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On test: FRS Plus, August 31, 2005
Instant anti-oxidants - just add water
FRS Plus is a sports supplement that promises to increase the effectiveness of your training. Pam Hinton, assistant professor of Nutritional Sciences at the University of Missouri-Columbia, takes a look.
Free Radical Scavenger-Plus is a fruit-juiced (10 percent fruit juice) based sports drink supplemented with vitamins C and E, thiamin, riboflavin, folate, B12, niacin and a small amount of caffeine (equivalent to 1/3 of a cup of coffee per serving). The “active ingredients” in FRS-Plus are quercetin and catechin, naturally occurring antioxidants found in certain plants. FRS is and the drink comes as a liquid concentrate that comes packaged in a bottle reminiscent of organic chemistry. The colorful orange and yellow “aromatic rings” appropriately reflect the basic chemical structure of quercetin and catechin. The FRS concentrate comes with a 2-ounce plastic cup that is convenient for accurately diluting the FRS with water in a ratio of 1:3. FRS-Plus Original provides 110 kcal per serving with all of the calories coming from sugar. FRS-Plus Low Calorie has 7 g of carbohydrates, providing 30 kcal per serving; it is sweetened with sucralose, neotame, and acesulfame. According to the label, an 8-ounce serving of FRS should be consumed twice per day, providing 500 mg of quercetin and 100 mg catechins.
The rationale behind the formulation of FRS-Plus is that large amounts of antioxidants, consumed regularly, will prevent the formation of “reactive oxygen species” (ROS). These molecules (superoxide radical anion, 02-; singlet oxygen 102; hydrogen peroxide H2O2; hypochlorous acid HOCL) result from oxidative metabolism and because they are highly unstable, cause damage to cell membranes. Exercise, particularly activities that involve eccentric muscle contractions (muscle lengthens during force production, e.g., back-pedaling on a fixed gear) cause acute tissue damage that often progresses to the clinical syndrome of delayed onset muscle soreness (DOMS). The symptoms of DOMS include muscle pain, stiffness, and loss of strength. Pain and tenderness peak 24-48 hours after exercise and are recovered within one week. Three to four days after exercise, stiffness and swelling are at their worst and resolve within 10 days. Loss of muscle strength is greatest within the first 48 hours and typically takes five days to recover.
Disruption of the cell membrane is central to the mechanism of muscle injury that leads to DOMS. Mechanical stress, such as that resulting from eccentric muscle contractions, damages the cell membrane so that there is a net influx of calcium. The increase in intracellular calcium concentration activates phospholipase A2, the enzyme responsible for cleaving arachidonic acid (AA) from the membrane phospholipids. Free AA is metabolized by cyclo-oxygenase and lipoxygenase to prostaglandins (PG), thromboxanes, and leukotrienes. PGE2 increases permeability of the vasculature and sensitizes afferent nerve fibers to mechanical and chemical signals, causing pain. Leukotrienes also increase vascular permeability and direct neutrophils to the damaged tissues where they generate free radicals as a byproduct of phagocytosis. Further tissue damage results from oxidative damage initiated by the ROS.
There is limited evidence from human and animal studies that prophylactic treatment with antioxidants may help to prevent and speed recovery from DOMS. Vitamin E (Rokitzki, 1994; Shafat, 2004; Sumida, 1989) and vitamin C (Jakeman, 1993; Kaminski, 1992) supplementation reduced muscle damage and accelerated recovery of muscle strength after DOMS in humans and treatment with a chemical free radical scavenger (Zerba, 1990) reduced muscle damage in animals. The idea behind FRS Plus is that it may prevent injury to cell membranes and reduce the secondary damage that results from ROS.
Recently food scientists have identified compounds in plant food that prevent chronic diseases associated with oxidative damage to cells (CVD, cancer, macular degeneration) because of their antioxidant activity. Hundreds of these compounds, often referred to as “nutraceuticals” or “phytochemicals,” have been identified and classified based on their chemical structures. Quercetin and catechins are both flavonoids; quercetin can be further classified as a flavonol and catechin as a flavanol. Quercetin is the most frequently occurring flavonoid in the food supply. The best food sources are onion, leeks, kale, broccoli, blueberries, wine and tea, providing 5-120 mg per serving. The foods with the greatest catechin concentration are fruits and tea (20-160 mg per serving). The concentration of flavonoids in foods varies considerable, depending on growing conditions, ripeness, storage and method of food preparation. Cold storage helps preserve flavonoids; but, over time, storage at room temperature results in significant degradation—up to a 60% reduction after nine months. The average daily consumption of flavonols in the U.S. is 20-25 mg; total flavonoid consumption in the typical Western diet is estimated to be 100-150 mg per day.
