Sigma Nutrition Radio

Links: Episode page (with links to studies mentioned) Subscribe to PREMIUM Receive Danny's free weekly email About This Episode: The benefits of consuming a higher fiber diet have been consistently demonstrated in nutrition research. Epidemiology clearly shows that higher intakes, compared to lower intakes, leads to a risk reduction for a range of diseases, including cardiovascular disease and colon cancer. And based on this epidemiological evidence, most dietary guidelines recommend dietary patterns that provide adults with 30-35g of dietary fiber per day. However, what do we know about intakes beyond this? Do we continue to see benefit in a linear fashion? Is there a ceiling to benefit? At what level would we see “optimal” benefit or the greatest magnitude of risk reduction? The ability to answer such questions is hampered by the fact it’s difficult to find cohort studies where the “high” fiber level is high enough to relate to this issue. However, there have been some controlled studies looking specifically at “very high” intakes, i.e. those far above current recommendations. In addition, there are some populations where habitual dietary intake gives a fiber intake far above the typcial intakes in Western cohorts. So in this episode we go through this data to try to see what we can conclude about this fascinating question of ‘what are the health effects at very high fiber intakes?’ New to Sigma Nutrition? Learn more about us here.

Links: Go to episode page (with resources) Subscribe to PREMIUM Receive Danny's weekly email About This Episode: In the last couple of decades, carbohydrates have experienced an increasing amount of negative campaigning. In general, the main argument is that carbohydrates have been viewed as the root cause for obesity, diabetes and several other diseases including heart disease and behavioral disorders. However, there can often be a lack of appreciation that not all carbohydrates are equal in their health effects. Beyond this, now there has even been confusion as to whether high fiber diets with whole grains are good for you or bad. This is mostly a result of strong claims made by people with large online followings and promoting specific diets. What does the best evidence tell us about different carbohydrate types and impacts on health outcomes? Should carbohydrates be viewed as inherently harmful? How solid is the evidence on whole grains, legumes and other high-fiber carbohydrate-rich foods? To help us tease through the science in this area, in this episode we get some answers from nutrition epidemiologist, Dr. Andrew Reynolds. About the Guest: Dr. Andrew Reynolds is a nutrition epidemiologist working with achievable lifestyle and environment change in the prevention and management of non-communicable diseases, such as type 2 diabetes and cardiovascular disease. He primarily conducts randomised controlled trials and meta-analyses. Much of his work is to inform evidence-based dietary or clinical guidelines, policy, and food reformulation. Links: Go to episode page (with resources) Subscribe to PREMIUM Receive Danny's weekly email

Links: Go to episode page (with resources) Subscribe to PREMIUM Receive Danny's free weekly email About This Episode: “Personalized nutrition” has been promoted as an approach that will improve people’s health by prescribing them specific dietary recommendations based on their own genetic and phenotypic data. The premise is that given we each respond differently to foods, having general dietary recommendations may be doing many people a disservice. And by using an array of personal data, it is now possible to give unique diets that improve health. The early and interesting findings of research in this area was met with much fanfare, and indeed, many companies are now offering commercial direct-to-consumer services based on genetic and physiological testing, followed by “personalized” dietary prescription. Such testing may include genetic tests, microbiome testing, glucose monitoring data, and more. This data is then fed into machine learning algorithms to prescribe dietary recommendations. However, do the marketing claims match the current evidence? Does the “proof” it works that is often cited, actually back up the claims? Do personalized nutrition diets actually lead to improved health outcomes over generic, conventional dietary recommendations? Do personalized nutrition diets lead to better outcomes than standard dietetic/nutrition practice? To answer these questions, we go through the main studies cited in favor of personalized nutrition being superior to typical dietary advice, and see if they indeed support the claims. So is personalized nutrition superior to standard dietary advice? Let’s find out… Note: This is a Premium-exclusive episode, so in order to listen to the full episode you’ll need to subscribe to Sigma Nutrition Premium. However, you can listen to a preview here.

Links: Go to episode page (with further resources) Subscribe to PREMIUM Get Danny's weekly email, the Sigma Synopsis About This Episode: While it has long been acknowledged that high intakes of saturated fat can increase risk of atherosclerotic cardiovascular disease due to their impact on blood lipids, there are some who question the association between saturated fat and heart disease. Specifically, they may state that the evidence for this association is weak or non-existent, typically by pointing to some commonly cited studies that show null associations between saturated fat and CVD outcomes. On this basis, they may conclude that there is no basis to aim to limit saturated fat intake to current recommended levels or that reducing saturated fat intake will not actually improve health outcomes. In this episode, Alan and Danny look at the four most commonly cited publications showing a null association, highlighting some key issues. Beyond that, they look at a number of other lines of evidence on saturated fat that allows one to come to a confident answer on this question. So does reducing saturated fat intake to recommended levels actually reduce heart disease risk? Let’s discuss…

Links: Go to episode page (with resources) Subscribe to Sigma Nutrition PREMIUM Receive Danny's free weekly emails About this Episode: The beneficial impact of a high-fiber diet is something that has been promoted in nutrition for a long period of time. But there remain a variety of interesting questions to researchers, practitioners and the general public alike. How much fiber do we actually need? What are current fiber recommendations based on? What outcomes have the strongest evidence for benefit? Should we have targets for fiber sub-types? Are some types of fiber “better” than others? Do functional fibers added to food products still retain the benefits we see with dietary fiber? To help get to some evidence-based answers on these issues, our guest in this episode is one of the researchers at the forefront of dietary fiber research for decades, Professor Joanne Slavin.

