In this episode Alan and Danny discuss the role of cholesterol in the body and claims that are made suggesting low levels of blood cholesterol are harmful to health.

Starting with the premise that cholesterol is an important molecule in the body and plays a role in many processes, discussed are two related claims:

1. we should avoid low cholesterol levels as it can harm our health
2. elevated levels of cholesterol may actually be protective against disease or mortality.

The episode also critiques claims about cholesterol being “conditionally essential” and that low LDL-C/ApoB increases risk of mortality, cancer and infection.

Show notes at sigmanutrition.com/episode424/

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.

Show notes available at sigmanutrition.com/episode423/

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.

Show notes can be found at sigmanutrition.com/episode422/ and the Sigma Statement on the gut-brain axis can be found at sigmanutrition.com/gut-brain-axis/

Dr. Brendon Stubbs, PhD, is a Senior Clinical Lecturer and researcher at King's College London, conducting research in physical activity & mental health, the mind-body interface, and meta-research. He has published over 600 academic papers in several leading journals across multiple scientific fields. He has informed policy guidelines in the UK, Europe and the World Health Organization.

Dr. Stubbs is also a clinical physiotherapist, being Head of Physiotherapy at the South London and Maudsley NHS Foundation Trust. He has a MSc in Neurological Rehabilitation & PhD in Pain Medicine & Rehabilitation.

Show notes to this episode are available at sigmanutrition.com/episode421/

Kevin Boehnke is a researcher at the University of Michigan, in the Chronic Pain and Fatigue Research Center. His current research focuses on therapeutic applications of illicit or semi-licit substances (cannabis, psychedelics). His goal is to rigorously assess appropriate use of these substances and to help address the public health harms caused by their criminalization.

Carrie Cuttler is an Assistant Professor at Washington State University. Her research at the Health and Cognition Laboratory there focuses on elucidating the potentially beneficial and detrimental effects of chronic cannabis use and acute cannabis intoxication. Her recent work has focused on examining links between cannabis use and mental health (e.g., ADHD, PTSD, OCD, depression, anxiety).

Show notes available at sigmanutrition.com/episode420/

Wishing all the Sigma audience a great 2022!

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.

Dr. Bryan obtained his doctoral degree from Louisiana State University School of Medicine in Shreveport where he was the recipient of the Dean’s Award for Excellence in Research. He pursued his post-doctoral training as a Kirschstein Fellow at Boston University School of Medicine in the Whitaker Cardiovascular Institute. After a two year post-doctoral fellowship, in 2006 Dr. Bryan was recruited to join faculty at the University of Texas Health Science Center at Houston by Ferid Murad, M.D., Ph.D., 1998 Nobel Laureate in Medicine or Physiology.

Show notes at sigmanutrition.com/episode419/

Click here to subscribe to Sigma Nutrition Premium

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.

Show notes available at sigmanutrition.com/episode418/

Click here to subscribe to Sigma Nutrition Premium

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.

Show notes can be found at sigmanutrition.com/episode417/

Dr. David Nunan, PhD is a Lecturer and Senior Research Fellow in the Centre for Evidence-Based Medicine at the University of Oxford. There, he is the Director of the Postgraduate Certificate in 'Teaching Evidence-Based Health Care' and the lead tutor for the internationally-renowned 'Teaching Evidence-Based Medicine' course.

He is a principal investigator with research interests in prevention and treatment of lifestyle-related conditions, improving the understanding and use of research evidence, and meta-epidemiology (research on research). David has experience in a breadth of methodologies including diagnostic studies, statistical analysis, qualitative research and clinical trials.

Show notes available at sigmanutrition.com/episode416