Plasma carotenoid and vitamins a and e concentrations in older African American women after wheat bran supplementation: effects of age, body mass and smoking history

OBJECTIVE: This study investigated the relationships of plasma vitamins A, E, and carotenoids with age, BMI and former/non-smoking history after adjusting for wheat bran supplementation. METHODS: All 39 African American women in the church-based, volunteer sample, 40-70 years old, supplemented their daily diets for 5-6 wks. with 1/2 cup of a riboflavin-spiked wheat bran cereal. RESULTS: Urinary riboflavin concentrations increased from 0.8 +/- 0.1 mg/day at baseline to 7.5 +/- 0.5 mg/day after supplementation, confirming the 99.2 +/- 10.5% self-reported adherence. Plasma nutrient concentrations did not change significantly with supplementation nor was never/former smoking history related to diet. Plasma retinol and serum cholesterol were significantly higher (p < 0.0002) in persons older than 55 years compared to younger adults. Plasma retinol (microg/dL) but not serum cholesterol was associated significantly with menopausal status and hormone replacement therapy (HRT; p = 0.05); progressive increases in retinol concentrations were found in the women after adjusting for pre/post supplementation: lowest in pre-menopause (47.7 +/- 4.8); intermediate concentrations in post-menopause on HRT (54.6 +/- 3.0); highest level in post-menopause without HRT (61.1 +/- 3.0). Similarly, a progressive increase was found in lipid-unadjusted alpha-tocopherol concentrations and menopausal status with or without HRT. Vitamin A and cholesterol intakes were not significantly different by age group. Plasma carotenoids were not significantly different by age or fiber supplementation, but alpha- and beta-carotene and beta-cryptoxanthin were significantly lower with BMI > or = 30. In contrast to carotenoids, both plasma levels of gamma-tocopherol and lipid-adjusted gamma-tocopherol were significantly higher with obesity compared to those with BMI < 30. CONCLUSION: Plasma alpha- and beta-carotene and beta-cryptoxanthin were negatively associated with obesity, whereas gamma-tocopherol measures were consistently elevated with high BMI. The increase in age-associated plasma retinol in postmenopausal women was likely related to decreased estrogen concentrations in the African American women. Smoking history was not influential in this study.