We recently published a new article in the journal Nutrients where we looked into the plasma proteome in relation to intake of added sugar and sugar-sweetened beverages (SSBs) and risk of type 2 diabetes (T2D).
The article Identification of Inflammatory and Disease-Associated Plasma Proteins that Associate with Intake of Added Sugar and Sugar-Sweetened Beverages and Their Role in Type 2 Diabetes Risk can be found in whole on the following link.
In this study, we aimed at examining how added sugar and sugar-sweetened beverage intake associate with 136 measured plasma proteins and C-reactive protein in the Malmö Diet and Cancer–Cardiovascular Cohort (n = 4382), and examine if the identified added sugar- and SSB-associated proteins associate with T2D incidence.
We identified nine plasma proteins that associated with added sugar intake. Out of these, two proteins associated significantly with increased T2D incidence: CXCL13 and CD40L. We identified seven proteins that associated with SSB intake and six of these were strongly associated with T2D incidence: HGF, tPA, CHI3L1, IL1ra, PRSS8 and FUR. These six associations were much stronger than those of the two proteins that associated with added sugar intake. This indicates that SSB intake associates with a T2D-pathological proteomic profile, while this cannot be stated for added sugar intake.
We could not find any significant linear association between added sugar intake and CRP, and neither could we replicate a significant association between SSB intake and CRP which many previous studies have seen, although a tendency for such an association could be observed (p-trend = 0.09). Nevertheless, a significant positive interaction effect between added sugar intake and CRP on the risk of T2D was observed (p = 0.01), where increased T2D risk from high added sugar intake could only be observed at higher CRP levels.
“In conclusion, this is a hypothesis generating study that is the first of its kind to identify plasma proteins and proteomic signatures that are associated with added sugar and SSB intake. Turning to the proteome to elucidate the complex potential relationship between sugar intake and T2D incidence did not provide a clear enlightenment, but despite the fact that no significant associations were observed between added sugar and SSB intake with levels of CRP, the data suggests that SSB intake is related to a T2D-pathological proteomic signature, while this was not observed for added sugar intake. Replications in larger and more recent cohorts are necessary to verify our results.”
A new article was recently published in the European Journal of Nutrition entitled Gut microbiota composition in relation to intake of added sugar, sugar-sweetened beverages and artificially sweetened beverages in the Malmö Offspring Study.
The role of the gut microbiota for health has been largely realized in the past years, and the public media is not shy of jumping to strong conslusions in regards to it. For example, have you ever heard that a high intake of added sugar or low-calorie sweeteners are not good for your small bacterial friends in your gut? I think a lot of people might. Which surely is interesting since this has been very scarcely studied in humans until now.
We studied 1371 individuals in the Malmö Offspring Study who had provided faecal samples to be analysed using 16S rRNA sequencing. After a lot of data processing, we ended up with 64 different bacterial genera to study. Participants had also performed a 4-day food record and a short food frequency questionnaire so we could study their intake of added sugar, sugar-sweetened beverages and artificially sweetened beverages.
We statistically evaluated if intake of added sugar (as well as with the support of the urinary sucrose and fructose biomarker as mentioned in a previous blog post), sugar-sweetened beverages and artificially sweetened beverages associated with any of the 64 bacterial genera or with various measures of microbiota composition and diversity, such as alpa diversity, beta diversity and the Firmicutes:Bacteroidetes ratio.
Our main findings are best summarized in the conclusion of the article as cited below. For more, please follow the link to the full article.
“In conclusion, many previous studies have discussed how intake of added sugar and sweetened beverages may increase cardiometabolic risk and our study can only find very modest support for that such risk could be partially acting through mechanisms involving the gut microbiota. After full covariate adjustment, we found an association between sugar-sweetened beverage intake and the Firmicutes:Bacteroidetes ratio, which previously has been linked to obesity. Among the 64 individual bacterial genera, only the inverse association between sugar-sweetened beverage intake and Lachnobacterium remained significant after adjustment of multiple testing. Both epidemiological and interventional studies, preferably with metagenomic sequencing and of larger study samples, are needed to further evaluate if a link exists between intake of sugars and sweeteners and the human gut microbiota.”
Stina and Ulrika during the dietary assessment seminar.
We are very excited for the course start of Public Health Nutrition which we are teaching in the Public Health Master’s Programme at Lund University. The course gives a comprehensive overview of the field on nutrition, covering everything from basic nutrition to nutrition research methods and public health nutrition policy. Due to the Covid-19 pandemic, all lectures and seminars are held in the CRC aula and/or online to maintain social distancing.
