| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Letters to the Editor |
Yale University School of Medicine Department of Epidemiology and Public Health New Haven, CT 06520-8034 E-mail: susan.mayne{at}yale.edu
Dear Sir:
After reading the interesting report by Steinberg and Chait (1), we felt obligated to point out apparent errors in the carotenoid data presented, both with regard to dietary intake and to plasma concentrations. For example, in Table 2 the ß-carotene intake is in the range of 896–1586 mg/d in the control group, a value that is exceedingly unlikely because the normal dietary intake of ß-carotene is in the range of 2–3 mg/d (2). We assume that this was a typographical error and that the actual intended units were µg/d for the baseline dietary intake of both ß-carotene and lycopene. As for the test group, the authors showed in Table 2 that dietary intake of ß-carotene ranged from 1096 to 1318 mg/d at baseline and then rose to 9121 mg/d with supplementation. Again, we assume that the intended units at baseline were µg/d. The estimated dietary intake of ß-carotene for the test group at week 8 should have been 
32 mg/d (30 mg ß-carotene/d from the supplemented juice plus normal dietary intake), not 9121 mg/d. As for the plasma concentrations reported in Table 3, again, the ß-carotene values are implausible. The concentration of ß-carotene in plasma at baseline was in the range of 2.3–2.5 µmol/L. Based on data from the third National Health and Nutrition Examination Survey (3), the 95th percentile for plasma ß-carotene in Americans aged 
4 y is 0.91 µmol/L. It is unprecedented to have a population mean this high in an unsupplemented population, especially in a population of smokers, who are known to have lower plasma ß-carotene concentrations than nonsmokers (2). These apparent errors in the carotenoid data obscured the interpretation of this interesting article because the effectiveness of antioxidant supplementation in a population can only be assessed relative to the baseline and postintervention antioxidant status of that population. Because both the dietary intakes and resulting plasma concentrations of ß-carotene are incompatible with the existing literature on carotenoids, the antioxidant status of this population cannot be assessed.
REFERENCES
Department of Nutrition University of California, Davis 3143 Meyer Hall One Shields Avenue Davis, CA 95616 E-mail: fmsteinberg{at}ucdavis.edu
Dear Sir:
In response to the letter by Mayne and Cartmel, we have provided the correct values for ß-carotene and lycopene for our recently published paper (1) and apologize for the confusion related to the erroneous data. The lycopene and ß-carotene intakes in Table 2 are incorrect. This resulted from a systematic error that occurred when the proprietary dietary nutrient database was updated. This error in the database was discovered only after receipt of Mayne and Cartmel's letter to the Editor. The correct initial (baseline) intakes of ß-carotene were 1.1 and 1.3 mg/d for the control and test groups, respectively. These intakes are low to normal relative to normal ranges of intake from population-based surveys. The correct mean dietary intake of ß-carotene for the control group at the end of the study (week 8) was 2.3 mg/d, whereas that for the test group (including the supplemented juice) was 26.9 mg/d. This value for the test group was based on a final quality-control analysis of the ß-carotene content of the juice at the end of the study (0.11 mg ß-carotene/g juice) plus normal dietary intake. The correct initial lycopene intakes for the control and test groups were 0.4 and 0.8 mg/d, respectively; values at the end of the study were 22.5 and 191.7 mg/d, respectively. Thus, these corrected values are consistent with normal ranges of intake in population-based surveys.
The plasma carotenoid concentrations in Table 3 are off by a factor of 10 because of the misplacement of the decimal point. The correct initial concentrations for the control and test groups were 0.25 and 0.23 mmol/L, respectively, which fall within expected ranges on the basis of data from the third National Health and Nutrition Examination Survey. After supplementation, the test group had a plasma concentration of 1.21 mmol/L, which is outside the normal range and was expected, whereas the concentration in the control group at the end of the study was 0.39 mmol/L.
In summary, the correct intakes of ß-carotene and lycopene represent those of the general population; therefore, the antioxidant status of the population can be assessed. The relative magnitude of change in the plasma ß-carotene concentrations was not altered by the error; therefore, our interpretation is still valid.
REFERENCES
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
