Sigma Nutrition Radio

Global food systems have been increasingly subjected to financial speculation, leading to adverse consequences for growers, consumers, and public health. But what are the systemic vulnerabilities that impact food security, equitable access to nutritious food, and the broader socio-political frameworks influencing these outcomes? Understanding the financial mechanisms shaping food production and distribution is highly relevant for health professionals, policy makers, and researchers concerned with nutrition, equity, and global health systems. This episode urges a critical re-evaluation of current food policies and invites consideration of more ethical, resilient approaches to safeguarding food systems. Professor Martin Caraher is Emeritus Professor of Food and Health Policy at the Centre for Food Policy, City St. Georges, University of London. His research encompasses food poverty, food security, the role of food aid, and the broader implications of food systems on public health. Timestamps [01:12] [05:27] [13:10][17:20] [34:03] Related Resources episode pageProf. Caraher’s Recommended Reading ListSigma email newsletterSigma Nutrition PremiumApplied Nutrition LiteracyProf. Martin Caraher – Food Poverty & Food Aid Provision@MartinCaraher@NutritionDanny

Seed oils have recently become a hotly debated topic in nutrition, fueled by sensational claims on social media. In this episode, the central theme is examining whether seed oils are truly harmful or if they’ve been unjustly demonized. The discussion tackles prevalent claims – that seed oils drive inflammation, oxidation, and chronic disease – and compares them against the current scientific evidence. This is highly relevant to nutrition science and clinical practice today, as many patients and practitioners are encountering conflicting information about vegetable oils. By exploring the origins of seed oils, their biochemical effects, health outcome data, and the misinformation ecosystem, the episode aims to clarify how omega-6 rich seed oils fit into a healthy diet and what evidence-based guidelines say. Timestamps Related Resources Sigma email newsletterSigma Nutrition PremiumApplied Nutrition LiteracySeed Oils on Trial: Is the Panic Justified?502: Sydney Diet-Heart Study – Is Linoleic Acid Causing Heart Disease?504: Vegetable Oil vs. Saturated Fat – Analysis of the LA Veterans Study505: Oslo Diet-Heart Study: Cholesterol-lowering Diets & Cardiovascular Events329: Diet & Inflammation

In this Quack Asylum episode, Danny and Alan critically examine the claims surrounding “detoxification protocols” – specialized diets, cleanses, or supplements marketed to eliminate toxins from the body for better health. The central theme is whether these detox plans actually improve health outcomes or if they’re built on pseudoscience and fear. Many alternative health proponents argue that modern life exposes us to countless toxins that accumulate in our bodies, causing chronic diseases, and thus we must undergo periodic detox regimens to cleanse ourselves. There is genuine concern about environmental pollutants and chemicals – indeed, numerous substances in our food, water, and air can be harmful at sufficient doses​. Nutritional science also recognizes that certain nutrients (e.g. vitamins, antioxidants) play roles in the body’s natural detox pathways. However, there’s a large gap between acknowledging real toxic exposures versus endorsing commercial “detox” diets or products. Many people, including health professionals, encounter patients or clients interested in detox plans, so understanding the science (or lack thereof) behind these claims is important. Timestamps [03:20][06:10][08:22][11:30][25:46][50:30][55:20][01:04:54][01:09:10] Related Resources Sigma Nutrition PremiumSigma email newsletterepisode pageApplied Nutrition Literacy

Emulsifiers are a ubiquitous component of the modern food supply, found in everything from salad dressings and dairy products to pastries and sauces. Traditionally regarded as safe by regulatory agencies, emulsifiers play a vital role in enhancing the texture, stability, and shelf-life of countless processed foods. Yet, in recent years, emerging research has prompted a reevaluation of this assumption, raising intriguing questions about whether regular consumption of these additives might have previously overlooked health consequences. Recent epidemiological studies have suggested possible associations between higher emulsifier intake and chronic health issues. Concurrently, mechanistic research has provided some biological pathways through which emulsifiers could disrupt gut health. This episode aims to critically examine the scientific literature surrounding dietary emulsifiers, differentiating credible evidence from speculation, and outlining what can—and cannot—be concluded about their potential risks. Timestamps [01:18][05:15][09:32][14:55][26:12][30:01][35:05][47:15] Related Resources Sigma Nutrition Premiumepisode pageSigma email newsletterApplied Nutrition Literacy