Interested in this course? Read more about it here!
We have recently published an article about the association between dietary fiber intake and risk of incident aortic stenosis in Nutrition, Metabolism and Cardiovascular diseases. Check it out here!
Background and aims: Although aortic stenosis is the most common valvular heart disease requiring intervention in Europe, the role that diet plays in development of the disease is largely unknown. The pathophysiology of aortic stenosis is however similar to other cardiovascular diseases that fiber intake has been associated with. The aim of this study was consequently to investigate the association between dietary fiber intake as well as the main food sources of fiber, i.e. fruit and vegetables and whole grains, and risk of incident aortic stenosis.
Methods and results: The Malmö Diet and Cancer Study is a Swedish prospective population-based cohort study with baseline data collection performed between year 1991-1996. Dietary habits were recorded through seven-day food diaries, 168-item diet questionnaires, and interviews, and data on incident aortic stenosis was collected through national registers. Among the 26,063 participants, 672 cases were ascertained during a mean follow-up period of 20 years. Cox regression was used to estimate the association between dietary intakes and incident aortic stenosis. No associations were found between incident aortic stenosis and intake of dietary fiber (HR for the highest vs lowest quintile: 0.93; 95% CI: 0.72-1.24), fruit and vegetables (HR: 0.98; 95% CI: 0.76-1.28), or whole grains (HR: 1.00; 95% CI: 0.79-1.26) in the main model.
Conclusion: The findings of this study do not indicate that consumption of dietary fiber or fiber rich foods are associated with incident aortic stenosis.
The interest in the relationship between what we eat, the composition of our microbiota, and how it affects our health has led to a recent surge in research studying these associations.
In this post we have briefly summarized three presentations from the Nutrition 2020 online conference arranged by the American Society of Nutrition.
The speakers on the topic of “Plant-Based Foods and a Healthy Microbiome” were: • Paul Cotter, PhD, Head of Food Biosciences, Teagasc Fermoy, Cork, Ireland • Kieran Tuohy, PhD, Head of Department, Food Quality and Nutrition, Fondazione Edmund Mach San Michele all’Adige, Trentino-Alto Adige, Italy • Thais Cesar McGovern, PhD, Associate Professor, Sao Paulo State University, Araraquara, Sao Paulo, Brazil
Paul Cotter on the potential of plant-based fermented foods and fiber to modulate the gut microbiota While our body consists of 10 trillion cells and 23 000 genes, our microbiota consists of 100 trillion cells and 3 million genes. Thus we’re more microbial than human in our makeup. The microbiota exists at multiple different places within our body; on the skin surface, the oral cavity, the vagina, in breast milk. However, the largest proportion is found within our guts. Both in the stomach and the small intestine, but to an even greater extent in the large intestine.
Photo: pixabay
The microbiota play different roles, some are beneficial, some are undesirable, while some do very little at all. Just recently we’ve started to understand the role of different microbes thanks to technological advancements. The same advancements that have impacted human genomics. That is, insights related to DNA sequencing.
In the past, the study of microbiota relied upon culture-based approaches. This approach could study one microbe at a time, and only those that could be grown in a laboratory. Gut microbe in particular is hard to be cultured in a laboratory, as they live in an anaerobe environment and require specific nutrients. However, these limitations don’t apply to studying the DNA of the microbes thanks to DNA sequencing-based approaches.
When referring to all the DNA of the microbes present in a particular environment, the term metagenomic DNA is applied. The DNA sequencing method applied today is thus referred to as whole metagenome sequencing or shotgun sequencing. In addition to bacteria, also fungi and viruses, and other microbial communities that are present, can be studied. It also gives an insight to not only what microbes are present, but also what their specific role might be. So the genes in the gut are related to the production of toxins, antibiotic resistance etc. The question is then if we by altering our diet can affect what genes (i.e. microbes) are present in our guts? And thus decrease or eliminate undesirable microbes, and increase the presence of desirable microbes.
Thanks to this, and other approaches, we’re starting to get a much better understanding of the impact of the gut microbiome on health. This refers to, among other functions, vitamin synthesis, digestion, immune stimulation, and impact on gut-brain axis. The gut microbiota changes over our lifetime. It is impacted by a lot of factors early in life, such as whether we had vaginal birth or cesarean, whether or not we were breastfed, exposure to antibiotics etc. Although to a more subtle degree, it is also impacted later in life by factors such as diet, antibiotics, hygiene, whether we have pets, exercise, stress, medications etc.
