Here’s a quick quiz for you: What’s the most popular drug among bodybuilders? It isn’t any type of anabolic steroid or growth hormone, nor does it involve thyroid, beta agonists or any other anabolic substance. The most popular drug among bodybuilders is also the most popular drug world-wide: caffeine.
In the United States about four out of five Americans eat, drink or swallow a product that contains caffeine. Caffeine is ubiquitous in nature, existing in more than 60 known plants. About 75 percent of the caffeine consumed comes from coffee, with the other 25 percent mainly from tea and cocoa. Coffee, at an average 100 milligrams of caffeine per cup, contains twice as much caffeine as tea. A 12-ounce bottle of cola contains between 35 and 55 milligrams of caffeine.
Most people use caffeine to obtain benefits associated with it, including increased mental alertness, faster thought processes and reduced fatigue. Other effects—not specifically sought by most people—include stimulation of the heart, increased secretion of stomach acid and increased urine output.
Caffeine is thought to be an ergogenic aid in that it can enhance athletic performance. A study examined some of the fat-burning properties of caffeine under resting conditions and found that it increased energy expenditure 13 percent.1 Other effects included 24 percent increased fat oxidation, with 76 percent being recycled, likely due to the resting conditions in the study. Most of the effects were attributed to increased sympathetic nervous system activity, or the release of sympathetic hormones, such as epinephrine and norepinephrine, after the subjects took caffeine.
Caffeine-induced fatty acid release can interfere with insulin activity, leading to insulin insensitivity; however, research shows that exercise relieves that particular problem. Indeed, one recent study showed that drinking coffee offers protection against type 2 diabetes and suggested that nutrients besides caffeine, such as magnesium, may be the protective factors in coffee.2
Another recent study found that caffeine protects against Alzheimer’s disease by reducing the toxic effects of a protein called beta-amyloid on brain neurons3; buildup of beta-amyloid is considered a primary event in the onset of Alzheimer’s.
Since caffeine promotes the release of sympathetic hormones that stimulate body processes, it’s not surprising that it can induce severe anxiety in some people. Indeed, “caffeineism” is so distressing that an estimated 20 percent of people cannot tolerate anything containing caffeine. One study, however, found that exercise can relieve anxiety brought on by high doses of caffeine.4
The release of sympathetic hormones by caffeine can stimulate the heart and increase blood pressure. Some drugs prescribed to treat cardiovascular disease, known as beta-blockers, block the effects of sympathetic hormones on the cardiovascular system. Caffeine would appear to be a problem because of the way it affects the cardiovascular system, but most studies have found no significant adverse effects except when excess intake is involved.
For example, one study examined the effects of caffeine on the body’s homocysteine levels.5 A toxic by-product of the metabolism of the essential amino acid methionine, homocysteine is linked to cardiovascular and other diseases. Healthy volunteers drank a liter a day of coffee for a month, and 24 of the 25 participants showed significant elevations of homocysteine in the blood. Vitamin B12, folic acid and vitamin B6 neutralize the effects of homocysteine, converting it into an innocuous substance that’s excreted from the body.
Another recent study found that drinking four cups of filtered coffee a day for one month increased cholesterol levels.6 Previous studies had shown that drinking unfiltered coffee increased cholesterol, an effect scientists traced to elements in coffee called diterpenes. Coffee filters captured the chemicals, making filtered coffee safe—or so they thought. Even so, the increase in cholesterol from coffee is significant only to those who already have elevated cholesterol. To others the effect is insignificant.
Drinking more than about five cups of coffee daily—particularly at night—can lead to insomnia. Besides caffeine coffee contains other substances, such as theophylline, a drug commonly used to treat bronchial asthma because it dilates the bronchial tubes. Coffee does that too. Another coffee ingredient, theobromine, was recently found to have cough-suppressant power superior to that in over-the-counter cough medications. Caffeine isn’t linked to any organ damage and peaks in the blood about two hours following ingestion. It’s metabolized by the liver, then excreted by the kidneys.