Nutrition is increasingly being considered as a modifiable factor that may influence neurodevelopmental outcomes. While severe deficiencies in certain nutrients are known to have dramatic effects, there is growing interest in the potential impact of more subtle insufficiencies — particularly during critical windows such as pregnancy, infancy, and early childhood. In conditions like ADHD, dyslexia, and autism spectrum condition (ASC), questions have been raised around whether specific nutrients may play a role in cognitive performance, attention, or learning. In this episode, Dr. Emma Derbyshire discusses the evidence on choline and other brain-related nutrients in the context of neurodiversity. Timestamps [02:02][05:38][07:26][10:49][14:24][17:14][23:05][25:05][30:14][38:45] Related Resources episode pageSigma email newsletterSigma Nutrition PremiumApplied Nutrition LiteracyNutrition for ADHD and Dyslexia: Unlocking the Potential for Learning and Wellbeinghttps://www.nutritional-insight.co.uk/

This is a segment from one of our Premium-exclusive AMA (ask me anything) episodes, where we answer questions submitted by Premium subscribers. To listen to the full episode, you’ll need to be a Premium subscriber and access the episode on the private Premium feed. Questions Answered in This Episode [02:00][08:48][20:33][28:39][43:31][59:48][1:10:37][1:14:35] Links Sigma Nutrition Premiumsigmanutrition.com

The intersection of nutrition, dermatology, and skin health is an area of growing interest, yet one that remains riddled with misinformation and oversimplified claims. The influence of dietary patterns, specific nutrients, and lifestyle factors on conditions such as acne, eczema, psoriasis, and skin aging has been widely debated, with varying levels of evidence supporting different interventions. While some nutritional strategies may play a role in optimizing skin health, the challenge lies in distinguishing practical, evidence-based approaches from overstated or anecdotal claims. A significant issue in this space is the naturalistic fallacy—the belief that diet alone can replace medical treatments, or that conventional dermatological interventions should be avoided in favor of “natural” approaches. This has led to widespread vilification of certain foods, such as dairy, gluten, and sugar, despite a lack of strong supporting data. Similarly, supplements and probiotics are often promoted with broad claims, while their actual efficacy is highly context-dependent—varying based on individual nutrient status, disease severity, and baseline dietary intake. In this episode, Dr. Thivi Maruthappu, a consultant dermatologist and researcher in nutritional dermatology, joins Danny Lennon to explore the current state of evidence in this field. Guest Information Dr Thivi Maruthappu MA PhD FRCP ANutr is a consultant dermatologist, nutritionist and leading researcher. As the UK’s first and only dual-qualified dermatologist and nutritionist, her pioneering expertise bridges the gap between diet and skin health. Dr Thivi continues to work in the NHS and has her own practice based at London’s renowned Cleveland Clinic. Dr Thivi studied Medicine at Oxford University and completed Dermatology training in London. She undertook a PhD to understand the links between our skin and internal health and this research featured in top tier scientific journals. She is one of a handful of dermatologists to have completed training in severe eczema and psoriasis during a fellowship at St John’s Institute of Dermatology, London and achieved a Certificate in Nutrition Science from Stanford Medical School, USA. Timestamps [02:52][03:37][05:57][12:15][16:07][20:25][24:10][27:45][31:35][35:20][43:05] Related Resources Sigma email newsletterSigma Nutrition PremiumApplied Nutrition LiteracyDr. Maruthappu’s website