The hypothesis for Paul Cotter and his research team is to see whether we can “mine” the microbes in our guts for products that can promote health and treat disease. But also to see if fibre and fermented foods can have beneficial changes to the composition and function of the gut microbiota. It is believed that the adaptation of a westernized lifestyle have had a negative impact on our microbiota. Even to the degree that certain microbes are becoming extinct, and not being passed on from one generation to the next. This is due to our diets (to a large degree related to decrease intake of fibers and fermented foods), use of antibiotics, formula-feeding etc. Choosing for example a Mediterranean diet over a Western diet can have a profound effect on our health as well as our gut microbiota, by enhancing the diversity and the functions of our microbiota.
For example, a fibre-rich diet improves the production of short-chain fatty acids and other metabolites that can contribute to enhanced production of mucus and the production of antimicrobial peptides, reduce excessive gut permeability and oxygen levels. Moreover, dietary fibers bind to toxic bile acids, which leads to the release of minerals and phenolic compounds that can be absorbed by the distal gut. Some fibers are regarded as being prebiotic, i.e. enchances the growth of desirable microbes, such as bifidobacterium and lactobacillus. There is now growing interest in next generation probiotics, such as faecalibacterium, akkermansia etc.. Enhancement of these microbes can occur directly through the impact of fibers on the microbial community, or indirectly through the growth of other microbes which then provide compounds that are released and utilized by the desired microbes.
Fermented foods, which has been produced for millennia all across the planet, have recently be given a renewed interest in western countries due to their potential health benefits, such as increasing levels of “missing” microbes in our gut. Some praise of fermented foods have gone too far though in relation to their health benefits, e.g. that all fermented foods are equally good for you and that they can cure every ailment out there. However, even in research, fermented foods have been associated with a wide range of health benefits, including the prevention of type 2 diabetes, cardiovascular disease, obesity, osteoporosis, depression, IBS etc. Some of the strains of microbes found in fermented foods are closely related to strains marketed as probiotics as well. For researchers, the long-term goal will be to harness the microbes in fermented foods in order to generate foods with evidence-based health-promoting features.
Photo: pixabay
There’s a wide variety of fermented foods, including both beverages (e.g. kombucha) and solid foods (e.g. kimchi, kefir). The study of the microbiome in fermented foods have led to the discovery and interest of entirely new species, and we are just starting to research what their potential role is and what metabolites they may be producing. The study of fermented foods also looks at cluster of genes, i.e. health associated gene clusters, which may be associated with colonizing, surviving or modulation pathways. These clusters are mainly found plant-based fermented foods, specifically brine- and sugar-foods. A recent study has also shown that a lot of the lactobacilli found in the human microbiome are very similar to the ones found in fermented foods. Thus highlighting the fermented foods as the most likely original source of those lactobacilli and providing evidence for their direct impact on the human microbiome.
In conclusion, there is increasing interest and appreciation for the role of the gut microbiota in human health, and there is also increasing evidence that fibres and fermented foods may enhance both gut microbiota composition and function.
Kieran Tuohy on Phytonutrient:Microbiome Interactions for Human Health In the last century of human evolution our diets have become much less diverse than ever before in history, to a large degree due to the current agricultural practices (e.g. “the green revolution”). More specifically, our diets have become less diverse in dietary fibers and polyphenols, which in turn affects our microbiome negatively.
Phytonutrients (or polyphenols) provide the colour and many of the flavours in the fruits, vegetables, and berries we eat. They are complex aromatic compounds with a complicated chemistry, and 90 to 95% of these compounds escape digestion in the stomach and small intestine and reach the colon. When they come in contact with the intestinal microbiota in the large intestine they are broken down into smaller phenolic acids (smaller aromatic compounds). This changes their biological availability and can now be absorbed from the intestine. It also changes their biological activity. E.g. many of them are naturally antioxidant. Many of them also act as signaling molecules in different cells around the body, and have been implicated with some of the health benefits observed from diets high in fruits and vegetables.
The phytonutrients may also interact directly with the microbiota in the intestine, inhibiting and promoting different microbes within the microbiota. They may also affect the production of short-chained fatty acids and bind to bile acids to change their functionality.
Photo: pixabay
In a cross-over study, where the intervention of interest consisted of two high flavanol apples consumed daily for eight weeks, resulted in a significant reduction in total cholesterol, LDL cholesterol, and triglycerides in a group of hypercholesterolemic subjects(1).
