Sigma Nutrition Radio

Danny Lennon

The podcast for lovers of nutrition science! Listen to detailed discussions with researchers and leading experts about the science of nutrition, dietetics and health. read less
健康・フィットネス健康・フィットネス

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What are Dietary Reference Intakes? Origins, Development & Use (SNP 26)
2日前
What are Dietary Reference Intakes? Origins, Development & Use (SNP 26)
Acronyms: RDA = Recommended Dietary Allowance AI = Adequate Intake UL = Tolerable Upper Intake Level EAR = Estimated Average Requirement About This Episode: Dietary Reference Intakes (DRIs) are a set of nutrient reference values, developed in the US, that are used to assess and plan the nutrient intake of healthy individuals. They provide guidelines for the recommended amounts of various nutrients to maintain health and prevent deficiencies or excesses. Different countries may have their own sets of dietary reference values or guidelines that serve similar purposes but may be named differently. DRIs include several different reference values: Recommended Dietary Allowance (RDA)Adequate Intake (AI)Tolerable Upper Intake Level (UL)Estimated Average Requirement (EAR) DRIs play a crucial role in nutrition and public health for several reasons. DRIs provide specific recommendations for the intake of essential nutrients, helping individuals and health professionals understand the amounts needed to maintain good health. By establishing RDAs and ULs, DRIs help prevent nutrient deficiencies and toxicity, ensuring that individuals consume an appropriate range of nutrients. Governments and health organizations use DRIs to develop public health policies, nutrition programs, and guidelines for food fortification to improve the overall health of populations. For nutrition professionals, understanding DRIs is essential as it forms the basis for assessing and planning dietary recommendations for individuals and populations.   Note: This episode is one of our Premium-exclusive episodes. To listen to the full episode, you’ll need to be a Premium subscriber and access the episode on the private Premium feed. Otherwise, you can hear a preview of the episode above or on the public feed of the podcast.   Links: Go to episode pageSubscribe to Sigma Nutrition Premium
#512: Alzheimer’s Disease – Drs. Ayesha & Dean Sherzai
13-02-2024
#512: Alzheimer’s Disease – Drs. Ayesha & Dean Sherzai
Links: Go to episode page (with episode resources)Subscribe to PREMIUMGet the Sigma email newsletterSee Sigma's recommended resources About This Episode: Alzheimer’s disease has a profound impact on individuals, families, and societies worldwide. As a progressive neurodegenerative disease, it not only robs individuals of their cognitive abilities but also places an immense emotional and economic burden on caregivers. Mechanistically, the causes of Alzheimer’s are incredibly complex and not fully understood. And in terms of treatment, the landscape appears challenging. Drug discovery efforts for dementias, including Alzheimer’s, have faced setbacks, leaving a void in effective treatments. Consequently, attention has shifted toward preventive strategies, including dietary patterns. From a prevention standpoint, both genetics and lifestyle should be considered. Which throws up many interesting questions… To what extent do genetic factors contribute to Alzheimer’s risk compared to lifestyle choices, and how does this interaction influence disease development? What role does lifestyle play in Alzheimer’s risk, and is there evidence supporting the influence of specific nutrients on cognitive health? How do diet patterns impact Alzheimer’s risk? Are there discernible risk differences associated with specific dietary choices, and how do these interact with genetic factors, such as the ApoE genotype? In this episode, Drs. Ayesha Sherzai and Dean Sherzai are on the podcast to answer these questions and discuss this topic in more depth. About The Guests: Dr. Ayesha Sherzai is a neurologist and co-director of the Alzheimer’s Prevention Program at Loma Linda University, where she leads the Lifestyle Program for the Prevention of Neurological Diseases. She completed a dual training in Preventative Medicine and Neurology at Loma Linda University, and a fellowship in Vascular Neurology and Epidemiology at Columbia University. She is also a trained plant-based culinary artist. Dr. Dean Sherzai is co-director of the Alzheimer’s Prevention Program at Loma Linda University. Dean trained in Neurology at Georgetown University School of Medicine, and completed fellowships in neurodegenerative diseases and dementia at the National Institutes of Health and UC San Diego. He also holds a PhD in Healthcare Leadership with a focus on community health from Andrews University.