Links: Go to episode page Subscribe to PREMIUM Receive Danny's free weekly email Description: Blood glucose responses play a crucial role in maintaining good health, and any abnormalities in glucose regulation can lead to several chronic conditions. Diabetes is one such disease that results from a lack of insulin production or the body’s inability to use insulin effectively, leading to elevated blood glucose levels. There has been debate about what exactly constitues a “healthy” and “unhealthy” blood glucose response. While it is suggested that unhealthy blood glucose responses are characterized by erratic and unpredictable “spikes” in blood glucose levels, sometimes vague terminology leads to people worrying about normal blood glucose responses. This may be particularly related to the increasing prevalence of continuous glucose monitoring (CGM) devices that allow individuals to track their glucose levels in real-time. While these devices can be helpful for people with diabetes to manage their glucose levels, they can also lead to unnecessary concern and anxiety about small, normal glucose elevations. In recent years exciting advances have been made in diabetes remission research. And off the back of that, more research has looked at various dietary interventions that could either directly impact remission, or act as an adjuct to other interventions. In this discussion with Dr. Nicola Guess, we discuss a range of topics related to glycemia, diabetes, and diet. This includes the potential for high-protein interventions, what utility CGMs actually have, what to make of diabetes remission trials, and future directions for the field.

Links: Go to episode page (w/ resources) Get Danny's weekly emails Subscibe to Premium Description: Understanding the concept of an “exposure” is a critical aspect to nutrition science literacy. The ‘exposure of interest’ refers to the variable or factor that is being studied to determine its relationship with a particular health outcome. For example, in a study examining the relationship between diet and heart disease, the exposure of interest may be a particular nutrient or food group, such as saturated fat or red meat consumption. But when reading research we need to be able to critically examine the levels of an exposure and ask were these suitable for the research question at hand. For example, is there a sufficiently wide contrast in the exposure between the groups being compared? How do the reported levels of intake relate to what we know about this exposure from the wider literature? Much has been made of the many ’null’ associations found in nutrition epidemiology. But in many cases, these may be accounted for by looking at the exposure contrast or absolute intakes in those studies. Something we referred to as “null by design”. In this episode, Danny and Alan go through the most crucial aspects to understand about the exposure of interest in nutrition, hopefully leading to an enhanced understanding of interpreting nutrition research.  

Links: Episode page with related links Subscribe to Sigma Nutrition Premium Receive Danny's free weekly email Description: Substantial evidence shows that a high intake of saturated fat in the diet has the potential to significantly raise LDL-C and ApoB-containing lipoproteins in many people, and in turn increase their risk of developing atherosclerotic cardiovascular disease (ASCVD). However, people may raise what seems to some contradictory evidence, or what is sometimes thought of as a paradox: the impact of full-fat dairy on CVD risk. This paradox arises because given the saturated fat content of full-fat milk, yogurt and cheese, we typically don’t see the same impact on blood lipid profiles. In addition, epidemiology can often show such foods in a favourable light. And the dairy fat story gets more interesting when we look at evidence showing there is a huge difference in the impact of consuming different dairy foods (e.g. butter vs cheese/yogurt). So this leads to many questions that people rightly ask, which we aim to address in this episode. Questions such as: Why doesn’t increased dairy consumption lead to same increases in CVD risk as other saturated fat sources? Do results from full-fat dairy studies prove that saturated fat isn’t a problem? What is it about cheese/yogurt that makes it different to butter? How do low-fat and full-fat dairy compare? Diets including/excluding dairy: how to compare? Subscribe to Sigma Nutrition Premium

Links: Go to episode page (with resources) Subscribe to Sigma Nutrition Premium Receive our free weekly emails Introduction: Discordance between low-density lipoprotein particle (LDL-p) and low-density lipoprotein cholesterol (LDL-C) occurs when the levels of these two biomarkers do not match up as expected. Discordance between Apolipoprotein B (ApoB) and low-density lipoprotein cholesterol (LDL-C) is similar, except rather than counting just LDL particles, ApoB is a measure of the numbers of lipoproteins that have an ApoB attached. Discordance between ApoB and LDL-C can lead to either an underestimate or overestimate of ASCVD risk. And therefore there may be important implications for someone who does have discordance. Additionally, it is such cases that suggest that a measurement of ApoB may provide additional information beyond traditional lipid measures in assessing a person’s cardiovascular risk. Recent work from researchers at Liverpool John Moores University has investigated whether discordance is associated with certain dietary patterns. In this episode, one of the researchers involved, Dr. Ian Davies, is on the podcast to discuss this work in addition to wider questions in the diet-lipids-CVD field that remain to be answered.

Links: Go to episode page (w/ resources) Subscribe to PREMIUM Receive Danny's free weekly email Description: Fructose is a type of sugar that is commonly found in fruits, vegetables, and many processed foods. In recent years, there has been a lot of discussion and debate about the impact of fructose on health, with some claiming that it is a major contributor to obesity, diabetes, and other chronic diseases. However, these claims are often at odds with what the scientific literature actually says. One of the most common claims about fructose is that it is inherently “bad” for health, and that consuming too much of it can lead to a wide range of health problems. This idea has been popularized in many popular diet and health books, and has led to a widespread fear of fructose among the general public. However, many of these claims are based on outdated or oversimplified research, and do not reflect the complex reality of how fructose interacts with the human body. Another common claim about fructose is that it is uniquely responsible for the current obesity epidemic, and that reducing fructose intake is the key to weight loss and better health. While it is true that excessive consumption of sugary foods and beverages can contribute to weight gain and other health problems, the idea that fructose is uniquely responsible for these issues is not supported by the scientific evidence. In fact, many studies have found that total sugar intake, rather than fructose specifically, is the most important factor in the development of obesity and related health problems. In this episode we discuss the unique aspects of fructose metabolism, why some studies appear to show unique harm of fructose, and the implications of this for dietary choices. Go to episode page