Discussions around ultra-processed foods (UPFs) and their role in public health have gained significant traction in recent years. While some advocate for categorizing and regulating these foods due to their potential negative health effects, others argue that such classifications can oversimplify the issue and detract from more actionable dietary changes. In this episode, Dr. Duane Mellor, a registered dietitian and researcher, joins us to explore the complexities of the UPF debate. Rather than dismissing the concept outright, Dr. Mellor emphasizes the importance of nuanced discussion, bridging the gap between research findings and practical, evidence-based dietary guidance. Throughout this conversation, we unpack the broader implications of ultra-processed foods in the food system, consider how added fat, salt, and sugar contribute to public health challenges, and explore realistic approaches for dietary improvements. Guest Information Dr. Duane Mellor, PhD is a registered dietitian, academic researcher and science communicator. Dr. Mellor is currently working in clinical dietetics, working to support people, families and carers living with diabetes. Previously Dr. Mellor worked in medical education at Aston University, holding the position of Associate Dean for Public Engagement in the College of Health and Life Sciences. After initially working in the areas of clinical trials, Dr. Mellor’s other research interests focused on improving nutrition and health by working with communities to celebrate their heritage through food and help tackle barriers resulting from societal inequalities. Timestamps [03:02][06:39][09:53][14:52][20:47][26:13][42:31][50:30][51:15] Related Resources Sigma email newsletterSigma Nutrition PremiumApplied Nutrition LiteracyMellor, 2024 – The role of food science and technology in navigating the health issues of ultra-processed foodssigmanutrition.com

In the realm of health psychology, our understanding of eating behaviors extends beyond mere physiological hunger cues. Research indicates that factors such as learned associations, cultural influences, and individual perceptions play pivotal roles in shaping our dietary choices. Recognizing this complexity is essential for developing effective dietary interventions that move beyond simplistic recommendations, acknowledging the intricate web of cognitive, emotional, and societal factors at play. A significant discussion within nutrition science centers on the regulation of eating patterns, particularly the balance between internal cues and external structures. While intuitive eating emphasizes responding to one’s internal hunger signals, studies suggest that these signals are often influenced by external factors such as distractions and learned behaviors. An alternative approach, known as “pinned eating,” proposes structuring meals around fixed times and contexts. In this episode Prof. Jane Ogden, Professor of Health Psychology at the University of Surrey, discusses these concepts and some of the research her group has carried out. Guest Information Professor Jane Ogden is a distinguished health psychologist at the University of Surrey, with over three decades of experience in researching eating behavior, weight management, and women’s health. She earned her PhD from the Institute of Psychiatry in London in 1990 and has since contributed extensively to the field through her research and publications. Throughout her career, Professor Ogden has authored several influential books, including “Health Psychology: A Textbook,” now in its seventh edition, and “Thinking Critically about Research.” Her work is widely recognized, leading to her receiving an honorary Doctor of Science from the University of Buckingham in 2022. Timestamps [02:01][02:41][10:33][13:58][16:46][21:30][26:34][29:10][33:25][35:29][44:28][47:23] Links: Sigma Nutrition PremiumSigma email newsletterSigma Nutrition websiteApplied Nutrition LiteracyOgden et al., 2020 – The impact of intuitive eating v. pinned eating on behavioural markers: a preliminary investigation

Sleep is one of the most critical yet often overlooked components of health, performance, and overall well-being. Poor sleep quality or insufficient sleep can disrupt circadian rhythms, impair glucose metabolism, and alter hunger signals, leading to increased food intake, reduced insulin sensitivity, and other undesirable outcomes. In this episode, we bring together expert discussions from some of the leading researchers in sleep science, to explore what defines high-quality sleep, the mechanisms behind sleep regulation, and the factors that influence sleep-wake cycles, from light exposure to psychological stress. Timestamps Note: Full episode only available on Sigma Nutrition Premium. [02:14][05:32][07:50][12:46][19:06][24:47][34:30][47:10][52:44][58:27][01:06:26] Related Resources Sigma email newsletterSigma Nutrition PremiumApplied Nutrition Literacy38: Dan Pardi, PhD316: Michael Grandner, PhD209: Amy Bender, PhD433: Greg Potter, PhD328: Meeta Singh, MD536: Ian Dunican, PhD61: Kirk Parsley, MD