#511: Null By Design – When “No Effect” Doesn’t Mean No Effect
06-02-2024
#511: Null By Design – When “No Effect” Doesn’t Mean No Effect
Links: Go to episode page (with episode resources)Subscribe to PremiumReceive the Sigma Nutrition newsletter About This Episode: Numerous nutrition studies present findings of “no effect,” but interpreting such results requires caution. A null finding, indicating an absence of impact from a nutrient or exposure, may not necessarily suggest a lack of effect overall. Instead, it could stem from issues related to the study’s design, the nature of the exposure, or participant characteristics. We’ve often referred to such studies as being “null by design”. These studies, often termed “null by design,” may yield inconclusive results due to insufficient contrast in exposure levels to reveal a significant effect size. Additionally, participants’ baseline nutrient status or intake can contribute to false negatives. For instance, if a study provides a nutrient to individuals already replete in that nutrient, it may lead to an erroneous conclusion. This phenomenon can be understood by considering the bell curve of activity for a nutrient. Moreover, a lack of methodological rigor can generate ‘false negatives.’ If previous literature indicates associations between high intake of a specific food or nutrient and certain outcomes, a study comparing levels of intake well below that threshold may produce a misleading result. Some challenges arise from an overly reductionist perspective. In disease processes, reductionism simplifies diseases to a single primary source at the cellular and molecular level. This perspective assumes that if a nutrient shows a relationship with health or disease outcomes at a population level, its biological activity should manifest in isolation. However, applying such assumptions to exposures like diet may not be tenable. In this discussion, we delve into the concept of “null by design” and present three specific studies with null findings, emphasizing the need for careful interpretation.
#510: Social Comparison: Evidence on its Impacts & What We Can Do – Shannon Beer
30-01-2024
#510: Social Comparison: Evidence on its Impacts & What We Can Do – Shannon Beer
Links: Go to episode page (with supporting links/resources)Subscribe to PREMIUMLearn more about Sigma NutritionCrushing Comparisons course About This Episode: Social comparison theory, developed by psychologist Leon Festinger in the 1950s, posits that individuals determine their own social and personal worth based on how they stack up against others. This theory suggests that people engage in social comparisons to evaluate their abilities, opinions, and attributes, often choosing relevant others for comparison. In the realm of body image and self-perception, social comparison theory becomes particularly pertinent, as individuals tend to assess their own bodies in relation to societal ideals and the bodies of others. This process of comparison can have profound implications for body dissatisfaction and the development of disordered eating patterns. This raises thought-provoking questions about the impact of social comparison theory on body image and eating behaviors. In this episode, Shannon Beer explores these questions and offers valuable insights into the complex interplay between societal influences, individual perceptions, and the development of body dissatisfaction and disordered eating. About The Guest: Shannon Beer is a registered nutritionist, health and confidence coach and certified Compassionate Mind Training facilitator. Shannon works with people aiming to improve their health through facilitating lasting behaviour change in their approach to diet, exercise and body image. She has developed a coaching framework that applies motivational interviewing, cognitive behavioral coaching, and acceptance and commitment therapy-aligned processes in a client-centered alliance toward their own values-based goals.
#508: Why Athletes Can Achieve High Performance During an Energy Deficit – Jose Areta, PhD
09-01-2024
#508: Why Athletes Can Achieve High Performance During an Energy Deficit – Jose Areta, PhD
Links: Go to episode page (with study links)Subscribe to PremiumSigma's recommended resourcesGet our weekly email newsletter About This Episode: Insufficient energy availability can significantly disrupt normal hormonal, metabolic, and physiological processes, prompting the body to initiate a coordinated response aimed at conserving energy. While commonly viewed as beneficial for weight loss and managing cardiometabolic conditions in the current obesity epidemic, chronic energy deficiency in the context of modern sports and exercise nutrition is linked to adverse health outcomes and diminished athletic performance. Nevertheless, the evidence regarding the negative impact of energy deficit on physical capacity and sports performance is not entirely clear. Although severe energy deficiency can impair physical capacity, it’s noteworthy that humans can enhance aerobic fitness and strength even in the presence of significant energy deficits. Strikingly, many elite athletes compete at the highest levels despite displaying evident signs of energy deficiency. This raises intriguing questions about how the human body adapts to energy deficits, challenging conventional views on the relationship between energy availability and athletic prowess. To discuss some potential reasons for this ability to maintain peak physical performance while suppressing energetically demanding physiological traits, researcher Dr. Jose Areta of LJMU is on the podcast to discuss his work in this area. About The Guest: Dr. José Areta currently works as a lecturer in Sports Nutrition and Metabolism at the School of Sport and Exercise Sciences at LJMU. José’s primary interest is in the area of training-nutrient interactions in humans. In other words, he investigates how to manipulate ingestion of carbohydrates, fat and protein around training to optimise physical performance and health. The outputs of his research have not only expanded the knowledge of the field but had significant impact and influence on determining current dietary recommendations and practices world-wide. His work has provided novel insights in relation to the amount, timing, quantity and distribution of carbohydrates, fat and protein and dietary supplements around training. Over the last few years José has been developing his research in the area of the endocrinological, metabolic and physiological effects of energy restriction, in which he is currently growing his research team and capability.
