Episode 128: Tommy Wood talks about high-fat diets and the metabolic flexibility of the human gut

// Sep 23, 2021

In today’s episode, Dr. Tommy Wood returns for his fifth appearance on STEM-Talk. Tommy is a UK-trained physician and an assistant research professor of pediatrics at the University of Washington. He also is a visiting research scientist and a valued colleague of ours here at IHMC.

Today’s interview focuses on a new paper that Tommy just had published by the American Society for Microbiology. It’s titled, “Reframing Nutritional Microbiota Studies To Reflect an Inherent Metabolic Flexibility of the Human Gut: A Narrative Review Focusing on High-Fat Diets.”

We discuss the paper and follow up on some research Tommy has done since his last appearance on STEM-Talk, a two-part interview that took place a little more than a year ago. In that two-part interview, episodes 110 and 111, we touched on Tommy’s research into the importance of metabolic health and how only one in eight Americans is considered metabolically healthy.

We also talk to Tommy about a new grant he just received to examine the effects of azithromycin on premature brain injury in a ferret model. As part of this grant, Tommy will be collaborating with his wife, Dr. Elizabeth Nance, who also is an assistant professor at the University of Washington and was our guest on episode 71 of STEM-Talk.

Show notes:

[00:03:15] Dawn opens the interview mentioning Tommy’s new paper published by the American Society for Microbiology titled “Reframing Nutritional Microbiota Studies to Reflect an Inherent Metabolic Flexibility of the Human Gut: A Narrative Review Focusing on High-Fat Diets.” Dawn mentions that in our last interview with Tommy, he talked about the importance of insulin sensitivity and metabolic health, yet as Tommy has pointed out, more than 80 percent of Americans have some kind of metabolic disease or dysfunction. Given that, Dawn asks Tommy to revisit key points regarding insulin resistance; the importance of metabolic health; and why so many Americans struggle with this issue.

[00:06:18] Ken points out that the common view held in much of the nutritional-microbiota research is that high-fat diets are harmful to human health, at least in part through their modulation of the gut microbiota. Ken goes on to say that there are a number of studies that support the inherent flexibility of the human gut and our microbiota’s ability to adapt to a variety of food sources, suggesting a more nuanced picture than the commonly held view. Ken asks Tommy to give an overview of the gut microbiome and how research in the past decade has explored the effects of the gut microbiome on our metabolism, immune systems, our sleep, and our moods and cognition.

[00:09:50] Dawn asks Tommy to explain the history of how fat, and high-fat diets, became public enemy number one in many circles, including gut microbiome research.

[00:12:46] Ken mentions that there are many limitations when it comes to preclinical nutritional research, with many studies on the role of fat in the diet being based on animal models, particularly rat models, which presents several problems since the natural diet of a mouse is low in fat and high in carbohydrates.

[00:15:50] Ken asks Tommy about the need for a more nuanced view of fat and our microbiota’s ability to adapt to different food sources.

[00:17:33] Ken points out that while people might throw around the term “healthy gut microbiota,” the research into the gut microbiota is so new that we don’t yet know for sure what a healthy gut microbiota should look like.

[00:21:22] Ken asks Tommy how we should go about reframing the debate about fat and high-fat diets to better reflect the overall evidence.

[00:23:48] Dawn mentions that in the past decade, researchers have significantly improved our understanding of the gut microbiome. She asks about Tommy’s belief that there is a need to understand the gut microbiome in an evolutionary context as well.

[00:25:18] Tommy gives an overview of the gut-barrier function and its role in health and disease.

[00:25:31] Dawn asks Tommy to talk about the significance of the study by Duke University’s David Lawrence that Tommy cited in his aforementioned paper, which highlights how quickly and reliably the human gut microbiota adapts to dietary changes.

[00:30:42] Dawn mentions that there is a lot of research supporting the therapeutic effects of a ketogenic diet on overall health in the context of epilepsy and multiple sclerosis. She asks if there is any such research that focuses on the gut.

[00:34:01] Dawn asks about the assertion in Tommy’s aforementioned paper that while butyrate production may be reduced on a ketogenic diet, other molecules can potentially take butyrate’s place to maintain the gut barrier function, an assertion that challenges many assumptions about normal metabolic pathways in the gut.

[00:36:21] Ken asks if there have been any studies that Tommy knows of that have assessed the effects of ketones, or a ketogenic diet, on the gut barrier function.

[00:39:50] Dawn asks about the mouse models and preclinical studies that show that ketogenic diets or ketones are cancer suppressive.

[00:40:52] Ken mentions that Tommy addresses three objections concerning the effects of fat and protein on our gut microbiota in his paper, asking Tommy to briefly go over these objections and his responses to them.

[00:45:42] Dawn asks Tommy what he believes are the questions that need to be asked or answered when it comes to nutritional microbiota research.

[00:46:36] Dawn mentions Tommy’s 2020 IHMC evening lecture about nourishing the human brain titled “Brain Health Across the Lifespan.” Dawn asks about the grant Tommy just received to examine the effects of azithromycin on premature brain injury in a ferret model.

[00:48:35] Dawn asks Tommy what it is about azithromycin that he finds particularly exciting as a potential neuroprotective agent.

[00:50:52] Ken mentions that Tommy will be collaborating on the grant with his wife, Dr. Elizabeth Nance, a faculty member of the University of Washington who was our guest on episode 71 of STEM-Talk. Ken asks Tommy how he and his wife’s work on this project will intersect.

[00:53:42] Dawn asks Tommy how Elizabeth is doing.

[00:54:26] Ken asks how Tommy’s findings on neuroprotection in babies might be transferable to adults looking to optimize their neural health.

[00:59:02] Dawn closes the interview asking Tommy about his dogs and his most important goal in life.


Learn more about IHMC

STEM-Talk homepage

Ken Ford bio

Ken Ford Wikipedia page

Dawn Kernagis bio

Tommy Wood bio

Tommy Wood talk on brain health