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

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. We investigated the association between the maternal dietary intake of B-vitamins and having a child with a CHD. 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. 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 mu g, controls 175 mu g) than the Dutch recommended dietary allowance of 300 mu g. 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 >= 14.5 mu mol/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 mu g and 3.8 mu g, 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). 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.