Dietary herbal supplements with phenylephrine for weight loss.

This study was designed to evaluate the efficacy and safety of a dietary herbal supplement containing citrus aurantium and phenylephrine in the treatment of obesity. Two pilot studies enrolled healthy subjects with body mass indexes 25-40 kg/m(2) to similar 8-week weight loss programs. Safety was assessed by physical examination and laboratory tests at screening and 8 weeks. The first pilot study randomized eight subjects to citrus aurantium (herbal phenylephrine) or placebo. Body composition by DEXA scan, waist circumference, and resting metabolic rate (RMR) were measured at baseline and 8 weeks. Food intake and appetite ratings were measured at baseline and week 2. The second pilot study randomized 20 subjects to two 2-hour RMR tests a week apart after phenylephrine (20 mg) or placebo followed by phenylephrine (20 mg) three times a day for 8 weeks. In the first pilot study, the citrus aurantium group gained 1.13 +/- 0.27 (mean +/- SEM) kg compared with 0.09 +/- 0.28 kg in the placebo group (P < .04). RMR at baseline rose more in the citrus aurantium group, 144.5 +/- 15.7 kcal/24 hours, than the placebo group, 23.8 +/- 28.3 kcal/24 hours (P < .002), but not at 8 weeks. DEXA, waist circumference, food intake, and hunger ratings were not different. In the second pilot study, the phenylephrine group lost 0.8 +/- 3.4 kg in 8 weeks (not significant), and RMR increased more in the phenylephrine group (111.5 +/- 32.6 vs. 37.4 +/- 22.7 kcal/24 hours, P = .02). There were no significant safety issues in either study. Although no toxicity was seen, these pilot studies suggest phenylephrine is not efficacious for weight loss.

Globin digest: no evidence for a weight loss mechanism.

This study was designed to document the mechanism through which globin digest, a dietary herbal supplement, might cause weight loss by exploring possible fat malabsorption, calorie malabsorption, energy expenditure, and fat oxidation. Six healthy subjects were placed on an outpatient diet for 14 days and given a meal containing 40.9 g of fat on days 5 and 11, and stools were collected for 72 hours after each meal for analysis of fecal fat content. Four grams of globin digest was given with one meal and placebo with the other. In another separate study, six subjects were placed on a 100-g fat, weight-maintaining diet for 14 days. All food was prepared by the Pennington Center (Baton Rouge, LA) metabolic kitchen. Globin digest (2 g) or placebo was given with each of three meals per day, and stool was collected for calorie determinations during the last 72 hours of each week. Subjects received globin digest during one of the 2 weeks and placebo during the other. Resting metabolic rate and respiratory quotient were measured on the last day of each 1-week period. There was no increase in 72-hour fecal fat or fecal calories by bomb calorimetry during either of the studies. There was no difference in the respiratory quotient. Globin digest did result in an increase in resting metabolic rate. However, this increase was not statistically significant. Globin digest, if effective, does not cause weight loss or fat loss through fat malabsorption or a relative increase in fat oxidation. Future studies are needed to document the efficacy of globin digest for weight loss in humans before further mechanistic investigation is attempted.

The effect of an herbal supplement containing black tea and caffeine on metabolic parameters in humans.

OBJECTIVE: The objective of this study was to test an herbal supplement containing black tea (the fully oxidized form of Camellia sinensis) and caffeine for stimulation of thermogenesis. METHODS/MATERIALS: A double-blind, placebo-controlled, crossover study was conducted on 16 healthy, weight-stable, non-smoking subjects, ages 21-55 years, with body mass index (BMI) of 20-30 kg/m2, and on no medications other than oral contraceptives or hormone replacement therapy. Subjects had no caffeine for 48 hours, no exercise for 24 hours, and no food for 12 hours before each visit. Area under the curve (AUC) for resting metabolic rate (RMR), respiratory quotient (RQ), blood pressure, pulse rate, and temperature were measured. At each visit RMR was measured at baseline and at one and two hours following oral administration of a supplement containing principally 600 mg black tea extract (60 percent polyphenols, 20 percent caffeine) and 442 mg guarana extract (36 percent caffeine) or matching placebo. RESULTS: The RMR and systolic blood pressure (SBP) AUCs increased significantly (p less than 0.02 and p less than 0.01, respectively) in the herbal supplement group compared to placebo. The AUC increase in RMR over the two-hour test period was 77.19 kcal/24 hr2 +/- 120.10 kcal/24 hr2 with an average rise of 52.38 +/- 29.52 kcal/24 hrs. The AUC rise in SBP over two hours was 10.3 mm Hg/hr +/- 14 mm Hg/hr. The average rise in SBP over two hours was 3.7 mm Hg +/- 4.4 mm Hg. DISCUSSION: The herbal supplement increased metabolic rate without changing substrate oxidation. The rise in SBP was consistent with the amount of caffeine the supplement contained.