Cover Image

Not for Sale

View/Hide Left Panel
Click for next page ( 41

The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement

Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.

OCR for page 40
40 (McArdle et al. 1991). Dr. C. Everett Koop, former Surgeon covered under the Federal Dietary Supplement Act. General of the U.S. Public Health Service, was fond of saying However, because the quality of dietary supplements "we are what we eat" as he cautioned Americans that most of is not regulated by the FDA, their production is not regulated by the Good Manufacturing Practices Act. the ten frequent disease killers in our society are related to The contents and quality of dietary and nutritional what we eat. Nutrition experts recommend a balanced diet high supplements on the store shelves varies dramatically. in complex carbohydrates and low in fat to help individuals There is no guarantee that the labeling of the contents in attain peak performance. Although it is true that some supple- packaging accurately depicts what the package, bottle, ments may provide health benefits, others are unnecessary, or other container actually holds. Objective validation of claims of safety or efficacy is not readily available. because in a proper diet the food we eat should be able to The supplement business is a "buyers beware" market- supply all the nutrients, vitamins, and minerals our bodies place (Kurtzweil 1999; Straus 2002; GAO 2009). require. Additionally, many supplements, if taken incorrectly, or if they happen to contain metals, toxicants, or much larger Consumers therefore must exercise caution with all doses of whatever identifiable compound the consumer thought health food supplements. Products imported to the he or she was taking, can cause risks to one's health. Ubiquitous United States from overseas suppliers, especially some products in the pharmaceutical and food industries, advertisements promote many pills, powders, gels, drinks, have perpetually raised issues of manufacturing quality and more to help a person gain weight or muscle mass, to lose assurance. Depending on the source or supplier, the weight, or to simply feel better; or they promise to make one manufacturing standards for these compounds is not faster or stronger, and so on. always in accordance with the quality assurance that might be found for products typically monitored for An evaluation of the numerous dietary supplements compliance in the U.S. market. There have been instances in which herbal and health supplements or available is especially difficult because many such products component ingredients acquired from overseas, espe- contain multiple ingredients, they can have a changing compo- cially those purchased over the Internet, were contam- sition over time, or because individuals use them intermittently inated with toxic metals or with other drugs. Federal at doses that tend to be difficult to measure, and mostly the government agency (e.g., FDA, NIDA, and DEA) alerts amounts ingested are not recorded (IOM report: Greenwood and warnings about hazardous products sometimes and Oria 2008). The descriptions that follow do not lend lag months behind outbreaks of problems with such imported purchases. To minimize the risks of contam- themselves to orderly "clumping" of supplement products ination health food, dietary, and herbal supplements into categories. The attempt here is to describe chemical should be purchased only from reliable sources. Deter- substances that are widely included in commercial products; mining what constitutes a reliable source can at times in particular, highlighting those that contain psychoactive be problematic. ingredients that in some way might affect the performance or health of commercial drivers who take them. PSYCHOACTIVE HERBAL SUPPLEMENTS In an attempt to be somewhat comprehensive, this syn- Guarana (Paullinia cupana) thesis also provides modest coverage of other ingestible items that do not strictly qualify as nutritional supplements Guarana comes from the seeds of a South American plant-- per se (e.g., drinking appropriate amounts of water to sustain a shrub--the vast majority of which is grown in a small area proper hydration); however, they are included in this report in northern Brazil. Guarana gum or paste is derived from the because such practices involve additional chemical sub- seeds, rich in xanthenes approximately equivalent to caffeine. stances (e.g., fluoride and/or sodium and minerals contained Guarana paste is inserted into herbal supplements to food and in drinking water) that may impact driver health or perfor- beverages. Viewed as a tonic in South America, and especially mance. Again, the