Coffee, perhaps not generally thought of as an herb, is in fact one of the most popular herbs in the world. Its effects on mental alertness and fatigue are well known to those who drink their regular morning cup of coffee. The effects of coffee are due to one of its chemical constituents, caffeine. In addition to coffee, other herbs and supplements contain caffeine.
Coffee is of interest for people with MS because of its possible effects on fatigue. No systematic approaches exist to using coffee or other caffeine-containing herbs in people with MS. Despite the fairly widespread use of caffeine products by people with MS, very little research has been done in this area.
The largest study to date was conducted by the Rocky Mountain Multiple Sclerosis Center—the results of this study have been published in a preliminary form (1) and may be viewed at www.ms.cam.org, the CAM website of the Rocky Mountain MS Center. This study was an online survey that involved nearly 2,000 people with MS. Those who appeared to have MS fatigue were questioned about the various conventional and unconventional therapies that they had tried. For the respondents, about 50 percent believed that some form of caffeine was helpful for their fatigue. Another MS study that included caffeine involved a therapy known as Prokarin—the results of this study are difficult to interpret for several reasons, including the fact that Prokarin contains caffeine as well as histamine (see the chapter on Prokarin).
In the general population, strong evidence suggests that coffee improves mental alertness, thereby potentially improving mental fatigue. In contrast, coffee does not appear to improve physical power or endurance and therefore probably does not have a beneficial effect on physical fatigue.
Another area of possible relevance to MS is immune system alteration by caffeine. Some studies indicate that caffeine may decrease the activity of lymphocytes, a type of immune system cell, and produce changes in a protein in the brain known as the adenosine receptor. In theory, these effects could be beneficial for MS, but studies in this area are too preliminary to allow any definite conclusions.
Other herbal sources of caffeine exist. Tea contains a significant amount of caffeine. In the United States, black tea, derived from the leaves of Camellia sinensis, is the most popular form. Green tea is prepared from the same plant, but the leaves are processed differently. Another well-known source of caffeine is chocolate and other food products derived from the cacao plant. Cola nut, also known as kola nut and bissy nut, contains caffeine. Guarana is a South American caffeine-containing herb that may be consumed as a tea or in tablet form. Another South American herb that contains caffeine, maté or yerba maté, is not especially popular in the United States but is popular in some South American countries. Finally, the most direct approach is to take caffeine itself, which is available in tablet form as a dietary supplement.
The amount of caffeine available from these products is variable. A convenient reference point to start with is a 6-ounce cup of percolated coffee, which contains approximately 100 milligrams of caffeine. It is important to note that less caffeine is present in instant coffee and darker roast coffees, including latté, cappuccino, and other popular espresso-based coffees. In comparison to a typical cup of coffee, approximately one-half the amount of caffeine (30 to 60 milligrams) may be obtained from a cup of tea, cocoa, or maté; a 12-ounce bottle of a cola drink; or an 800-milligram tablet of guarana. Relatively low amounts of caffeine (5 to 10 mg) typically are contained in a chocolate bar. Caffeine tablets often contain 100 or 200 milligrams of caffeine and are roughly equivalent to one or two cups of coffee.
The frequency with which one ingests caffeine may influence the herb's ability to improve mental alertness. With high levels of fatigue in the morning, people often drink extra cups of coffee at that time. However, research indicates that this may not be the most effective approach. It has been reported that small amounts of caffeine (about 20 milligrams or about one-fifth of a cup of coffee) taken on an hourly basis may be especially effective for promoting wakefulness.
The FDA regards coffee and other caffeine-containing herbs as generally safe. One precaution to be aware of is the possible effect of caffeine on a developing fetus. Because of this concern, the FDA recommends that pregnant women avoid or limit caffeine consumption. Maté is an herb that has raised concern. Studies indicate that maté, especially in high doses, may increase the risk of cancers of the mouth, throat, kidney, bladder, and lung. Notably, two North American forms of maté, Ilex cassine and Ilex vomitoria, are classified as not safe by the FDA.
Some specific concerns exist about MS and caffeine-containing products. Caffeine use may worsen MS-associated bladder problems because it increases urination and may irritate the urinary tract. Caffeine use may increase the risk of osteoporosis, a condition to which people with MS may be especially prone. In addition, theoretical risks are associated with the use of high doses of green tea. This form of tea contains relatively high levels of antioxidants, which, in theory, may stimulate the immune system
(see "Vitamins, Minerals, and Other Nonherbal Supplements"); this effect may be harmful for people with MS.
High doses of caffeine should be avoided because they may produce anxiety, insomnia, heart palpitations, upset stomach, nausea, vomiting, high blood pressure, tremors, muscle twitching, and increased cholesterol levels. The long-term use of large doses of caffeine may lead to an addiction-type situation in which higher and higher doses are required for the same effect and in which abrupt discontinuation causes mild withdrawal symptoms such as headache, irritability, dizziness, and anxiety. The safety of caffeine in women who are pregnant or breast-feeding is unclear.
Caffeine-containing preparations also interact with other supplements and medications. Simultaneously taking moderate doses of two or three caffeine-containing supplements may lead to excessive levels of caffeine. Also, both the stimulant actions and the adverse effects of caffeine may be accentuated when it is consumed with ma huang (ephedra) or with grapefruit juice. The blood levels of caffeine may be increased by multiple medications, including oral contraceptives, cimetidine (Tagamet), and verapamil (Calan).
The usual maximum daily dose of caffeine is 250 to 300 milligrams. This is equivalent to two to three cups of coffee or four to five cups of tea. The timing and dose of caffeine that may be most beneficial for MS-related fatigue has not been studied.
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