by Craig Weatherby
Last month, we published “Weight Gain and Omega-6 Fats” ...the second in a series of four reports from a recent fat-science conference, penned by omega-3 expert Joyce Nettleton, D.Sc. (You can see her last report, “Moody Omega-3 Message from Science Summit” in this issue).
As Dr. Nettleton's summary suggested, a growing body of evidence indicates that the average American's extreme over-consumption of omega-6 fatty acids from vegetable oils may be fueling the obesity epidemic… and causing many people to carry around some extra, hard-to-lose body fat.
It's one thing to read the results of cell and animal studies, and even human clinical and population studies, all of which support the idea that America's extreme “omega imbalance” promotes inflammation, disease, and weight gain.
But it's quite another to watch what happens when someone adopts an omega-6-rich diet like those eaten by most Americans, and see what changes, if any, medical tests detect.
Thanks to an experiment that intrepid science writer Susan Allport performed on herself—with the assistance of university scientists—we know what happened to one healthy woman.
Susan authored The Queen of Fats (University of California Press 2006), which remains the best book on the scientific and cultural history of these essential nutrients, and subject of its subtitle: Why Omega-3s were removed from the Western diet and what we can do to replace them.
You can think of her experience as Susan's own version of the Morgan Spurlock documentary “Super Size Me”, for which he ate nothing but highly processed, vegetable-poor fast-food meals for a month.
Susan's experiment seems much less extreme than Mr. Spurlock's, because she merely raised the proportion of omega-6 fats in her diet, to mimic the omega-6/omega-3 intake ratio of the standard American diet.
But that apparently modest shift produced alarming results, very rapidly.
Here's Susan's engaging account of her remarkable experiment, which she encouraged us to publish as a public service.
Omega-6 Me: One woman's journey to the dark side of the American food supply
By Susan Allport
Why would anyone put herself on a diet associated with weight gain, diabetes, heart disease, and depression?
That's the question I asked myself as I sped east on Route 84, on my way to the University of Connecticut. There, I would spend the night and undergo a series of tests before beginning this experimental meal plan.
For the next month, I was planning to eat a diet with a gross imbalance of the two essential fats: omega-3s and omega-6s, fats that are called leaf fats and seed fats because omega-3s originate in the green leaves of plants and omega-6s are much more abundant in seeds.
[Editor's note: As Susan explains, the long-chain omega-3s in fish (EPA and DHA) are the kind the body actually needs, and if needed, we can make them from short-chain omega-3 fat in plants (ALA). Fish and shellfish get long-chain omega-3s either directly from algae and phytoplankton, or by eating creatures that dine on algae and plankton and pass EPA and DHA (mostly DHA) up the aquatic food chain.]
These two fats, both of which are polyunsaturates, are currently grouped together in most health recommendations, including the U.S. Dietary Guidelines. But evidence is mounting that a balance between them is critical for good health.
The leaf fats, omega-3s, are the more dynamic of these fats. They speed up the activity of cells and are concentrated, not surprisingly, in all our most active tissues: brains, eyes, hearts, and sperm.
They originate in green leaves—including phytoplankton, the microscopic green leaves of the ocean—and accumulate in animals that eat green leaves: fish, of course, as well as grass fed cows and other animals.
Omega-6s, the seed fats, are slightly less dynamic and much more inflammatory. They help animals fight infections and store fat for the winter. In excess—as in the American diet and the diet I was planning to go on—they've been implicated in everything from obesity to heart disease; cancer to Alzheimer's and other mental disorders.
And that was what was worrying me. How much damage would I do to myself in a month? How much weight would I put on? I've spent much of my adult life trying to find that happy combination of foods that keep me slim without dieting; healthy and energetic without an unhealthy obsession with food. Now, I would be throwing all that hard earned knowledge away. Six years ago, when I began writing about omega-3s and paying attention to the balance of omega-3s and omega-6s in my diet, the pounds fell off and I could maintain a healthy weight without any effort. Now, I would be shifting the balance of those fats in my diet—and my tissues.