1. Koutsos A, Riccadonna S, Ulaszewska MM et al. (2020) Two apples a day lower serum cholesterol and improve cardiometabolic biomarkers in mildly hypercholesterolemic adults: a randomized, controlled, crossover trial. Am J Clin Nutr 111, 307-318.
Thais Cesar on Interaction Between Consumption of Citrus and Intestinal Microbiota: Improvement of Intestinal Function and Metabolism of Glucose and Lipids Recent evidence have indicated that citrus fruits contain phenolic compounds that can modulate the composition and activity of the gut microbiota. They inhibit and pathogenic bacteria and stimulate the growth of beneficial bacteria contributing to intestinal homeostasis and gastrointestinal health. Consumption of citrus fruits have been associated with anti-inflammatory and antioxidant effects, as well as improved glucose and cholesterol levels.
While nutrients affect the composition and function of the gut microbiota, the gut microbiota in turn influence the absorption, metabolism and storage of nutrients by producing metabolites that affect the function of organs within the body. Moreover, the interaction of nutrients and gut microbiota affect the health and disease risk of the individual.
Certain dietary patterns have particularly beneficial effects on the gut microbiota, such as vegetarian (or vegan) diets, resulting in a higher intake of fibers, resistant starch, and non-starch polysaccharides, and the Mediterranean diet, with a high intake of fruits, vegetables, legumes, and mono-unsaturated fats, and a low intake of red meat. Both diets have a positive effect through (among other aspects) increasing the production of short-chain fatty acids. Meanwhile, a western diet have a negative effect on the gut microbiota by e.g. increasing the intake of ultraprocessed foods, which is associated with a reduction in microbiota diversity and the permanent loss of microbiome functions (which also negatively affects the next generation).
More recently studied dietary patterns are the microbiota-targeted diets, with increased intake of probiotics, prebiotics, phytochemicals, or symbiotic combinations, to improve gut microbiota composition.
However, few studies have looked at the impact of fruits and vegetables on the modulation of gut microbiota.
For citrus fruits, there is evidence for a significant association with reduced risk of cardiovascular disease and diabetes. Some of the bioactive compounds found in citrus fruits are vitamin C, carotenoids, and flavonoids (primarily hesperidin and naringin). The citrus flavonoids have beneficial effects through antioxidant activity, anti-inflammatory activity, and modulation of gut microbiota. Polyphenols interact with the gut microbiota which in turn transform polyphenol compounds into bioactive metabolites that stimulates the growth of beneficial bacteria and inhibits pathogenic bacteria. Thus, citrus flavonoids have a prebiotic effect. Both fresh orange juice and processed orange juice have been associated with positive effects on gut microbiota(1-3). Furthermore, intake of orange juice was also shown to improve the glycemic and lipid profile(3). For the composition of the gut microbiota, intake of orange juice has been associated with an increase in akkermansia, lactobacillus, and bifidobacteria, and a reduction in proteobacteria and firmicutes. Akkermansia is associated with decreased glucose, insulin, HOMA-IR, triglycerides, and LDL-C, and increased HDL-C, while lactobacillus is associated with decreased glucose. Orange juice intake also improved intestinal function, such as consistence of stool and bowel frequency.
1. Duque A, Monteiro M, Adorno MA et al. (2016) An exploratory study on the influence orange juice on gut microbiota using a dynamic colonic model. Food Research International 84. 2. Lima ACD, Cecatti C, Fidelix MP et al. (2019) Effect of Daily Consumption of Orange Juice on the Levels of Blood Glucose, Lipids, and Gut Microbiota Metabolites: Controlled Clinical Trials. J Med Food 22, 202-210. 3. Fidelix M, Milenkovic D, Sivieri K et al. (2020) Microbiota modulation and effects on metabolic biomarkers by orange juice: a controlled clinical trial. Food Funct 11, 1599-1610.
Dairy is somewhat of a controversial topic these days. For example, when searching for “Why is dairy…” on Google, the first two autofill-suggestions are “Why is dairy bad for you?” and “Why is dairy good for you?”. The fact is that some view dairy as a superfood, while others view it as straight-up dangerous. For that reason, I was very interested in the session “Exploring the Links between Diet and Inflammation: Dairy Foods as Case Studies” during the NUTRITION 2020 LIVE ONLINE conference organised by the American Society of Nutrition.
