Is nutrition science reliable enough to make solid public and personalized health recommendations?

Photo © AdobeStock.com/AYDIN OZON

Nutrition research has advanced tremendously in the last 50 years. But is the state of the science good enough yet to provide ironclad health recommendations that will actually optimize public health, including the effects of dietary supplementation?

This question was posed at this year’s “Science in Session” conference hosted by the Council for Responsible Nutrition (CRN; Washington, DC) in Dana Point, CA, on October 3. In honor of the supplement trade association’s 50^th anniversary, the theme of this year’s annual scientific conference examined how far nutrition and supplement research has come, and where it still needs to go.

From Disease Prevention to Optimal Health

A century ago, nutrition scientists were primarily focused on solving micronutrient deficiencies to prevent diseases like goiter (with supplemental iodine), rickets (with vitamin D), and, later, neural tube defects (with folic acid), pointed out “Science in Session” speaker Jeffrey Blumberg, PhD, research professor at the Friedman School of Nutrition Science and Policy at Tufts University. These scientists learned that supplementing diets deficient in these nutrients could help prevent certain diseases. By the 1950s, the notion of eating fortified foods, or even taking supplement pills (beginning with yeast tablets and cod liver oil), became widespread, Blumberg explained. At the same time, policymakers sought to take this information to make public health recommendations, giving birth to concepts such as recommended dietary allowances (RDAs) and dietary reference intakes (DRIs) in the U.S.

Researchers also began establishing a hierarchy of scientific evidence with the goal that dietary recommendations would be based on rigorous scientific evidence, with the weakest types of evidence (expert opinions, case reports, animal studies, etc.) at the bottom of the hierarchy. “This was the basis of evidence-based medicine,” Blumberg said. Meanwhile, the toolbox also expanded thanks to advances in genomics, nutritional biochemistry, molecular nutrition, computing power, and statistical modeling.

Fast forward to today, and widespread diseases resulting from micronutrient deficiencies have largely been eradicated in the U.S. Today, the focus for Americans isn’t eradicating disease but rather optimizing public health. In this vein, researchers and policymakers still seek to use scientific evidence to make nutrient intake recommendations.

But how robust and reliable is that science today? To be sure, many gains have been made in the past century, pointed out “Science in Session” speaker Paul Coates, former director of the Office of Dietary Supplements (ODS) at the National Institutes of Health (NIH) and currently adjunct professor at the School of Public Health at Indiana University Bloomington. For instance, U.S. government agencies like NIH, ODS, FDA, USDA, and the National Institute of Standards and Technology (NIST) have worked together over decades to develop analytical methods and reference materials that have helped improve the scientific tools for designing and conducting nutrition studies.

For ODS, Coates added, the push for more robust research on the safety and efficacy of supplements stemmed from public health concerns, such as the concerns over ephedra products back in 1999. Back then, he said, most of the evidence of the effects of ephedra’s effects was largely anecdotal, and there were suggestions that ephedra could be harmful. During this time, Congress directed ODS to study the impact and risks of ephedra, and ODS began working with other agencies to develop analytical methods and reference materials to better do so.

“We learned the strategy for evaluating evidence—all of the evidence—related to the health effects of dietary interventions, including both interventional and observational data,” Coates said. He added that in later years, ODS would go on to apply this scientific rigor to evaluating the effects of other kinds of nutrients, including omega-3 fatty acids, B and D vitamins, and calcium. When it came time to study vitamin D, for instance, scientists addressed the current “unreliable array of methods for the measurement of vitamin D status in populations,” he explained. ODS created a vitamin D standardization program and collaborated with governments from other countries to build better methods. This “resulted in a standardization of the way we think about the measurement of vitamin D status,” he said.

“It gave us the confidence to be able to say, ‘We need to evaluate all of the evidence to effectively inform research public policy and health practices,’” said Coates, who headed ODS for 19 years. It also empowered FDA regulators to “clamp down” on ingredients of concern, such as ephedra.

Agencies and researchers are now better equipped with tools to measure nutrient status in the public and to study the potential benefits of supplements. This has led to the development of some public health recommendations. “I think the most important thing that ODS evolved itself to do is how do we translate the results of research for policymakers, for clinicians, and especially for the public,” Coates said.

Unsurprisingly, more research is needed. “There’s still a paucity of evidence regarding the health effects of not all, but some, supplements," he said. "There’s still not much progress on updating the dietary supplement reference intakes for most vitamins and minerals, something that I find challenging.”