emphasis in the main body of this chapter so in Brazil, for decades guarana has been inserted into numer- is predominately to describe substances with psychoactive ous soft drinks much the way caffeine is added to soft drinks effects. In cases where the synthesis team did not identify in the United States. Now, guarana is increasingly found in sufficiently strong evidence in the scientific literature, we rel- drink products in the United States. In Japan, guarana extract egated what we have to say about those substances (supple- formerly was incorporated into chewing gum, and advertised ments or not) to Appendix C to this report. Such is the case, to prevent drowsiness (Sato et al. 1984). for example, with several of the herbal substances used as relaxants; stress and tension alleviants, for sleep-inducing Because the major active guarana constituent "guaranine" supplements involving amino acids; and with the use of daily is nearly identical to caffeine, guarana is claimed to be an multi-vitamins. In the cases where the scientific evidence iden- effective energy booster and is likely to have similar physio- tified for psychoactive effects was slim, those descriptions logical and behavioral effects to those of caffeine. Guarana appear in the Appendix C of this report (see Table 4). also contains similar related alkaloids such as theobromine and theophylline--both of which are also found in coffee and Caveat, a general caution: Most nutritional, health, and dietary supplements sold commercially (e.g., in tea (Bertrand and Carneiro 1932; Bempong and Houghton health food shops or grocery stores) are not approved 1992; Bempong et al. 1993; Leung and Foster 1996; Walker by the FDA. Many of these chemical components are et al. 2000; TTCP 2001). Each of these compounds has well-

OCR for page 40
41 TABLE 4 LIST OF SUPPLEMENTS AFFECTING HEALTH AND PERFORMANCE Category Where Found Use/Effect Comments Herbals Guarana Health food stores, Mild stimulants; have Some studies indicate mild Ginkgo Biloba truck stops, inserted some effect on cognitive effects akin to those of caffeine. into soft drinks and and reaction time No adverse effects energy drinks performance demonstrated Ginseng, Passion Flower, Health food stores, Relaxants to alleviate Psychoactive effects not Kava Kava, Valerian, boutique over-the- tension, stress, induce substantiated, relegated write- St. Johns Wort counter shops sleep up to report's appendix Physical Performance Enhancers Carbohydrates White rice, bread, pasta, Can improve/maintain As restorative can improve and sugars physical performance memory Amino Acids: Tryptophan, Health food stores, Tyrosine helpful for stress Scant evidence of cognitive Tyrosine found in meats resistance; some sleep performance enhancements improvements Multi-vitamins, Minerals Purchased in numerous Replace/supplement Not likely to improve and Antioxidants stores bodily needs not met performance; but may speed through good nutrition energy recovery Anabolic Steroids Naturally in body, DHEA for muscle Can enhance well-being, but available through building and popular with also impair cognition; must athletic outlets longevists continue treatment to prevent loss of effects Hydration Water Ubiquitous supply; now Essential nutrient; proven Bottled water may contain available in bottles benefits to the body sodium and minerals, not everywhere fluoride Vitamin and Mineral Sold in grocery stores Feel good drinking them Not much noticeable effect, Drinks/Waters vs. sodas taste is okay Functional Energy Drinks In many stores and Belief they restore or FEDs contain large amounts of (FEDs) highway rest stops boost energy; used as caffeine, taurine, sugar, etc. alcohol drink mix Energy Bars, Chews, etc. Stores, truck stops Energy boost, picker- Not enough data to verify uppers, suppress hunger energy boost effects Dietary and Weight Loss Health food stores, diet To lose weight; mostly in Often contain multiple Products clubs, over the Internet fad dieting substances not verified for efficacy or safety known effects as nervous system stimulants. As such they also Guarana extract powder, providing 500 to 1,000 mg of have some effect on increasing metabolic rate, suppressing guaranine, is claimed to provide mild stimulant properties appetite, and enhancing both physical and mental performance, and enhanced physical and mental performance. Higher levels and they have a mild diuretic effect. Guarana has been said to of intake have not been demonstrated to provide additional decrease fatigue, reduce hunger, help with arthritis, and has increases in performance, but may result in adverse side effects been used to treat diarrhea. Guarana has a history