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We examined the effects of citric acid and l-carnitine administration on physical fatigue. In a double-blind, placebo-controlled, 3-way crossover study, 18 healthy volunteers were randomized to oral citric acid (2,700 mg/day), l-carnitine (1,000 mg/day), or placebo for 8 days. The fatigue-inducing physical task consisted of workload trials on a cycle ergometer at fixed workloads for 2 h on 2 occasions. Before the physical load, salivary chromogranin A, measured as a physiological stress marker, was lower in the group given citric acid than in the group given placebo. Also, after the physical load, the subjective feeling of fatigue assessed with a visual analogue scale was lower in the citric acid group than in the placebo group. In contrast, l-carnitine had no effect on chromogranin A or subjective fatigue. These results suggest that citric acid reduces physiological stress and attenuates physical fatigue, whereas l-carnitine does not.

Blood cholesterol-lowering effect and safety of tea catechins were examined in a placebo-controlled double-blind study in which a beverage containing tea catechins (a 250ml beverage containing 197.4mg of catechins) was given twice a day at breakfast and dinner for 12 weeks. The subjects used were adult males and females with mild and borderline hypercholesterolemia with the range of serum total cholesterol levels 180-259mg/dl (male/ female, 38/22; age, 48±9 years; total cholesterol, 222±20mg/dl), who were not taking drugs that may affect lipid metabolism. The study was initiated with a 2-week pre-observation period followed by a 12-week intake period and a 2-week post-observation period. The results revealed that the serum total cholesterol levels in the test beverage group (initial intake level) was significantly decreased at 8 weeks (228±23mg/dl to 220±21mg/dl, p