Just how far have we come in terms of nutrition treatments for diabetes care? At the American Diabetes Association’s 81st annual Scientific Sessions last week, many of the sessions focused on exploring the evolving role of nutrition in diabetes therapies (although not necessarily focused on low-carbohydrate diets).
In Diabetes “Diets” Since the Discovery of Insulin: Looking Back, and Then to the Future, Melinda D. Maryniuk and Hope Warshaw took us through an overview of just how far we’ve come in nutrition interventions, from the 1920s to present-day. From starvation diets that included whiskey to “keep the patient more comfortable,” to the evolution of exchange lists, and finally to present-day individualized nutrition plans, Maryniuk and Warshaw provided a peek inside the history of diabetes nutrition management that focused on a robust review of interventions (many of which were not strictly low-carbohydrate diets).
As this year is the 100th anniversary of the discovery of insulin, the question was raised as to whether this development hampered the advancement of early nutrition treatments. Although nutrition research took a backseat after the discovery of insulin, a 1993 DCCT ancillary study revealed that intensive therapy alone was not sufficient enough to achieve glycemic targets. According to Linda M. Delahanty, MS, RDN, who Warshaw quoted in her presentation, “We learned the role of the RD/RDN and careful attention to diet was key to achieving glycemic targets in intensive diabetes therapy without undue hypoglycemia or weight gain.”
Throughout the 90s, nutrition therapy was cemented as an ongoing therapy in conjunction with medications and insulin for Type 2 diabetes management. Person-focused nutrition therapy, which included the more psychological and psychosocial reasons for why people eat the way they do, became foundational to care in lieu of rigid, one-size-fits-all meal plans–and the trend is continuing today.
Throughout the 2000s, the ADA has taken a more lenient approach, taking into account personal preferences and individualization of care. Instead of rigid diets, emphasis is being placed on patients eating a variety of nutrient-dense foods as part of a flexible diet that they can stick to for the long haul. And according to the most recent ADA recommendations, one of the four key goals of diabetes nutrition therapy is to address individual nutrition needs based on personal, cultural, literacy, numeracy, access to healthy foods, and willingness and ability to make behavior changes while understanding a person’s barriers.
While Maryniuk and Warshaw emphasized the importance of more individualized nutrition care moving forward, Paul W. Franks, PhD and Kevin D. Hall, PhD debated whether we’re ready for such a leap in Debate: Precision Nutrition: Are We There Yet?
Franks argued that “now is the time to invest aggressively in precision nutrition research and investigate how discoveries can be translated into practice,” citing several studies backing his claims that biological characteristics influence one’s response to lifestyle interventions, and that a person’s biological data can be intelligently combined to help optimize dietary choices. Franks also pointed out that precision nutrition is already the standard of care for monogenic disorders such as Folling’s disease.
Franks acknowledged that in order for precision medicine to work, it will need to be fitted to the individual’s circumstances and preferences, stating that work is currently underway to investigate how acceptable precision nutrition recommendations are to the end-user.
“Although people try to juxtapose precision nutrition with other approaches to diabetes prevention, these things are rarely mutually exclusive, and, indeed, often go very comfortably well together,” argued Franks.
However, when it comes to individualized nutrition, Hall pointed out that we may still have a long way to go in terms of accurate glucose monitoring to inform nutrition interventions. Hall stated that even these “gold standards” for measuring energy intake tend to be imprecise, resulting in considerable variability in weight outcomes.
Hall cited a 28-day metabolic ward study resulting in discordant CGM glucose excursions when recording the glucose response of one person wearing two different CGMs simultaneously in response to two different meals. Additionally, Hall cited a study of repeated glucose iAUC (2 hr) within CGM measuring identical meals, which produced highly variable results even when measuring the same meal one week apart.
Hall stated that, while the mean incremental responses of venous measurements are sound and correspond with data from oral glucose tolerance tests, this doesn’t mean that they should be used for precision nutrition at the individual level.
“Maybe incrementally, [venous measurements] are pretty good on average, but again, at the individual level, which is the target of precision nutrition, I think we have to be a little bit careful,” said Hall.
Hall posited that precision nutrition needs precision methods, including domiciled feeding studies; further development and validation of technologies and biomarkers; determining surrogate marker responses; elucidating physiological mechanisms; and designing and interpreting large, long-term nutrition studies.
Hall stated that he believes drilling down to more precise nutrition for differences in gender, ethnicities, and family histories might be possible in the future, most likely starting with careful subgroup analyses in well-powered trials and observational studies. He proposed that studies should be designed with as little noise as possible, while focusing on outcomes that are truly clinically meaningful (and that also translate into meaningful outcomes at the population level).
In response to Hall, Franks rebutted, “It strikes me that there’s enough evidence to show that there is promise in [precision nutrition], and there’s enough evidence to show that standard approaches do not work well, and so we have to do something… and I think doing nothing is not the solution here.” Hall agreed with that statement.
While precision nutrition continues to evolve, the research on standard nutrition interventions marches on. In Food is Medicine for People with Diabetes and At-Risk of Diabetes, eight different presenters showed promising findings on the correlation between nutrition interventions and health outcomes for people with diabetes. Just some of the study findings from the presentations included:
- Clinically significant weight loss following 90 days of carbohydrate-restricted nutrition therapy (predicted by mean blood beta-hydroxybutyrate);
- Improvements of time-in-range for people with Type 2 diabetes as a result of meal delivery;
- Equalization of glycemic control between short and adequate sleepers via calorie restriction;
- Reduced consumption of unhealthy foods, improved food security, and lowered cardiometabolic risk among adults with or at risk of Type 2 diabetes as a result of medical prescriptions for vegetables
We have covered significant ground in nutrition interventions since the 1920s, and we still have much more to cover, especially in terms of developing precision nutrition efforts. But all trends continue to point toward more individualized care via data-driven interventions, exploring new medications and treatments, and taking into account behavior change strategies on both group and individual levels.
As Warshaw quoted Madelyn L. Wheeler, MS, RD, CDE in her presentation: “Diabetes nutrition recommendations have [witnessed] cycles… between greater or lesser amounts of: specific foods, food groups, and/or macronutrients. In this new millennium we will break this cycle… by focusing on the process of MNT to help people meet individual goals, rather than ‘one size fits all’ recommendations. How will this happen? Quality research!”