Dietary vitamin A intakes of Filipino elders with adequate or low liver vitamin A concentrations as assessed by the deuterated-retinol-dilution method: implications for dietary requirements.
BACKGROUND
The vitamin A requirements of elderly humans have not been studied.


OBJECTIVE
In a cross-sectional study of 60-88-y-old men (n = 31) and women (n = 31) in rural Philippines, we assessed the dietary intakes of elders with adequate (> or = 0.07 micromol/g) or low (< 0.07 micromol/g) liver vitamin A concentrations to estimate vitamin A requirements for this age group.


METHODS
Total-body vitamin A was assessed by the deuterated-retinol-dilution technique; liver vitamin A concentrations were assessed by assuming that liver weight is 2.4% of body weight and that, in this marginally nourished population, 70% of total-body vitamin A is in the liver; serum retinol was measured by HPLC; and dietary intakes were assessed with 3 nonconsecutive 24-h dietary recalls. The mean vitamin A intake + 2 SDs of subjects with adequate liver vitamin A concentrations was used to estimate an acceptable or sufficient vitamin A intake value for elders.


RESULTS
The mean (+/- SD) vitamin A intakes of the men and women with adequate vitamin A in liver were 135 +/- 86 and 134 +/- 104 microg retinol activity equivalents (RAE)/d, respectively; intakes of the men and women with low vitamin A in liver were 75 +/- 53 and 60 +/- 27 microg RAE/d, respectively. Total-body vitamin A or liver vitamin A but not serum retinol correlated with dietary RAE, preformed vitamin A, beta-carotene, fat, and protein. An estimated acceptable or sufficient dietary vitamin A intake associated with adequate liver vitamin A concentrations in elders is 6.45 microg RAE/kg body wt; for a reference 76-kg man and a 61-kg woman, these values are approximately 500 and 400 microg RAE/d, respectively.


CONCLUSIONS
The dietary vitamin A intakes of elders with adequate or low liver vitamin A concentrations as estimated by use of the deuterated-retinol-dilution technique are useful for assessing vitamin A requirements.
Ribaya-Mercado
Judy D
JD
Jean Mayer US Department of Agriculture Human Nutrition Research Center on Aging at Tufts University, Boston, MA 02111, USA. judy.ribaya-mercado@tufts.edu
Solon
Florentino S
FS
Fermin
Liza S
LS
Perfecto
Christine S
CS
Solon
Juan Antonio A
JA
Dolnikowski
Gregory G
GG
Russell
Robert M
RM
D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D004032:Diet; D005260:Female; D006801:Humans; D008099:Liver / Q000378:metabolism*; D008297:Male; D011939:Mental Recall; D008875:Middle Aged; D009749:Nutrition Surveys; D009751:Nutritional Requirements; D010679:Philippines; D012424:Rural Population; D014801:Vitamin A / Q000008:administration & dosage / Q000097:blood*
D014801:Vitamin A