This is the third and final installment in a series about how food industry meddling biases nutrition science research to its advantage and at the expense of our health. In this blog post, we’re going to expand a bit more on the topic of good nutrition science—what it looks like in practice and why it matters.
In the previous post in this series, we briefly touched on the hallmarks of good nutrition research: large sample size, long study duration, open-ended research questions, no conflicts of interest, and a focus on dietary patterns rather than the benefits of specific foods. Today’s post will expound on this a bit more with a concrete example.
But first, a major disclaimer.
Even the best, most rigorous nutrition science has its limitations. Dietary patterns’ effects on human health are inherently messy to measure, and there are both benefits and pitfalls to the different methods scientists use to approximate what a given person typically eats. Interventional trials can help fill in the gaps of observational studies, but they are usually of shorter duration, or compliance may be lower in the case of a longer follow-up design. This makes tying a particular diet to a certain health outcome a little more challenging. Add on top of that the genetic heterogeneity throughout the population, as well as lifestyle variability from person to person. Accurate data collection is notoriously difficult in nutrition research, and there are lots of intervening factors to control for on top of that.
All that said, the statistical methods nutrition scientists use to minimize so-called confounding variables and other forms of noise are very powerful. So even when the data aren’t perfect, there are still plenty of useful conclusions we can draw from the totality of nutrition research. We know which foods confer more health risks than benefits (like processed meats), and we have a firm grasp on what kinds of dietary patterns are better at supporting our health (more whole plants!). Even still, those generalizations can’t speak to any one person’s risks or benefits while following a given diet or eating a certain food. Every individual must use evidence-based guidelines to judge for oneself what dietary pattern to follow, and working with a dietitian or a general practitioner can help a person make that determination in a more objective way.
With these considerations, let’s look at an example of high quality nutrition research.
The PREDIMED study, conducted throughout the 2000s and published in 2018, is well known among nutrition scientists for its rigorous methods and impressive results. With just under 7,500 participants, it boasts a large sample size, which is important for adequate statistical power. The study tested two variations on the Mediterranean diet (one with extra olive oil and one with extra nuts) against a control “low fat” diet in adults over 55 who were at a higher risk for cardiovascular events like heart attacks. They made sure the three groups were balanced in terms of baseline risk factors, then measured the rate of cardiovascular events in all three groups over a follow-up period of about five years.
The two Mediterranean diet groups were told to adhere to 14 dietary principles, including consuming legumes at least three times a week, having at least five servings of fruits and vegetables per day, and restricting red meat intake. All three groups received regular nutrition education sessions with a dietitian respective to their different dietary patterns. There was no control over the calories participants could eat, and there was also no physical activity component to the protocol. Regular contact with the participants helped ensure high adherence to the study diets. After all the data were collected and analyzed, researchers found that both Mediterranean groups had about 30% fewer cardiovascular events than the control group.
This summary offers just the highlights of the PREDIMED study, as you’ll see if you read it in its entirety. Even so, it’s clear that this example has most of the attributes of high quality nutrition science we’ve covered: big sample size with thousands of participants, open-ended research questions, no “p-hacking”, decent study duration, sound methods, and a focus on dietary patterns. And while PREDIMED is great, it can’t stand alone. There are plenty of things that could be improved, a fact true of all studies. What’s useful about it, though, is that it tracks with established nutrition research and helps us get clearer on what we’re getting right and what we’re getting wrong about nutrition.
So, how can we set a higher standard for nutrition research in the future? There are numerous policies, governmental and institutional, that could help. Perhaps the most obvious is that we need more public investment in nutrition research in academia and agencies like the National Institutes of Health. This would reduce the attractiveness of corporate sponsorship and hopefully stop food industry actors from using the authority of scientists as a cover for their dubious research agendas. Another approach is to weed out bad science further down the pipeline. In the same way all study proposals must be approved by an ethics committee known as an Institutional Review Board, we could also enforce review committees that screen for methodological flaws and poor study design so low quality research is never carried out.
Scientific integrity matters for its own sake, but in the end I think what’s most important is that people’s actual lives are on the line.
In the United States and across the world, millions are needlessly living with more illness, disability, and pain as a result of poor nutrition. We need more precise nutrition science to be the foundation of medical interventions and governmental assistance programs like SNAP and the National School Lunch Program. Only when we can collectively agree on the facts of—and therefore the solutions to—our personal and public health crises can we hope to restore health to our communities and hold bad actors accountable for the harm they have inflicted.
Everything about science is difficult; conducting it, interpreting it, and communicating it each requires an underappreciated amount of expertise and diligence. I should know first-hand. I feel responsible in part for the health of the people who read my articles and always worry that something I say could lead to a bad outcome for someone. That’s why the initial goal of this series was to help inoculate readers against the food industry’s hidden influences in nutrition science—for the sake of their own personal health. Yet I hope joining me on this deep-dive has also galvanized you, our readers, to spread awareness and advocate for healthier food environments in your communities. We all have a right to the full, unadulterated facts today’s science can tell us about the ways food affects our bodies. If you agree, please continue to support our policy work throughout the new year so together we can fight for everyone to have access to better nutrition.
Madeline is the Food System and Nutrition Policy Analyst at Balanced. She holds a B.S. and M.S. in Nutrition from the Univ. of Texas and Tufts, respectively. As a nutrition expert, she advocates for more plant-based dining options in critical institutions with the aim of building healthier food environments and fostering better public health outcomes.
You can reach her here: madelineb@balanced.org
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