The Mediterranean Zone (16 page)

Recently the FDA announced a potential ban on trans fatty acids. Well, not exactly, since the FDA has never approved of them as food additives in the first place. They just kind of happened. First developed by Procter & Gamble (America’s premier soap company) in the early 1900s, trans fatty acids quickly became a cheaper alternative to lard and butter as a source of fat with the introduction of Crisco into the American diet. Fortunately, Crisco tasted terrible. It was only with the advent of World War II and the rationing of butter that gave trans fatty acids their real push in the American diet in the form of margarine. Since trans fats are made from vegetable oils rich in omega-6 fatty acids, good marketing (led by the American Heart Association) convinced most Americans that they were “healthier” because they contained less saturated fat as well as being less expensive than butter.

American consumers continued to embrace shortening and margarine
as alternatives to butter until initial research in the late 1980s indicated maybe these miracle fats weren’t such a health bargain after all as evidence began mounting that trans fats seemed to be associated with increasing the risk of heart disease instead of lowering it.

However, by this time the processed food industry had learned to love trans fats. They were needed for manufactured products with an extended shelf life that could stand up to long-distance transport and an even longer life on the supermarket shelves without going rancid. The traditional method of adding saturated fats (such as lard) was no longer economical, but making lard-like fats from liquid vegetable oils was a way out of their shelf-life problem. Vegetable oils are a cheap source of calories, and the process to transform them into stable trans fats needed for extended shelf life is equally inexpensive.

Today it is still not certain why trans fats are so bad for us at the molecular level. We do know that the more trans fatty acids you consume, the more likely you are to develop heart disease. The usual suspects as to why they increase heart disease, such as lowering good cholesterol and increasing bad cholesterol (which trans fats do), are unlikely to explain why trans fatty acids also increase cellular inflammation. One theory is that trans fatty acids inhibit the formation of beneficial long-chain omega-3 fatty acids by interfering with key enzymes in their production. Another theory is that trans fatty acids make cell membranes more rigid, making it more difficult for hormones to transmit their signals to the interior of the cell. While the medical community agrees that trans fatty acids are detrimental to health, there are still a lot of remaining nagging questions about the actual mechanism of trans fats and how to explain their association with increased heart disease.

The Lyon Diet Heart Study, discussed earlier, demonstrated the difficulty in understanding the extent mechanism of trans fatty acids. In that study, subjects in the experimental group who were consuming margarine rich in trans fatty acids had 70 percent fewer heart attacks than the group consuming high amounts of omega-6 fatty acids. This remains, to my knowledge, the only long-term intervention study with trans fatty acids, and it generated just the opposite results than expected. This is not to say that trans fats were good, only that they were less harmful than the omega-6 fats that the control group was consuming. In fact, recent studies looking at all the data in cardiovascular patients who had replaced saturated
fats with only omega-6 fats came to the conclusion that increasing the levels of omega-6 fatty acids seems to increase cardiovascular mortality.

Regardless of the questions on the mode of action of trans fatty acids posed by the results of the Lyon Diet Heart Study, the public outcry against trans fatty acids required the processed food industry to quickly look for a substitute that was almost as cheap as trans fatty acids. They found the solution in interesterified fats, a man-made fat created by combining totally hydrogenated vegetable oils with unsaturated vegetable oils. These interesterified fats contain no trans fatty acids, but studies have indicated this new type of fat may have the unintended consequence of causing increased insulin resistance. This is another case of “shoot, ready, aim” by the processed food industry.

There is no clear molecular mechanism to explain the association of trans fatty acids or potentially interesterified fats with chronic disease. Keep in mind trans fatty acids were developed as a replacement for saturated fats because of the crusade started by the American Heart Association to remove saturated fats from the American diet, as they were perceived to be the “real” cause of heart disease. (Sidebar: McDonald’s used to fry its French fries in beef tallow, which is similar to lard. But after the publicity campaign started by Nebraska businessman Phil Sokolof generated such negative publicity, they replaced lard and beef tallow with trans fats.) However, in 2010 Harvard did another observational study indicating that there seemed to be no association of saturated fats with heart disease. This means the push by the American Heart Association for using omega-6 acids to replace saturated fats was probably never justified in the first place.