To the casual observer, the foods in my experimental diet would look just like my normal fare: lots of whole grains, nut butters, vegetables, fruits, lean meats, fish, and salads. But they would differ in a small way that I, and a growing number of scientists, know to be very important: the fats I would cook with; the oils I would dress my salads with would be vegetable (or seed) oils that are very rich in omega-6s, oils such as safflower, sunflower, corn, and soybean oil, oils that constitute most of the added fats in the American food supply.
Omega-3s and omega-6s compete for positions in our cells, as scientists have known since the 1950s, such that anyone consuming a diet too rich in omega-6s (and that would be me) would have fewer omega-3s in all of her tissues—no matter if she continued to eat fish.
Americans consume 10 times as many omega-6s as they do omega-3s, according to the Agricultural Research Service. And it is that imbalance—not the amount of fish we eat—that is causing us to be deficient in omega-3s, the scientists who study these fats realize. A healthy balance is on the order of 4:1.
So why was I doing this? Because no one, as far as I know, had ever done it before—and the results might just convince a few skeptics that the balance of omega-6s to omega-3s is really important. No one has ever taken an individual with healthy amounts of omega-3s in her tissues, and then switched her to a diet high in omega-6s— while monitoring the results.
This is very different from putting people with large amounts of omega-6s in their tissues on a high omega-3 diet— something researchers do all the time by giving fish oil to average Americans. Because we store large amounts of omega-6s (but not omega-3s) in our fat tissue, it can take years to see the benefits of those omega-3s. So the results of many of those studies have been equivocal or confusing. And it is very different from giving omega-6s to someone whose diet—and tissues—are already laden with these fats (the case with most Americans), a change that would have very little effect.
But going in the opposite direction might be very quick, I hypothesized. If animals, as I have suggested in my book The Queen of Fats, use the differences between omega-3s and omega-6s to prepare for the changing seasons— for periods of activity and reproduction when the faster fats of green leaves are available and periods of hunkering down and survival when the slower fats of seeds are more abundant, then the response to a high omega-6 diet would have to be pretty quick if it was going to be useful. This is why I volunteered to omega-6 myself for 30 days, and this is what I thought I might show.
The scientists I told about this project were enthusiastic (it was my body, after all, not theirs!). Doug Bibus, a worldwide authority on fats at the University of Minnesota, agreed to test my blood on a daily basis with his home omega-3 kit (www.omega3test.com) and monitor how the omega-3s and omega-6s changed over the course the month.
Bibus also put me in touch with Jeff Volek, an associate professor in the Human Performance Laboratory at the University of Connecticut, who offered to measure my resting metabolic rate, the amount of energy my body expended at rest, before and after the diet. He suggested running a number of other tests that his lab performs routinely, as well.
And so I was driving up to the University of Connecticut on the night before the diet would begin. Volek has all his subjects spend the night on campus, and fast for 12 hours, in order to minimize the noise, or day-to-day variation, in the resting metabolic test.
The next morning, I was woken at 6:15 am by a call from one of Volek's graduate students, Dan Freidenreich, who drove me the short distance from the inn to the Gampel Pavilion, which houses Volek's lab, as well as the stadium where the indomitable Huskies play. Dan left me in the car while he fetched a wheelchair to transport me to my first stop: a cot in a small, darkened room. The idea was that I should exert myself as little as possible before the test of RMR, or resting metabolic rate. By these careful measures, Volek has greatly reduced this test's day-to-day variation.
Dan weighed me and then I lay down and promptly fell back asleep. In half an hour, he woke me and covered me with a plastic tent-like contraption that would measure all the oxygen I would consume over the next thirty minutes, in a relaxed but wakeful state. Each liter of O2 consumed, Volek later explained, was the equivalent of about 5 calories. A woman my weight and height might be expected to have a resting metabolic rate of about 1367 calories a day.
Next up was the blood draw—five vials that would be divided at the end of the month between Volek and Bibus. And then a body composition scan using a state-of-the-art dual-energy X-ray machine to determine the amount, and distribution, of fat and lean tissue throughout my entire body (I was dressed in a hospital gown for this test, but had never felt so naked).
