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

• [02:21] IGF-1 and Diet: Examining the Relationship
• [09:15] IGF-1 as a Biomarker: Challenges with Sensitivity and Specificity
• [11:54] IGF-1 and Cancer Risk: Insights and Complexities
• [25:51] IGF-1 in Aging: Cognitive Function and Longevity Considerations
• [43:38] Key Takeaways: IGF-1, Diet, and Practical Advice

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• Murphy et al., 2020 – observational and Mendelian randomization analyses

Fitness pursuits can bring various benefits. However, within the modern fitness industry there is a complex interplay of body image ideals, societal pressures, and disordered eating behaviors.

Research continues to illuminate how certain practices and messaging within the industry—such as the overvaluation of leanness or the impact of social media personas—can fuel body dissatisfaction and disordered eating.

For fitness coaches and enthusiasts alike, this raises important questions:

• What defines success in fitness?
• How can individuals engage in training and nutrition without falling into harmful traps?
• And how can professionals align their practices with values that support long-term well-being for themselves and their clients?

In this episode, Michelle Carroll, a PhD researcher in clinical psychology, explores these questions in depth. Drawing on her academic work and personal experiences, she discusses the implications of fitness industry norms, the challenges of online coaching, and practical steps for fostering healthier relationships with food and body image.

• [01:15] Defining disordered eating and body image
• [03:47] Motivations behind this research
• [05:37] Impact of the fitness industry on body image
• [08:29] Challenges and misconceptions about body image
• [14:26] Physical capital and pressures on fitness professionals
• [18:20] Consequences of harmful fitness industry messaging
• [35:04] Positive changes and gaps for future research
• [40:16] Practical advice for professionals and individuals

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• Michelle’s website
• Michelle on Instagram: @michellecarroll1
• Disordered Eating Informed – Course

Healthspan, healthy ageing, and chronic disease are pivotal topics in today’s health discourse, emphasizing not just the length of life but the quality of those additional years. Focusing on healthspan means striving for a longer period of life free from disease and disability, which is increasingly important as global life expectancies rise. Healthy ageing involves adopting lifestyle habits that promote physical, mental, and social well-being throughout the lifespan, thereby reducing the risk of chronic diseases such as heart disease, diabetes, and neurodegenerative disorders.

Addressing chronic diseases risk requires a proactive approach centered on prevention and early intervention. By prioritizing healthspan and healthy ageing, individuals can significantly decrease the likelihood of developing chronic illnesses, leading to improved quality of life and reduced healthcare costs.

Sigma Nutrition Radio has consistently addressed these critical themes across many episodes. In this episode, we go back over some of the best episodes of 2024 in this area, including discussions on Alzheimer’s, cholesterol-lowering medications, impact of exercise, and the debate about red meat.

• (03.12) Alzheimer’s: Genetic susceptibility vs. modifiable factors
• (14.59) Heart disease: the “risk factor, disease, event” framework
• (22.10) The strength of evidence we have for the impact of exercise on mortality and longevity
• (28.23) Why high blood pressure is so problematic
• (37.23) Where do we see risk for unprocessed red meat?
• (48.34) The evolution over the years of dietary fat research
• (53.20) Claims about the proposed risks of consuming seed oils
• (56.16) How does fat quality impact heart disease risk?
• (60.35) History of Portfolio Diet research for reducing LDL-C

• 512: Alzheimer’s Disease – Drs. Ayesha & Dean Sherzai
• 525: Cholesterol-Lowering Medication – Dr. Paddy Barrett
• 524: Strength & Fitness Levels for Reducing Chronic Disease Risk & Promoting Health Ageing – Jordan Feigenbaum, MD
• 527: How to Prevent & Treat Hypertension – Dr. Mohammed Alo, DO
• 528: Is Unprocessed Red Meat Problematic for Our Health?
• 532: Dietary Fat: Evidence vs. Misinformation – Alice Lichtenstein, DSc
• 515: Does Dietary Fat Quality Causally Affect Atherosclerosis Risk? – Jacob Christensen, PhD
• 507: Does a Higher Portfolio Diet Score Reduce Heart Disease? – Andrea Glenn, PhD

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Navigating the complex and often underemphasized requirements of professional standards, legal considerations, and insurance can be challenging for sports nutrition practitioners and personal trainers.

Many professionals, especially early in their careers, may overlook or minimize these responsibilities, focusing primarily on the practical and enjoyable aspects of helping clients achieve their goals. However, staying informed and adhering to these standards is not only essential for providing ethical, competent service but is also crucial for minimizing liability.

Ignoring or misinterpreting scope-of-practice guidelines and insurance limitations can leave well-meaning professionals exposed to significant legal and financial risks that could have lasting consequences on their careers.

In this episode, Alex Thomas joins Danny Lennon and Eric Helms to discuss the essential, if often overlooked, responsibilities that define a successful and resilient career in sports nutrition.

Together, they explore best practices for insurance, scope of practice, and the importance of aligning with professional organizations that provide educational and legal support.

• [01:57] The SNA Introduction
• [03:31] The importance of professional standards
• [09:58] Legal consequences and real-world examples
• [15:23] Insurance and scope of practice
• [23:27] Navigating the gray areas in nutrition practice
• [30:51] Legal risks in nutrition advice
• [34:50] Ethical dilemmas and referral networks
• [36:53] Emerging trends and risks in nutrition services
• [48:49] Becoming a competent sports nutrition professional

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• Sports Nutrition Association

Carbohydrate metabolism and metabolic health have become central themes in the science of nutrition, with questions about fuel utilization, the impact of different diets, and the potential of ketone supplements driving new research.

As researchers continue to uncover how the body adapts to various energy sources, there are emerging insights into how glucose tolerance, glycogen utilization, and even ketogenic diets influence not only physical performance but also long-term health outcomes.

