
Sigma Nutrition Radio
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.
Latest episodes

Nov 8, 2022 • 56min
#460: Dr. Priya Sumithran – Body Fat Regulation, Pros & Cons of Weight Loss Interventions, and GLP-1 Receptor Agonists
Obesity increases the risk of a range of chronic diseases and negative health outcomes. And trials where a sufficient amount of weight loss is achieved show health improvements. However, despite the “straightforward” nature of causing weight loss through a hypocaloric diet, it is clear that most people who lose weight will regain some or all of the weight. This is a result of both the physiologic control of intake and expenditure (i.e. homeostatic regulation by the body to avoid staying at a lower body or fat mass), and environmental factors. Diet-induced weight loss is followed by a number of hormonal change that encourage weight regain. So how do we tackle this problem? In this episode, Dr. Priya Sumithran discusses this physiologic control of body mass, in addition to environmental and behavioural factors that make weight loss maintenance difficult. Dr. Sumithran also discusses what this means for setting weight loss targets, choosing the correct intervention, and looking to non-weight-centric approaches for certain individuals. We also discuss the evidence on GLP-1 receptor agonist drugs, such as Semaglutide, as a treatment for obesity. Links: Episode page Subscribe to Premium Sigma live event - Berlin Sigma recommended resources

Nov 1, 2022 • 52min
#459: Nicky Keay, MB BChir – Hormones & Healthspan: The Endocrine System Across the Life Course
Dr. Nicky Keay discusses hormone diurnal variation, bone health, amenorrhea, HRT, perimenopause, and aging implications in the context of the endocrine system across different life stages. The intricacies of hormones, importance of timing in hormone testing, and maintaining hormonal balance through lifestyle interventions are emphasized.

Oct 25, 2022 • 12min
What Are Stable Isotopes? How Are Tracers Used in Nutrition Research? (Preview)
Stable isotopes have been used as tracers in human nutritional studies for many years. But what are they? Why do we use ‘tracers’ in nutrition studies? And what are some practical examples? A chemical element can have different forms or ‘isotopes.’ These different isotopes have the same atomic number and position in the periodic table but have different atomic masses and physical properties. An isotope that is not radioactive is said to be ‘stable’. In physiology and metabolism research, stable isotopes are used as ‘tracers.’ As the name implies, it allows us to ‘trace’ the fate of compounds, thus giving a very detailed insight into the metabolism of nutrients and the regulation of many disease processes. In this episode, Dr. Alan Flanagan explains what stable isotope tracers are, how they are used to answer nutrition science questions and some examples that you may come across. This is a ‘Nutrition Science Explained’ episode. These episodes are exclusive to Sigma Nutrition Premium. To listen to the full episode and access the transcript, you must subscribe to Sigma Nutrition Premium.

14 snips
Oct 18, 2022 • 1h 36min
#458: How Foods Impact Satiety, Hunger & Appetite
Given the negative consequences of consistent overconsumption of food (leading to a caloric surplus), having a dietary intake that is of appropriate calorie intake is an important aspect of long-term health. Therefore, thinking about which foods and diets can help promote appropriate satiety to keep calorie intake in check is a key focus for many researchers and practitioners. There is a complex system of human appetite control. This appetite system influences food consumption and associated motivational drives such as hunger, as well as interacting with and being influenced by energy expenditure. Satiety is an important psycho-biological process involved in the expression of human appetite, inhibiting hunger and intake following food or beverage consumption. In this episode, the Sigma team discusses the human appetite system, how different nutrients and foods impact satiety, and the implications of this research. Links: Subscribe to Premium Show notes for this episode Live event in Berlin, Germany Sigma Recommended Resources

Oct 11, 2022 • 1h 10min
#457: Austin Robinson, PhD – Salt Sensitive vs Salt Resistant, Impacts of Sodium on Health, & Racial Differences in Risk
Hypertension (elevated blood pressure) is a condition that significantly increases the risk of several diseases and is a major cause of premature death worldwide. In the US, recent estimates suggest that about half of the adult population has hypertension. At a population level, high sodium intake is one of the main dietary risk factors. All population health guidelines recommend keeping sodium intake below certain levels. While, on average, blood pressure correlates with sodium intake, there is a wide range of responses on an individual level. People who see increasing sodium intake lead to increased blood pressure are termed “salt sensitive”. Others, however, don’t see much change in blood pressure with increased dietary sodium. Such individuals are classed as “salt resistant”. In this episode, Assistant Professor at Auburn University, Dr. Austin Robinson, is on to discuss whether people who are salt resistant need to keep their sodium intake low or not. And other individual and group differences that exist for hypertension risk and sodium physiology? Links: Subscribe to Premium Episode overview Live event in Berlin Recommended Resources

