Dietary folate intake during pregnancy and birth weight in Japan.
BACKGROUND
Inadequate folate status has been associated with many negative reproductive outcomes, such as neural tube defects (NTD), low birth weight and placental abruption.


OBJECTIVE
The objectives of this study were to evaluate the levels of dietary folate intake during pregnancy in Japanese women and the subsequent birth weight of their babies.


METHODS
A longitudinal prospective study was conducted with 197 women with a singleton pregnancy in 2005. Dietary folate was investigated 3 times: in the first trimester at 12 weeks, in the second trimester at 20 weeks and in third trimester at 32 weeks using a diet history questionnaire (DHQ). Non fasting blood samples were collected from the women for measurement of homocysteine, hemoglobin, ferritin, unbound iron-binding capacity (UIBC) and total iron-binding capacity (TIBC).


RESULTS
Energy intake increased as pregnancy advanced, but not significantly. The daily intake of folate increased from 248.5 +/- 113.1 microg/d in the first trimester to 275.4 +/- 100.2 microg/d in the third trimester (P = 0.04). This was well below the recommended level of 440 microg/d and only 10% of mothers were above the levels. In the third trimester, plasma homocysteine concentration was significantly higher in the low folate group of less than 250 microg/d (P = 0.02), but not the first and second trimesters. Dietary folate intake and plasma homocysteine concentrations were not likely to be predictors of birth weight in our subjects.


CONCLUSIONS
Our study shows that Japanese women's energy and folate intakes do not meet their energy needs during pregnancy and are at an extremely low recommended dietary allowance level throughout pregnancy.
Watanabe
Hiroko
H
Human Health Science, Graduate school of Medicine, Kyoto University, Shougoin, Kyoto-chi, Kyoto, Japan.
Fukuoka
Hideoki
H
Sugiyama
Takashi
T
Nagai
Yasushi
Y
Ogasawara
Kayoko
K
Yoshiike
Nobuo
N
D000328:Adult; D015415:Biomarkers / Q000097:blood; D001724:Birth Weight / Q000187:drug effects* / Q000502:physiology; D002149:Energy Intake / Q000502:physiology*; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage* / Q000097:blood*; D005494:Folic Acid Deficiency / Q000097:blood / Q000453:epidemiology / Q000503:physiopathology; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D007231:Infant, Newborn; D007564:Japan; D008137:Longitudinal Studies; D008297:Male; D039382:Maternal Nutritional Physiological Phenomena / Q000502:physiology*; D009751:Nutritional Requirements; D009752:Nutritional Status; D011247:Pregnancy; D011256:Pregnancy Outcome; D011446:Prospective Studies; D014803:Vitamin B Complex / Q000008:administration & dosage / Q000097:blood
D015415:Biomarkers; D006710:Homocysteine; D014803:Vitamin B Complex; D005492:Folic Acid