Understanding how the body responds to different energy sources, particularly in relation to carbohydrate restriction, brings crucial context to popular nutrition strategies and the potential benefits—or trade-offs—they offer.

In this episode, Professor Javier Gonzalez joins to discuss these topics in detail, exploring the latest findings on how dietary choices affect athletic performance, chronic disease risk, and the mechanisms underlying metabolic adaptations.

You will gain insight into topics like reactive hypoglycemia, carbohydrate oxidation, and why individualized responses to diet matter.

• [01:36] Understanding carbohydrate metabolism
• [06:33] The role of glucose in metabolic health
• [09:59] Exercise and glucose dynamics
• [17:35] Carbohydrate intake and athletic performance
• [25:03] Diet impact on exercise and metabolism
• [30:44] Pre-workout carbohydrates and reactive hypoglycemia
• [35:31] Recent study: Ketogenic diet vs. sugar restriction
• [41:09] Future research directions in metabolic health
• [45:07] Ketone esters and their role in exercise performance
• [49:22] Carbohydrate metabolism and common misconceptions

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• Paper: Ketogenic diet but not free-sugar restriction alters glucose tolerance, lipid metabolism, peripheral tissue phenotype, and gut microbiome: RCT

Appetite and satiety are fundamental concepts shaping how we eat, why we feel hunger, and what keeps us satisfied after meals. From the biological signals sent by our gut to the psychological influences of food cues, understanding these processes can provide valuable insights into how we manage our food intake.

In this episode, we delve into the interplay between hormones, food properties, and external factors that regulate appetite and fullness, exploring how these mechanisms work together—or sometimes fail—in modern eating environments.

We will examine fascinating topics such as the satiety cascade, sensory-specific satiety, and the impact of nutrient composition on hunger regulation. This episode also highlights how individual differences, such as satiety phenotypes, shape eating behavior, offering a nuanced perspective on the science of satiety.

Whether you’re interested in applying these concepts to your diet or supporting others in managing hunger, this discussion offers practical takeaways grounded in scientific evidence.

To listen to the full episode, subscribe to Sigma Nutrition Premium.

• [02:22] Understanding appetite and satiety
• [07:28] Biological mechanisms behind hunger regulation
• [10:57] Sensory and psychological cues affecting food intake
• [26:54] Nutrient composition and its influence on satiety
• [43:11] Practical strategies for managing hunger

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In the realm of nutrition science, individual differences are more profound and impactful than many realize. For decades, we’ve developed dietary recommendations with a “one-size-fits-all” approach, assuming that most people respond similarly to specific nutrients. But Dr. Martin Kohlmeier, a pioneer in precision nutrition, challenges this very notion.

How might an individual’s genetic makeup alter their need for certain nutrients?

With advances in nutrigenetics, we’re beginning to see how personalized nutrition could bridge long-standing gaps in dietary efficacy. Dr. Kohlmeier’s work highlights fascinating examples, from the APOE4 gene’s influence on cholesterol metabolism to variations in folate metabolism that could affect everything from heart health to birth outcomes.

As Dr. Kohlmeier explains, precision nutrition is not simply about adding genetic testing to a wellness regimen. Instead, it requires rethinking nutrition research from the ground up—ensuring studies capture these individual variations and that public health policy moves beyond broad averages.

With genetic testing now more accessible than ever, could commercial pressures and oversimplified testing derail the science before it even gets going? In this episode, we dive deep into the potential and pitfalls of precision nutrition, exploring the future of personalized dietary advice and the road to truly individualized health.

• [02:33] Introduction of Dr. Martin Kohlmeier and his background
• [05:10] Rethinking assumptions in nutrition science
• [07:42] The role of genetic variations in nutrient responses
• [13:15] Practical examples of genetic impact on nutrition
• [22:55] Misinformation and commercial misuse in nutrigenetics
• [29:48] Case studies: cholesterol sensitivity (APOE4) and folate metabolism (MTHFR)
• [41:03] Public health implications and the need for tailored research
• [49:27] Future directions and the path forward for precision nutrition

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• Kohlmeier, 2023 – One size does not fit all: on the need for categorical stratification in nutrition science, practice and policy

In this episode, we dive deep into the world of ocular nutrition with Professor John Nolan, exploring how specific nutrients can play crucial roles in preserving eye health, improving vision and supporting cognitive function.

With age-related macular degeneration (AMD) affecting millions globally, Professor Nolan sheds light on groundbreaking research showing how certain carotenoids—natural pigments found in plant foods—could impact eye health and perhaps even neurodegenerative conditions like Alzheimer’s disease.

But what are these compounds exactly, and why are they so impactful?

Through in-depth clinical studies, Nolan has identified optimal nutrient formulations that could bridge the gap in conditions as diverse as macular degeneration and cognitive decline. He makes a compelling case for why the timing and quality of these interventions could matter as much as diet itself.

Finally, this episode goes beyond individual health to consider public health implications, particularly the need for better regulation in the supplement industry and enhanced nutritional education for medical practitioners.

• [01:20] Professor Nolan’s academic journey and early inspirations in vision science
• [02:12] Groundbreaking research on age-related macular degeneration (AMD)
• [04:24] How carotenoids contribute to eye health and disease prevention
• [07:27] Expanding from eye research to exploring brain health connections
• [16:23] Overcoming challenges in developing effective nutritional supplements
• [20:57] The role of preventative nutrition in eye and cognitive health
• [27:28] Key findings from major human trials on carotenoids and vision
• [33:37] Evidence linking carotenoids to cognitive health and aging
• [42:53] Practical insights for medical practitioners on using nutrition for eye health

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• Caretenoid supplement mentioned by Prof. Nolan: MacuPrime