Few dietary supplements meet the nutritional needs of pregnant women, new research asserts.

The new research was published last week in The American Journal of Clinical Nutrition. It was the work of a large team led by Katherine Sauder, Ph.D., of the University of Colorado’s School of Public Health.

In the paper titled “Selecting a dietary supplement with appropriate dosing for 6 key nutrients in pregnancy,” Sauder and her team took a two-pronged approach.

First, they gathered population-based survey data to assess the nutritional status of pregnant women in this country. The researchers used data from the NIH Environmental influences on Child Health Outcomes (ECHO) program.

Data culled from large population survey

They collected dietary data from 2,450 participants from six cohorts across five states. This consisted of 24-hour dietary recalls that were either self-administered or conducted with the help of a reviewer. About two-thirds of the participants completed two or fewer such recalls; the remainder completed three or more.

The cohorts generally reflected the U.S. population at large in terms of demographics and educational status. The makeup of the study population reflected the ongoing trend toward obesity in the country, too, with 51% being classified as overweight or obese.

The researchers were looking for dietary intakes of six specific nutrients that have been identified as important or critical for making healthy babies: vitamins A and D, folate, calcium, iron and omega-3 fatty acids.

The research showed pregnant women were most likely to fall short of adequate intakes from diet alone for Vitamin D and iron, with 83% to 96% being at risk among both younger and older individuals. Omega-3s were next on the descending ladder of risk of insufficient intakes, with calcium, folate/folic acid and vitamin A rounding out the list of nutrients of concern.

The researchers judged there was essentially no risk of excessive intakes of these nutrients from diet alone.

Only one supplement met researchers’ specification

The second part of the study was looking at the ingredients in dietary supplements on the market, based on a search of the Dietary Supplement Label Database maintained by the National Institutes of Health.

The researchers were looking for supplements that could enable 90% of the pregnant women to exceed the average requirement of the given nutrients, while restricting the intake of 90% of participants to below the upper limit for each nutrient within each age group. For the omega-3s, the researchers used the benchmark intake of 100 mg/day.

The researchers parsed through more than 21,000 entries of products that were labeled to contain at least one of the six nutrients of interest. Of that huge list of products, 421 were labeled as prenatal products.

The researchers found none of the prenatal products met their criteria that would have enabled 90% of the ECHO cohort to obtain enough of the six nutrients while ensuring at least 90% of them didn’t get too much any one nutrient.

Only one product in the entire NIH database met their specifications, and that was not even labeled as a prenatal. That product was branded as Shaklee Life with Iron. The researchers noted this product is both inconvenient (mandating a user take seven pills a day) and very expensive, at more than $200 a month.

“The large U.S. dietary supplement market is not meeting the nutrient needs of pregnant women,” the researchers concluded.

Formulators need to keep in mind increased food intake during pregnancy

Andrea Wong, Ph.D., senior vice president of scientific and regulatory affairs for the Council for Responsible Nutrition (CRN), said it’s important to place the emphasis on getting adequate nutrients through the diet first.

“We appreciate the study authors’ efforts to add to the body of research on nutrient needs and supplementation during pregnancy. This latest research reinforces what skilled dietitians and nutritionists have been saying for years—dietary supplements, even prenatal supplements—are simply ‘supplements’ to a healthy diet, not substitutes,” Wong said via email. “While these critical products absolutely do fill some nutritional gaps, they are not intended to replace healthy eating, and certainly not during the critical time of pregnancy.”

“The results of the study are not surprising—getting sufficient levels of all the necessary nutrients to support a healthy pregnancy means eating right, as well as using a prenatal multivitamin and other dietary supplements when needed,” she added.

Lisa Thomas, until recently the senior director of product development at network marketing giant Herbalife, said meeting the nutritional needs of pregnant women is a particular challenge because they are being pushed to consume more food anyway so their nutrient intakes will be higher.

“Most people find they cannot eat as much food as you need to support the higher intake levels of these nutrients,” Thomas said during an interview. “With that being said, there is no perfect prenatal for every woman.”

Horse pills versus something people can tolerate

And, Thomas said, the researchers’ emphasis that only one product met their specifications—and their apparent consternation that the product requires a seven-pill dose— might reflect some level of naiveté concerning the realities of supplement formulation and marketing.

“Do you really want a pregnant woman who is having nausea every day trying to choke down one huge horse pill?” she asked. “There is probably a reason [the Shaklee product] is seven pills a day.”

Wong concurred with that point.

“Including every key nutrient in a single product at levels to meet the needs of nearly every woman during pregnancy is, of course, challenging,” she observed. “These products absolutely increase the daily intake of these nutrients, but even as food patterns vary across the population, one product should not be expected to provide exactly 100 percent of each person’s precise nutritional needs.”