Oct 4, 2022 • 1h 3min
#456: Prof. Glenn McConell – Glucose Uptake During Exercise & Muscle Insulin Sensitivity
Exercise improves metabolic control both via increasing muscle glucose uptake during muscle contractions by insulin-independent mechanisms and by increasing skeletal muscle insulin sensitivity after physical activity. A reduction in skeletal muscle insulin sensitivity is an early event in the development of not only prediabetes, metabolic syndrome, and type 2 diabetes but is also associated with other conditions such as cardiovascular disease and some cancers. One of the researchers that has been at the forefront of research in this area for many years is Professor Glenn McConell. In this episode we discuss glucose uptake during and after exercise, looking at both insulin-dependent and insulin-independent mechanisms. In addition we discuss the crucial importance of muscle insulin sensitivity and some important research breakthroughs on the topic. Links: Subscribe to Premium Episode show notes Live event: Berlin

Sep 27, 2022 • 47min
#455: Jill Joyce, PhD – Improving the Diets of Tactical Populations
The term ‘tactical populations’ has been applied to those working in law enforcement, fire, first responders, and military. In addition to the importance of their work, the work they do itself presents some challenges for health and nutrition. Despite the fact that such individuals make up a significant number of the population and their work plays a crucial role in society, there is currently very little research on fire and law enforcement nutrition. Most research is on the prevalence of disease and the occupational risk factors and related pathophysiology. Lifestyle research, descriptive and interventions, is way behind. Dr. Jill Joyce is the co-director of the OSU Tactical Fitness and Nutrition Lab at Oklahoma State University. She does research looking at real-world interventions in these populations, particularly firefighters, in an attempt to improve their diets and health. In this episode, we look at both the theoretical and pragmatic realities of improving diet and health in firefighters and some other tactical populations. Links: Subscribe to Premium Access show notes Live event in Berlin

Sep 20, 2022 • 15min
SNP9: AMA – Blood Pressure, LDL Lowering, PCOS & More!
In this Premium-exclusive ‘Ask Me Anything’ episode, Alan & Danny answer a range of listener questions. Topics include obesity rates, lowering blood pressure, cholesterol drugs, PCOS, and what issues they have changed their minds on. See the full list of questions below. [02.37] Do you feel that there is hope (or an effective way forward) for obesity rates to come down? Based on your response, why/why not? [11.28] In this field, it seems like so many of us have had positions we’ve held very seriously that we now see as poorly supported by research, or just have a significant paradigm change. It would be great to hear you look back to how your views have evolved over the years. [30.34] Apart from lowering salt intake and eating foods high in potassium are there other things you can take or do to reduce blood pressure? [40.34] What is the best ratio of DHA vs EPA to increase my Omega 3 index? [46.20] Statins v Ezetimibe: Differences between the two? Mechanism of action? Are there situations, conditions, genetic markers where one may work better than the other? [56.20] I’m starting a PhD in the fall concerning the pathophysiology of metabolic diseases and I’d like to take some courses that would help me in my research. Would you have any recommendations for a beginner scientist? [59.01] Is astaxanthin a good substitute for algae oil for someone who follows a vegan diet? [60.45] Do you have any suggestions how to better manage hunger in obese women with PCOS? [64.33] Do you have any recommendations for anyone wanting to get involved in chrononutrition research? Links: Subscribe to Premium Live Event: Berlin, Germany on November 26th 2022 Episode transcript Resources mentioned in this episode

Sep 13, 2022 • 1h 25min
#454: Eric Helms, PhD – Plant or Animal Protein: Rethinking Protein & Muscle
When it comes to eating to promote muscle hypertrophy, muscle repair/recovery and maintenance of mass and function, protein has been an obvious focus. Indeed muscle mass and quality are dependent on the continuous remodeling of skeletal muscle proteins. This is related to the amount of muscle protein balance, i.e. the net difference between muscle protein synthesis (MPS) and muscle protein breakdown (MPB). Because of this, MPS has long been used as a proxy measure for muscle repair and/or growth of muscle. Protein feeding increases MPS, with the amino acid leucine having a specifically strong impact on MPS. Therefore both the dose of protein and the amino acid profile of the protein have been looked at to assess which protein sources are “superior” for muscle mass and function. This has typically led to viewing animal proteins as better than plant proteins. But many assumptions are layered into conversations on the topic. In this episode we explore some important points that are often neglected. Is MPS as reliable as we assume? Does the amino acid profile tell us everything about the anabolic effect of a protein? Does dose and timing matter as much as we think? How does the picture change when we look at whole foods or mixed meals? Link: Subscribe to Premium Go to show notes Live Event: Berlin, Germany MASS Research Review Muscle & Strength Pyramids: Training & Nutrition Books

Sep 6, 2022 • 1h 12min
#453: Nick Gant, PhD – Cognitive Performance: Impact of Caffeine, Nicotine & Creatine (Rebroadcast)
The brain plays a central role in both physical and psychological function and performance. The brain also has a very high energy demand. In addition, fatiguing conditions can cause impairment of cognitive performance. One area of research in neurometabolism related to the potential use of nutrients on improving cognitive function, as well as “rescuing” the fatigue-related declines in performance. Nick Gant is Director of the Exercise Neurometabolism Laboratory at the University of Auckland. His group uses interdisciplinary approaches from the nutritional sciences and neurosciences to investigate the role of nutrition in brain health and performance. Nick is particularly interested in foods and supplements that prevent brain fatigue and improve physical and cognitive function. Subscribe to PREMIUM