515 episodes

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.

Sigma Nutrition Radio Danny Lennon

    • Health & Fitness
    • 4.9 • 119 Ratings

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.

    #515: Does Dietary Fat Quality Causally Affect Atherosclerosis Risk? – Jacob Christensen, PhD

    #515: Does Dietary Fat Quality Causally Affect Atherosclerosis Risk? – Jacob Christensen, PhD

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    The question of whether dietary fat quality causally affects atherosclerosis risk has been a subject of extensive research and debate within the field of nutrition and cardiovascular health.
    Atherosclerosis, the build-up of plaque in arteries, is a key factor in the development of cardiovascular diseases, including heart attacks and strokes. Traditionally, dietary fat has been implicated in contributing to atherosclerosis, with a focus on reducing overall fat intake. However, recent studies have shifted the focus towards the quality of dietary fats rather than their quantity.
    Not all fats are created equal, and researchers are now paying closer attention to the types of fats consumed in the diet. Saturated fats, commonly found in animal products and some tropical oils, have long been associated with increased cholesterol levels and atherosclerosis. On the other hand, unsaturated fats, including monounsaturated and polyunsaturated fats found in olive oil, nuts, and fish, have been linked to potential cardiovascular benefits. Research suggests that replacing saturated fats with unsaturated fats may have a positive impact on blood lipid profiles and reduce the risk of atherosclerosis.
    Additionally, genetic factors and individual responses to different fats may play a role in how dietary fats impact atherosclerosis risk.
    In this episode, Dr. Jacob Christensen discusses the research in this area and some conclusions about whether we can say dietary fat quality causally increases atherosclerotic cardiovascular disease (ASCVD) risk. This includes looking at the relationship between low-density lipoprotein (LDL) particles and ASCVD, the link between dietary fat quality and LDL particles, and then finally the relationship between dietary fat quality, LDL particles, and ASCVD.
    About the Guest:
    Jacob J. Christensen is a clinical dietitian and researcher at University of Oslo. His research interests include cardiovascular diseases, lipid metabolism, nutrition, genomics and data science.

    • 1 hr 14 min
    #514: Plant-derived Fatty Acids – Ella Baker, PhD

    #514: Plant-derived Fatty Acids – Ella Baker, PhD

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    There is a lot of interesting research going on related to plant-derived fatty acids, owing to their potential to help improve health and provide sustainable alternatives to other sources of healthy-promoting fatty acids.
    In addition to work looking at the long-investigated alpha-linolenic acid (ALA), some research is now starting to look at more novel fatty acids like stearidonic acid (SDA), and pinolenic acid (PLA), each presenting unique structures and potential benefits within various plant sources. One intriguing focal point is Ahiflower oil, a distinctive source that harbors both ALA and SDA.
    In this episode, Dr. Ella Baker of the University of Southampton discusses some of the science behind plant-derived fatty acids, offering a deeper understanding of their distinctive qualities, conversion pathways, and the captivating interplay between omega-3 and omega-6 fatty acids.
    Dr. Baker’s research to date focuses on the metabolism, functionality, and underlying mechanisms of action of plant-derived fatty acids. Her interests include novel plant-derived fatty acids and exploring the effects on membrane structure and function.

    • 33 min
    #513: Kidney Stones & Diet – Deepa Kariyawasam, RD

    #513: Kidney Stones & Diet – Deepa Kariyawasam, RD

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    Kidney stones, crystalline deposits formed within the kidneys, present a formidable challenge to individuals grappling with their debilitating effects. These mineral accumulations, though small in size, can inflict significant pain and discomfort as they navigate through the urinary tract.
    Understanding the nuances of dietary management and treatment for kidney stones is crucial for those seeking relief and prevention.
    What makes this subject particularly intricate is the diversity of kidney stones – a mosaic of compositions ranging from calcium oxalate to uric acid. Recognizing that not all kidney stones are created equal, dietitians and renal specialists tailor their recommendations to address the specific nature of the stones, unveiling a spectrum of dietary strategies that aim to alleviate symptoms and impede the recurrence of these insidious formations.
    In this episode, specialist renal dietitian Deepa Kariyawasam brings us through the main causes of kidney stones, the potential dietary interventions, and how to guide individuals toward personalized pathways for kidney stone management.

    • 31 min
    What are Dietary Reference Intakes? Origins, Development & Use (SNP 26)

    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.
     
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    • 10 min
    #512: Alzheimer’s Disease – Drs. Ayesha & Dean Sherzai

    #512: Alzheimer’s Disease – Drs. Ayesha & Dean Sherzai

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    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.

    • 1 hr 10 min
    #511: Null By Design – When “No Effect” Doesn’t Mean No Effect

    #511: Null By Design – When “No Effect” Doesn’t Mean No Effect

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    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.

    • 54 min

Customer Reviews

4.9 out of 5
119 Ratings

119 Ratings

Ni Riain Photography ,

highly informative podcasts

Well done Danny on highly informative podcasts
Your podcast #331 on diabetes with Prof Roy Taylor was SO informative

Radamist0 ,

The illusion of knowledge

Dubious science. Weak epidemiology. Same old mainstream dietary guidelines. Sad!

Realshifty ,

Education

If my mind had the mental capacity to understand what Danny has probably forgotten I’d be happy. It’s amazing the amount of free knowledge and science based education you can learn from this. Top marks

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