Usage patterns, health, and nutritional status of long-term multiple dietary supplement users: a cross-sectional study

doi:10.1186/1475-2891-6-30

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Nutr J. 2007; 6: 30.

Published online 2007 Oct 24. doi: 10.1186/1475-2891-6-30

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Table 4

Serum nutrient and biomarker concentrations of a sample of long-term users of multiple dietary supplements (Multiple Supp), and of multivitaminmineral users (Single Supp) and non-users (No Supp) from NHANES 2001–2002 and NHANES III 1988–1994.

Characteristic	No Supp n = 602	Single Supp N = 176	Multiple Supp N = 278	p-value*
	Mean (SE)

NUTRIENTS
RBC folate (nmol/L)^‡	646.7 (8.9) a	891.1 (30.7) b	1153.4 (11.8) c	<0.001
Retinol (μg/dL)^†	59.2 (0.5) a	64.3 (0.7) b	65.0 (1.0) b	<0.001
Ascorbic acid (mg/dL)^†	0.66 (0.02) a	0.94 (0.02) b	1.62 (0.03) c	<0.001
Alpha tocopherol (mg/dL)^†	1.1 (0.01) a	1.4 (0.02) b	2.9 (0.06) c	<0.001
Alpha carotene (μg/dL)^†	4.5 (0.1) a	5.9 (0.2) b	27.5 (1.3) c	<0.001
Beta carotene (μg/dL)^†	18.5 (0.3) a	27.0 (1.2) b	62.7 (2.8) c	<0.001
Ferritin (μg/L)^‡Male	198.2 (6.1) a	205.2 (12.6) a	117.6 (5.9) b	<0.001
Ferritin (μg/L)^‡Female	101.7 (7.1) a	74.9 (8.4) b	117.4 (3.3) c	<0.001
25-hydroxyvitamin D (nmol/L)			131.4 (45.3)^§
BIOMARKERS
Homocysteine (μmol/L)^‡	9.6 (0.2) a	9.1 (0.5) a	6.1 (0.3) b	<0.001
C-reactive protein (mg/dL)^‡	0.46 (0.04) a	0.32 (0.03) b	0.19(0.03) c	<0.01
Total cholesterol (mg/dL)^‡	211.5 (2.9) a	212.1 (3.6) a	203.1 (2.7) b	<0.05
LDL-cholesterol (mg/dL)^‡	125.1 (2.8)	129.5 (4.2)	122.1 (2.6)	NS (>0.05)
HDL-cholesterol (mg/dL)^‡	50.9(0.5) a	53.3 (1.4) a	57.5 (1.1) b	<0.001
Ratio total-cholesterol to HDL-cholesterol^‡	4.5 (0.07) a	4.3 (0.13) a	4.0 (0.09) b	<0.001
Triglycerides (mg/dL)^‡	180.1 (16.7) a	145.3 (9.4) a	121.0 (6.8) b	< 0.01

*Multiple regression techniques were employed to examine differences in nutrient and biomarker concentrations of user groups. Differences in nutrient concentrations were adjusted for sex and age. Differences in biomarker concentrations were further adjusted for age², education, income and income², and body mass index (BMI). P-values represent the statistical significance for comparisons of user group means with different letters; if these comparisons varied in significance level, the most significant is shown.

^†Data obtained from NHANES III 1988–1994.

^‡Data obtained from NHANES 2001–2002.

^§Comparable 25–hydroxy vitamin D data not available from NHANES.

LDL = low-density lipoprotein,
HDL = high-density lipoprotein.