Milk intake in pregnancy

The article about milk intake during pregnancy and decreased birth weight1 has several flaws. It may also serve to perpetuate typical physician perceptions that bovine milk is necessary for human health.

The study found that pregnant women who restricted milk intake had babies that weighed 120 g less on average than the babies of women who did not restrict milk intake. But the real questions are whether the lower birth weight had any negative clinical impact (acute or chronic) and whether the babies were underweight. Could there even have been benefits associated with delivering slightly smaller babies?

Both groups of women in the study had good protein intakes. Caloric intakes were almost equivalent. Does the small (10 g) difference in daily protein intakes between the 2 groups account for the difference in birth weights? How does one separate out the effect of vitamin D and calcium? Should we be measuring serum vitamin D levels to help quantify the differences in intake?

Note that there was no randomization in the study. Perhaps the women who restricted their milk intake also had restricted diets more generally. If the milk restrictors tended to eat smaller servings of food, then the diet surveys would have overestimated their protein and caloric intakes. I also wonder if natural bovine hormones in milk, or if hormonally active pesticides that bioaccumulate in milk, can increase birth weight.

People from my ethno-religious background are virtually all lacto- vegetarians and some are becoming vegans. I've heard dozens of stories about physicians telling family members and friends (both lacto-vegetarians and vegans) that they were hurting their unborn babies, their children and themselves and that they must consume meat. Physicians should be able to take an adequate history to determine whether any diet, vegan or otherwise, provides the micro- and macronutrients needed in pregnancy. A basic knowledge of vegetarian and vegan foods that provide protein and other nutrients is also necessary. For instance, physicians should note that vitamin D is added to milk and that soy milk now contains equivalent amounts of protein, calcium and vitamin D.