Variation in concentration and labeling of ginger root dietary supplements

Ginger root dietary supplements are often used to alleviate symptoms of nausea and vomiting associated with pregnancy. In this study, we determined the variation in 6-gingerol, 6-shogaol, 8-gingerol, and 10-gingerol concentrations and labeling of different brands of ginger root dietary supplements.

Ten different ginger root dietary supplements were purchased randomly at local pharmacies and health food stores. The 6-gingerol, 6-shogaol, 8-gingerol, and 10-gingerol concentrations of the dietary supplements were determined by high-performance liquid-chromatography. In addition, we examined the container labeling for the amount of ginger root powder or extract in each capsule, the serving size, ingredients, expiration date, lot number, standardization procedure, and suggested use.

The 6-gingerol concentration of the ginger powder dietary supplements ranged from 0.0 to 9.43 mg/g, (mean +/- standard deviation, 2.56 +/- 2.95 mg/g), 6-shogaol ranged from 0.16 to 2.18 mg/g (1.27 +/- 0.58), 8-gingerol ranged from 0.00 to 1.1 mg/g (0.47 +/- 0.34), and 10-gingerol ranged from 0.00 to 1.40 mg/g (0.36 +/- 0.51). The amounts of 6-gingerol, 6-shogaol, 8-gingerol, and 10-gingerol in the ginger root dietary supplements varied widely on both a milligram per gram basis and on a milligram per capsule basis. Likewise, the suggested ginger serving sizes varied from 250 mg to 4.77 g per day.

The results of this study indicate that there is a wide variation in the gingerol composition and in the suggested serving sizes of ginger root powder from different manufacturers.

II-3.