The scan was followed by an ultrasound of the artery in my arm (the brachial artery) and an assessment of how well this artery responded to an increase in flow—what scientists call sheer stress. This test, called Flow-Mediated Vasodilation, was developed in the 1990s and is a good measure of overall vascular health and a good predictor of the risk of developing atherosclerosis, hypertension and heart failure.
Omega-6s have been implicated in all these conditions (because of their inflammatory nature and because they also increase blood pressure and promote blood clotting and constriction of the blood vessels), and Volek thought it would be interesting to see if my month-long diet would produce a change in my arteries. I doubted it, but was impressed by how quickly I was taken through this, and all the tests. Each was conducted by a different graduate student, highly trained in his or her particular assay.
The morning ended with breakfast at the inn where I had stayed. I ordered scrambled eggs and whole wheat toast, something my omega-3 self would rarely ask for in a restaurant. Eggs are high in omega-3s when they are laid by chickens that forage for greens and insects—or chickens that have been fed a high omega-3 diet, such as flax and fish meal. But commercial eggs, of the kind that would be served in a restaurant, are sure to be high in omega-6s. The chickens that laid them are sure to have been fed on corn and soy.
And thus this month of omega-6 eating began.
I won't bore you with the details of every meal, but here are the kinds of changes I made:
Instead of my usual cereal (whole grain flakes with flax seed), I had either oatmeal or a whole grain cereal—without flax seed. Instead of the 1% milk I usually bought, from grass fed cows, I now bought 1% milk from grain fed cows. On those days when I didn't eat cereal, I had either eggs (commercial ones, of course) with whole grain toast or toast with peanut butter. My omega-3 self would have always spread Smart Balance peanut butter on this toast, made with flax oil and peanuts. For this diet, though, I bought freshly ground peanut butter, which is high in omega-6s, from the health food store. The other foods I always had at breakfast, bananas, grapefruit juice, and tea, remained the same.
I often had a sandwich and a bowl of soup – or a salad of arugula from my garden. When it was a peanut butter and banana sandwich, I made it with the whole peanut butter. When it was tuna fish, I made it with a mayonnaise made with soybean oil, instead of my usual canola-oil based mayonnaise. Canola, like flax and walnuts, are three seeds that happen to be rich in omega-3s, and all play a big part in my normal diet. My usual salad dressing is made of lemon juice, mustard, and a mixture of canola and extra virgin olive oils. For this diet, though, I dressed my salads with a mixture of safflower, sunflower, corn, and soybean oils.
Dinner was usually lots of vegetables or salad, accompanied by chicken, fish, pasta, or a baked potato. When I ate at home, I always used my mixture of high omega-6 oils as the cooking fat. When I ate out, I made the assumption that the restaurant also used one or more of these oils—because they tend to be less expensive and more shelf stable than oils that are high in omega-3s. I also made the assumption that the meats and fish they served were from grain fed rather than wild or grass fed animals. These assumptions probably overestimated the amount of omega-6s in my experimental diet—because many restaurants do, in fact, use canola oil for cooking, but it allowed me to eat out during this month. Fish was on my menu, at least twice a week, as recommended by the AHA, and I usually had wine or beer with dinner.
Dessert was often fruit, though sometimes ice cream or a piece of chocolate. I snacked throughout most days on fruit, raisins, and almonds—instead of my usual, omega-3 rich walnuts.
It wasn't an unhealthy diet—by most people's standards, and it certainly wasn't a “supersize me” diet. I knew it would be easy to put on five pounds from a month's worth of eating fast food, as Morgan Spurlock had shown. But I wanted to see what would happen if I just switched the balance of omega-6s and omega-3s in my diet. What would happen if I kept the quantity, and the kind, of food the same, but just changed the essential oils?
Most medical organizations, as I've said, wouldn't see anything harmful in this change, but a large number of scientists believe that our reliance on cheap, high omega-6 vegetable oils is the underlying cause of many of our health problems.
Both omega-3s and omega-6s are essential: We can't make them ourselves and must consume them in our diet. But a balance between them creates tissues with just the right amount of speed and activity, inflammation and blood flow. Ever since vegetable oil consumption began to skyrocket in the 1950s (replacing butter and lard) so has the incidence of inflammatory diseases, such as heart disease, and metabolic diseases, such as obesity and diabetes.