But what about the newest dietary “villains,” which, unlike trans fats, are natural food ingredients that have been in the human diet for thousands of years? These include carbohydrates, fructose, milk, and gluten. Or the new dietary “hero,” saturated fat? Unlike the scientific consensus on the negative effects of industrialized trans fatty acids (whatever the molecular reason), there remains great controversy relative to the role these food ingredients have in our current health-care crisis.

As I mentioned in the opening chapter, there is no magic bullet in nutrition, nor is there any single evil villain. Nutrition is far too complex to
operate like that. This is why you have to search for a more comprehensive view to be consistent with all the data.

So let’s look at these new dietary villains or heroes that are so popular in media headlines to see how strong the evidence is for each. In the process, I will also try to relate each to the real villain of our crumbling health, which is increased cellular inflammation.

The mantra of the Atkins diet is that carbohydrates increase insulin, and excess insulin makes you fat. Simply remove carbohydrates from your diet and replace them with fat. In fact, replace them with lots of saturated fats, such as bacon and heavily marbled porterhouse steaks. I totally agree with the problem of elevated insulin levels but not the proposed solution of the Atkins diet. It is true that carbohydrates (primarily glucose, since fructose has very little effect on insulin) do cause a transitory increase in insulin levels. But if you don’t suffer from insulin resistance, then your insulin levels return to their normal levels quickly. The problem begins when insulin levels stay elevated all the time. Scientifically, this is called hyperinsulinemia, and it is caused by insulin resistance disrupting the signals between the insulin at the surface of the cell and the message it is trying to transmit to the interior of the cell. Insulin resistance is one of the first metabolic consequences of increased cellular inflammation. The cause of cellular inflammation is not carbohydrates
per se,
but the deadly
combination
of elevated insulin and omega-6 fatty acids.

Eventually you have to do clinical studies to back up your theories. I published one such study in the
American Journal of Clinical Nutrition
in 2006 comparing the Zone Diet to the Atkins diet. In this study, twenty obese individuals had all their meals prepared for them in a metabolic kitchen at Arizona State University. For six weeks half of the subjects were on the Zone Diet, the other half followed the Atkins diet. Each group ate the same number of daily calories for six weeks using prepared meals, following the guidelines for each respective diet program. During that time those subjects on the Zone Diet lost more weight, lost more fat, had more endurance activity, and were happier (using a standard psychological test) than those following the Atkins diet in this highly controlled study. More
ominously, the Atkins diet doubled the levels of cellular inflammation in only six weeks. A more recent study from Harvard Medical School indicated that subjects on the Atkins diet (compared to subjects who ate the same number of calories but with more carbohydrates and less fat) had higher levels of cortisol, a stress hormone known for its deleterious effect on increasing fat accumulation, specifically abdominal fat, and lower levels of thyroid hormone, which causes fatigue and depression.

On a low-carbohydrate diet, you also have the problem of brain fog. Unlike other organs in the body, the brain can’t use fat for energy. Because the brain is 60 percent fat, this would lead to the very undesirable situation of the brain cannibalizing itself to make energy. That’s why the brain needs a constant supply of glucose in the blood for its energy needs. If glucose is not present in sufficient levels in your diet, then the body secretes more of the stress hormone cortisol to break down muscle mass to make more glucose. This is known as neo-glucogenesis. That’s exactly what the Harvard research demonstrated. Since the brain needs about 130 grams of glucose per day, it makes sense to eat approximately that amount of carbohydrate each day. The rest of your body can easily live off stored fat, but the brain can’t.

