by Неизвестный
RESEARCH CAPSULE
Caffeine Does Not Help Weight Loss
There is a popular belief, most likely derived from the inclusion of caffeine in diet pills, that caffeine is an aid to weight loss. This notion is debunked in Chapter 8, but I mention it here in order to clear up yet another popular myth: drinking coffee when you quit cigarettes does not help prevent weight gain, either. This concept was carefully tested in a controlled scientific experiment, and caffeine (even when combined with another stimulant known as ephedrine) provided no benefit. There was no difference in success rate, weight gain, cravings, or withdrawal symptoms between the caffeine and placebo groups.
Source: J. Norregard, S. Jorgensen, K. L. Mikkelsen et al., ’the Effect of Ephedrine Plus Caffeine on Smoking Cessation and Postcessation Weight Gain,” Clinical Pharmacology and
Therapeutics, December 1996;60(6):679–86.
Critical Point #2: Your Adenosine Receptors
Caffeine and its breakdown products (collectively called methylxanthines) have a number of effects on the body. First, they disrupt the normal function of adenosine receptors, biochemical control switches found throughout the brain, kidneys, gastrointestinal tract, cardiovascular system, and respiratory system.
Now stay with me here; this sounds complicated, but it’s important, and by the time you finish this page, you’ll know more about the biochemistry of coffee than most MDs.
Have you ever inserted the wrong key in a door and foiind that the key fit just fine but it wouldn’t unlock the door? That’s what caffeine does in an adenosine receptor. It fits, but does not perform the adenosine function. Now imagine that
you’re standing there and you can’t get the wrong key out of the lock. You are thus prevented from entering the room. Likewise, when caffeine plugs an adenosine receptor, an important biochemical message that was supposed to be sent to the cell is not delivered.
In the brain, adenosine dampens or slows down neuron firing. It acts like a fuse box to prevent your circuits from getting overloaded. When caffeine inactivates this control mechanism, your neuron circuits keep firing, and you feel alert. The problem is, your circuits keep firing, and firing, and firing.…
Critical Point #3: The Stress Response
It doesn’t take a genius to see that there might be a downside to all of this neuron activity. In fact, uncontrolled neuron firing creates an emergency situation, which triggers the pituitary gland in the brain to secrete ACTH
(adrenocorticotrophic hormone). ACTH tells the adrenal glands to pump out stress hormones—the next major side effect of caffeine. A single 250-milligram dose of caffeine (the equivalent of about 21/2 six-ounce cups of coffee) has been shown to increase levels of the stress hormone epinephrine (commonly known as adrenaline) by more than 200 percent.12 Caffeine also stimulates the production of norepinephrine, another stress hormone that acts directly on the brain and nervous system. Epinephrine and norepinephrine are responsible for increased heart rate, increased blood pressure, and that “emergency” feeling. In fact, the emergency is quite real. Caffeine can trigger a classic fightor-flight stress reaction with all of the results listed in Illustration 1.
ANATOMY OF THE FIGHTOR-FLIGHT RESPONSE
Caffeine can produce a cascade of physical and emotional changes as a result of increased stress hormones. This fightor-flight response is hardwired into all animals as a survival mechanism.
NOWHERE TO RUN
Take a moment to consider a “then and now” scenario. Remember that the fightor-flight reaction was in great part responsible for our survival as a species. For 1.6 million years, this neuroendocrine response gave us increased strength,
stamina, and speed when we needed it. But today, the same trigger mechanism is killing us. That’s because even though our bodies haven’t changed at all in the last 25,000 years, everything else has.
Our ancestors needed every ounce of energy their bodies could produce to deal with sudden danger (a saber toothed tiger, for example). Today stress is different: a crammed schedule, looming deadlines, lost car keys, or an unfair boss. And while we may have excellent coping skills, there is one factor that tips the balance toward panic, and that is caffeine. It lowers the stress threshold so that events we would normally handle suddenly become insurmountable. Not only that, you will soon see that caffeine reduces the brain’s problem-solving ability. As part of the ancient survival response, stress stimulates neuron activity in the primitive part of the brain known as the limbic system. However, the vast majority of problems we face today require reason, imagination, and creativity: all functions of the “higher brain” or cerebrum.
The fightor-flight response was designed for stress that was episodic.
Everything was fine, then there was a tiger, our adrenals pumped out epinephrine, and we ran like the dickens. Today, however, stress tends to be chronic, and when you consider that most people typically consume caffeine at regular intervals during the day, you begin to understand the magnitude of the problem. Our bodies are in a constant state of “emergency alert,” and the results can be devastating.
can be devastating.
For most of us, the appropriate response to stress is not fight or flight at all.
You may be sitting at a desk or driving in your car when the stress mechanism is triggered. If that’s the case, the sugar and fat that are dumped into your bloodstream go unused. The sugar creates additional metabolic stress, and the fat clogs your arteries. Your muscles tense, but to no useful purpose (after all, you can only grip the steering wheel so hard). And since blood flow has been diverted from the gastrointestinal tract, the food you just ate is converted to a fermenting and putrefying mass.