of use in such as tension, irritability, and nausea. Guarana mostly acts treating hangovers from alcohol abuse and headaches related as a cognitive enhancer through increased catecholamine to menstruation (Duke 1985). production. The likely psychoactive effectiveness of caffeine probably also applies to guarana. Claimed benefits are that The mode of action with guarana is primarily attributable guarana improves mood and cognitive performance, and assists to methylxanthine alkaloid caffeine. Guarana's effects on the in fighting fatigue. CNS therefore are similar to those of caffeine. The duration of effects is similar to that of free caffeine at about 3 to 5 h. In one of the earliest published studies on guarana's effects Guarana contains about twice the caffeine found in coffee on performance, Galduroz and Carlini (1994, 1996) conducted beans (about 3% to 4% caffeine in guarana seeds as com- a long-term study on normal, elderly, adult subjects, but found pared with 1% to 2% for coffee beans). Concentrated guarana no significant psychoactive effects on thinking or mental extract powders contain caffeine at levels of as much as functions. However, in lab studies with healthy young adults, 40% to 50%. Thus, 5 g of guarana at 3.5% to 5.6% caffeine, Kennedy et al. (2004) demonstrated the psychoactive effects taken less than 1 h before activity, will make approximately and the cognition-enhancing properties of guarana. These 175 to 280 mg of caffeine available in the body at the time researchers gave 75 mg of a dried ethanolic extract of guarana of commencement of the activity (TTCP 2001). Popular (approximately 12% caffeine), 200 mg of Panax ginseng, and South American guarana supplements deliver about 50 to a combination of the two (75 mg/200 mg) to 28 healthy young 200 mg of caffeine per day (similar to the amount found in participants (ages 18 to 24) in a multi-day study. Cognitive 1 to 2 cups of strong coffee). performance and subjective mood were assessed pre-dose

OCR for page 40
42 and at 1, 2.5, 4, and 6 h post-dose using serial subtraction Assessment of guarana. The work of Kennedy et al. tasks and mood scales from the cognitive drug research (2004, 2008) indicates the potential of guarana use for bring- (CDR) computerized assessment battery. Throughout the day, ing about positive effects on cognitive performance. Because all three treatments resulted in improved task performance guarana has already invaded the supplement marketplace in the compared with placebo. For guarana, improvements were seen United States, further research on guarana appears warranted. across attention tasks (but with reduced accuracy) and on a sen- Studies are needed to examine the effects of typical doses of tence verification task. Both ginseng and the ginseng/guarana guarana individually as well as synergistically when com- combination increased the speed of attention task performance, bined with other psychoactive ingredients currently in food and enhanced speed of memory task performance, but exhib- supplements available on the store shelves. Further, educational ited little evidence of modulated accuracy. Guarana, and the materials about the make-up of guarana and its potential effects combination of guarana with ginseng, and to a lesser extent on health and performance are needed for the user public, and ginseng itself, led to significant improvements in serial sub- for commercial drivers and for their employers. traction task performance. In another study, Kennedy et al. (2008) assessed the acute Ginkgo Biloba effects of either a mix of vitamin/mineral/guarana supplement or placebo drink in 129 healthy young adults (ages 18 to 24). For thousands of years extracts and infusions made from the Thirty minutes post-dose, participants completed six con- leaves of the small bushy Ginkgo Biloba tree have been used secutive runs on a 10-min battery of cognitive demand tests in traditional Chinese medicine for treatment of a variety of (i.e., 60 min of testing). The vitamin/mineral/guarana com- problems including asthma and digestive disorders. Ginkgo bination resulted in improved task performance in compari- biloba represents one of the most studied and commonly used son with placebo in terms of increased speed and accuracy herbal remedies in the world. In many western countries, of performing a rapid visual information processing task. especially in Europe, the use of an extract made from the While on the supplement mix, subjects reported attenuation green ginkgo leaf serves as a popular OTC herbal supplement of mental fatigue on a mental fatigue scale. advertised for its antioxidant properties, and as a prescribed remedy for use on a