Category Archive

Chrononutrition is a research area that looks at the relationship between temporal (time-related) eating patterns, circadian rhythms, and metabolic health. In this episode, we look at recent research (including that from the Big Breakfast Project) and how understanding and conclusions from the field have shifted over time.

Do vegan diets increase risk of depression? We look at: 1) research on the proposed mechanisms, 2) impact of such diets on outcome measures.

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.

It has been consistently shown in research that elevated dietary sodium consumption is associated with high blood pressure and an increased risk of cardiovascular disease. In addition, low levels of dietary potassium intake are associated with these same risks. However, there is some debate on how to characterize these relationships.

In a study published in European Heart Journal in July 2022, using data from the EPIC-Norfolk study, researchers attempted to answer whether the associations between potassium and both blood pressure and cardiovascular disease: 1) differ between men and women? and 2) depend on daily sodium intake.

In this episode Dr. Alan Flanagan and Danny Lennon discuss the details of this study and then link it to the overall evidence base and what this may mean for potassium (and sodium) intake considerations.

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.

Folate (also known as viatmin B9) actually relates to a collection of folates; both natural dietary folates and synthetic forms, primarily folic acid. This folate/folic acid that is consumed via the diet or supplementation is a precursor for the formation of tetrahydrofolate (THF), which is a carbon donor and acts a cofactor for a number of enzymes that play important roles in several processes. In this episode, Alan and Danny discuss the role of folate in the methlyation cycle, the impact of folate insufficiency/deficiency, genetics variatnts of the MTHFR gene (and other genes) that impact folate metabolism, and the impact of folate on health outcomes; including heart disease, birth defects, cancer, and brain health & cognition.

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.

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.

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.

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.

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. 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.

In this episode the Sigma team discuss the research looking at ‘psychobiotics’; i.e. probiotics that have health impacts on those with pyschiatric disorders or symptoms. They discuss the origins of the research, the gut-brain axis, mechanisms by which gut microbiota could impact mood, and then the human trials to date that have examined probiotics’ effects on mood, anxiety, depression, bipolar disorder and other outcomes.

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.

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.

In this episode we discuss the potential impact of dietary polyphenols on cardiovascular disease risk; including impacts on blood pressure, flow-mediated dilation, and other related outcomes. We talk about some potential mechanisms and then several specific randomized, controlled trials.

In this episode we discuss the potential impact of dietary polyphenols on cognitive health; including cogitnitve funciton, memory, and risk of dementia and Alzeimher’s. We talk about some potential mechanisms, cohort studies, and then direct controlled trials.

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.

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.

In this episode Danny and Alan discuss the three primary models used to explain body mass regulation: 1) Set Point Model, 2) Settling Point Model, 3) Dual Intervention Model. They discuss the role of feedback systems, environment, behaviour, as well as discussing both the “thrifty gene hypothesis” and John Speakman’s “drifty gene hypothesis”.

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…