#506 Sports Nutrition: Translating Research to Practice – Andreas Kasper, PhD
19-12-2023
#506 Sports Nutrition: Translating Research to Practice – Andreas Kasper, PhD
Links: Go to episode page (with links to studies)Subscribe to PREMIUMJoin Sigma's email newsletterSigma's Recommended Resources About This Episode: Navigating the intricate landscape of sports nutrition is one that constantly evolves and challenges our understanding of optimal athletic performance. The delicate balance between advancing research and ensuring practical applicability in the high-speed realm of sports nutrition is a perpetual struggle. Decision-making is difficult, especially when faced with a scarcity of evidence. It’s a challenge that resonates with many professionals in the field, prompting reflections on the art of making informed choices in the absence of conclusive data. In this episode, Dr. Andy Kasper, PhD shares his experiences and research in the field of elite sports nutrition. Dr. Kasper, a PhD in Nutrition and Physiology from Liverpool John Moores University, currently spearheads the Performance Nutrition department at Newcastle United Football Club. His illustrious career spans across elite football, rugby union, and rugby league, with notable stints at clubs like Chelsea, Fulham, Derby, England Rugby Union, Sale Sharks, London Irish, and Wasps, to name a few. A prolific contributor to academic publications, Dr. Kasper’s insights have not only shaped the scientific landscape but have also directly influenced the nutritional strategies employed by top-tier athletes. Our conversation will traverse a myriad of topics, from the transformative changes witnessed in sports nutrition to invaluable advice for practitioners navigating this intricate terrain. We’ll also delve into the delicate balance between advancing research and ensuring practical applicability in the fast-paced world of sports nutrition. Dr. Kasper will shed light on the Paper-to-Podium Matrix, a concept that bridges the gap between scientific discoveries and their real-world implementation in the pursuit of athletic excellence.
#501: Sex-based Training Recommendations: Evidence-based or Hype? – David Nolan, PhD
07-11-2023
#501: Sex-based Training Recommendations: Evidence-based or Hype? – David Nolan, PhD
Links: Go to episode page (with study links)Subscribe to PREMIUMReceive emails from Sigma NutritionSigma's Recommended Resources About This Episode: The field of research exploring sex differences in exercise response has yielded intriguing findings, shedding light on the complex interplay between biology, physiology, and training adaptations. One of the fundamental areas of investigation pertains to sex disparities in strength, power, and hypertrophy. Historically, it’s been well-established that males, on average, exhibit greater absolute strength and muscle mass compared to females. This discrepancy often traces its roots back to inherent physiological distinctions. However, when it comes to responses to strength and hypertrophy training, the narrative becomes more nuanced. Research indicates that, when individuals of both sexes follow matched resistance training protocols, the relative improvements in strength and hypertrophy are quite similar. So, do women need to be trained differently than men? The answer, it appears, is not as much as one might assume. The principles of progressive overload, specificity, and other training fundamentals remain constant. While individualization is key, the idea of drastically distinct training guidelines based on sex lacks compelling empirical support. The guest in this episode, Dr. David Nolan, is a researcher in the area of sex differences in exercise response, and has looked at the influences of menstrual cycle and hormonal contraceptive use in female athletes on their performance. In this episode, we discuss the research to date, and what this means practically for athletes and coaches.
#498: The PROPEL Trial & Weight Loss Interventions in Primary Care – John Apolzan, PhD
10-10-2023
#498: The PROPEL Trial & Weight Loss Interventions in Primary Care – John Apolzan, PhD
Links: Subscribe to PREMIUMGo to episode page (with linked studies)Receive the weekly Sigma email newsletterRecommended resources About this Episode: The PROPEL (Promoting Successful Weight Loss in Primary Care in Louisiana) trial was a cluster-randomized weight loss trial, specifically tailored to address the pressing health concerns of an underserved population in Louisiana, where obesity rates have reached alarming levels. The core of the intervention comprises a pragmatic, high-intensity lifestyle-based obesity treatment program, thoughtfully designed to be integrated within primary care settings. Over a 24-month duration, this multi-component weight loss program is delivered by skilled health coaches who are embedded in primary care clinics, with the aim of instigating substantial and sustainable weight loss outcomes. In this study, 803 participants were enrolled, of whom 67% identified as Black and 84% as female, thereby ensuring a diverse representation. The research design randomized 18 clinics, allocating them equally into two groups: usual care and an Intensive Lifestyle Intervention (ILI). The usual care group continued to receive their customary primary care, serving as the benchmark against which the ILI’s efficacy will be measured. In this episode we have the opportunity to delve deeper into the intricacies of the PROPEL trial and gain insights from one of its lead researchers, Dr. John Apolzan of the Pennington Biomedical Research Center.