Another problem? “Research funding for dietary supplements is still an issue,” he said. “Only a minority of companies are willing or able to invest in research…Federal funding is still meager compared to the other research priorities. Unfortunately, that’s also true for most of nutrition science. It’s paltry compared to the amount of money spent on the purchase of dietary supplement products by the U.S. public.”

Still General, Not Personalized

The early days of nutrition research led to some broad public health recommendations, such as the EARs, which address the health needs of an average population. “We’re really interested in averages and apply standard deviation and covering 97% or 98% of the population,” Blumberg explained.

But among those average recommendations, a campaign for personalized nutrition is growing. The thought is that dietary and supplementation recommendations must take into account individualized nutrient status and health needs, which differ between individuals depending on genetics, lifestyle, and environment.

Are today’s nutrition research and scientific tools reliable enough to make accurate health recommendations for the public, let alone for individuals?

Most of the “Science in Session” speakers agreed that we still have a long way to go in this quest. At the forefront is a need for better biomarkers. Without determining the right biomarkers to measure, and the reliability and significance of those biomarkers, we can’t properly measure individuals’ nutrient status, nor can we judge the effects of interventions in clinical trials and come out with solid outcomes, no matter what other tools we have at our disposal.

“We have to be very thoughtful about this,” said Blumberg during a panel discussion. “I see too many people saying, ‘Let’s just throw all these bricks in a pile, and AI machine learning will give us the answer.' But I think the old phrase is, ‘Garbage in, garbage out.’ If you’re not really thoughtful about picking which biomarkers you’re going to use, and knowing that you can measure them reliably, you just end up with a mess. AI is not going to solve that problem for you.”

Considering Whole Health

Understanding the complexity of diets is also a challenge whether you’re designing studies or picking biomarkers, said “Science in Session” speaker Regan Bailey, associate director of the Precision Nutrition Institute for Advancing Health Through Agriculture and a professor of nutrition at Texas A&M University. Nutrition science must take into account all of the factors that can impact nutrition status and health, including what an individual eats and whether there are “substitution effects,” “synergies,” or “antagonism,” Bailey said.

“With diet,” she said, “it’s really complicated.” She continued: “What I’m saying is that we can’t just look at one nutrient and one outcome. We have to look at all dietary exposures together.”

She emphasized the need to establish “some kind of integrated biomarker of nutritional exposures that we can then tie to what we’re really concerned about: chronic disease.”

“I think there have been tremendous advances,” she added, “but we need to come up with a way to look at nutrition status as a whole. If something is high, something else is probably low, and so looking at the constellation of markers, particularly that status rather than the one in isolation, [is important].”

Better biomarkers will result in better data, the panelists pointed out. Without them, we can’t properly advise the public on what they should eat and how they should supplement to maintain optimal health. As of now, Blumberg said, “I don’t think we’re adequately collecting the data that we really need…and so it’s really hard to be consistent, maintain programs and funding…”

This need is also on the radar of the government agencies that fund nutrition research. “Science in Session” speaker Wendy Weber, branch chief of Clinical Research in Complementary and Integrative Health Branch, Division of Extramural Research at NIH’s National Center for Complementary and Integrative Health (NCCIM), said that when NCCIM decides on which studies to fund, the agency’s goal is now “whole-person health and whole-person research.” She explained that NCCIM is not only looking at how various methods and technologies can be used in concert to study health; the agency is also looking at how it studies health, period.

“A lot of these factors—the psychological, nutritional, the physical aspects of this—often go together, and we’re very interested in this idea of multicomponent interventions,” Weber said. “It’s not just one thing. There’s not one magical answer.”

Weber added that one of NCCIM’s priorities today is also funding research on “those earlier building blocks,” meaning the foundational study tools and earlier-stage research studies that can lay the groundwork for larger studies. Previously, she said, “a lot of those earlier steps were missed before we jumped into those largely trials…”

The agency is also prioritizing reliable biomarkers as one of the early building blocks. Weber described these as “reproducible biological signatures.”

Making Solid Recommendations

Until we strengthen nutrition science tools, we can’t make more advanced recommendations for public and personalized health. And we see resulting confusion today, including conflicting information in the public and the media about what to eat and what not to eat. Bailey said that “it’s really hard for consumers to get behind what kind of advice they should have.”

“We really need to take a break and do good science,” she added.

If personalized nutrition is to become the next step in public and personal healthcare, we need to make sure we’re laying a strong groundwork for the science. “We have these public health recommendations,” Bailey said. “Precision nutrition is really that interface. We know if we can identify people who are going to respond to the same way to a diet, then we can make actual recommendations towards reducing that risk for primary and for secondary prevention.”

Blumberg concluded: “Now is the time to pause. Now is the time to admit that we know next to nothing about how we implement precision nutrition…”