CAFFEINE IMPAIRS DIGESTION
Impaired digestion is more of a problem than most people realize—and it gets worse with caffeine (see Chapter 5). That jumbo thirtytwo-ounce soft drink or the double espresso we have with meals is a major contributor to the bloating, pain, and gas that roughly 50 percent of American adults experience after they eat. And these symptoms are only the physical signs of maldigestion. Unseen are the harmful byproducts of fermentation and putrefaction. Some of these byproducts are absorbed back into the bloodstream, and the toxins that stay in the gut increase your risk of gastrointestinal disease.
David Morgan, director of the University of South Florida’s Institute on Aging, puts stress-induced maldigestion into an evolutionary perspective when he states, “There’s no reason to digest your breakfast if you are about to become lunch.… [Under stress] a whole series of maintenance and repair activities just stop.”13
CAFFEINE’s ICY GRIP
Have you ever noticed your fingers getting cold after a cup of coffee? That’s another part of the stress response known as vascular resistance, in which peripheral blood vessels constrict. This response is great if you’re fighting for your life—if you’re cut, you’ll lose less blood and your blood will clot faster.
But if you’re sitting at breakfast reading the morning paper, vascular resistance will only raise your blood pressure and significantly increase your chances of having a heart attack or stroke.
Of course, vascular resistance affects blood vessels throughout the body, not just in your fingertips. The coldness in your hands and feet indicates that billions
of cells are suffering from reduced metabolic efficiency. That means less oxygen is getting to those cells and less carbon dioxide and other wastes are being removed. It means that fine blood vessels in the brain are constricting and cerebral blood flow is reduced. And because caffeine increases brain activity at the same time, a situation known as relative brain hypoperfusion results.14 In this condition, the brain is deprived of oxygen, and the consequences, when repeated day after day, can be quite serious.
Critical Point #4: Cortisol, the Long Burn
Epinephrine, it turns out, is only half the story. With daily caffeine use, another stress hormone known as cortisol becomes elevated.15 The important thing to remember about cortisol is th
at it tends to remain in the bloodstream much longer than epinephrine or norepinephrine. In fact, people who consume more than 300 milligrams of caffeine per day may have elevated serum cortisol for eighteen out of every twenty-four hours. And that sets them up for countless health problems.
You don’t really “feel” cortisol the way you feel adrenaline. It’s hard to pinpoint exactly what’s wrong, and after a while, most people don’t even realize that they’re different. The quality of their sleep is diminished, their immune system is adversely affected, age-related deterioration is accelerated, and there is a gradual but significant change in mind, mood, and behavior.
One client who kicked the caffeine habit recently told me, “It’s as though a cloud has been lifted from my body and mind. I had no idea that I was such an angry and frustrated person.” That’s because cortisol has a powerful effect on personality.
Critical Point #5: Your Dopamine Levels
As neurobiologists unravel the mechanism of addiction, it becomes more and more clear that not only is caffeine addictive, but it also encourages other addictions to substances like nicotine. The key factor in this interaction appears to be a brain chemical known as dopamine.
Dopamine belongs to a class of biochemicals known as neurotransmitters. As the name implies, these remarkable substances, produced by the brain and nervous system, help control the transmission of information from neuron to neuron. Some neurotransmitters (called excitory neurotransmitters) speed up this
neuron. Some neurotransmitters (called excitory neurotransmitters) speed up this information exchange. Inhibitory neurotransmitters slow neuron firing.
But these biochemicals do not merely control the speed of the brain; they also affect (some would even say determine) our feelings. They are therefore a powerful influence on behavior. Dopamine is associated with feelings of pleasure and elation, and scientists now believe that all addiction involves the ability of a substance to raise dopamine levels in the brain. Some substances, like amphetamines, do this by stimulating the brain to release greater amounts of dopamine, while cocaine and others block the brain’s ability to clear dopamine from nerve endings. Either way, greater amounts of dopamine are available to stimulate receptor sites in the brain, thus producing the drug high.
In May 1997, Time magazine ran a cover story on addiction and listed caffeine with other addictive drugs. But they only stated that caffeine “may trigger release of dopamine.” 16 In reality, the evidence for the caffeinedopamine connection is unquestionable. A decade ago, scientists confirmed that caffeine raises dopamine levels. One study even noted that the mechanism by which this occurs is “similar to that observed during amphetamine administration.”17 In the last two years no less than twenty-six scientific studies have described the ways that caffeine interacts with dopamine to alter feelings and behavior. Research shows that caffeine also interacts with opiate receptors, and this may very well strengthen the addictive quality of the compound.18
Now, I know what you’re thinking. There’s no comparison between coffee and opium, cocaine, and amphetamines. Those drugs drive people to destructive behavior, while coffee merely produces a sense of stimulation. But that is precisely the point. We now know that all of these drugs act along similar biochemical pathways, in the same areas of the brain. It turns out that there is a continuum of addiction, and just because one substance is incredibly harmful does not mean that we should ignore other substances that are only moderately harmful. Moreover, it is not just the positive dopamine and adrenal stimulation that coffee drinkers are after. As in all truly addictive behaviors, coffee and cola drinkers need their fix in order to avoid the negative experiences of headache, fatigue, irritability, and depression.