One matter that kept popping up throughout the entire conference was sponsored sessions and commercially funded research, which is inevitable to encounter within nutrition research. During this conference I was confronted with many thoughts about this topic. “Can this research be trusted?” but also “is it fair to disregard research just because it’s funded by commercial actors?“. Due to this, I felt I had to incorporate some discussion about this topic in the blog post.
Diet and inflammation
Charles B. Stephensen (USDA-Western Human Nutrition Research Center) started off the session with a brief introduction to immune activation, and how the process differs depending on the cause. He mentioned how obesity induced inflammation can result in low-grade chronic systemic inflammation as there is no pathogen to resolve, and how inflammatory cells exacerbate disease by causing insulin resistance.
He continued by describing how dietary interventions can dampen inflammation. As an example he brought up PREDIMED, a large Spanish primary prevention trial which showed significant reductions in several biomarkers of inflammation for those following the Mediterranean Diet. He suggested that these results are due to components of the diet that address the underlying cause of inflammation, such as unsaturated fatty acids, phenolics and fiber that may for example diminish damage of adipose tissue depots.
What about dairy and inflammation?
The next speaker, Mario Kratz (Fred Hutchinson Cancer Research Center) continued by presenting some research about the impact of total dairy intake and dairy fat on biomarkers of systemic inflammation.
Dr. Kratz chose to focus on results from a few randomised controlled trials which he deemed to be the most informative and representative. He specifically focused on results about fasting plasma hsCRP, IL-6, TNFalpha and adiponectin, biomarkers which have previously been strongly linked to systemic inflammation.
In a cross-over RCT (funded by the American National Dairy Council), Zemel et al. 2010 found a consistent reduction in biomarkers of systemic inflammation on a low-fat milk intervention compared to a soy drink control among 20 participants, without any differentiating effects on body weight or composition. The study was a cross-over study where both groups received smoothies with either low-fat milk or soy drink, and the biomarkers were measured at 0, 7 and 28 days.
Similar results were found in an RCT with cross-over design by Labonté et al. 2014. Among 112 men and women with elevated hsCRP, both the control and dairy diet decreased biomarkers of systemic inflammation. The dairy diet included low-fat milk and yoghurt, and full-fat cheddar, while the control diet consisted of fruit and vegetable juice, cashew nuts and one cookie per day. The authors conclude that consumption of a combination of low- and high-fat dairy products as part of a healthy diet has no adverse effects on inflammation. The study was funded by the Dairy Research Cluster Initiative. Another similar study (randomised cross-over design) found no difference in biomarkers of inflammation between dairy foods and the control (fruit juice and granola) among the 37 participants.
Dr. Kratz emphasised that these studies were conducted in individuals without dairy allergies, and that the impact would likely be different in those with dairy allergies. He concluded by stating that the current evidence does not suggest that dairy consumption is pro-inflammatory. To the contrary, many studies indicate that it is actually anti-inflammatory! To be honest, I felt that this conclusion was rather sensationalistic and made a mental note to double check the research before forming my own opinion on the topic.
Fermented dairy products and inflammation
Bradley W. Bolling (University of Wisconsin-Madison) rounded off the session by discussing why dairy might not be pro-inflammatory, it contains saturated fat, right? I think he brought up a good point, which is that dairy is extremely complex with a wide array of bioactive components, even more so fermented dairy products. Thus, it is difficult to attribute the health impact of dairy to one single component of it. He then brought up a study about fermented dairy products (yoghurt and cheese) and postprandial inflammation, and stated that there is emerging evidence of yoghurt and cheese improving immune health but that no scientific agreement has been reached yet.
To conclude the take-home messages of this session: Different dietary patterns as well as different individual foods have been found to affect inflammation, with many high quality RCTs indicating that dairy is either neutral or anti-inflammatory. We don’t know yet what the mechanisms behind any anti-inflammatory effects of dairy are. It is important to keep in mind that the molecular composition of dairy is complex, meaning that the health effects are likely not be attributable to one single component.
Dear dairy
In my view, most of the speakers of the session had quite high credibility as they discussed the topic in a very pragmatic way, that is, not sensationalising it and I found the session to be interesting overall. However, one feeling that I did have throughout the entire session was “can these researchers and studies be trusted?”. The entire session was sponsored by National Dairy Council, and all researchers and presented studies had been reimbursed and funded by dairy related organisations.
Funders with commercial interests can affect research in various ways. Of course, they may in some cases just fund research without any involvement in study design and publication, thus not restricting academic freedom. In other cases however, they may have a say in what results get published, sway the interpretation of the results to be favourable for their own interests, or design studies in ways that promote the desired results.
