Recovery from impaired dark adaptation in nightblind pregnant Nepali women who receive small daily doses of vitamin A as amaranth leaves, carrots, goat liver, vitamin A-fortified rice, or retinyl palmitate.
BACKGROUND
It is not known whether daily consumption of vitamin A-containing foods is efficacious for treating nightblindness.


OBJECTIVE
We assessed the effect of supplementation with vitamin A from food or synthetic sources on dark adaptation and plasma retinol concentrations in nightblind pregnant Nepali women.


METHODS
Nightblind pregnant women were randomly assigned to 1 of 6 treatment groups to receive 6 d/wk for 6 wk either 850 microg retinol equivalents/d as retinyl palmitate, vitamin A-fortified rice, goat liver, amaranth leaves, or carrots or 2000 microg retinol equivalents/d as retinyl palmitate. Dark adaptation was assessed weekly by using the pupillary threshold (PT) test; plasma retinol concentrations were measured before and after the intervention. These outcomes were also assessed in a comparison group of nonnightblind pregnant women.


RESULTS
In the nightblind women, the mean PT improved significantly (P<0.0001) from -0.71+/-0.04 to -1.42+/-0.02 log cd/m2, and the final mean PT did not differ significantly from that in the nonnightblind women (-1.43+/-0.04; P=0.55). Improvement in dark adaptation was greater in the liver group than in the vitamin A-fortified rice group (P<0.02). Plasma retinol concentrations increased significantly (P<0.0001) from 0.95+/-0.05 to 1.07+/-0.05 micromol/L. The plasma retinol response was greater in the higher-dose capsule and liver groups than in the vegetable groups and significantly greater in the liver group than in the vitamin A-fortified rice group (both: P<0.05).


CONCLUSIONS
Improvement in dark adaptation did not differ significantly between women who received vitamin A as liver, amaranth leaves, carrots, or retinyl palmitate.
Haskell
Marjorie J
MJ
Program in International Nutrition, Department of Nutrition, University of California, Davis, CA 95616, USA. mjhaskell@ucdavis.edu
Pandey
Pooja
P
Graham
Joanne M
JM
Peerson
Janet M
JM
Shrestha
Ram K
RK
Brown
Kenneth H
KH
D000293:Adolescent; D000328:Adult; D000818:Animals; D003623:Dark Adaptation / Q000187:drug effects*; D004032:Diet; D004224:Diterpenes; D005260:Female; D005527:Food, Fortified; D006041:Goats; D006801:Humans; D008099:Liver / Q000737:chemistry; D008460:Meat; D009390:Nepal; D009755:Night Blindness / Q000178:diet therapy* / Q000188:drug therapy; D011247:Pregnancy; D011248:Pregnancy Complications / Q000178:diet therapy* / Q000188:drug therapy; D000084562:Retinyl Esters; D016896:Treatment Outcome; D014801:Vitamin A / Q000008:administration & dosage* / Q000031:analogs & derivatives* / Q000097:blood / Q000627:therapeutic use; D014802:Vitamin A Deficiency / Q000178:diet therapy* / Q000188:drug therapy
D004224:Diterpenes; D000084562:Retinyl Esters; D014801:Vitamin A; C014794:retinol palmitate