Artificial Sweeteners & Liver Cancer - Is There a Link? 6% Increased Risk of Hepatocellular Carcinoma per 330ml of Artificially Sweetened Soft Drink in Human Study

Are we "pouring liver cancer", when we consume soft drinks regularly? Recent data from the EPIC study appears to suggest just that - specifically if the soft drinks are artificially sweetened.

I certainly don't belong to the anti-sweetener faction on the Internet, but the results scientists from the International Agency for Research on Cancer, the University Paris Sud, the Institut Gustave Roussy and the Centre for Research in Epidemiology and Population Health (CESP) in France, the Winship Cancer Institute in Atlanta, the Hellenic Health Foundation and the University of Athens Medical School in Greece, the Harvard School of Public Health in Boston, Aarhus University and the Danish Cancer Society Research Center in Denmark and the Cancer Council Victoria and the University of Melbourne in Australia in the latest issue of the European Journal of Nutrition are serious enough to not to discard them as another unwarranted horror-story of the anti-sweetener lobby (Stepien. 2014).

You can learn more about sweeteners at the SuppVersity

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Sweeteners & the Gut Microbiome Each is Diff.

Sweeter Than Your Tongue Allows!

Stevia, the Healthy Sweetener?

Sweeteners In- crease Sweet- ness Threshold

The aim of the study was to assess associations between intake of combined soft drinks (sugar sweetened and artifiially sweetened) and fruit and vegetable juices and the risk of hepatocellular carcinoma (HCC), intrahepatic bile duct (IHBC) and biliary tract cancers (GBTC) using data from the European Prospective Investigation into Cancer and Nutrition cohort of 477,206 participants from 10 European countries.

After 11.4 years of follow-up, 191 HCC, 66 IHBC and 236 GBTC cases were identified. Hazard ratios and 95 % confidence intervals (HR; 95 % CI) were estimated with Cox regression models with multivariable adjustment (baseline total energy intake, alcohol consumption and intake pattern, body mass index, physical activity level of educational attainment and self-reported diabetes status).

Don't be fooled by the size and name of the EPIC cohort! For the laypress the large cohort size will make this study appear as if the results must be God given. Personally, I am yet not impressed by scientists handing food frequency questionnaires out to almost half a million people (65%-68% correlation with what the people actually eat | Streppel. 2013), but it obviously blurs the errors. Personally, I still wouldn't take this as a complementary ticket for the exuberant consumption of artificially sweetened soft drinks.

As the researchers rightly point out, this makes the study at hand one of the few to study the possible link between soft drink consumption and cancers of the liver and biliary tract, which could - "[g]iven the rising consumption of sweetened non-alcoholic beverages and their likely link to several metabolic disorders that play a role in the development of these cancers" (Stepien. 2014) - be a major contributor to the ever-increasing number of liver carcinoma.

Figure 1: HR (95 % CI) for HCC by categories of soft drink and juice consumption compared to non-consumers in the EPIC cohort | % above the bar indicate risk increase / decrease - all trends are significant, but only the risk increase in the highest consumption group reaches individual significance (Stepien. 2014).

As you can see in Figure 1 (risk increase in % is sign. only for the high consumption), the scientist found a general link between soft drink consumption and hepatocellular carcinoma risk: +83% risk increase for those who consume soft drinks habitually (= more than 6 drinks per week) and +38% for the "juicers" (people who consume fruit and vegetable juices on a daily basis) - those are quite impressive numbers, even if there was no link to any of the other forms of cancer the scientists investigated.

A 6% risk increase does not equate a risk of 6%! I just realized on Facebook that people are still misinterpreting risk increases as absolute risks. If you have a risk increase of 6% of a crude baseline risk of 101/476968 [number of cancer patients / number of subjects] = 0.021%, a 6% risk increase will bring you up to a risk of 0.024% which means that 2.24 people out of 10,000 are at risk of developing hepatocellular cancer. This is not an exact calculation, obviously, because I don't have all the data to do it properly, but it gives you an estimate of the absolute risk, which is minimal!

In view of the previously cited way in which the consumption of these drinks contributes to the metabolic disorders that "play a role in the development of these cancers" (Stepien. 2014 | I would even say they trigger them), it is yet not half as surprising as the results of the scientists' sub-group analysis. In spite of that, the data Stepien et al. generated suggests that it's not the consumption of the "bad" + obesogenic sugary version of the drinks which shows an incremental risk increase of +6% for heaptocellular carcinoma on a per serving base, but its artificially sweetened cousins!

Figure 2: Spline regression models for the intake of soft drinks (left) and juices (right) in relation hepatocellular carcinoma risk. Reference 0 mL/ week. Knots correspond to 10th, 25th, 50th, 75th and 90th percentile of intake. The maximum corresponds to the 99th percentile. Solid lines- HR, dashed lines- 95 % CI (Stepien. 2014).

