#575: How Does Dairy Impact Cardiometabolic Health? – Prof. Jean-Philippe Drouin-Chartier
Dairy is often treated as a single food group, yet milk, yogurt, cheese, and butter can have very different effects on health. Some evidence links yogurt to favourable outcomes, while butter is known to raise LDL cholesterol. And then there’s the paradox of cheese: high in saturated fat, but not consistently associated with higher heart disease risk. These complexities raise the question of whether the “dairy matrix” (the combination of nutrients and food structure) explains why not all dairy acts the same. In this episode, Prof. Jean-Philippe Drouin-Chartier, a nutrition researcher and registered dietitian, is on the show to examine what recent trials and large population studies tell us about dairy foods and cardiometabolic health. The discussion covers blood lipids, blood pressure, glucose metabolism, and how guidelines should interpret this evolving evidence. Timestamps [02:18] Interview start [09:38] Dairy consumption and type 2 diabetes [16:06] Dairy and cardiovascular disease [21:42] Dairy, blood pressure, and hypertension [25:56] Dietary guidelines and dairy [43:30] Key ideas segment (Premium-only) Related Resources Subscribe to Sigma Nutrition Premium Join the Sigma email newsletter for free Website: sigmanutrition.com Enroll in the next cohort of our Applied Nutrition Literacy course Referenced studies linked here
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#574: Microplastics & Health: What Do We Know? – Prof. Ian Mudway
They’re in our oceans, our air, our food, and now even in our bodies. Microplastics, once a distant environmental issue, have become a topic of urgent relevance in medicine, public health, and nutrition. The idea that tiny plastic particles are circulating through the food chain and accumulating in human tissues has sparked headlines, speculation, and concern. But how much of this fear is grounded in solid science? And how much is still unknown? As the research into microplastics rapidly grows, so too does the confusion. Claims range from the plausible to the alarmist, yet the real picture is far more complex. What does current evidence actually tell us about the health implications of microplastic exposure? How do we weigh these emerging signals against the backdrop of other environmental threats we understand much better? And how should scientifically-minded practitioners think about this issue, especially when patients begin asking questions? This is a conversation that calls for clarity, nuance, and a rigorous look at what we know versus what remains speculative. In this episode, Professor Ian Mudway, an environmental toxicologist, discusses the current scientific understanding of microplastics and human health. Timestamps [03:31] The public’s fascination with microplastics [08:35] Defining microplastics and nanoplastics [11:35] Environmental presence of microplastics [14:54] Human exposure to microplastics [18:23] Challenges in measuring microplastics [21:38] Public perception vs. scientific reality [27:08] Challenges in microplastic research [29:53] Environmental impact and human health [33:08] Complexities of plastic additives [40:34] Future directions in microplastic research [48:09] Key ideas segment (Premium-only) Resources Subscribe to Sigma Nutrition Premium Join the Sigma email newsletter for free Enroll in the next cohort of our Applied Nutrition Literacy course Gresham College YouTube lectures Go to sigmanutrition.com
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#573: A Philosophy of Elite Performance Nutrition – Daniel Davey
In this episode, performance nutritionist Daniel Davey discusses how his approach to elite sports nutrition has evolved over his career. Davey reflects on his decade working with top Irish teams (Dublin GAA/football and Leinster Rugby) and how stepping away from those environments led him to rethink the role of a nutrition practitioner. The central theme is a shift from a traditional prescriptive model, where the expert provides meal plans and quick solutions, to a philosophy centered on athlete empowerment, education, and long-term habit development. Davey emphasizes that true high performance is achieved not by spoon-feeding athletes every nutrient, but by cultivating their independence, adaptability, and ownership of the process. This episode delves into practical strategies for fostering that ownership, such as encouraging self-reflection, building a supportive “nutrition culture,” and focusing on sustainable habits over short-term fixes. This discussion is highly relevant to nutrition science and clinical practice because it addresses the often-overlooked behavioral and cultural aspects of dietary change. Health professionals will recognize parallels to coaching clients in any setting: the importance of engaging individuals in their own nutrition planning, the value of reflective practice, and the balance between providing support and encouraging autonomy. Timestamps [02:38] Interview start [07:29] Empowering athletes [12:36] Challenges and reflections [16:53] Practical applications and philosophy [23:33] Building sustainable habits [28:00] Empowering decision-making through clarity [30:03] The importance of consistency and planning [31:47] Leadership and team dynamics [34:38] Personal growth and overcoming challenges [40:27] The concept of non-negotiables [52:31] Key ideas segment Resources Join the Sigma email newsletter for free Subscribe to Sigma Nutrition Premium Enroll in the next cohort of our Applied Nutrition Literacy course See Sigma's Recommended Resources Daniel Davey’s previous appearences on the podcast: go to episodes 306 and 194
