Requirements during pregnancy for many trace minerals (those required only in small amounts) have not been established because of the obvious problems involved in experimentally producing diet deficiencies or excesses. Some observations have been recorded, however. When maternal diets are deficient in iodine, abnormalities of growth are seen. Iodized salt as well as commercial dough products in which iodine is used as a dough conditioner are important dietary sources.

Maternal chromium deficiency has been suggested as a cause of gestational diabetes (an abnormality of blood sugar metabolism, which is sometimes seen during pregnancy). Chromium was once plentiful in our diets when whole-grain breads were a staple item. However, because of increased processing of our food supply, a potential for deficiency does exist. Thus, the simple solution of including whole-grain products such as breads and cereals and/or brewer’s yeast provides significant sources of this nutrient and should be relieved any fear of deficiency.

Zinc is another trace element which has received much attention recently. The current recommended daily allowance for pregnant women 11 to 13 mg. per day. Dietary deficiencies are known to produce abnormalities in the skeletal and/or central nervous systems of some animal spices. Also, a few causes of similar abnormalities have been reported among humans in the geographic areas where zinc deficiency is common. Since zinc content of many foods is reduced by “refining,” an unprocessed or “natural” food source would be advisable.