When trying to get an overview of the topic by reading some papers myself, however, I did find that the presented results are in line with current evidence, regardless of how the studies were funded. For example, here’s a quote from Bordoni et al. 2017: “Our review suggests that dairy products, in particular fermented products, have anti-inflammatory properties in humans not suffering from allergy to milk, in particular in subjects with metabolic disorders.“. They do however state that the clinical relevance of inflammatory markers is currently debated among researchers and regulatory authorities, which I thought was very interesting!
It is important to always be attentive when reading research articles and be aware of any bias that may be present, but in my opinion, it is equally important not to disregard certain research simply out of principle. If we doubt everything that we cannot know for sure, we are no wiser than he who did not use his legs but sat still and wasted away because he had no wings to fly with.
The nutritionist association in Sweden, Nutritionistföreningen, recently published an interview with Emily Sonestedt. The interview consisted of 7 questions including why she chose to become a nutritionist, and any advice she would give to other nutritionists! You can read the full interview (in Swedish) here.
The Faculty of Medicine at Lund University is highlighting the World Blood Donor Day on June 14 by publishing eight articles about research related to blood done at the university.
Emily Sonestedt has tried to answer the question: Is it possible to eat your way to healthier blood? You can read the full article (in Swedish) by clicking on the excerpt below.
All articles related to the Blood Donor Day can be found here. You can also read more about World Blood donor Day on the WHO website.
It is widespread knowledge that a diet with better carbohydrate quality is beneficial for our health. But what does this actually mean? This was recently discussed during a so-called Sponsored Satellite Program at the American Society for Nutrition’s conference Nutrition 2020 Live Online. The session was named Importance of Carbohydrate Quality and was sponsored by Nestlé Research and Development. Since I (Stina Ramne speaking), now have spent almost 3 years completely focused on the health effects of a high added sugar intake during the progression of my PhD, I will not only summarize what the four speakers brought forward during this conference session, but also give at little bit of my personal view of it.
The first speaker was Luc Tappy, University of Lausanne, who gave an informative and brief introduction to what carbohydrates are and how they are divided into sugars, starches and fibers.
He also brings forward a very interesting perspective of how to look at carbohydrate quality. A perspective which I have never heard of before and which also appears somewhat ancient and not really up to date with today’s nutritional needs and challenges (I’ll come back to why this is). Tappy claims that quality (independent of what is referred to) is defined as “meeting the customers needs, while being absent of adverse effects”. Since carbohydrates is not an essential nutrient in any way, the need and role that carbohydrates have is simply to provide energy. So a carbohydrate of good quality in this sense, is a carbohydrate that efficiently provides energy, while have no adverse effects. Tappy very neatly shows how those parameters seldom go hand in hand and that it is often the case that carbohydrates or carbohydrates-rich foods often fulfils one, but lacks the other of these qualities. For example, he ranks sugar-sweetened beverages as the most efficient energy-providing carbohydrate-rich food, but also the food with the strongest evidence for adverse effects. Whole fruit and whole grains provide energy less efficiently, but lack adverse effects. When comparing starch, sucrose and fructose, it gets a bit more nuanced. Fructose is first of all not perfectly absorbed, and secondly, it’s partly metabolized to lipids instead of glucose, hence it does not provide energy as efficiently as starch, which generally is perfectly degraded to glucose and used as energy. Fructose is also the saccharide with the strongest evidence for adverse health effects. In summary, with the carbohydrate quality definition provided by Tappy, fructose is clearly a shit-food, starch is quite OK, and sucrose falls in the middle (probably because it’s also a combination of fructose and glucose in its molecular composition).
What did remain unaddressed in Tappy’s presentation, which I consider is an important point, is the reason why the parameters of “efficiently provide energy” and “absence of adverse effects” don’t go hand in hand. This is simply because today’s society’s most profound nutrition challenge is that we have too much energy available, resulting in weight gain, obesity and all the diseases following that. The so-called adverse effects are caused by to efficient energy allocation. The big hole in Tappy’s reasoning is the claim that the need we have from carbohydrates is to efficiently provide energy, which simply is not true in most of today’s high- and middle-income societies. Previously, it is true this has been a need that we had from carbohydrates, such as before the agricultural and industrial revolutions when food supplies were scarce. Also, as recently as during the first half of the 20th century, a time defined by wars, this was true. Now, on the other hand, the need we have from carbohydrates are different. What we actually need from carbohydrates is in my opinion somethings else.
