Postprandial chylomicron and plasma vitamin E responses in healthy older subjects compared with younger ones.
The effect of ageing on vitamin E bioavailability in humans was assessed by comparing chylomicron and plasma alpha-tocopherol postprandial concentrations after a dose of vitamin E (432 or 937 IU as d1-alpha-tocopherol acetate), in eight young (20-30 years old) and eight healthy elderly men (64-72 years old). The fasting plasma alpha-tocopherol concentration was significantly higher in the elderly (33 +/- 2 mumol L-1) than in the young (22 +/- 2 mumol L-1). In both groups, the plasma and chylomicron alpha-tocopherol postprandial concentrations were significantly, approximately twofold, higher after the 937-IU meal than after the 432-IU meal. For both test meals, the chylomicron alpha-tocopherol areas under the curve were significantly lower in the elderly than in the young subjects: 98.9 +/- 16.5 (young group) vs. 55.3 +/- 7.8 (elderly group) mumol L-1 h for the 937-IU test meal and 60.4 +/- 14.1 (young group) vs. 26.0 +/- 7.6 (elderly group) mumol L-1 h for the 432-IU test meal, whereas the plasma alpha-tocopherol area under the curve was significantly higher in elderly than in young subjects: 337.56 +/- 16.11 (937-IU test meal) vs. 159.81 +/- 35.55 (432-IU test meal) mumol L-1 h in the young group and 709.55 +/- 69.33 (937-IU test meal) vs. 436.39 +/- 41.08 (432-IU test meal) mumol L-1 h in the elderly group. We concluded that (a) the amount of vitamin E appearing in plasma is proportional to the dose ingested (up to 937 IU); (b) the intestinal absorption of vitamin E is not increased, even possibly decreased, in the elderly; and (c) the amount of vitamin E transported by non-chylomicron lipoproteins is apparently higher in the elderly. This suggests that vitamin E postprandial transport is affected by ageing, mainly as the consequence of age-related modifications of lipoprotein metabolism.
Borel
P
P
Unité des Maladies Métaboliques et des Micronutriments-INRA (National Institute of Agronomic Research), Clermont-Ferrand, France.
Mekki
N
N
Boirie
Y
Y
Partier
A
A
Grolier
P
P
Alexandre-Gouabau
M C
MC
Beaufrere
B
B
Armand
M
M
Lairon
D
D
Azais-Braesco
V
V
D000328:Adult; D000367:Age Factors; D000368:Aged; D001682:Biological Availability; D002914:Chylomicrons / Q000097:blood*; D006801:Humans; D008055:Lipids / Q000097:blood; D008297:Male; D008875:Middle Aged; D019518:Postprandial Period; D014801:Vitamin A / Q000097:blood; D014810:Vitamin E / Q000097:blood*
D002914:Chylomicrons; D008055:Lipids; D014801:Vitamin A; D014810:Vitamin E