Determinants of plasma retinol concentrations of middle-aged women in rural China

Abstract

The purpose of this study was to assess the correlates and possible determinants of plasma vitamin A among middle-aged women in rural China. The vitamin A adequacy of the different diets at the five widely varying survey sites was also assessed. Patterns of correlations among dietary and biochemical measurements were strikingly different from previous studies in Western subjects. Plasma beta-carotene was uncorrelated with beta-carotene intake even after adjusting for potential confounders. In counties with low preformed vitamin A intake, plasma retinol correlated with plasma copper (P = 0.007), which in turn was correlated with dietary intake of copper (P = 0.007). In these counties plasma retinol was correlated with plasma beta-carotene (P = 0.001) and was increased 10% in women in the first 2 y of menopause (P = 0.028). Plasma retinol and C-reactive protein levels are inversely correlated (r = -0.15, P < 0.001), indicating that vitamin A status and inflammatory response may be related but the causal direction is unknown. Despite low intake of vitamin A (county averages of 13-78% of recommended daily allowance [RDA]), and particularly of preformed vitamin A, only 3% of these women had plasma retinol levels below 0.7 mumol/L, considered to indicate possible marginal deficiency. Plasma levels of retinol and beta-carotene were more influenced by intrinsic factors such as menopause, lipid status, retinol requirements, and possibly copper status and inflammation than by extrinsic factors such as diet and lifestyle.

Retinol and mineral status in grazing foals during the dry season

“…Similar results were obtained by Root et al (1999) when studying women in China whose main source of vitamin A was beta-carotene from fresh vegetable diets. Simpson et al (2004) listed copper-dependent liver proteins in ewes treated with different dietary copper levels.…”

Plasma Retinol and Prognosis of Postmenopausal Breast Cancer Patients

“…However, a previous study on participants of the fenretinide breast cancer prevention trial showed that retinol levels increased significantly in the 5 years after recruitment in nonmenopausal women ages 46 to 55 years but were stable in same-aged women recruited after menopause (25). Another study found that retinol levels increase significantly (10%) in the first 2 years of menopause (35). Abbreviation: BC, breast cancer.…”

C-reactive protein concentration and concentrations of blood vitamins, carotenoids, and selenium among United States adults

“…In a study of nuns aged 77-99 y, Creactive protein concentration was inversely related to plasma concentrations of a-, b-carotene, lycopene, and total carotenoids (Boosalis et al, 1996). Among Chinese women, plasma retinol concentration was inversely related to Creactive protein concentration (Root et al, 1999). Among patients with type II diabetes mellitus, vitamin E supplementation of 800 U/day resulted in decreases of C-reactive protein concentrations (Upritchard et al, 2000).…”

“…However, little is known about how nutritional status is associated with concentrations of inflammatory markers. A number of studies, which generally included either small numbers of participants or were conducted in special populations, have described inverse relationships between C-reactive protein concentration and circulating concentrations of antioxidants (Labadarios et al, 1987;Louw et al, 1992;Boosalis et al, 1996;Sattar et al, 1997;Talwar et al, 1997;Root et al, 1999;Curran et al, 2000;McMillan et al, 2000;Upritchard et al, 2000). In addition, inverse associations were shown between C-reactive protein concentration and concentrations of carotenoids and serum retinol using NHANES III data (Kritchevsky et al, 2000;Stephensen & Gildengorin, 2000;Erlinger et al, 2001).…”