Category Archive

The endocrine system plays a central role in growth, development, metabolism, reproduction, and physical well-being throughout life. Hormones interact in complex networks, orchestrating a range of critical functions. Over the life course, we experience various changes in hormone levels, fluctuations, patterns, and actions. Additionally, lifestyle factors and disease processes can impact the levels and functions of hormones.

In this episode, Dr. Nicky Keay, a medical doctor with expertise in the field of exercise endocrinology, is on the podcast to discuss a variety of endocrine-related issues, including: hormone diurnal variation, bone health, amenorrhoea, HRT, perimenopause, and thinking about hormones and aging.

In this episode, the Sigma team discusses the human appetite system, how different nutrients and foods impact satiety, and the implications of this research.

One area of research in neurometabolism related to the potential use of nutrients on improving cognitive function, as well as “rescuing” the fatigue-related declines in performance. In this episode, the potential impact of creatine, caffeine, nicotine and exogenous ketones were discussed.

With the advances in understanding the importance of the gut (including its bacterial contents) for human health, much interest and attention has been placed on how to eat to promote positive ‘gut health’. This has led to many exciting research questions and labs doing fascinating work.

However, on the opposite side, it has led to a spike in opportunistic quacks to jump on the wave of enthusiasm and promote diets, supplements, testing kits and products that don’t reflect the current evidence base.

So what do we actually know? What aspects of diet should we focus on to improve gut health? For those with gut symptoms (bloating, pain, irritable bowel, etc.) is it possible to include more vegetables and fiber without the pain?

A study published in March 2022 suggested that consumption of artificial (non-nutritive) sweeteners is associated with a 13% increase in risk of cancer. And so in this episode, Dr. Alan Flanagan, Dr. Niamh Aspell, and Danny Lennon discuss this specific study and give their thoughts on what are fair conclusions to come to.

In this episode, Dr. Hazel Wallace discusses: the impact of menstrual cycle phase on cravings, at-risk nutrients in pre-menopausal women, functional hypothalamic amenorrhea, interaction of diet and PMS, the physiological changes at menopause and potential role of diet.

In this episode we address the idea that you shouldn’t eat vegetables, or that they aren’t beneficial. We will specifically look at a number of claims that relate to: 1) The claim that vegetables aren’t beneficial for health, or that there is no health benefit to high vegetable intake; 2) The claim that vegetables are actually detrimental to health, and their removal improves health.

In this episode, researcher and dietitian Dr. Julie Abayomi discusses important nutrients in pregnancy (e.g. iodine, DHA, and folic acid), as well as potentially problematic nutrients/foods (e.g. high-mercury fish and caffeine). In addition, she discusses the current debates about weight gain/loss during pregnancy, as well as what supports are needed for health professionals supporting pregnant women.

There have been many claims made about the benefits of a detoxification “protocol” or “plan”, based on specific dietary and supplemental regimens. Many of the arguments propose that many things we come into contact with are toxins and they can accumulate and compound in effect over time, causing a range of issues. Therefore, by removing these toxins (via a “detoxification protocol”), we can have better health.

And indeed it is well known that there are a large number of toxins in the environment, many of which can potentially be deleterious to health. And it also known that many nutrients are involed in processes of the body’s detoxification pathways.

However, is there any evidence that a detoxification diet, plan or “protocol” improves health? Is there any reason to suggest targeting certain nutrients or supplements leads to “better detoxification”? And do we need to avoid non-organic food, toothpaste and non-stick frying plans in avoid to avoid these toxins?

There has been much concern voiced over the years about the potential harms to both human health and the environment of genetically-modified (or more accurately, genetically-engineered) crops. tolerance, and even enhanced nutritional content. But are these advantages possible without harm? In this episode, Alan and Danny discuss the current evidence on genetically engineered crops (or GMOs) and their effect on human health, biodiversity, and the economy.

Coeliac disease treatment requires adherence to a gluten-free diet for life. Therefore there is much research underway to develop alternative treatment options that may help these patients. One novel antigen-focused therapy that has been hypothesised is the use of plant bioactives.

Specifially, in vitro work by Dr. Charlene Van Buiten has looked as whether there is a mechanism by which polyphenols from green tea could be of benefit. Her work shows that these polyphenols can mitigate gliadin-mediated inflammation and intestinal permeability in vitro.

One propsed intervention for increasing longevity and/or healthspan is fasting. But what does the current evidence tell us? Does the evidence actually match the hype? In this episode Dr. Niamh Aspell, Alan Flanagan and Danny Lennon discuss some of the data on fasting and longevity.

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.

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.

There is now widespread use of various “artificial sweeteners” in foods and beverages. Most commonly non-nutritive sweeteners are used to sweeten a products, whilst having less sugar and calories than a traditionally sugar-sweetened version of that product. For example, diet drinks (e.g. diet soda) are most commonly associated with artificial sweeteners. However, they are also in a wide variety of food products and supplements.
For a long-time there has been skepticism and alarm raised about their potential health effects. From claims of them increasing our food intake, all the way to causing cancer. And food safety authorities have conducted rigorous examinations of the safety data on each of these compounds.
In this episode, the Sigma team discuss the initial research that raised alarm bells, the current process of safety evaluation for non-nutritive sweeteners, the amounts they are consumed in, and the studies published thus far examining their health impacts.