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#572: Can You Trust Industry-Funded Nutrition Studies? Here’s How to Tell
Nutrition science plays a pivotal role in shaping public health advice, but the influence of industry funding on research has become a pressing concern. In this episode we want to examine whether we can trust nutrition studies funded by food and beverage companies, and how you can discern study credibility. The discussion is highly relevant in today’s landscape, where conflicts of interest and bias in research are under scrutiny amidst debates on sugar, processed foods, and diet recommendations. By exploring how industry sponsorship might skew results or interpretations, this episode speaks to broader issues of scientific trustworthiness and evidence-based policy in nutrition and public health. In this episode, we take a look at some recent publications that showed how study results and reporting differed significantly depending on if industry had funded the study or not. We delve into how this happens. As most often it is not a case of data fabrication or corruption, but rather how bias leads to studies being designed and reported differently. We walk through some examples, as well as highlighting some industry-funded studies that didn’t provide a “pro-industry” result and conclusion. The hope is that the episode allows you to understand why this is a problem, how to spot it, and how to know if you can trust the results of an industry-funded study. Timestamps [00:36] Alan’s upcoming study [04:47] Discussion on industry funding in nutrition research [15:06] Case study: industry influence on red meat research [30:43] Case study: artificial sweeteners and industry influence [36:37] Case study: sugar industry’s role in research [38:06] Critical appraisal of industry-funded studies [51:58] Case study: when industry-funded study results can be trusted [01:01:51] Guidelines for assessing research quality [01:07:14] Key ideas segment (premium-only) Related Resources Join the Sigma email newsletter for free Subscribe to Sigma Nutrition Premium Join Alan's Alinea Nutrition Research Hub Enroll in the next cohort of our Applied Nutrition Literacy course Recommended episode: #472: Compared To What? – Understanding Food Substitution Analysis & Adjustment Models Studies mentioned: López-Moreno et al., Am J Clin Nutr. 2025 Jun;121(6):1246-1257 Tobias, 2025 – You are what you don’t eat Mandrioli D, Kearns CE, Bero LA (2016) PLOS ONE 15(3): e0230469 Schillinger et al., Ann Intern Med. 2016 Nov 1;165(12):895–897 Schmidt et al., 2021 – The impact of diets rich in low-fat or\ full-fat dairy on glucose tolerance and its determinants: a randomized controlled trial Schmidt et al., 2021 – Impact of low-fat and full-fat dairy foods on fasting lipid profile and blood pressure: exploratory endpoints of a randomized controlled trial
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#571: Is Zone 2 Training Actually Best for Health? – Prof. Brendon Gurd
In recent years “Zone 2 training” has gained immense popularity in fitness and health circles, often being proclaimed the “best” cardiovascular training for metabolic health. Zone 2 training is sustained, low-intensity exercise below the lactate threshold that is commonly employed by many elite level endurance athletes, with a variety of proposed performance benefits. This led to interest from health-conscious folks about its ability to improve markers like VO2 max and mitochondrial function, which are associated with better health outcomes and longevity. Prof. Brendon Gurd, an exercise physiologist at Queen’s University, is the co-author of a recent review published in Sports Medicine that examined some of the claims made around zone 2 training and health in the general population. This episode looks at whether the evidence truly supports Zone 2 as a uniquely effective training zone or if this hype has outpaced the research. These insights help professionals and individuals make evidence-based recommendations and avoid unintended negative consequences of following certain ideas. About The Guest Dr. Brendon Gurd is a Professor in the School of Kinesiology and Health Studies at Queen’s University, where his research focuses on exercise physiology and skeletal muscle adaptation. His work explores how different intensities and types of exercise influence mitochondrial content and function in muscle tissue, with the goal of understanding how to optimize health and performance through training. Timestamps [03:23] Discussion with Professor Brendan Gurd [05:56] Zone two training: Mechanisms and misconceptions [10:56] Practical applications and recommendations [22:16] Research gaps and future directions [35:47] Key ideas segment (Sigma Nutrition Premium) Links to Resources Subscribe to Sigma Nutrition Premium Join the Sigma email newsletter for free Enroll in the next cohort of our Applied Nutrition Literacy course List of Sigma's Recommended Resources Review paper: Storoschuk et al., 2025 – Much Ado About Zone 2: A Narrative Review Assessing the Efficacy of Zone 2 Training for Improving Mitochondrial Capacity and Cardiorespiratory Fitness in the General Population Lecture Slides: Prof. Brendon Gurd – Is Zone 2 the optimal intensity for inducing mitochondrial adaptation?
Discussions about the science of nutrition, dietetics and health. The podcast that educates through nuanced conversations, exploring evidence and cultivating critical thinking. Hosted by Danny Lennon.
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