The Mediterranean Zone (3 page)

There are hundreds of known hormones (and many more still to be discovered), yet the one hormone we hear about the most is insulin and usually in negative terms. It is true that excess insulin makes you fat and keeps you fat. However, without adequate levels of this hormone much of your metabolism would grind to a halt. It is insulin that drives basic nutrients (amino acids, glucose, and fatty acids) into cells to serve as building blocks for cellular renewal or potentially as energy for the cell. It is insulin that removes what could be toxic levels of fatty acids and glucose from the bloodstream to protect your other organs. It is insulin that safely stores those excess fatty acids and glucose in the blood in your fat cells and your liver to be released at exactly the right time when we need it for energy. It is insulin that controls our hunger. It is insulin that activates key enzymes needed for growth and renewal. Yet for insulin to act as this central hub for metabolism to work its wonders, it must be maintained in a zone that is neither too high nor too low. If insulin levels are too low, your cells will starve for lack of nutrients. If insulin levels are too high, obesity, chronic disease, and accelerated aging are likely in your future.

There are two ways to increase insulin levels. One way is to eat too many carbohydrates, especially grains and starches. The other is eating too many calories. Americans have been doing both for the past forty years. Not surprisingly, as insulin levels have increased in the population, so has the incidence of obesity and other chronic diseases. But focusing on insulin alone as the agent of our current health-care demise in America is like losing your wallet and then looking for it two blocks away under a streetlamp. While there is more light under the streetlamp, you are never going to find your wallet if you just look there.

The real cause of our health-care crisis is not just carbohydrate consumption alone, but also the even more rapid rise of omega-6 fatty acids in the American diet. When
excess
omega-6 fatty acids interact with
excess
insulin, the result is the generation of molecular building blocks necessary to produce very powerful inflammatory hormones known as eicosanoids. The combination of these two recent dietary changes (increased insulin
and increased omega-6 fatty acids) is like adding a lighted match to a vat of gasoline; it has resulted in an explosion of diet-induced inflammation.

We usually think of inflammation as something that hurts—you pull a muscle, then it swells and becomes inflamed (it hurts). You might consider this to be “hot” inflammation. The diet-induced inflammation I am talking about might be considered “cold” inflammation because you can’t feel it. Nonetheless, this diet-induced inflammation, technically called cellular inflammation, is the type that kills. Because you can’t feel it, cellular inflammation lingers for years, if not decades, until there is enough organ damage to generate chronic disease. It could be diabetes, heart disease, cancer, or even Alzheimer’s. The end result is that you age before your time. To add insult to injury, cellular inflammation makes you fatter.

Diet-induced inflammation disrupts the hormonal signaling within your biological Internet, which leads to disturbances in your metabolism. The end result of altered metabolism is the development of chronic diseases at an earlier age and the acceleration of aging, especially in the brain.

The basic biochemistry of increased dietary-induced inflammation hasn’t changed since I wrote my first book,
The Zone
, nearly twenty years ago. Keeping this type of inflammation in the Zone is much more difficult than simply controlling insulin (which is difficult enough). To control diet-induced inflammation for a lifetime, you have to control
both
insulin and the levels of omega-6 fatty acids. To simply reduce insulin levels without reducing omega-6 fatty acids at the same time completely misses the real cause of our current health-care problems.

The increase in diet-induced inflammation is only part of our growing epidemic of chronic disease. Remember, inflammation is a two-part process. The second component of our inflammatory response, the resolution phase, has also been under attack because of the decreased consumption of omega-3 fatty acids and polyphenols.

Each of these phases (inflammation and resolution) of the inflammatory process works independently of the other, but when they get out of sync together, you have a major metabolic disaster on your hands that accelerates virtually every known chronic disease.

Let’s examine each dietary trend and how it affects the different phases of inflammation.

We need
some
omega-6 fatty acids to maintain a healthy ability to fight off microbes and heal from injuries. But when the levels of omega-6 fatty acids in the diet become too high, they generate excess pro-inflammatory hormones. Until recently, the levels of omega-6 fatty acids found in the human diet were very low. It is estimated that the consumption of omega-6 fatty acids in the United States has increased by more than 400 percent in the past one hundred years, with most of that increase coming in the past fifty years.

So where are these omega-6 fatty acids coming from? The answer is vegetable oils such as corn oil, soybean oil, safflower oil, sunflower oil, and others. These are now the cheapest form of calories known and they make food taste better. This is why processed foods you might eat such as fried foods, pastries (think doughnuts), and virtually everything else you find in the aisles of the supermarket are rich in omega-6 fatty acids.

In addition, omega-6 fatty acids are prone to oxidation (especially in the absence of polyphenols), which generate free radicals and other exceptionally reactive compounds that can oxidize other key players in metabolism such as lipoproteins, proteins, and DNA. These oxidation products are far more destructive to your health than any amounts of free radicals coming from UV radiation. At least you can block free radical formation from sunlight using a sunscreen. But the only way to block oxidative production coming from omega-6 fatty acids is not to eat them or at least consume very high levels of nature’s most powerful anti-oxidants— polyphenols—to combat them.

The industrialization of food is the primary reason for the growth of high-glycemic carbohydrates in the diet. High-glycemic carbohydrates are those that enter into the bloodstream as rapidly as glucose. Yes, these carbohydrates are in junk food, but let’s not forget white bread, white pasta, white rice, and white potatoes. Sad but true, the whole-grain versions of these same carbohydrates are also high-glycemic carbohydrates. As you increase
any of these foods in your diet, you will increase the secretion of the hormone insulin.

