Sigma Nutrition Radio

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#454: Eric Helms, PhD – Plant or Animal Protein: Rethinking Protein & Muscle Sep 13, 2022

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When it comes to eating to promote muscle hypertrophy, muscle repair/recovery and maintenance of mass and function, protein has been an obvious focus. Indeed muscle mass and quality are dependent on the continuous remodeling of skeletal muscle proteins. This is related to the amount of muscle protein balance, i.e. the net difference between muscle protein synthesis (MPS) and muscle protein breakdown (MPB). Because of this, MPS has long been used as a proxy measure for muscle repair and/or growth of muscle.

Protein feeding increases MPS, with the amino acid leucine having a specifically strong impact on MPS. Therefore both the dose of protein and the amino acid profile of the protein have been looked at to assess which protein sources are "superior" for muscle mass and function. This has typically led to viewing animal proteins as better than plant proteins.

But many assumptions are layered into conversations on the topic. In this episode we explore some important points that are often neglected. Is MPS as reliable as we assume? Does the amino acid profile tell us everything about the anabolic effect of a protein? Does dose and timing matter as much as we think? How does the picture change when we look at whole foods or mixed meals?

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#453: Nick Gant, PhD – Cognitive Performance: Impact of Caffeine, Nicotine & Creatine (Rebroadcast) Sep 06, 2022

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The brain plays a central role in both physical and psychological function and performance. The brain also has a very high energy demand. In addition, fatiguing conditions can cause impairment of cognitive performance.

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.

Nick Gant is Director of the Exercise Neurometabolism Laboratory at the University of Auckland. His group uses interdisciplinary approaches from the nutritional sciences and neurosciences to investigate the role of nutrition in brain health and performance. Nick is particularly interested in foods and supplements that prevent brain fatigue and improve physical and cognitive function.

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#452: Stuart Phillips, PhD - Bacterially Synthesized Whey, Plant vs. Animal Proteins, Muscle & Extended Fasts, & Much More Aug 30, 2022

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This episode was oringally published as one of our "Expert – ask me anything" (AMA) episodes, which we published for Premium prescribers. In such bonus episodes, we collect questions from Premium subscribers and ask them direct to a world-class expert and past podcast guest.

If you're interested in subscribing to Sigma Nutrition Premium, then check all the details here.

In this episode Prof. Stu Phillips takes questions about synethized whey protein, plant proteins, post-exercise MPS, and many other topics related to protein, muscle function and ageing.

#451: Potassium & Blood Pressure: Influence of Sex & Sodium Aug 23, 2022

Show notes

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.

#450: Megan Rossi, PhD, RD – Diet For a Healthy Gut: Diversity, Fiber Types & Gut Health Pseudoscience Aug 16, 2022

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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? In this episode, gut health researcher at King's College London, Dr. Megan Rossi, discusses some simple heuristics to follow that will likely improve overall health, and promote positive gut health. Access show notes here Subscribe to Premium

#449: Do Artificial Sweeteners Increase Cancer Risk? (Study Analysis) Aug 09, 2022

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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.

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#448: Prof. Norman Temple – Can Science Answer Diet-Health Questions? Aug 02, 2022

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While we've never known more about diet and health, there remain many unanswered questions in nutrition science. However, there is often disagreements on how best to answer these questions, particularly in relation to informing practical diet advise that meaningfully improves health.

Prof. Norman Temple is one academic who has written on a number of these issues. One issue he highlights is the large discrepency in the practical value we have attained from cohort studies and RCTs, relative to mechanistic research. Another is the limitations of RCTs for nutrition-specific research questions.

In this episode, Prof. Temple discusses these issues, as well as what strategies can actually improve population diet, and thus health.

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#447: Does Eating Fish Increase Skin Cancer Risk? Study Analysis Jul 26, 2022

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A recent study reported a higher risk of developing melanoma in people who ate a relatively high intake of fish. This study caused headlines and it was picked up by many outlets (including the New York Times, Sky News, etc.).

In this episode, Alan and Danny dig into the nuances of this study to see if the headlines are justified.

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SNP7: Stephan Guyenet, PhD - Ask Me Anything! Jul 19, 2022

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This is an "ask me anything" (AMA) episode, which means a world-class expert and past podcast guest comes on the podcast to answer questions submitted by you, our podcast listeners.

Stephan Guyenet spent 12 years in academia studying neurodegenerative disease and obesity neuroscience. He was a postdoctoral fellow at the Univeristy of Washington, studying the neuroscience of obesity and eating behavior. Previous to that he completed a PhD in neuroscience.

Stephan is the author of the popular and well-received book 'The Hungry Brain', which lays out the science behind the brain's role in obesity.

