Sigma Nutrition Radio

Supplement safety is often discussed in very general terms, but in practice the risks depend heavily on the individual. A supplement that is reasonable for one person may be inappropriate for another based on their medications, health conditions, dose, formulation, or the other products they are already using.
This becomes especially important when supplements interact with medications or underlying medical conditions. Some interactions can change how a drug is absorbed, metabolised, transported, or cleared from the body. Others can amplify or oppose the drug's clinical effect, such as increasing sedation, lowering blood pressure or blood glucose, or affecting bleeding risk.
In this episode, Giulia Guerrini, a GPhC-registered pharmacist and researcher at Examine, talks about how clinicians and practitioners can think more systematically about supplement safety, side effects, contraindications, and drug–supplement interactions.
Timestamps:

[02:39] Interview start
[05:21] Why context matters
[06:38] Timing and formulation
[12:58] Rating interaction risk
[22:39] Berberine benefits and interactions
[27:33] Adaptogens quality concerns
[30:15] Melatonin safety questions
[36:30] Stacking supplements risks
[41:50] Quality control and regulation
[55:35] Key ideas segment (premium-only)
Links:
Free trial of Examine Clinician Edition – For health & nutrition professionals. Includes the Supplement Navigator (safety and interaction checking), plus all other Examine tools (study summaries, supplement database, in-depth guides, etc.)
Free trial of Examine+ – For anyone wanting to make evidence-based decisions about supplements and health. Includes: 100+ study summaries a month. The full supplement database. In-depth guides. ExamineAI. Doesn't include the Supplement Navigator.
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A common idea is that repeated exposure to sweet taste strengthens our preference for sweetness, which then drives greater intake of sweet foods and drinks. This idea is often used in arguments about fruit, low-calorie sweeteners, diet drinks, and the supposed need to "reset" taste preferences by avoiding sweetness altogether.
But does the evidence actually support that causal chain?
In this episode, Prof. Katherine Appleton, Professor of Psychology at Bournemouth University, discusses what is known about sweet taste exposure, sweet preference, and how these concepts are measured in the scientific literature.
Timestamps:
[04:26] Interview starts

[05:51] Does exposure to sweetness lead to greater preference?

[08:36] Sweet liking and other terminiology

[10:50] Phenotypes and measurement

[16:08] Do preferences develop differently in children vs adults ?

[18:54] Liking versus wanting

[23:21] Low calorie sweeteners

[29:41] Sensory specific satiety

[34:23] Practical guidance for clinicians

Links:
Go to episode page (incl. links to studies)
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Electrolytes have become one of the most heavily marketed areas of modern sports nutrition and wellness. What was once a relatively specific tool for certain endurance athletes has increasingly been reframed as an everyday requirement for hydration, energy, focus, productivity, and general health optimisation.
But how much of this messaging is grounded in physiology, and how much is an example of industry taking a real mechanism and extending it far beyond the evidence?
In this episode, we examine why many common use cases are unlikely to require an electrolyte product. Along the way, we explore how wellness marketing, biohacking culture, diet communities, and social media narratives can turn narrow sports nutrition applications into broad claims that many people come to accept as true.
To discuss this topic, Danny is joined by Zoe Rom, a science and environmental journalist,  and Kylee Van Horn, a sports dietitian, to discuss how these claims are shaped by marketing, culture, and the attention economy.
Timestamps:
[04:00] Interview start

[07:03] Wellness industry rebrand

[09:16] Electrolytes 101

[16:02] Fear marketing and vague symptoms

[22:50] When athletes actually need them

[28:19] Salt fix and anti science narratives

[33:53] Keto biohacking and identity

[43:42] How to evaluate your need

[48:43] Who should skip electrolytes

Links:
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Your Diet Sucks podcast
Fly Nutrition – Endurance Sports Nutrition

This is a Premium-exclusive episode. Go to the Premium feed to listen. Or subscribe to Premium.





Blood glucose is easy to measure, but not always easy to interpret. This Premium-only episode brings together insights from several previous guests to examine blood glucose responses in more detail.
We discuss the misuse of clinical thresholds, the difference between OGTT results and free-living CGM data, and whether "flatter" glucose curves are actually better in normoglycemic people.
The episode also covers when repeated high glucose excursions may be worth investigating, how sugar intake should be interpreted in context, and why skeletal muscle and exercise play such an important role in glucose regulation.
Overall, the aim is to clarify what glucose responses can tell us, what they cannot tell us, and how to avoid pathologizing normal physiology.
Links: 
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When considering the health impact of foods, it is important to consider "compared to what?". Increasing the amount of a certain food or nutrient in the diet, typically implies a displacement of another.
While comparisons are more obvious in trials, in epidemiology food substitution models can be useful to help us determine the health effects of increasing/decreasing intake of a food, food group or nutrient.
However, these models are often misinterpreted and miscommunicated as if they are a game of "rock, paper, scissors", where one food beats another, and the losing food must be removed from the diet or considered harmful to health.
In this episode we discuss the problem of treating substitution analyses as food-ranking contests, rather than context-dependent comparisons shaped by the comparator, the unit of substitution, the baseline diet, and the outcome being studied.
Timestamps:

[01:30] Misuse of "compared to what?"
[06:39] What substitution models do
[10:43] Specified vs unspecified substitution
[16:57] Why the units used matter
[26:45] Example: organic vs conventional produce
[31:22] When substitutions are useful
[34:35] If legumes beat fish, does that mean fish intake should be zero?
[44:31] Naive vs bias-adjusted: artificial sweeteners case study
[49:14] Checklist: how to interpret food substitution analyses
Links:
Go to episode page (all study references linked)
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Episode #472: Compared To What?
Episode #589: Causal Inference in Nutrition Science – Daniel Ibsen, PhD