In the presence of high levels of insulin, the transformation of omega-6 fatty acids into arachidonic acid (the molecular building block of inflammatory eicosanoids) is rapidly accelerated, and cellular inflammation increases as shown below.

One of the consequences of increased cellular inflammation is the development of insulin resistance—the beginning stage of diabetes. Although insulin can still bind to its receptor at the cell surface, the transmission of that signal to the interior of the cell becomes compromised. Instead of being taken up by the target cells, blood glucose and fats remain elevated. As a result, the pancreas is forced to continually increase the secretion of even more insulin to help drive the excess blood glucose and fat into its target cells. This results in elevated blood insulin levels around the clock. The constantly elevated insulin levels now accelerate the further metabolism of omega-6 fatty acids into even more inflammatory eicosanoids. The result is a fast-forwarding of even more cellular inflammation. Increasing insulin resistance, caused by diet-induced inflammation, drives the metabolic complications of obesity, not simply eating carbohydrates.

Humans have always had two anti-inflammatory dietary cards up their sleeves. The first of these dietary insurance policies is adequate intake of omega-3 fatty acids. Unlike pro-inflammatory omega-6 fatty acids, omega-3 fatty acids are anti-inflammatory. As long as omega-6 and omega-3 fatty acids are in balance, you maintain a healthy inflammatory response that enables you to respond to microbial invasion or injuries, but does not cause a chronic inflammatory attack on your own body. More important, omega-3 fatty acids are necessary to turn off, or resolve, the inflammatory response to allow the body to return to normal. The lack of omega-3 fatty acids in the diet is the second half of a one-two hit to your future wellness. First, you have an overreaction of an initial inflammatory response due to increased omega-6 fatty acids, and second, you can’t turn it off effectively because of a lack of omega-3 fatty acids.

It is estimated that intake of omega-3 fatty acids in the American diet is only 5 to 10 percent of what it was a century ago. This is because fish (until recently) has always been an inexpensive source of protein. The more fatty fish you eat, the more anti-inflammatory omega-3 fatty acids you consume, as they are stored in the fat of the fish. Also children in the first half of the twentieth century had to take a tablespoon of cod liver oil (the world’s most disgusting food) before they could leave the house. Today fatty fish consumption is down and cod liver oil is no longer standard issue in every home in America. As a result, the ratio of omega-6 to omega-3 fatty acids in Americans has increased dramatically in the last century, and again most of that increase has come in the last fifty years.

When I wrote
The Zone
in 1995, little was known about polyphenols. Today we know a lot more, including the fact that they are potent anti-inflammatory agents, but only if you consume a lot of them. High levels of polyphenols activate a genetic master switch that turns off inflammatory genes. Unfortunately, the consumption of colorful carbohydrates rich in
polyphenols (fruits and vegetables) has decreased at exactly the same time that the consumption of white carbohydrates and omega-6 fatty acids has increased. The result is more cellular inflammation.

It is best to think of cellular inflammation in terms of a nuclear reactor. As you pull out the anti-inflammatory control rods (omega-3 fatty acids and polyphenols), the core of the reactor (omega-6 fatty acids and elevated insulin combining to generate more cellular inflammation) begins to heat up. If you push the anti-inflammatory control rods back into the nuclear reactor, the pro-inflammatory core cools down. Of course, if you take out the anti-inflammatory control rods completely, then you get a meltdown of the reactor. This is what has been happening in America for the past fifty years.

So there you have it. There is no single “evil one,” such as fructose, milk, or wheat (more about these dietary mythologies later), but a combination of factors that are putting us at high risk of increased cellular inflammation and a resulting lifetime of misery. This is why our current epidemics of obesity and diabetes seem to have appeared out of nowhere and why we seem powerless to reverse them.

The role of inflammation in weight gain, development of chronic disease, and aging is complex. The following will give you a short overview that you can explore in greater detail in the Appendices.

Although the diet book industry is devoted to weight loss, no one seems to describe how we actually get fat. I will describe the actual process in greater detail in the Appendices, but let me summarize it here.

It is true that excess insulin makes you fat and keeps you fat. However, excess insulin is not caused by lack of willpower, but by the disruption of your fat metabolism by cellular inflammation. Under ideal conditions, fat gets taken up from the blood and is stored in your fat cells to be released at a later time (such as when you are sleeping) to supply energy for the rest of your body. The levels of insulin in the blood control this process. When you develop insulin resistance, this careful balance of fat uptake and fat release is disrupted. The end result is that you get fatter as fat from the bloodstream is accumulated more readily by your fat cells and cannot be as easily used as fuel by other cells. Carbohydrates alone don’t make you
fat; it is the diet-induced inflammation they contribute to in the presence of excess omega-6 fatty acids that makes you fat.

Many of our chronic diseases can be viewed as disturbances in metabolism. These include diabetes and heart disease. Other chronic diseases, such as autoimmune disorders (arthritis, lupus, multiple sclerosis, asthma, allergies, and so on), are a consequence of increased cellular inflammation, and many neurological disorders (ADHD, depression, Parkinson’s, Alzheimer’s, and so on) and cancer may be viewed as a combination of both.

As you increase cellular inflammation, the necessary hormonal signaling that is required for a stable metabolism is disrupted. Increased cellular inflammation also activates the most primitive part of the immune system to mount a continuing attack mode. Eventually this leads to organ malfunction, and we call that chronic disease.