GAO Report Highlights Dosage Variability in Prenatal Supplements

By By Mike Montemarano, Associate Editor | 01.29.24

The agency called for greater standardization, and to give FDA greater regulatory authority over dietary supplements.

The Government Accountability Office (GAO) recently published a report which highlighted the results of tests it conducted on 12 popular prenatal supplements.
 
Eleven of the 12 supplements tested had at least one nutrient above or below acceptable deviations established by the U.S. Pharmacopoeia (USP), for nutrients such as folic acid, iodine, iron, or vitamin A, C, or E.
 
Additionally, one of the 11 products had an amount of folic acid that may cause a health concern, based on metrics established by the Institute of Medicine, GAO reported.
 
Of the six nutrients tested, vitamin E showed the greatest variability between different prenatal supplement products, with a range of 28% to 332% of the amount stated on the label. Vitamin A was the nutrient most frequently found in amounts outside the acceptable deviations from the label value, with deviations found in nine of the 12 supplements.
 
GAO also found trace amounts of two heavy metals, namely lead or cadmium, in half of the tested prenatal supplements, but not in amounts likely to cause a health concern based on metrics used by the U.S. Food and Drug Administration.
 
The GAO, in its reporting, called for granting FDA greater pre-market oversight (potentially through a mandatory product listing) as a strategy to inform how it can improve upon the post-market inspection and oversight authorities it is granted. “Moreover, there is no federal statutory definition of what a prenatal supplement is and what these products should contain, resulting in a large and highly variable product market,” GAO stated.
 
While self-regulation, such as third-party verification, may be helpful in how well supplements conform to label contents, five of the 12 prenatal supplements which had third-party verification seals performed similarly to non-verified products, although none of the products with third-party seals had nutrient levels which could cause a health concern, noted researchers.
 
Stakeholders from the dietary supplement industry, including USP and NSF, worked with GAO to identify a number of challenges related to supplements and their oversight.
 
Some stakeholders supported additional oversight of dietary supplements by FDA, such as the Council for Responsible Nutrition (CRN), which has been a longstanding advocate of mandatory product listing. USP and NSF have advocated for the establishment of stronger standards and definitions for prenatal supplements.

A ‘Buyer Beware’ Market?

In a “Watchdog Report” podcast posted by GAO, Karen Howard, director of science, technology assessment and analytics at GAO, said “supplements, including prenatal supplements, are very much a buyer beware marketplace.”
 
“There are no standards for what should be in a prenatal supplement or how much should be there,” Howard said. “Manufacturers can actually add whatever amounts of those nutrients they want. One supplement might contain a very different amount of nutrients than another supplement contains.”
 
Shortages of folate and iodine were concerning, Howard noted, as they could lead pregnant women to have intakes of these nutrients at levels below what they actually need.
 
GAO recommended Congress grant FDA additional authority specific to how it regulates prenatal supplements, Howard said.
 
“We think that’s especially important in this market in particular because the population is so vulnerable—pregnant individuals, and their developing babies. So, we strongly encourage Congress to consider increasing FDA’s legal authority to regulate in this area,” Howard said. “Oversight usually occurs only after [supplements are] on the market and action can only be taken after a problem is identified, which might be too late.”

No Surprises

Experts from trade associations representing the dietary supplements industry said that, for many reasons, the variability seen among the 12 products tested was neither surprising nor cause for alarm.
 
CRN said in a statement that the variations observed should in no way deter pregnant women from taking supplements in consultation with their doctors.
 
“This report strikes an unnecessarily alarmist note when the vast majority of these supplements are not only safe, but vital to the health of mothers and their unborn babies,” said Andrea Wong, senior vice president of scientific and regulatory affairs at CRN. “The worst possible outcome would be for women to read this report and decide not to take prenatal supplements, when research shows the critical benefits these nutrients provide in the form of supplementation.”
 
Loren Israelsen, founder and president of the United Natural Products Alliance (UNPA), said there were a number of limitations in GAO’s reporting, such as a lack of consideration about storage time and conditions. This reduced the relevance of the findings as they pertain to how competently products were manufactured, he said. 
 
“The authors wrote that they bought products both from online and from brick-and-mortar. This study spanned from March to December, and we don’t know when they purchased these products. If it was at the height of summer heat and products were stored in hot conditions, this would’ve contributed to degradation—that’s a really important blind spot in a study where the subject is overages.
 
“The expiration dates are also unknown, and that’s equally important. Maybe half of the products were relatively fresh, and maybe some products were close to two years old and also subjected to high heat, which, even for a relatively short time, would cause lower values…. Materials and methods sections of studies are very detailed for precisely these reasons. It gives the reader a chance to really evaluate a study and draw a conclusion.”
 
Variations in potency are commonplace, Israelsen noted, which is why standard-setting organizations like USP provide allowances for that variability in ingredients by certain percentage values. Further, FDA requires that dietary supplements contain 100% of the declared amounts of ingredients. “To do that, you have to build overages into the product and build out a degradation curve for each ingredient, which is difficult to do. Every nutrient is different, so there’s a great deal of complexity in working with multiple ingredients.” 

A Case for Mandatory Product Listing?

Israelsen described the authors’ conclusion that establishing a mandatory product listing (MPL) for all dietary supplements, based on this study, was a “curious” one. He questioned whether the prospect of MPL was relevant to the present findings.
 
“I don’t think that it’s a fair conclusion to draw to state whether mandatory product listing would make any difference at all in a study like this,” he said, noting that it won’t change the fundamental way the industry operates. “We do know that FDA really, really wants MPL, and those reasons go beyond wanting to have a better understanding of how many products are on the market. It’s a tool designed for FDA to efficiently, and with the least administrative restraints, pursue companies that don’t register. Companies selling things that they shouldn’t, which we would like to see exit the industry, won’t participate in MPL.”

Calls for a New Prenatal Standard

Israelsen agreed with the report that a discussion on establishing a standard prenatal is due.
 
“There’s no FDA-recognized standard for the composition of prenatal vitamins. Should there be? That’s a fair question which hasn’t been debated or discussed much to my knowledge,” he said.
 
On that note, the National Institutes of Health (NIH) will be hosting a workshop in June exploring the topic of standardizing prenatal vitamin supplements. “Hopefully that process brings us to an FDA-recommended standard of what the basic composition of a prenatal vitamin should consist of, to ensure that all of the key nutrition is in there.”
 
This standardization, which could be achieved through research by NIH’s Office of Dietary Supplements and validation through standard-setting organizations like USP, would be necessary to give FDA what it needs to more strongly regulate the prenatals market as GAO calls for, Israelsen noted. 
 
“There are multiple industries that offer prenatal products, including pharmaceuticals, nutraceuticals, and medical foods for certain types of pregnancies,” he said. “So this isn’t just a dietary supplement issue, it’s broader than that. I think that FDA has the authority they need to regulate prenatal products, what they’re missing is the standards…. USP would typically be the authority that establishes a compendial standard for products like this, and I think that would be the best place to start.”