In this episode we address the idea that you shouldn’t eat vegetables, or that they aren’t beneficial. We will specifically look at a number of claims that relate to: 1) The claim that vegetables aren’t beneficial for health, or that there is no health benefit to high vegetable intake; 2) The claim that vegetables are actually detrimental to health, and their removal improves health.

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.

Zoya Huschtscha, PhD is a researcher and assistant lecturer at Monash University (Australia), in the Department of Nutrition and Dietetics. She completed her PhD at the same institution, where her research focused on interventions to prevent and treat sarcopenia; i.e. the loss of muscle function and mass, typically with age. Zoya also has a Masters of Dietetics. In addition to her academic work, she works in private practice as a sports dietitian.

This episode looks at the impact of cannabis on health; specifically physical pain and mental health. Trials on cannabis and the two main cannabinoids, CBD and THC, are discussed. Does the current evidence match the hype?

Dr. Nathan Bryan, PhD is an Adjunct Assistant Professor at Baylor College of Medicine. Dr. Bryan has been involved in nitric oxide research for the past 18 years and has made many seminal discoveries in the field. He was the first to demonstrate and discover an endocrine function of nitric oxide via the formation of S-nitrosoglutathione and inorganic nitrite.

In this episode Danny and Alan discuss the debate around whether a direct source of the long-chain omega-3 fatty acid DHA should be recommended. Many people do not consume the marine foods (primarily fatty fish) that contain DHA, and higher DHA intakes, DHA status, and omega-3 indices are predictive of certain health outcomes. But the essential omega-3 fatty acid alpha-linolenic acid (ALA) can be consumed from plant sources. So do those who do not consume direct sources of DHA have lower DHA status? Does this matter? And if so, then what pragmatic conclusions can we come to? All of this is covered in this episode.

Dr. Austin Baraki joins Danny and Alan to critically evaluate the assumption that blood levels of a nutrient directly tell us about overall nutritional status. With many people getting blood tests done outside of clinical settings, there is significant risk of misinterpretation of what these measures mean. In this episode we discuss measures of calcium, sodium, vitamin D and others as examples of where misinterpretation and misunderstanding can happen.

Dr Eirini Dimidi of King’s College London discusses the research on diet in chronic constipation and functional bowel disorders. Dr. Dimidi is a Lecturer in Nutritional Sciences and a Registered Dietitian.

In this episode Alan and Danny discuss the role of nutrition in bone health. They cover the importance of bone health, bone disorders such as osteoporosis, how nutrients play a role in bone remodelling, and the evidence of dietary and supplementation trials on bone health outcomes.

In this episode Alan and Danny answer a variety of questions sent in from listeners. Topics covered include: fruit consumption, protein dosing, salt for hypotensive people, public health & plant-based diets, and the tactics of quacks.

Prof. Leanne Redman is a Professor of Reproductive Endocrinology & Women’s Health, based at the Pennington Biomedical Research Center. As the director of the Reproductive Endocrinology and Women’s Health Laboratory, she is focused on understanding the intergenerational transmission of obesity. She has published on maternal diet, preeclampsia, and gestational diabetes, amoung other issues.

James Betts is Professor of Metabolic Physiology at the University of Bath, where he is Co-Director of the Centre for Nutrition, Exercise & Metabolism.
His research employs randomised controlled trials to study the effects of nutrition on metabolic regulation.

Carole Hooven, PhD, is lecturer and codirector of undergraduate studies in the Department of Human Evolutionary Biology at Harvard University. She earned her PhD at Harvard, studying behavioral endocrinology and evolution of sex differences in humans (physiology, behavior and cognition). She has recently written a book on how testosterone influences behaviour and explains many sex differences. The book is titled ‘T: The Story of Testosterone, the Hormone that Dominates and Divides Us’.

In this episode Danny & Alan discuss the impacts of nitrates and nitrites on health. They look at the beneficial impacts of dietary nitrate, as well as issues around nitrites in processed meat.

Vitamin D status is linked to a variety of health outcomes, and avoiding or correcting deficiency is important. However, does supplementing with vitamin D actually benefit most people? Is there evidence for supplementation improving health outcomes like mortality, cancer risk, depression or other outcomes? In this episode Danny and Alan look at intervention trials of vitamin D supplementation.

Dr. Gil Carvalho is a medical doctor, researcher and science communicator. With a wide background in several fields, he currently spends a lot of time communicating nutrition science principles to the public.

What is the relationship between shift work and health? What nutrition, sleep and lifestyle strategies can help shift workers? Listen…

How does diet impact irritable bowel syndrome (IBS)? What foods should someone with IBS avoid? How is a low FODMAP diet implemented? The episode discusses the evidence.