number of vascular problems, treat- Few other experimental studies of guarana were located. ment of memory loss, dementia, and macular degeneration The findings of Kennedy et al. apparently have not yet been (O'Hara et al. 1998). Ginkgo biloba's popularity grew in the replicated. Therefore, one cannot yet strongly support state- United States during the late 1990s and it continues through ments regarding the cognitive performance benefits of guarana. today. In 2002, the National Health Interview Survey found that ginkgo was the third most popular natural product in the As with caffeine, guarana also is likely to be effective in United States and determined that ginkgo was being used in enhancing physical performance when a person is working at some form by about 4% of American adults. a high percentage of aerobic capacity. Guarana may have moderate positive effects on anaerobic performance and Two main groups of active constituents responsible for muscular endurance. ginkgo biloba's medicinal effects are terpene lactones and Guarana tends to suppress appetite and therefore is ginkgo flavone glycosides, present in varying concentrations potentially useful for weight loss and obesity control. in the leaf of the ginkgo tree. Ginkgo effects may arise from a Neither guarana, nor simply caffeine by itself, appear to be single active ingredient or by the combined actions of the many especially effective as stand-alone weight loss aids; how- active ingredients. Approximately 40 different flavonoids have ever, in combination with other thermogenic and nervous been isolated. Commercial extracts of ginkgo are generally system stimulants, guaranine or caffeine may extend the standardized with regard to the content of the primary active activity and potency of certain supplement ingredients. As components, with the flavone glycosides and terpenoids with any caffeine-containing substance, too much guarana compromising 24% and 6% of the total extract, respectively. can lead to nervousness, tension, and headaches. No long- At the physiological level, ginkgo extract is both a platelet- term adverse consequences have been reported with guarana activating factor antagonist and a free radical scavenger. (TTCP 2001). The exact mode of action of ginkgo biloba in the body is not precisely known. The bioactive properties of ginkgo biloba In the United States, the commercial bottled drink industry extracts are varied. Ginkgo appears to modulate a number and marketers of energy boost compounds recently began of neurotransmitter systems and it exerts effects on cellular inserting considerable amounts of guarana into their products, metabolism. These and other mechanisms underlie a number along with other psychoactive compounds (including caffeine, of reported health effects of ginkgo, including improvements taurine, and ginseng). Guarana is found in some soft drinks, in blood circulation and neuroprotective roles after various colas, lemonade, energy drinks, supplement powders, and neuronal insults (Kennedy et al. 2000), for treatment of certain food bars. Many of these new products containing guarana forms of tinnitus (ringing in the ears), for short-term memory are found on the "energy boost product shelves" at truck stops loss, for senile dementia, and as a blood thinner to prevent along major highways in the United States. stroke. As therapy, the usual dosage has been 120 to 240 mg

OCR for page 40
43 of ginkgo biloba daily, or 40 to 120 mg as a prophylactic brain were dose-dependent, but not in a linear dose-related manner. tonic (Kleijnen and Knipschild 1992). They concluded that the cognitive-enhancing effects of ginkgo are more likely to be apparent in individuals aged There is a lack of standardization of ginkgo biloba extracts 50 to 59 years. Elsewhere, beneficial effects of ginkgo on in the supplement marketplace, making dose comparisons cognitive performance have been reported after 4 to 6 weeks across studies difficult. Little information has been published of treatment in elderly individuals and for those suffering regarding the pharmacokinetics, pharmacodynamics, and/or from dementia. the duration of ginkgo effects (Gilbert 1997). Preliminary data for some active ingredients give a time-to-peak plasma Using a similar test paradigm to the one previously men- at 1 to 3 h and a half-life of 3 to 6 h. A usual dose of ginkgo tioned, Kennedy et al. (2001) examined the combined effect extract ranges from 120 to 600 mg. Chronic treatments usually of administering both ginkgo biloba and Panax ginseng on administer 120 mg of ginkgo daily for up to 6 weeks, and this cognitive performance, memory, and mood. They gave a com- has demonstrated no