There is research suggesting that industrialization has significantly altered the composition of our gut microbiota, with certain microbial species now absent in many industrialized populations. Given the known associations between gut microbiome diversity and health, researchers have begun investigating whether restoring lost microbial species and adopting dietary patterns similar to those of non-industrialized populations could lead to measurable health benefits. In a newly-published study, the investigators aimed to explore whether L. reuteri could be successfully reintroduced into the microbiome through the “Restore Diet” and whether such a shift would result in improvements in key cardiometabolic and inflammatory markers. One of the authors, Dr. Anissa Armet, is on the podcast to discuss this area and both the potential and limitations of microbiome restoration efforts. Timestamps [03:48][08:45][11:44][21:03][43:23][47:46][01:04:04] Links Sigma email newsletterSigma Nutrition PremiumApplied Nutrition LiteracyThe NiMe Diet: Scientific Principles and RecipesCardiometabolic benefits of a non-industrialized-type diet are linked to gut microbiome modulationHigh Protein Cookbook for Muscle Health During Cancer Treatment

Every five years, the U.S. Dietary Guidelines are updated based on the latest scientific evidence to help shape national nutrition recommendations. A panel of experts was assembled to review the existing research, evaluate new findings, and provide recommendations that will inform the next edition of the guidelines. One of the committee members involved in this process is Professor Christopher Gardner, a leading nutrition scientist at Stanford University, who joins us to share key insights from the committee’s work. In this discussion, Professor Gardner provides an inside look into how the committee evaluated dietary patterns, the role of plant-based proteins, and the ongoing debate surrounding ultra-processed foods. He explains the rigorous process of reviewing scientific literature, the challenges in translating research into policy, and the critical role of health equity in shaping the recommendations. By exploring these themes, this episode aims to provide clarity on the scientific foundation behind the upcoming dietary guidelines. Whether you’re a nutrition professional, researcher, or someone interested in how dietary recommendations are formed, this conversation sheds light on the key discussions shaping the future of nutrition policy. Timestamps [03:38][07:18][12:10][25:41][33:39][36:04][41:05][47:52][58:24] Related Resources Applied Nutrition LiteracySigma Nutrition PremiumSigma email newsletterScientific Report of the 2025 Dietary Guidelines Advisory CommitteeEpisode 223

Understanding the complexities of diet-disease relationships requires a nuanced approach to nutritional science. Unlike other scientific disciplines, nutrition research often grapples with the inherent challenges of studying dietary patterns and nutrient intakes in free-living populations over long periods. The cumulative effects of dietary exposures, combined with the necessity to control for confounding factors such as total energy intake and population-specific dietary habits, highlight the need for rigorous study designs and careful interpretation of findings. Despite their utility, these methods are often misunderstood or misrepresented in public discourse. Addressing these misunderstandings requires a clear communication of key principles underpinning nutritional science, including the role of cumulative exposure, the importance of contextualizing absolute and relative risks, and the necessity of evaluating the long-term effects of dietary patterns. This episode aims to provide a comprehensive overview of these essential ideas, equipping readers with the tools to critically appraise the evidence and engage meaningfully with the ongoing conversation around nutrition research. Timestamps [03:26][06:01][19:39][26:30][34:34][39:29][41:58][43:55][57:16] Related Resources Applied Nutrition LiteracySigma email newsletterSigma Nutrition Premium531: Correlation, Causation & Cliché478: Exposures in Nutrition – Why They’re Crucial to Understand511: Null By Design – When “No Effect” Doesn’t Mean No Effect378: Nutritional Epidemiology472: Compared To What? – Understanding Food Substitution Analysis & Adjustment Models

