
Sigma Nutrition Radio
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.
Latest episodes

May 3, 2022 • 39min
#436: Charlene Van Buiten, PhD – Coeliac Disease & the Search for Novel Therapies
Charlene Van Buiten, PhD, is a leading researcher in coeliac disease and its treatments. In this conversation, she delves into the intricate nature of coeliac disease, emphasizing it as an autoimmune disorder influenced by gluten. Her innovative research on plant bioactives, particularly polyphenols from green tea, reveals their potential to reduce inflammation and improve gut health. The discussion also highlights the challenges of maintaining a gluten-free diet and the hope for new therapeutic interventions on the horizon.

Apr 26, 2022 • 1h 26min
#435: Fasting & Longevity – Does the Evidence Match the Hype?
The podcast discusses the potential use of fasting to increase longevity and/or healthspan. They explore different types of fasting regimens, the relationship between fasting and longevity, and the effectiveness of fasting and other dietary patterns in relation to chronic disease prevention. They also examine the safety and efficacy of the Fasting Mimicking Diet in cancer patients. The hosts emphasize the need for more human data and imaginative approaches in fasting studies.

Apr 19, 2022 • 16min
SNP2: "Fish is Bad For You" [PREVIEW]
While dietary guidelines universally include fish as a food group that can be consumed regularly in a healthy dietary pattern, there are some potential risks of fish consumption that get raised. Some have some legitimacy, for example the frequency of consumption of high-mercury fish. However, other claims can go to extremes ("eating fish is bad for you") that are based in ideology rather than evidence. In this Quack Asylum episode, we use a video made by a medical doctor as an example of where quackery can raise its head on this topic. Specifically, there are four claims made in the video that we investigate and see if there is any basis to them. This is a Premium-exclusive episode. In order to listen to the full episode and access the show notes, you will need to subscribe to Sigma Nutrition Premium.

Apr 12, 2022 • 1h 12min
#434: Is a Vegan Diet Really Best for Diabetes?
Many different diets have been put forward as solutions that treat type 2 diabetes. Some will claim the diet “reverses” diabetes, some say it puts it into “remission”, while others more conservatively recommend a diet to manage diabetes symptoms in a healthy way. There has been some debate on the use of terms like reversal, cure or resolution. And recently more clarity has been found in defining each. One of the diets that has been recommended by some for the purposes of “reversing” or treating diabetes is a low-fat, whole food plant-based (WFPB) diet. Specifically, there is a claim that it is superior to other diets in treating diabetes. Some of these claims relate to popular online diet & lifestyle programs that use such a diet. While there is also a number of studies that are commonly cited in support of the claims. In this episode, we evaluate these claims by looking at the published research in this area, across epidemiology, human intervention trials and mechanistic rationale. We also ponder what it means for something to be the “best” diet to treat a chronic disease. Access show notes Attend Sigma event in Dublin, May 2022 Subscribe to Sigma Nutrition Premium

Apr 6, 2022 • 1h 43min
#433: Greg Potter, PhD - The Bidirectional Relationship Between Sleep and Diet
In this conversation with Greg Potter, PhD, a researcher specializing in the links between sleep and diet, fascinating insights emerge about their bi-directional relationship. They discuss how sleep deprivation can alter food preferences and energy intake, as well as the effects of specific nutrients on sleep quality. Topics like chronotypes and the impact of melatonin, caffeine, and other supplements are explored. Listeners will learn effective dietary strategies to enhance sleep and the intricate mechanisms connecting our sleep patterns to what we eat.

Mar 30, 2022 • 59min
#432: Bill Harris, PhD - Omega-3 Fatty Acids & Health
Omega-3 fatty acids have long been associated with various health outcomes. A type of omega-3 called alpha-linolenic acid (ALA) is found in various plant foods such as flax seeds or chia seeds. Other omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are found typically in marine food sources such as oily fish (e.g. salmon, mackerel) and algae. And while higher intakes of such foods have shown benefit, there has been some confusion over the benefit of such nutrients due to some large omega-3 supplementation trials reporting null findings. So what should we make of the current evidence base? Does supplementation lead to heart disease risk reduction or not? Do we need direct sources of EPA and DHA in the diet? Does ALA have unique benefits? What is an omega-3 index and why is it important? In this episode, fatty acid expert Dr. Bill Harris dives into each of these questions and clarifies what the current evidence tells us about the effect of these fatty acids on our health. Overview: 04:02 - Fatty acid definitions/subtypes 09:14 - Omega-3 status & the Omega-3 Index (O3I) 20:03 - Omega-3 supplementation trials for CVD 41:15 - DHA, brain health, cognition in later life, development, etc 49:45 - Should we be concerned about omega-6 fatty acids? Show note available at: sigmanutrition.com/episode432/ Subscribe to Sigma Nutrition Premium here: sigmanutrition.com/premium/

7 snips
Mar 24, 2022 • 1h 24min
#431: Artificial Sweeteners - Health Impacts and ‘Safe’ Levels
The podcast discusses the use of artificial sweeteners in foods and beverages, addressing concerns about their health effects. Topics include the different types of sweeteners, safety evaluation processes, the alleged link between sweeteners and cancer, their impact on body weight and appetite, misconceptions about E numbers, and the risks and benefits of artificial sweeteners.