adverse effect on performance of healthy bination dose of 320, 640, and 960 mg, along with a matching young subjects. placebo, to 20 healthy young adult volunteers, and tested at 1, 2.5, 4, and 6 h after the day's treatment. The most striking Ginkgo is said to improve aspects of cognitive perfor- result was a dose-dependent improvement in performance on mance. Claims for ginkgo extract include those suggesting it a "quality of memory" factor for the higher dose. This effect enhances mental function in healthy individuals and that it appeared targeted at secondary memory rather than the work- has been shown to be effective in the elderly for "cerebral ing memory component. There was also a dose-dependent insufficiency" (an imprecise term describing memory loss, decrement in performance of the "speed of attention" factor confusion, depression, dizziness, and tinnitus). More than for both the 320- and 640-mg doses. 400 animal and clinical trials looking at a variety of medicinal properties and clinical uses for ginkgo biloba suggested that Canter and Ernst (2007) reviewed 15 studies with random- its purported cognitive-enhancing effects are most likely ized, placebo-controlled, double-blind clinical trials looking attributable to its flavonoid and ginkgolide compounds (the for the effects of standardized ginkgo biloba extracts on latter found nowhere else in nature), which may arise from cognitive function. They did not find enough convincing uptake inhibition and enhanced release of neurotransmitters evidence for a robust positive effect of ginkgo biloba on any (Kleijnen and Knipschild 1992). aspect of cognitive function in healthy young individuals after either acute or longer-term administration. Thus, of the Kennedy et al. (2000) examined ginkgo extract (at doses few studies with healthy young subjects, the only effects of of 120 mg, 240 mg, and 360 mg) for cognitive performance ginkgo have been modest improvements in memory. No reports effects, at 1, 2.5, 4, and 6 h after administration using measures described cognitive performance of healthy individuals being from the CDR computerized assessment battery. Ginkgo impaired by ginkgo extract. produced a number of significant changes on performance measures, the most striking of which was a dose-dependent Assessment of ginkgo biloba. Canter and Ernst (2007) improvement of the "speed of attention" factor following presented what may appear to be a convincing indictment. In both the 240- and 360-mg doses, which was evident at 2.5 h, reality, there were not a sufficient number of reportable studies and was still present at 6 h after administration. Additionally, of ginkgo biloba and cognitive or psychomotor performance there were time- and dose-specific changes in performance to make definitive statements in this synthesis about the effi- (positive and negative) on the other three cognitive factors caciousness or utility of ginkgo biloba to meet the primary (accuracy of attention, speed of memory, and quality of interests of the commercial driving community. Additional memory) of the CDR. Across three such experiments, the targeted research might help elucidate these issues. effects of the 120-mg dose of ginkgo (normal dose level) on cognitive speed were equivocal, even appearing to have a Herbal and Nutritional Supplement Remedies negative effect on speed of attention task performance; only to Relieve Stress and Tension, and modest effects were demonstrated in memory task performance Promote Relaxation and Sleep (Kennedy et al. 2000, 2007; Scholey and Kennedy 2002). There were improvements in self-rated mood following ginkgo, Proponents of nutritional supplements advocate various herbs and to a lesser extent a combination product (ginkgo, guarana, to relieve stress. These herbal compounds include Passion and vitamin mix) as well (Kennedy et al. 2002). Flower, Lavender Oil, Kava, Valerian, Ginseng, and Saint John's Wort. Additional nutrient supplements that help with Some studies reported that ginkgo improved memory in anxiety or stress are proteins such as 5-HTP, and amino acids healthy subjects, but an absence of effects on other cognitive such as Tryptophan, Tyrosine, and Theanine. Most of these tasks (Warot et al. 1991; Wesnes et al. 1997; Rigney et al. 1999). supplement products are commercially available in boutique Rigney et al. (1999) reported positive ginkgo extract effects health food stores, nutrition shops, and in some grocery stores. (acutely administered) were more pronounced for memory, Although the synthesis team identified some descriptive particularly working memory, and the effects demonstrated and scientific reports of studies of their effects on health and