This episode focuses on the intersection of nutrition, lifestyle, and women’s health, with a particular emphasis on managing complex conditions such as PCOS, endometriosis, and premenstrual dysphoric disorder (PMDD). Registered dietitian Marjorie Nolan Cohn shares insights from over two decades of clinical practice, highlighting the importance of addressing foundational health behaviors—such as adequate sleep, hydration, and nutrient-dense dietary patterns—before introducing targeted interventions like supplementation. Marjorie explores the nuanced relationship between body weight, metabolic health, and fertility, while addressing misconceptions around weight loss as a primary health goal. The episode examines the role of long-term, individualized care in improving symptoms and outcomes for women experiencing significant menstrual-related challenges. Practical considerations for practitioners, including strategies to build trust, identify key barriers, and provide holistic support, are outlined alongside the importance of interdisciplinary collaboration to improve care quality. Marjorie Nolan Cohn is a registered dietitian with a Masters Degree in Food and Nutrition Science from the Indiana University of Pennsylvania. She is the Clinical Director of Berry Street, a company providing virtual in-network nutritional counseling to people across the US. Timestamps [04:32][08:39][13:40][16:28][19:03][23:28][39:01] Related Resources Sigma email newsletterSigma Nutrition PremiumApplied Nutrition LiteracyBerry Street

Over the past couple of decades, renowned researcher Dr. Marie-Pierre St-Onge has uncovered fascinating links between how we sleep and what we eat, revealing how these two lifestyle factors influence energy balance, cardiovascular health, and metabolic function. In this episode we’ll explore Dr. St-Onge’s findings on sleep regularity and its association with reduced mortality risk, providing actionable insights for optimizing your lifestyle. With a focus on combining rigorous methodologies and controlled dietary interventions, her research sheds light on the complex mechanisms connecting sleep, diet, and metabolic health. Timestamps: [03:39][07:03][10:20][15:44][23:40][37:33] Links: Sigma email newsletterSigma Nutrition PremiumApplied Nutrition LiteracyHow Sleep & Nutrition Interact – Alan Flanagan, PhDepisode page

Multivitamin and multimineral supplements have long been a topic of both scientific inquiry and public debate. While they are often marketed as convenient solutions for achieving nutritional adequacy, their true value remains contentious. Are these supplements essential insurance policies against nutrient deficiencies, or are they merely expensive placebos? Importantly, how should we weigh their potential benefits against the lack of robust evidence for long-term health outcomes such as reduced mortality or chronic disease risk? These questions demand a nuanced exploration, grounded in the context of specific populations and individual needs. Ultimately, the role of multivitamin supplements cannot be assessed in isolation but must be viewed through the lens of context and specificity. How do we balance the biological plausibility of benefits against the variability of individual diets, the presence of fortification policies, and the challenges of achieving dietary adequacy in certain life stages? These considerations invite a more thoughtful and less binary discussion about whether, when, and for whom multivitamins are a worthwhile addition to the diet. Timestamps [00:22][00:53][04:04][07:10][23:39][41:43][50:18] Related Resources Sigma email newsletterSigma Nutrition PremiumApplied Nutrition LiteracyMultivitamin Madness: There’s More to Life than DeathMacPherson et al., 2013 meta-analysis of randomized controlled trialsJenkins et al., 2021 meta-analysisCOSMOS trial – Vyas et al., 2024 analysis of three substudiesLoftfield et al., 2024 – Multivitamin Use and Mortality in 3 CohortsBlumberg et al., 2017 nutritional adequacy paper

