Folic acid fortification of all white flour, enriched pasta, and cornmeal products became mandatory in Canada to reduce risk of neural tube defects at birth. Furthermore, Health Canada and the Society of Obstetricians and Gynaecologists of Canada recommend women take daily prenatal folic acid supplements in addition to folic acid fortified foods during pregnancy. However, the influence of maternal folic acid supplementation on offspring development, specifically the highly abundant and metabolically active skeletal muscle, is currently unknown. Thus, the purpose of this study was to determine the effect of supplemental folic acid (four times higher than normal dietary consumption), in utero and throughout suckling on muscle size, function, and metabolism in male and female CD-1 mouse offspring. The major findings were that maternal exposure to supplemental folic acid (i) had no impact on postpartum growth rates or muscle mass in female and male offspring, (ii) had no impact on skeletal muscle contractile kinetics in females and male offspring, and (iii) increased maximal phosphofructokinase activity in extensor digitorum longus of female and male offspring. These findings suggest that exposure to folic acid supplementation in utero and throughout suckling at levels four times higher than recommended had minimal effect on skeletal muscle size, function, and metabolism regardless of sex. Future research is needed explore the underlying biological pathways and mechanisms affected by folic acid supplementation during pregnancy and lactation on offspring skeletal muscle tissue, specifically in humans.
Keywords: extensor digitorum longus; folic acid; lactation; maternal supplementation; pregnancy; soleus.