Mar 17, 2022 • 21min
SNP1: "Don’t Eat Vegetables" [Preview]
In this Premium episode Alan and Danny aim to address the idea that you shouldn’t eat vegetables, or that they aren’t beneficial. Two related ideas have been circulated in some nutrition/health communities on the internet: Vegetables aren’t beneficial for health (or that there is no health benefit to high vegetable intake). Vegetables are actually detrimental to health, and their removal improves health. Such advice is usually defended through some combination of the following claims, which we examine in this episode: Humans are naturally carnivores, or have evolved to thrive on animal foods, and only turn to plants in times of famine. Certain indigenous populations such as the Inuit or the Masai, eat close to no vegetables, yet have robust health. Many of the nutrients present in vegetables can be obtained from animal foods. And beyond that, these nutrients are more bioavabilable when coming from animal sources. Fibre is not an essential nutrient, and high-fibre diets don’t lead to the health benefits that are typically claimed. Certain compounds in plants are actively harmful to us. Some of these compounds are natural pesticides, aimed to hurt us. Others are anti-nutrients, which decrease absorption of other key nutrients. Plants/vegetables contain compounds/nutrients exacerbate clinical conditions such as IBS or autoimmune disorders, and removing all plants including veg, leads to improved outcomes in these people. There is no benefit to a diet high in vegetables compared to a diet with low/no vegetable consumption. Premium subcribers can access the detailed study notes to this episode here. Click here to subcribe to Sigma Nutrition Premium.

Mar 14, 2022 • 1h 20min
#430: Soy - Yes, No, Maybe?
Click here to subscribe to Sigma Nutrition Premium The popularity of soy foods and soy-based products has been increasing in recent times. This has been particularly the case as a dairy alternative, with people switching to using soy ‘milk’ and soy-based yogurts and cheese. Additionally, soy has become popular as a meat alternative in a variety of dishes for those looking to reduce meat intake. Soy foods such as tofu can be used in recipes in place of meat, and soy-based ‘meat alternatives’ that are vegetarian and vegan friendly have been developed. With this increased prevalence, there has been some debate about the health effects of consuming soy foods and products. On one side, there have potential benefits highlighted of inclusion of soy in the diet. It contains phytoestrogens, which may have beneficial effects. Additionally, it is low in saturated fat, and so is potentially beneficial when used in place of saturated fat-rich foods. However, some have claimed that the phytoestrogens (isoflavones specifically) in soy can be a cause for concern due to the ability of these compounds to mimic the effects of the hormone oestrogen. One common claim is that high soy intake is detrimental for men particularly, as it is “feminizing”; causing gynecomastia, loss of libido and erectile dysfunction. So what is the truth? Is soy a health food? A harmful endocrine disruptor? Or simply neutral? In this episode we dive into the research and look at the evidence to date tells us about these questions. We consider two big health outcomes in particular; cardiovascular disease and breast cancer. And then final discuss what this means practically for our dietary choices. Click here for show notes to this episode Click here to subscribe to Sigma Nutrition Premium

20 snips
Mar 8, 2022 • 1h 47min
#429: Kevin Hall, PhD & Stephan Guyenet, PhD - Carbohydrate-Insulin Model vs. Energy Balance Model
Click here to subscribe to Premium The pathogenesis of obesity is clearly complex. And the need to have a comprehensive model to explain this pathogenesis is important. One such model, termed the Energy Balance Model, has largely been the consensus paradigm of obesity scientists to this point. Specifically, a recently published paper in the American Journal of Clinical Nutrition by Dr. Kevin Hall and his colleagues outlined the various nuances of the model, as well as common misconceptions about the model. However, there are others who propose that this is not the correct model of obesity, but rather that obesity pathogenesis can be better explained by a model called the Carbohydrate-Insulin Model (CIM) of obesity. While this model has been proposed in various forms over the past couple of decades, the most recently published revision/update of this model was that put forward by Dr. David Ludwig and colleagues, in a Perspective published also in the AJCN, in December of 2021. In this episode, Dr. Kevin Hall (lead author of the paper mentioned above) and Dr. Stephan Guyenet are on the podcast to discuss the debate surrounding these two models. Specifically, the discussion will focus in on the Hall et al. (2022) and Ludwig et al. (2021) papers, as well as previous work leading up to both. Click here to access show notes for this episode Click here to subscribe to Premium