“The nature of the [US dietary] guidelines is that we are beholden to the best available evidence at the time the guidelines are made,” however, there is widespread disagreement about what constitutes the best science and there is a lack of transparency into how the science ultimately is selected and used to make the guidelines, which can lead to distrust, Allison Steiber, chief science officer at the Academy of Nutrition and Dietetics, said at the Consumer Federation of America’s National Food Policy Conference in Washington, DC, late last month.
“There is a huge perception issue on what is quality as it relates to food and nutrition science. I think there is a big disparity with some people on this side saying, ‘Well, that is bad quality,’ and others on this side saying, ‘No, this is nutrition and that actually is great quality,’” she explained, adding, “We need to bridge that gap and come together as a community and have some agreement on what we do believe is quality science.”
And the process for determining what is “quality science” needs to be discussed transparently “in a more engaging process so that we understand how methods connect diet with outcomes such as mortality and morbidity,” Steiber said.
She acknowledged that this is a tall order given the methods used to evaluate the impact of nutrition ethically, feasibly and financially cannot be the same as the gold standards used in the pharmaceutical world.
“We don’t always have biochemical endpoints that allow us to objectively measure if a consumer is consuming a perfect dietary pattern or the correct amount of a particular nutrient. And so that, again, puts us at a great challenge and open for some criticism,” she said.
Despite the limits, though Steiber encourages stakeholders to identify “hard outcomes” for nutrition that the scientific community supports and on which they agree.
“We need hard outcomes in all the science we do … even if it is not the primary outcome, it is still having that outcome there that allows us to do better systemic research and create better guidelines,” she explained.
She also recommends that upcoming science focus on “the persistent gaps” in research that have been identified time and again in past dietary guideline review cycles. For this to succeed, she adds, there must be dedicated funding for these areas of research.
In addition, she recommends, future advisory committees consider “scoping” to better advance the dietary guidelines as a whole, including the persistent gaps.
She explained that scoping “allows you to map the evidence that has emerged since the last time you did your systemic reviews, and it is transparent and you can publish scoping figures that show where there is new emerging evidence.”
She added that scoping does not mean disregarding prior good evidence, but rather it better allows committee members to focus on what is new.
“If nothing new has come out” since the last review five years earlier, “we bring forward the current recommendation as the best available science and then we add in these new emerging areas. And that allows us to be a little bit more transparent. It also identifies gaps and allows our work group to make informed decisions,” she said.
Implementation must be considered from the outset
Raising the bar for the science on which the guidelines are based will only make a difference in Americans’ lives if they understand and can implement the guidelines once they are published, Steiber stressed at the conference.
“We need to ensure that while we are using the best science and that is evidence based, that the information we come out with is able to be translated to the public in a way that is understandable,” she explained.
One way to do this is to engage end-users, the public and patients in the guideline development process to ensure that committee members and those creating the guidelines can see the potential barriers and challenges to implementation from the very beginning, Steiber said.
Once the guidelines are published, they should be tested in terms of their effectiveness in improving outcomes, she said, adding, “While it is difficult to do this, I think it is essential to the process. It completes the cycle and if we fail to do that we don’t know if our guidelines are effective.”