Fibers!
Vitamins, minerals and polyphenols such as in fruit, vegetables and whole grains
“Fillers” that provide long-lasting satiety
Alternative parts to our diet so it’s not solely constituted by pure fats and environmentally detrimental animal foods and low-energy high-water-demanding vegetables (that generally are low in carbohydrates)
The second speaker was John Sievenpiper, Department of Nutritional Sciences, University of Toronto, who concluded the evidence summarized in meta-analyses of the health effects of carbohydrate quality based on 3 different domains on how to define good carbohydrate quality.
An interesting side note is that Sievenpiper started his presentation by very clearly going through a large slide with all his disclosures, but apparently he forgot the one he has had with Coca Cola. Well well, back to three domains of carbohydrate quality and its’ relations to cardiometabolic health.
Glycemic Index (GI) and Glycemic Load (GL)
Both high GI and GL are associated with increased risk of type 2 diabetes and coronary heart disease from the summarized prospective cohort evidence, and the effect is larger from GL compared to GI. From intervention trial evidence, low GI improve glycemic control and cardiometabolic risk factors in diabetes.
Dietary fiber
From epidemiolocal evidence, dietary fiber is associated with reduced risk of type 2 diabetes and coronary heart disease. From RCTs, high fiber diets, especially high viscous soluble fiber, improve systolic blood pressure and glycemic control in diabetics.
Food-based approach
Whole grains are associated with decreased risk of type 2 diabetes and coronary heart disease and RCTS of oats and barley have shown improved LDL-cholesterol and systolic blood pressure, and improved glycaemic control in diabetics.
Pulses are associated with reduced incidence in coronary heart disease, cardiovascular disease and hypertension from epidemiological evidence. RCTs of diets high in pulses have in summary shown reduced glycemic control, LDL cholesterol, body weight and systolic blood pressure.
Fruits are associated with reduced diabetes incidence and reduced cardiovascular- and all-cause mortality as seen in prospective cohorts. High fruit intake also reduced LDL-cholesterol as systolic blood pressure as evidenced from RCTs.
So if you weren’t convinced just yet how important it is get your carbohydrates from good quality sources, the Global Burden of Disease project have concluded that among all risk factors contributing to disability-adjusted-life-years in North America, low intake of whole grains made it into the top 10 list.
Last in the session followed two presentations by Flavia Fayet-Moore, Nutrition Research Australia, and Dariush Mozaffarian, Freidman School of Nutrition Science and Policy, Tufts University, that were so connected that I will discuss the two presentations jointly.
Dariush Mozaffarian’s research team have just published a new article in PLoS One suggesting and elaborating a new metric on how to measure carbohydrate quality. A refreshing addition to the classsic GI and GL metrics. The inspiration from this new metric came from the American Heart Association, which in 2010 suggested a total carbohydrate-to-fiber-ratio of >10g carb per 1g fiber, i.e. 10:1, to assess foods with unbeneficial carbohydrate quality, i.e. foods to limit intake of. Foods with a ratio between 10-5:1, on the other hand, were considered a good choice and foods with a ratio of <5:1 were an excellent choice (however, very few options exist).
Mozaffarian with colleagues have now evaluated this ratio, as well as made alternatives to it which also incorporate the free sugar content of the foods. This is important since many foods that are high in fiber and appear healthy, can at the same time be high in sugars, such as granola and dark bread. Favet-Moore and colleagues have also evaluated these carbohydrate quality metrics in an Australian population. She emphasizes the importance of validating different metrics in different populations, since food habits, preferences and options differs between different food cultures, even among food cultures that from a distance appears quite similar, such as American compared to Australian.
So what are these carbohydrate quality metrics and how do they relate to diet quality?
10:1 = 10 g carbohydrate: ≥1 g fiber 10:1:2 = 10 g carbohydrate: ≥1 g fiber: ≤2 g free sugars 10:1|1:2 = 10 g carbohydrate: ≥1 g fiber & ≥1 g fiber: ≤2 g free sugars
All these different metrics associated with a diet containing less calories, total fat and saturated fat, while more fiber, protein, potassium and magnesium in an American setting. In the Australian setting, all ratios associated with higher diet quality and higher nutrient intake. The 10:1 ratio was achieved by 50% of adults, the 10:1:2 was achieved by 33% of adults and the 10:1|1:2was achieved by 41% of adults.
