Aja. Wright et al., Beta-carotene and lycopene, but not lutein, supplementation changes the plasma fatty acid profile of healthy male non-smokers, J LA CL MED, 134(6), 1999, pp. 592-598
Citations number
20
Categorie Soggetti
Research/Laboratory Medicine & Medical Tecnology","Medical Research General Topics
Polyunsaturated fatty acids (PUFAs) are highly susceptible to free radical
attack. In vitro studies of carotenoids--including beta-carotene, lycopene,
and lutein--have shown them to be effective quenchers of singlet oxygen, t
o have good radical-trapping properties, or to be effective peroxyl radical
scavengers (sr to have a combination of these qualities), if carotenoids a
ct as antioxidants in vivo, then arguably plasma PUM should be conserved. T
he objective of the current study was to answer the question "Does suppleme
ntation with beta-carotene, lycopene, or lutein, at dietarily achievable le
vels, over a time period known to significantly increase circulating carote
concentrations, lead to an observable increase in fasting plasma PUFA?" Th
e normal diets of human volunteers were supplemented with either 15 mg/day
beta-carotene (n = 25), lycopene (n = 23), or lutein (n = 21) for 26 days i
n three independent double-blind, placebo-controlled supplementation studie
s. Supplementation with p-carotene increased plasma linoleic acid but left
the polyunsaturated:saturated (P:S) fatty acid ratio unaltered. In contrast
, supplementation with lycopene reduced linoleic acid, which resulted in a
large decrease in the P:S ratio, Lutein supplementation had no effect. it w
as concluded that neither beta-carotene, lycopene, nor lutein supplementati
on engender antioxidant effects that lead to the widespread general conserv
ation of plasma PUFAs. beta-Carotene and lycopene supplementation appear to
interact with the metabolism of linoleic acid, the "essential" fatty acid,
resulting in either an increase (beta-carotene) or decrease (lycopene) in
ifs plasma concentration. Alterations in plasma 18:2 or P:S ratios could ul
timately lead to changes in tissue cellular membrane composition and hence
to alterations in membrane fluidity and cell-surface protein expression.