Coffee is believed to stimulate the brain by blocking brain receptors for a chemical called adenosine, which slows the activity of the brain’s working cells, or neurons. By blocking adenosine, caffeine fosters a feeling of mental clarity and focus. On the other hand, it also constricts blood vessels in the brain, which would decrease blood flow and lower metabolic activity.
Since caffeine is a drug, you might expect to pay a price if you quit cold turkey. The effects of withdrawal include headache, drowsiness and fatigue, mainly due to an increase in adenosine receptors in the brain.
As with other drugs, caffeine’s physiological effects depend on the dosage. The amount in an average cup of coffee—100 to 200 milligrams—leads to increased mental alertness and reduced fatigue. At the one-gram level symptoms of caffeineism, such as anxiety, mild heart-rhythm disturbances and gastrointestinal disturbances, appear. If for some crazy reason you were to ingest 10 grams of caffeine—the amount in 100 cups of coffee—at one time, you’d die.
Many of the popular so-called fat-burning supplements on the market contain some form of caffeine. Typical ingredients include guarana, an herb from Brazil that contains 7 percent caffeine—compared to the 2 percent found in coffee. A popular stimulant sold in the 1970s called Zoom was composed entirely of guarana, and its activity matched its name. Another form found in supplements is mate, also from South America.
The addition of caffeine to fat-burning supplements makes sense, since it promotes the release of sympathetic hormones, such as epinephrine and norepinephrine, which induce a biochemical cascade of fat from fat cells. The combination of ephedrine, which also promotes sympathetic-hormone release, and caffeine was considered the most effective natural fat-burning combination. Adverse publicity about ephedrine, however, eventually led to its being banned by the FDA. Could the fact that head-to-head comparisons found the ephedrine-and-caffeine combo to be superior to popular prescription diet pills have anything to do with the ban on ephedrine? You bet it could.
Caffeine was considered so ergogenic that the Olympics banned it above a certain quantity in the blood. The assumption was that the only way to reach that level of caffeine was to use it purposely as a means of improving performance. Some world-class cyclists were said to even use caffeine suppositories.
Caffeine is described as ergogenic because it releases greater amounts of fat in the blood, which spares limited glycogen stores in muscle. That helps increase muscular endurance, and studies involving endurance athletes have consistently proved boosting power of caffeine. The evidence for any effect on anaerobic exercise, such as bodybuilding, has been less clear. Recent studies, however, show that under anaerobic exercise conditions, caffeine ingestion appears to increase muscular endurance and decrease fatigue. An important point about these studies is that they all involved the use of pure caffeine, not food products containing caffeine, such as coffee. The effects of pure caffeine are considered more reliable.
References
1 Acheson, K.J., et al. (2004). Metabolic effects of caffeine in humans: lipid oxidation or futile cycling? Am J Clin Nutr. 79:40-46.
2 Salazar-Martinez, E., et al. (2004). Coffee consumption and risk for type-2 diabetes mellitus. Ann Intern Med. 140:1-8.
3 Dall’lgna, O., et al. (2003). Neuroprotection by caffeine and adenosine A-2 receptor blockade of beta-Amyloid neurotoxicity. Brit J Pharm. 138:1207-09.
4 Youngstedt, S.D., et al. (1998). Acute exercise reduces caffeine-induced anxiogenesis. Med Sci Sports Exer. 30:740-45.
5 Urgert, R., et al. (2000). Heavy coffee consumption and plasma homocysteine: a randomized controlled trial on healthy volunteers. Am J Clin Nutr. 72:1107-10.
6 Strandhagen, E., et al. (2003). Filtered coffee raises serum cholesterol: results from a controlled study. Eur J Clin Nutr. 57:1164-68.
©,2013 Jerry Brainum. Any reprinting in any type of media, including electronic and foreign is expressly prohibited.
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