“Overall, 10:1 and 10:1|1:2 identify the largest nutritional improvement and the broadest product options” Mozaffarian
In my own opinion, this way of looking at carbohydrate quality appears very appealing, while still super simple. How come I haven’t thought of it? Kudos to everyone involved in this work!
Before we reach the end I just want to share some more thoughts. What I think this carbohydrate quality session lacked was a discussion about the finetuning in the lower end of the carbohydrate quality spectra, where we find sugars and sugar-rich foods and beverages. These foods and nutrients are too often lumped up into one and their potential health effects are generally not differentiated between them. In the same way as how fiber, whole grains, pulses, low GI-diet, etc were differentiated when summarizing their health effects by Sievenpiper, we must differentiate between sugar-sweetened beverages, total intake of added sugars and other sources of added sugar. I think it’s an issue that research findings on sugar-sweetened beverages so often are extrapolated to apply to total intake of added sugars when studies time after time fail to find convincing evidence about the risks of a high sugar intake in general, in contrast to the studies made on sugar-sweetened beverage intake.
If I would bring this all together into a simple message. Eating good quality carbohydrates is beneficial for health, independently of how you define carbohydrate quality. The foundation always lies in finding a balance between fibers and sugars. Or actually an imbalance, where fibers outweigh the sugars.
To get this blog rolling, we want to announce that we recently published a new article in Frontiers in Nutrition named Comparing Self-Reported Sugar Intake With the Sucrose and Fructose Biomarker From Overnight Urine Samples in Relation to Cardiometabolic Risk Factors. The article was published in the research topic Objective Dietary Assessment in Nutrition Epidemiology and was edited by Natasha Tasevska who has done all the initiative research about the urinary sucrose and fructose biomarker. The project was led by Stina Ramne and was made together with collaborators at Reading University, UK.
If you weren’t aware already, this is important background information. Misreporting of dietary intakes is a common challenge in nutritional epidemiology and, therefore, are nutritional biomarkers warranted to objectively assess intake.
As stated, the use of urinary sucrose and fructose as objective biomarkers of sugar intake has already been developed, evaluated and validated by Natasha Tasevska. However, this work has been done in 24-hour urine samples, meaning that all urine excreted during 24 hours must be collected. To facilitate data collection in large epidemiological studies, we found it very valuable to evaluate this biomarker in overnight urine samples, which only requires that a fasting morning sample (and any urine excreted during the night, if any) is collected. Much easier and less of a mess!
This study was conducted in the Malmö Offspring Study and is the first study to (1) examine this biomarker from overnight urine samples, (2) compare and relate the biomarker and self-reported sugar intake to cardiometabolic risk factors and (3) evaluate a composite measure of the biomarker and self-reported sugar intake.
“In summary, we found statistically significant correlations at levels of r≈0.20–0.30 and demonstrated the potential for using the sugar level in overnight urine samples to complement self-reported dietary data in investigations of cardiometabolic risk. The combination of urinary sugars and added sugar intake indicated that a higher sugar intake in women is associated with higher BMI, waist circumference and systolic blood pressure, and lower HDL cholesterol. Considering the potential gains from collecting only overnight urine instead of 24-hour urine in regard to participant burden, drop-out rates, missing data and selective participation, the overnight urinary sugar biomarker calls for further validation.”
The Nutritional Epidemiology group at Lund University was established by Elisabet Wirfält. In 2017, Emily Sonestedt became the PI. Since then, the group has been growing. Currently, Emily supervises five PhD students to add to the list of current and former Master and Bachelor students that have passed through Our Team.
Nutritional epidemiology is a field that uses epidemiological methods to examine associations between diet and disease. As a group, our overall aim is to create and diffuse knowledge within the human nutrition field so that we achieve a healthier society. To do so, we use large population studies to investigate whether dietary composition influences the risk of developing diseases such as cardiovascular disease, obesity, type 2 diabetes and cancer, and whether genetic factors influence the observed relationships. Clarifying the importance of dietary habits is of great significance for public health because eating habits, in contrast to many other factors, can change during the life cycle.
Currently our Our Science revolves around the role of sugar consumption in the development of cardiometabolic risks, the role of genetic variations in the salivary amylase gene (AMY1) and starch intake on cardiometabolic risk, and the association between dairy products and cardiovascular disease.
ith this blog we hope to bring you closer to the research that we do in our group, whether you are a fellow nutrition scientist, a researcher from a different field, or a nutrition enthusiast. Follow us and we will do our best to keep you up to date in the Nutritional Epidemiology research field.
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