My temporary shift to a high omega-6 diet didn't result in any of these diseases (I hope), but I did experience an almost immediate thickening in my belly area. I know from the literature that omega-6s promote the development of fat tissue; still I was amazed it was happening to me. I didn't weigh myself during the diet since I feared that any weight gain might send me on a secret, subversive diet, but I felt sure that I was putting on pounds. Any other symptoms were more fleeting and hard to attribute to diet alone. My stomach felt on fire after several meals, and I flushed more and longer after drinking alcohol. My husband thought my body smell was different; and I was short of breath on several of my daily walks.
Flash forward 30 days, and I was thrilled to be at the end of my diet. By the time I returned to the University of Connecticut, I had a large, unpleasant wad of belly fat that I could grab in one hand. I was certain I had gained at least 5 pounds. I was shocked, therefore, when Dan picked me up in the morning, and then weighed me, before the follow up tests began. I couldn't believe it when he said that my weight was exactly as it had been a month before—56 kilograms or 124 pounds.
Could I have been wasting everyone's time? I wondered as I laid down on the cot to prepare for the test. And then I fell back asleep. My worries, apparently, were no match for the warmth of the room and the early hour.
Later that morning—after all the tests were completed, I learned from Volek just how profound the changes to my body had been. Yes, my weight was almost the same, but what weight I had gained—5.6 ounces or just under half a pound—was almost entirely fat and in my abdominal area, as the follow-up body scan showed—exactly as I had experienced it. Just as interesting, and the cause, perhaps, of this gain, was that my resting metabolic rate had fallen, by an intriguing five percent. This drop was within the day-to-day variation for this test (6.2%), but it was in the direction predicted by the diet and the magnitude to explain my small gain in weight.
In just one month, it seems, I had reduced the number of calories I needed to maintain my body at rest by 5%, the equivalent of 76 calories. This may not sound like a lot, but over time, those calories—the amount in a one-ounce piece of mozzarella, for example, or eleven whole almonds—would add up. If I didn't reduce my food intake in order to compensate for this decrease (go on a diet, in other words), I would put on a pound in about 46 days; 8 pounds in a year. And this 5% drop in metabolic rate was after just one month. What if I kept to this high omega-6 diet for six months? Or a year? A lifetime as most Americans do? Would my metabolic rate continue to fall?
The change in resting metabolic rate wasn't all. At the same time my RMR was falling, my arteries were becoming stiffer, or less able to expand and contract, as revealed by the follow-up ultrasound. In just 30 days, the amount of dilation my brachial artery was capable of had dropped by 22%, a change much larger than the day-to-day variation of this test. The direction of this change was also predicted by what is known about omega-6s, but the amplitude surprised everyone involved in this project.
In the coming weeks, these findings from Volek's lab were backed up by the results of the blood tests, analyzed by Bibus in Minnesota. At the same time my metabolic rate was decreasing and my arteries were becoming stiffer, the omega-6s in my red blood cells (and therefore the rest of my body) were increasing and the amount of omega-3s was falling—dramatically and precipitously.
In just ten days, the total amount of omega-3s in my red blood cells had dropped from 10% to 6%. The amount of omega-6s had risen from 21% to 29%. The substitutions continued during the last twenty days of my diet, but the biggest change was almost immediate, as I thought it might be. The omega-3s in my cells were quickly being replaced by seed fats, as I find it helpful to think of them, fats that change with the seasons for most animals, but that Americans eat, and overeat, all year long.
I'm glad to be back on my normal diet and hope that my month-long experiment in high omega-6 living helps readers to understand these fats. It would be easy to poke holes in this experiment, I realize. I am only one subject and anything but random. It would be easy to wait until this experiment was repeated on a larger scale. But wouldn't it be prudent to make the small changes in your diet that will lead to a healthy, year-round balance of these fats in your tissues. Your cells will know the difference—even if most doctors currently do not—and your body will thank you.
Susan Allport is a science writer and author of The Queen of Fats: Why Omega-3s were removed from the Western diet and what we can do to replace them (University of California Press, 2006).