The total antioxidant capacity of the diet is an independent predictor of plasma beta-carotene.
OBJECTIVE
To investigate the contribution of the total antioxidant capacity (TAC) of the diet to plasma concentrations of beta-carotene.


METHODS
Cross-sectional study.


METHODS
Department of Public Health and Department of Internal Medicine and Biomedical Sciences, University of Parma.


METHODS
A total of 247 apparently healthy adult men (n=140) and women (n=107).


METHODS
A medical history, a physical exam including height, weight, waist circumference and blood pressure measurements, a fasting blood draw, an oral glucose tolerance test and a 3-day food record.


RESULTS
We observe a negative trend across quartiles of plasma beta-carotene for most biological variables clustering in the insulin resistance syndrome, as well as for traditional and new risk factors for type II diabetes and cardiovascular disease (CVD), including C-reactive protein and gamma-glutamyltranspeptidase (P<0.05). Regarding dietary characteristics, energy-adjusted intake of fat, fiber, fruits, vegetables, beta-carotene, vitamin C, vitamin E and dietary TAC significantly increased with increasing plasma beta-carotene (P<0.05), whereas alcohol intake decreased (P=0.013). Adjusted geometric means (95% confidence interval) of plasma beta-carotene significantly increased across quartiles of dietary TAC, even when single dietary antioxidants were considered in the model (QI=0.087 mg/dl (0.073-0.102); QII=0.087 mg/dl (0.075-0.103); QIII=0.114 mg/dl (0.098-0.132) and QIV=0.110 mg/dl (0.093-0.130); P for linear trend=0.026). When the population was divided on the basis of alcohol consumption, this trend was also observed in subjects drinking <20 g alcohol/day (P=0.034), but not in those with higher alcohol intake (P=0.448).


CONCLUSIONS
Dietary TAC is an independent predictor of plasma beta-carotene, especially in moderate alcohol drinkers. This may explain, at least in part, the inverse relationship observed between plasma beta-carotene and risk of chronic diseases associated to high levels of oxidative stress (i.e., diabetes and CVD), as well as the failure of beta-carotene supplements alone in reducing such risk.
Valtueña
S
S
Department of Public Health, University of Parma, Parma, Italy. valtuena@libero.it
Del Rio
D
D
Pellegrini
N
N
Ardigò
D
D
Franzini
L
L
Salvatore
S
S
Piatti
P M
PM
Riso
P
P
Zavaroni
I
I
Brighenti
F
F
D000428:Alcohol Drinking; D000975:Antioxidants / Q000008:administration & dosage / Q000032:analysis / Q000378:metabolism*; D002318:Cardiovascular Diseases / Q000097:blood / Q000453:epidemiology; D016000:Cluster Analysis; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000453:epidemiology; D004032:Diet; D005260:Female; D005504:Food Analysis; D006801:Humans; D007333:Insulin Resistance; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood / Q000453:epidemiology; D008875:Middle Aged; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology; D011237:Predictive Value of Tests; D012307:Risk Factors; D014815:Vitamins / Q000008:administration & dosage / Q000097:blood*; D019207:beta Carotene / Q000008:administration & dosage / Q000097:blood*
D000975:Antioxidants; D014815:Vitamins; D019207:beta Carotene