Dietary intake of B-vitamins in mothers born a child with a congenital heart defect.

BACKGROUND: Periconceptional use of multivitamins reduces the risk of a child with a congenital heart defect (CHD). Data on the impact of maternal diet, however, are lacking.

AIM OF THE STUDY: We investigated the association between the maternal dietary intake of B-vitamins and having a child with a CHD.

METHODS: A case-control study was performed in 192 mothers of a child with a CHD and 216 mothers of a healthy child. Mothers filled out food frequency questionnaires covering the current dietary intake, and general questionnaires at 17 months after the index-pregnancy. Maternal blood samples were taken to determine B-vitamin and plasma total homocysteine (tHcy) concentrations as nutritional biomarkers. Pregnant and lactating mothers and those with another diet compared with the preconceptional period were excluded for analysis. Case-mothers and controls were compared using the Mann-Whitney U test and logistic regression.

RESULTS: The dietary intake of macronutrients and B-vitamins was comparable between both groups, but all mothers had a substantially lower median folate intake (cases 161 microg, controls 175 microg) than the Dutch recommended dietary allowance of 300 microg. Within the case-group, the intake of proteins and vitamin B(6) and the concentrations of serum vitamin B(12) and folate were significantly lower in hyperhomocysteinemics (tHcy > or = 14.5 micromol/l) than in normohomocysteinemics. The maternal educational level was positively associated with B-vitamin intake, except for vitamin B(12) in controls. Low educated case-mothers showed a significantly lower median vitamin B(12) intake than controls (2.8 microg and 3.8 microg, P = 0.01). The CHD risk doubled if vitamin B(12) intake in these mothers reduced by 50% (OR 2.0; 95% CI: 1.1-3.5).

CONCLUSIONS: A diet low in vitamin B(12) is associated with an increased risk of a child with a CHD, especially in low educated women. A disbalance in the maternal intake of proteins and low folate intake may play a role as well, but needs further investigation. As hyperhomocysteinemia is a strong risk factor for adult cardiovascular disease, these data may imply that the hyperhomocysteinemic mothers and their children should be targeted for nutritional interventions.