As with any nutrient, digestion, absorption and metabolism determine the biological activity of the ingested compound. It takes between 0.5 and 9 hours after ingesting quercetin for levels to peak in the blood, depending on whether the quercetin is free or bound to other compounds. Quercetin ingested in liquid form causes a much greater increase in blood quercetin levels compared with quercetin in whole foods (5000 nmol/L vs 0.3-0.75 nmol/L after ingestion of 100 mg of quercetin). The half life of quercetin in plasma is 11-28 hours. This means that after 11-28 hours the concentration of quercetin in plasma will be half its peak value. Because FRS Plus contains quercetin in liquid form it should produce higher plasma concentrations than if an equivalent amount were consumed in food. High plasma concentrations of quercetin could be maintained by consuming a total of 16 ounces of FRS Plus per day, in two doses, as recommended on the bottle.
Because of their chemical structure (hydrophobic aromatic rings and hydrophilic hydroxyl groups) flavonoids in the blood can interact with cell membranes. Hydrogen bonds form between the hydroxyl groups on the flavonoids and the phospholipids on the cell membranes, forming a layer of anti-oxidant protection around the cell. Although there is no direct in vivo evidence of antioxidant activity, the concentration of quercetin in blood can reach levels that prevent superoxide generation in test tube experiments. Based on human studies, the amount of quercetin in FRS Plus, when consumed as recommended, should elevate and maintain plasma quercetin concentrations within the range that offers anti-oxidant protection. Quercetin and catechin also may help to recycle the antioxidants, vitamins E and C.
Quercetin and catechin also may have ergogenic effects by increasing catecholamine (epinephrine and nor-epinepherine) availability. The catecholamines are released from the adrenal gland due to activation of the autonomic nervous system in response to stress, including exercise. Catecholamine release during exercise stimulates breakdown of fat in adipose and skeletal muscle so that the fatty acids can be used for energy. These hormones also act on the liver and skeletal muscle such that glycogen is broken down into glucose. In addition to acting as hormones, catecholamines also are neurotransmitters, causing an increase in heart and respiration rate and redistribution of blood flow to exercising muscle. Quercetin may increase catecholamine availability by interfering with the degradation of epinephrine and nor-epinepherine. Catechol-O-methyl transferase (COMT) is an enzyme that plays an important role in degradation of the catecholamines. COMT has a higher affinity for quercetin than for epinephrine and nor-epinepherine, so if quercetin is present the enzyme will work to break down quercetin instead of epinephrine. Although quercetin inhibits COMT activity in a test tube, it is difficult to speculate how quercetin affects COMT activity, and, therefore catecholamine availability in humans. A drug that inhibits COMT had no effect on plasma catecholamines, blood pressure, heart rate or electrocardiogram during exercise in healthy males (Sundberg, 1993).
Researchers at Pepperdine University recently studied the effects of 6 weeks of quercetin in FRS (600 mL per day) on performance during a 30 km time trial in recreationally competitive male cyclists. In this double-blind cross-over study, 11 cyclists underwent body composition, max VO2 and 30 km TT testing at baseline. Then half of them were randomly assigned to consume FRS Plus with quercetin and the others consumed the placebo (FRS plus without quercetin). After six weeks, the subjects underwent exercise testing and then switched treatments for the second six weeks, followed by another round of testing. The summary of the results on the frsplus.com website states, “An independent clinical trial at Pepperdine University revealed a dramatic improvement in time trial performance as a result of daily intake of FRS Plus over a 6-week period.”
If you read the complete report (available at the website), it is apparent that summary statement is accurate, but incomplete. For some of the performance variables, average power, % peak power, and gross mechanical efficiency at 8 km into the TT, FRS Plus improved performance compared to baseline, but so did the placebo. It is true that FRS Plus significantly improved the time it took for subjects to complete the TT (52.30 ± 2.03 vs. 50.70 ± 2.22 minutes). The average time for subjects following the placebo treatment was (51.53 ± 2.48), which was not significantly different from the baseline measurement. The researchers do not indicate if the average TT time for the FRS Plus group was significantly different from the time for the placebo group. The researchers could not attribute the improved performance to differences in metabolism and speculated that the improvements may have been due to increased catecholamines and/or antioxidant activity, but did not directly measure either.
So what’s the bottom line? Is FRS Plus worth the $1.15 per serving? Will it live up the claims on the bottle? For some athletes, the promise of “an increase in energy and alertness within 30 minutes of ingestion” may hold true. One tester described it as having, “a pretty good pick-me-up for about an hour after you drink it. It kind of reminds me of those herbal pills you can get at truck stops to help you stay awake while driving.” If quercetin significantly increases epinepherine and norepinepherine levels in the brain, this effect is certainly plausible.
Quercetin and catechin undoubtedly are antioxidants, but the degree to which FRS Plus prevents oxidative damage in athletes is not known. The downside of relying on FRS Plus as your primary source of phytochemicals is that you miss out on all the other nutrients that you would have consumed if you’d eaten a whole food. By eating fruits and vegetables, you get the entire spectrum of phytochemicals, not just one or two. FRS Plus tastes a lot like orange juice, although there is “vitamin” aftertaste because of the riboflavin. But, as sports drinks go, it is not too bad. I liked the FRS Plus mixed in a smoothie with berries, banana, and soy milk.
Price: US $18.95