programs combined receive less than $1 billion in government support annually.

What would happen if we made the omega-3 not just a supplement that we took to balance out our other bad behaviors, but rather the basis for a new human diet?

The other thing that is troubling about an omega-6 way of eating is the damage it does to the planet. After energy production, growing land food is the largest source of greenhouse gases in the planet. Feedlot beef generates a large portion of the world’s methane emissions, and methane is a much more potent greenhouse gas than carbon dioxide. And when we look at the carbon impact on seafood, it gives us further concern about the consequences of continuing our current carbon-intensive way of growing food.

What would it mean for both planetary health and human health if we followed a kind of omega principle where we figured out a way to make the omega-3 not just a supplement that we took to balance out our other bad behaviors, but rather the basis for a new human diet? What would an omega-3 world look like? More urgently for the person hitting middle age, what would human health look like in a world where omega-3s were the core of the food system, rather than relegated to a corner of a supplement shop?

A lot of this is spelled out in greater detail in my book The Omega Principle. But to start, here are some basic first steps:

Eat a Mediterranean/”pesceterranean” diet.

What does eating a Mediterranean diet mean? When I asked Walter Willett, one of the diet’s most cited scholars, he put it very simply: “It’s a whole package of healthy components—healthy forms of fat, whole grains compared to refined grains, a variety of fruits and vegetables, nuts, modest amounts of dairy, and low amounts of red meats. Put that all together and it basically describes the Mediterranean diet.” In the pesceterranean model, you would strive to make the animal protein portion of the diet as ocean-based as possible.

Try to get your omega-3s from food whenever possible.

When I asked NOAA scientist Gary Wikfors if any of his work at NOAA had influenced his personal eating habits, he replied very bluntly: “The first very practical aspect of my scientific knowledge that influences my own nutrition is to reject supplements. That comes from years of working with lipid chemists and algal samples and the precautions one has to take to avoid oxidation. No lipid is more prone to oxidation than omega-3. Oxidation will result in the creation of cytoxic compounds.”

These compounds are, at best, not helpful to living cells. In an industry where much fish oil is still being harvested using vessels that lack necessary refrigeration, oxidation remains a problem. Eventually it may be solved, but for now, follow the argument that a food should be eaten in context, and taking a lipid-based supplement outside of the context of other lipids seems to work against metabolic logic. In any case, four fillets of anchovies are enough to meet the 500-milligram daily dose most family physicians suggest for omega-3 consumption.

Check your omega 3:6 ratio.

While there will continue to be debates around taking omega-3 supplements, there does seem to be a fairly strong association between maintaining a healthy level of omega-3s in blood lipids and decreased risk of cardiovascular disease. It is now possible to determine the omega-3 level in your own blood. Several companies are currently active in this area. One, based in Sioux City, South Dakota, is called OmegaQuant. For a modest fee that does not require a visit to a physician, OmegaQuant will send you a finger-prick test and within a few weeks will provide you with the lipid profile of your blood, including a detailing of your omega-3/omega-6 ratio.

Eat oily fish low on the food chain.

Anchovies, herring, mackerel, and whiting are all fish that end up mostly being boiled down into animal feed and supplements, but they are, in fact, healthful and inexpensive.

Eat mussels or other farmed bivalves.

Mussels have a carbon footprint 30 times smaller than beef. At present, Americans barely eat them. Increasing consumption will encourage an increase in production.

Eat land-food meat and dairy sparingly and from grass-fed animals.

It is probably unrealistic to wean every reader from meat altogether. But a stride toward better management of the planet would be to limit the amount of meat we eat in general to a few portions per month — the amount, by the way, recommended in a Mediterranean diet. One gets even closer to the Mediterranean ideal if one favors pasture meat over feedlot animals. Grass-fed animals produce less methane and have a significantly lower carbon footprint. When raised on well-managed pasture, they have the added benefit of retaining nutrients on farmland and reducing the flow of wastes into rivers and other bodies of water. Grass-fed meat and dairy are also higher in omega-3s than feedlot animals, though keep in mind, their omega-3 levels are a fraction of those found in oily fish.

Image for post
Image for post
From The Omega Principle by Paul Greenberg, published by Penguin Press, an imprint of Penguin Publishing Group, a division of Penguin Random House, LLC. Copyright © 2018 by Paul Greenberg.

Welcome to a place where words matter. On Medium, smart voices and original ideas take center stage - with no ads in sight. Watch

Follow all the topics you care about, and we’ll deliver the best stories for you to your homepage and inbox. Explore

Get unlimited access to the best stories on Medium — and support writers while you’re at it. Just $5/month. Upgrade

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store