Robert Atkins was moving in the right direction by trying to reduce carbohydrates, but he took a major step backward by increasing saturated fats (which can increase cellular inflammation by binding to toll-like receptors) and forcing the body into abnormal hormonal responses (increased cortisol and decreased thyroid) by restricting carbohydrates too much.

The three major carbohydrates you consume are glucose (coming from grains and starches), fructose (coming from fruits and vegetables), and galactose (coming from dairy products). Rather than taking all three carbohydrates out of the diet to get a low-carb diet such as Atkins, maybe only one of the three was the problem. This idea came from a short letter to the
American Journal of Clinical Nutrition
in 2004 hypothesizing an association between the increased use of high-fructose corn syrup and increased obesity. Unfortunately, the authors of the letter neglected to mention that the total fructose consumption in America hadn’t changed much because
any increase in high-fructose corn syrup was matched by a corresponding decrease in refined table sugar consumption. Sucrose (table sugar) has nearly the same ratio of fructose to glucose (about equal proportions of each) as high-fructose corn syrup does.

Another important fact that the short letter sent to the
American Journal of Clinical Nutrition
failed to mention is that the intake of high-fructose corn syrup had already been in steady decline since 1999 with no effect on obesity statistics. In reality, the most rapid increase of any food ingredient in the past forty years has been the consumption of grains rich in glucose and omega-6 fatty acids, not fructose. This increase in glucose consumption means an increase in insulin levels, which, when combined with excess omega-6 fatty acids, translates into increased cellular inflammation.

Fructose, on the other hand, has very little effect on insulin levels. It is true the body metabolizes fructose differently than glucose. Since both fructose and glucose are highly reactive, the body works very hard to avoid letting either sugar stay in the blood too long. Fructose has very little impact on insulin levels because it goes directly to the liver to be slowly converted into glucose, lactic acid, and fat. Glucose, on the other hand, is driven by insulin into the liver and muscle cells (for conversion and long-term storage as glycogen) or into fat cells (for conversion to glycerol to aid the storage of fatty acids as triglycerides for long-term storage). As long as you don’t have insulin resistance, this process works very effectively for controlling the blood levels of both sugars. Although most fructose is converted slowly to glucose in the liver, the fat that is produced in the liver from fructose is repackaged into LDL lipoproteins to deliver fat to other tissues in the body for conversion energy. (Fat is high-octane fuel that allows you to make far more ATP per gram than per gram of carbohydrate.) As long as you don’t oversupply the body with fructose, then this is fine. Of course, if you force-feed the body with excess fructose (similar to force-feeding a duck grains in order to make foie gras—which literally translates as fatty liver) you might create some problems. Fruits are rich in fructose, whereas vegetables are far less so; if you eat a lot of vegetables and limited amounts of fruit, it is impossible to overwhelm the liver with fructose. Furthermore, in experiments where the levels of fructose and glucose are held constant, there was absolutely no difference between the two different types of simple sugars on obesity or metabolism.

It is true that fructose is slightly more reactive than glucose, thereby
potentially causing higher levels of free radical formation. This is where polyphenols come in. As the most powerful anti-oxidants known, they keep any potential excess free radicals coming from fructose (as well as glucose) metabolism under strict control. Studies have shown that when rats are fed a high-fructose diet and supplemented with polyphenols, all the metabolic abnormalities induced by the high-fructose feeding disappear. This is one of the reasons an apple a day keeps the doctor away. The beneficial effects of the apple polyphenols outweigh the possible negative levels of fructose in an apple. Of course, two servings of broccoli a day do an even better job than an apple at keeping the doctor away. That’s because there’s less fructose in the broccoli than the apple. Although grains and starches are free of fructose, they are composed of 100 percent glucose. This means they will dramatically increase insulin levels (whereas fructose will not) and generate lots of free radicals in the process (glucose is also very reactive especially in the blood). You need lots of dietary polyphenols to keep those free radicals coming from both glucose and fructose under control. So simply eat a lot of vegetables, limited amounts of fruits, and forget the grains and starches.