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Questions Answered In Full Episode

"When someone undergoes liposuction or other surgery that removes adipose tissue, is there a sudden reduction in leptin levels? While this may reduce leptin resistance, could the drop in leptin lead to increased hunger over time?"
"What is the current research around how chronic energy restriction (or following crash diets) affects appetite hormones and/ or appetite regulation long term? Is there a physiological mechanism influencing overeating attributable to appetite dysregulation caused by chronic dieting? I ask as this is something I am often tackling in my nutrition consultancy but research in biochemical and physiological mechanisms seems lacking."
"Can you talk about the conditions of anorexia and morbid obesity and how they essentially defy the rules of metabolic compensation? In other words- I understand anorexia to be a mental health condition where the individual starves themselves with a purpose to control weight. And morbid obesity being excessive consumption despite over fatness, etc. If the body has these numerous mechanisms by which calorie restriction or calorie over- consumption results in these compensatory processes-driving us to eat more/less slow us down/speed us up, and many more; do these individuals not "hear" these signals or are they just adept at ignoring them or is it that their bodies have lost the ability to compensate for their under or over consumption? Additionally, can anyone become anorexic or morbidly obese? Or is it merely genetics?"
"Why do some SDRIs (serotonin–dopamine reuptake inhibitors) and serotonin precursors reduce hunger/appetite? E.g. 5-HTP and Wellbutrin (Bupropion)"
"Question about the ideal weight program: As an iOS developer, my instinct is to assume determinism and quantifiability of the entire universe. I believe this to be fundamentally true. But what is hypothetically possible differs from what we can realistically know. I worry that attempts like yours to quantify some seemingly qualitative measures are doomed. I have similar concerns about happiness research. How do you reassure yourself you can really construct an algorithm that deciphers the "ideal weight program" for any given user – do you rely on averages?" a. Quick explanation of the ideal weight program
"In 2018 a poster was presented at the annual meeting of the Society for Neuroscience titled 'The human brain microbiome; there are bacteria in our brains!' which showed bacteria apparently penetrating and inhabiting the cells of healthy human brains. While the work was preliminary, have you heard of any further work in this area? What is your opinion on the possibility that, if bacteria do inhabit the brain, they could play a part in appetite regulation and/or obesity similar to how the gut microbiome can affect our health?"
"It seems like there are significant differences in policies put forth between researchers from biomedical backgrounds and ones from public health policy backgrounds. Dr [David] Allison touched on this during recent interviews, noting that there is very little evidence regarding the efficacy of upstream obesity prevention interventions, such community gardens, combatting food deserts, nutrition education, and cooking classes. On the other hand, governments are increasingly turning to such interventions, as well as policies such as front of pack labelling (Canada, 2022), nutrition facts tables, calorie labelling on menus, as well as the aforementioned ones. Given your research on determinants of health and obesity, what are some of the most promising interventions to prevent NCD morbidity, as well as stones unturned in public health policy? Would you agree with individuals such as Dr Allison that in our current environment, the only efficacious interventions are drugs and bariatric surgery?"
Question based on your debate on JRE with Gary Taubes: "Would the insulinogenic effect of protein, specifically something like whey protein which causes an insulin response, be something that should automatically refute Taubes arguments about insulins inherent role in increasing adiposity? Second, would overeating on any macronutrient increase insulin simply because you are eating more food (i.e. hypercaloric)?"
"Are there best practices for the maximum duration someone should spend in fat loss (or weight gain) phases? Or perhaps an optimal ratio of fat loss phase duration to "maintenance" phase duration? For example, should fat loss phases be for a maximum of 12 weeks followed by maintenance of at least equal duration before resuming a fat loss phase?
"I'm a naturally skinny guy who helps other naturally skinny guys bulk up. I think it largely comes down to a blunted pleasure response to food, smaller stomachs, and/or higher NEAT. A lot of us seem to be taller and more thinly built, too. But why do you think things are things so different for us? Why is it so hard to gain weight? And what can we do about it?"

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#446: How Climate Change Impacts Nutrient Status Jul 13, 2022

Show notes

Climate change refers to long-term shifts in temperatures and weather patterns. These shifts may be natural, such as through variations in the solar cycle. But since the 1800's, human activities have been the main driver of climate change, primarily due to burning fossil fuels like coal, oil and gas.

Climate change has the potential to negatively impact the nutrient value of plants, soil organisms, food stuffs, via a variety of ways. Climate change puts food supplies at risk. Floods, droughts, more intense hurricanes, heatwaves and wildfires can drive down crop yields, destroy livestock, and interfere with the transport of food. And rising carbon dioxide levels from human activity can make staple crops like rice and wheat less nutritious.

In this podcast the Sigma team take a look at the evidence on how climate change will impact nutrient status, if left unchecked. There will be also a look at what solutions have been put forward to tackle this issue. This episode will focus more on how climate change impacts nutritional & nutrient status, as opposed to converse (but equally important) issue of how food systems impact climate change.

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