While the data from the spline regression models in Figure 2 clearly indicates that every 330ml serving of soft drinks (+21% in the crude and +22% in the fully adjusted model), and for every 200ml of juices (+3% in the crude model, but no association in the fully adjusted model) was associated with a significant increase in hepatocellular carcinoma risk in this cohort, the difference between artificially sweetened and sugar sweetened soft-drinks surfaced only in a subsequent sub-group analysis:

"In additional analyses by the type of drinks (sugar-sweet ened vs. artificially sweetened), each additional serving of artificially sweetened soft drink was positively associated with HCC risk (HR 1.06, 95 % CI 1.03–1.09, n_cases = 101), while for sugar-sweetened soft drinks, this association was null (HR 1.00, 95 % CI 0.95–1.06, n_cases = 127). The difference between both estimates was borderline significant (p_heterogeneity = 0.07)." (Stepien. 2014)

No such difference was observed for sex, BMI category, alcohol intake pattern, nor the categories of juices (i.e. apple or other fruit juices were not worse than vegetable juice).

Before you panic, you should take into consideration that as large as the total cohort may have been the number of cases of hepatocellular carcinoma in the regular and artificially sweetened soft drink drinkers was N=127 and N=101, respectively. That's not just not half as impressive as the total number of participants (N = 477,206); it also raises the question how reliable the results actually is.

This is particularly true in view of the fact that Previously reported findings from the EPIC cohort have shown that high sugar intakes are positively significantly associated with HCC risk. A result which contradicts the link non-existing link between sugar sweetened beverage (SSB) intake and hepatocelular carcinoma in the study at hand and put another question-mark behind the results of the subgroup analysis.

I wrote only recently about the results of a rodent study by Suez et al. which may trace the increased HCC risk with artificial sweetener consumption back to unwanted changes in the gut microbime | read more

They stand in line, however, with the results presented by Schlesinger et al. (2013) and Romaguera et al. (2013) who found an association between artificially sweetened soft drinks and diabetes risk in their analysis of the EPIC data from France and, in this case more importantly, the results Suez et al. published in Nature recently (Suez. 2014). In said study, about which I also wrote about on the SuppVersity (read more), the researchers found that the consumption of non-caloric artificial sweeteners affects the intestinal microbiota composition in a way that leads to the development of glucose intolerance and could eventually also be responsible for the observations Stepien et al. made when they correlated the intake of artificially sweetened beverages of the 101 HCC patients in their with the intake of the 476978 "healthy" (=HCC-free) study participants.

Overall, I would still say that more research has to be done before we can safely say that the consumption of high amounts of artificially sweetened soft drinks, let alone the consumption of artificial sweeteners, in general, will put you at a significantly increased risk of developing hepatocellular cancer. An absolute risk, by the way, of which my elaborations in the 2nd red box tell you that it is still far below 0.03% | Comment of Facebook!

References: 

• Romaguera, D., et al. "Consumption of sweet beverages and type 2 diabetes incidence in European adults: results from EPIC-InterAct." Diabetologia 56.7 (2013): 1520-1530.
• Schlesinger, S., et al. "Diabetes mellitus, insulin treatment, diabetes duration, and risk of biliary tract cancer and hepatocellular carcinoma in a European cohort." Annals of oncology 24.9 (2013): 2449-2455.
• Stepien, et al. "Consumption of soft drinks and juices and risk of liver and biliary tract cancers in a European cohort." Eur J Nutr (2014). Ahead of print. 
• Streppel, Martinette T., et al. "Relative validity of the food frequency questionnaire used to assess dietary intake in the Leiden Longevity Study." Nutr J 12 (2013): 75. 
• Suez, Jotham, et al. "Artificial sweeteners induce glucose intolerance by altering the gut microbiota." Nature 514.7521 (2014): 181-186.

Obesity Research Update: SSBs vs. Artificially Sweetened Beverages, Food Availability, Prices, Variety & Palatability, or Eating Frequency - Is One or Are All Making Us Fat?

Food variety increases binge eating risk, studies show.

With the publication of the latest issue of "Advances in Nutrition" came a whole host of studies that may provide novel insights into potential causes of and solutions to the obesity epidemic. Among the things the researchers investigated and presented at the 20th International Congress of Nutrition were also studies on the possible involvement of artificial sweetened beverages, the availability and convenience of food, the effects of food prices on obesity, the effectiveness of changing the eating frequency, the importance of portion sizes in weight control, the impact of eating a highly variable and palatable diet.

You can learn more about meal frequency at the SuppVersity

Grazin' Bad For the Obese!

Breakfast Keeps You Lean?!

Frequent Protein Consumption

Myth: Few Meals More Bodyfat

8 Meals = Stable, But High Insulin

Int. Fasting & Exercise

• Sugar-Sweetened and Artificially-Sweetened Beverages in Relation to Obesity Risk - In his latest review, Mark A. Pereira set out to "critically evaluate the scientific evidence in humans on the potential effect of sweetened beverages on weight gain and risk of obesity in youth and adults" (Pereira. 2014).
  