Caffeine in some form is consumed by nearly 200 million Americans every day. The harmful effects of this drug are extremely well documented. It’s time we all woke up to the truth about the addictive nature of caffeine, as well as its potential for great bodily and mental harm.
The good news is that you can free yourself from caffeine addiction by using the clinically tested Off the Bean program presented in Chapter 10. And if facing
the clinically tested Off the Bean program presented in Chapter 10. And if facing life caffeine free is too frightening a thought, rest assured that you will find many healthful suggestions for increasing your own natural energy and restoring your adrenals and nervous system.
BUT WHERE WILLI GET THE ENERGY?
The fact is that caffeine never gave you energy. It stimulated your nervous system and adrenals, and that’s not energy, it’s stress. To get this point across to my clients, I ask them to imagine going to a bank for a loan. The loan officer is superfriendly and readily agrees. But as you’re leaving the bank, you read the fine print, which lists the interest rate at 75 percent! Would you be interested in such a loan? Likewise, the “energy” you receive from caffeine is really just a loan from your adrenals and liver, and the interest is extremely high. At some point (referred to as adrenal exhaustion) you may find yourself “bankrupt” and unable to repair the damage.
Stress—and by that I mean unresolved or unmanaged stress (perhaps more properly called distress)—is a silent saboteur of health. Every day, 1 million Americans are absent from work because of stress-related disorders. Experts agree that stress is a factor in most diseases, and a major factor in disorders such as anxiety, insomnia, depression, ulcers, rheumatoid arthritis, headache, hypoglycemia, asthma, herpes, hypertension, and heart disease. And yet, if you walk into most hospital waiting rooms, you’ll find a coffee machine. Perhaps that’s because we don’t understand how stress ruins our health. If you ask the average person, he or she will certainly tell you that stress causes tension. He or she may even know that this tension can increase blood pressure and give you headaches. But to make informed decisions about your caffeine intake, it’s important to know all the facts—and in this case, it’s fairly easy, because they all relate to your adrenal glands.
Critical Point #6: Your Adrenal Glands: Overworked and
Underpaid
You don’t gain much appreciation for the adrenal glands in physiology class.
The focus is too much on memorizing their structure and function. Besides, the adrenals are rather small (smaller than your thumb) and easy to overlook (many anatomy charts don’t even include them). So it wasn’t until I got into clinical practice that I realized how extremely important they are. I was seeing patients
practice that I realized how extremely important they are. I was seeing patients every day with serious health problems that strong, healthy adrenals could have prevented. Why were these people vulnerable to allergy, inflammation, hypertension, infection, and fatigue? What was it that weakened their adrenals?
To find the answer, you must learn something about these amazing glands. (A discussion of specific disorders associated with adrenal dysfunction is found in Chapter 5.)
The center of the adrenal gland, called the medulla, produces two major biochemicals: epinephrine and norepinephrine. As I mentioned, these are the fightor-flight hormones that create the stress response listed in Illustration 1.
But we need these hormones for more than the occasional emergency.
Epinephrine and norepinephrine are also required for any stressful activity, including sports and recreation.
Surrounding the medulla is the adrenal cortex, which produces a variety of other hormones that help regulate blood pressure, blood sugar, mineral levels, immune activity, inflammation, and cell growth and repair. In all, more than 150
hormones are produced by the adrenals or metabolized from adrenal hormones.
One group, known as glucocorticoids (including cortisol), act as a brake on the immune system. This is an essential function that prevents overenthusiastic immune cells from attacking the body’s own healthy tissues. But scientists have recently learned that excess glucocorticoid production (caused by stress and caffeine) can profoundly suppress immunity.19,20 The important point to underst
and is that caffeine combined with emotional stress has been shown to raise glucocorticoid production far more than either caffeine or stress alone.
Critical Point #7: Immunity and Aging
The vaccine response is one of the wonders of modern medicine. By exposing the body to a weakened (or even dead) strain of a disease, the body “remembers”
the enemy so that any future encounter with the microbe will result in a swift and strong immune response. Obviously, the effectiveness of a vaccine depends upon the production of these memory cells, called antibodies.
A research team led by Dr. Ronald Glaser gave a hepatitis vaccine to fortyeight students, half of whom were in the midst of final exams (and drinking more coffee). A month later, it was found that the students with elevated stress hormones developed the least protection (produced the lowest number of antibodies) against hepatitis.21
But the stress-immune response is not always characterized by suppressed
But the stress-immune response is not always characterized by suppressed function. The other side of the coin is called immune dysregulation, a condition in which the immune system attacks healthy tissue. There is an intriguing but not fully understood connection between stress, caffeine, and autoimmune disorders such as rheumatoid arthritis, lupus, and MS. Now we know that the onset of autoimmune disease is very frequently preceded by a period of severe stress or depression, but it’s not simply that stress weakens the adrenals and leads to poor immune control. Continued research has led to a very exciting breakthrough related to another hormone known as DHEA.
THE DHEA CONNECTION
DHEA (dehydroepiandrosterone) can accurately be called the vitality hormone.