While the fitness industry often emphasizes short-term goals such as rapid weight loss or aesthetic improvements, a growing body of evidence highlights the importance of fostering long-term habits for health and wellbeing. Understanding how psychological frameworks intersect with physical health behaviors is key to empowering clients and overcoming the challenges posed by rigid dieting practices or the influence of social media culture. Bodybuilding and fitness culture serve as both a microcosm and an extreme example of the challenges faced in this space. As the boundaries between physique sports and general fitness blur, many enthusiasts adopt unsustainable habits without fully understanding their long-term implications. How can fitness professionals effectively guide clients toward intrinsic motivations and healthier relationships with food and exercise while balancing the reality of external pressures? In this episode, Laurin Conlin offers her insights based on her coaching experiences, as well as formal training in exercise sciences and mental health counselling. Dr. Eric Trexler co-hosts the episode with Danny Lennon. Timestamps [05:41][09:58][13:15][22:01][34:52][37:19][41:23][52:13][62:13] Related Resources episode pageSigma email newsletterSigma Nutrition PremiumApplied Nutrition LiteracySports Nutrition Associationresearch reviews from Dr. Eric Trexler

Eating disorders and disordered eating behaviors represent complex, multifaceted challenges that affect individuals across all demographics, yet they remain widely misunderstood and under-recognized. These issues often extend beyond the stereotypical images associated with eating disorders, touching everything from rigid “clean eating” obsessions to the normalized extremes of diet culture. At the heart of these behaviors lies a disruption in one’s relationship with food, often fueled by societal pressures, unrealistic body ideals, and a pervasive focus on aesthetics over health. While these challenges are tenacious, recovery and improved relationships with food are possible with the right interventions, resources, and awareness. In this episode, Danny talks to Dr. Jillian Lampert, a registered dietitian with a PhD in public health nutrition, with a speciality in eating disorders and disordered eating. Timestamps [02:56][05:15][14:41][19:41][22:50][43:50] Related Resources Sigma email newsletterSigma Nutrition PremiumApplied Nutrition Literacyepisode pageThe Emily ProgramEating Disorders Coalition for Research, Policy, & Action (EDC)National Alliance for Eating Disorders

In a world flooded with information, discerning fact from fiction in fitness and nutrition has never been more challenging—or more important. The rise of social media and democratized science has given everyone a platform, but not all voices are equal. How do we navigate a landscape where influencers with massive followings wield the same credibility as seasoned experts? Why do pseudoscientific trends gain traction while nuanced evidence gets lost in the noise? In this episode we also dive into the evolution of coaching, examining how the obsession with quantifiable metrics has shifted the focus away from human connection. How can professionals balance the drive for scalable success with the need for meaningful client relationships? And what lessons can we draw from decades of shifts in the fitness industry to stay resilient amid rapid societal and technological changes? Timestamps 04:3306:0810:3217:3525:4943:0744:2447:2749:0754:4601:03:5901:08:34 Related Resources episode pageSigma email newsletterSigma Nutrition PremiumApplied Nutrition LiteracyMASS Research Review

IGF-1 (Insulin-Like Growth Factor 1) has emerged as a hot topic in health and nutrition discussions, often linked to longevity, cancer risk, and metabolic health. On one hand, IGF-1 is essential for growth, repair, and metabolic regulation; on the other, it is sometimes associated with disease processes, including cancer and cognitive decline. For those intrigued by the intersection of nutrition, biomarkers, and disease prevention, IGF-1 offers an opportunity to explore how science grapples with these complexities. Claims about manipulating IGF-1 through dietary changes — whether by reducing protein or adopting fasting protocols — are common. But does the evidence support these claims? If you’re curious about IGF-1 and the relationships between diet, disease, and healthy aging, in this Premium-exclusive episode Danny and Alan discuss this fascinating topic. To listen to the full episode, subscribe to Sigma Nutrition Premium Timestamps [02:21][09:15][11:54][25:51][43:38] Related Resources Sigma email newsletterSigma Nutrition PremiumApplied Nutrition LiteracyMurphy et al., 2020 – observational and Mendelian randomization analyses