The study, published in the journal of Preventive Medicine Reports, concluded that a low-income US household is more likely to spend a higher share of its annual income on weight loss, muscle building, and sexual function supplements.
It was conducted by a group of researchers from the Harvard T. H. Chan School of Public Health, Boston Children’s Hospital, Simmon College, and Bates College, and had an overall negative view of dietary supplements, arguing that “serious health risks of dietary supplements sold for weight loss, muscle building, and sexual function [are] well-documented.”
“These products [have] been flagged by the FDA as particularly dangerous,” they added. “Yet no prior research has investigated how these products may disproportionately burden individuals and families by gender and socioeconomic position across households.”
Hints that authors had their conclusion first, says CRN
Commenting independently on the report, Dr. Duffy MacKay, senior vice president of scientific and regulatory affairs at the trade association Council for Responsible Nutrition (CRN) called the study a ‘background noise.’
“There are hints that the authors had their conclusion first, and then searched for data to support it,” he said. The researchers had used aggregated data from the observational 2012 Nielsen/IRi National Consumer Panel, administered by the Kilts Center at the University of Chicago, with a nationally representative sample of more than 60,000 US households.
The data consists of household products purchased by the sample households, and researchers in this current study extracted Universal Product Codes for dietary supplements and isolated those that had packaging and advertising making claims in weight loss, muscle building, and sexual function. The study did not specify any ingredients or specific products the households bought.
“We don’t disagree with the authors that the three categories [have risky products], but those three categories are outliers,” MacKay said, adding that it is products in these categories that often have illegal substances masquerading as a supplement.
He found it unfortunate that the researchers highlighted products that are not part of the responsible industry. “For example, the side effects they mention for muscle building supplements—infertility, testicular cancer, stunted growth, coronary artery disease—these aren’t side effects of any legal muscle building supplement, but tainted supplements. You don’t get these from whey protein.”
Poorer households spend a larger share of annual income on supplements
In terms of purchase and expenditure data for dietary supplements, the Natural Products Association (NPA) president Dr. Dan Fabricant said that the study had some useful data, but “it isn’t an earth shattering conclusion.”
The researchers had found that lower-income households—those who make less than $30,000 in a year—spent more as a share of income, typically twice or quadruple to the share higher-income households spend on such supplements.
“It depends on levels of income, so yeah, [low income households] are already in harm’s way economically so you could say this for anything they buy,” Fabricant added. He took issue with the researcher’s conclusion despite absence of more granular data, such as when the supplements were bought and who in the family is the primary consumer.
“This indicates that [the researchers] were guessing,” he added.
A new angle for income disparity in dietary supplement access?
For MacKay, the income disparity angle the researchers chose was a missed opportunity. He argued that the researchers could have highlighted the fact that low-income Americans seem to buy dietary supplements for the wrong reasons.
“The biggest concern is that this report focused on the bait-and-switch of the dietary supplements industry black cloud, when in fact we can educate on the benefits of compliance in taking nutritional supplements,” he said.
There are numerous nutritional deficiencies among the US public, in which dietary supplements can play a beneficial role. In fact, both CRN and NPA lobby for multivitamins to be purchasable using government welfare programs.
A key lesson, according to MacKay, is that companies operating in the weight loss, muscle building, and sexual function categories need more due diligence in their supply chains and backing up claims with science. “There are a lot of critics out there, and this study shows that these are high-risk categories,” MacKay said.
He added: “But the biggest concern here, we can’t let background noise distract from what good we can do.”
Source: Preventive Medicine Reports
Published online ahead of print, https://doi.org/10.1016/j.pmedr.2017.03.016
Household expenditures on dietary supplements sold for weight loss, muscle building, and sexual function: Disproportionate burden by gender and income
Authors: S. Bryn Austin, et al.