  In particular, he compared the association of sugar-sweetened beverages (SSBs) include soft drinks, colas, other sweetened carbonated beverages, and fruit drinks with added sugar and their artificially sweetened counter-parts on obesity risk - with an expected outcome:
  

  "The totality of evidence to date demonstrates a pattern across observational and experimental studies of an increased risk of weight gain and obesity with higher intake of SSBs" (Pereira. 2014).

  The actual problem is that it is difficult to establish the strength of the association and the independence from other potentially confounding factors. In that, Pereira highlights that the primary reason for unclear conclusions regarding the robustness of any effect of SSBs is due to the heterogeneity and methodologic limitations of both observational and experimental studies on this topic.
  
  

  

  Experimental evidence shows artificial sweeteners help weight loss | more

  The latter is all the more true for studies investigating the effects of artificial sweetened beverages on obesity risk. As Pereira points out, "there is no clear mechanism for this pathway, and the epidemiologic studies are highly inconsistent" (Pereira. 2014).
  
  More specifically, none of the currently available epidemiologial studies was able to make sure that the associations the scientists observed were not the result of reverse causality, i.e. obese people consuming artificially sweetened beverage, because they are (already) obese and not the other way around. As Pereira points out, this is more than just a theoretical issue, "higher-quality studies demonstrate this possibility" (Pereira. 2014).
  
  Accordingly, the field needs "higher-quality experimental studies in humans, with relevant direct comparisons between sweetened beverages and their sweetened solid-food alternatives" (Pereira. 2014).
• Food Availability/Convenience and Obesity - Penny Gordon-Larsen reviewed the ever-increasing number of studies investigating the impact of certain qualities of the neighborhood environments on obesity risk. As Gordon-Larsen points out, "there are inconsistencies in the evidence base, suggesting a nuanced association between neighborhood environment, food availability, diet behaviors, and obesity" (Gordon-Larsen. 2014).
  
  With the currently available evidence being limited by a predominance of cross-sectional studies, a high reliance on commercial business listings, a lack of attention to the process by which diet resources are established and expanded within neighborhoods and the potential for individuals to selectively migrate to locate near such facilities, it is difficult to make a reliable conclusion with respect to the influence of food availability and convenience on obesity risk.
  
  Against that background it is difficult to tell, whether the results of a recent study from New York which shows that there is an inverse association between BMI and food outlet density (−0.32 BMI units across the IQR, 95% CI −0.45 to −0.20) is actually significant.
  

  

  Figure 1: Adjusted association between body mass index and food environment measures (Stark. 2014)

  Specifically in view of the fact that there is a positive association between BMI and the proportion of BMI-unhealthy food outlets (0.26 BMI units per IQR, 95% CI 0.09 to 0.43) and no association with outlet diversity. If we went by the results of this study, though, it would appear that living close to food outlets serving donuts, hotdogs and pizza will increase your obesity risk - according to a detail analysis of the New Yorker researchers, this risk is specifically pronounced for people living in areas with "poverty zip codes" (Stark. 2014).
• Food Prices and Obesity - is there a link? As a SuppVersity reader you will know that politics and researchers have repeatedly been debating about taxes on unhealthy foods. To estimate, whether these taxes would work, we would yet have to know "the extent to which overall energy intake or weight outcomes" are actually influenced by food prices.
  

  

  Table 1: Few people know that there are already food taxes in several countries all around the world - with little sucess | öow taxation is defined as less than 10 %; and moderate as 10 % or greater. *the dates for Denmark and Ireland indicate the dates during which the tax was in operation (Mytton. 2014)

  Finkelstein's et al.'s review is one of the first to access this link between food or beverage price changes and energy intake or weight outcomes among U.S. consumers. According to the researchers from the Duke University, the Yale University, and the University at Buffalo School of Medicine and Biomedical Sciences,
  

  "the current evidence indicates that, by themselves, targeted food taxes and subsidies as considered to date are unlikely to have a major effect on individual weight or obesity prevalence." (Finkelstein. 2014)

  Unlike the researchers I am thus not really optimistic that "food taxes and subsidies may play an important role in a multifaceted approach to reducing obesity incidence" (Johnson. 2014) - in particular, if the taxes are determined in accordance with the current US food pyramid, so that "healthy grains" are not taxed at all and "unhealthy eggs" are taxed in a way that even an "industrially" produced egg will costs a dollar.
• Evidence for Efficacy and Effectiveness of Changes in Eating Frequency for Body Weight Management - As Ashima Kant point out, in self-reported diets of free living individuals, frequent eating is associated with higher energy intake. In spite of the scientific evidence, beliefs about the possible beneficial effect of higher eating frequency for managing body weight persist.
  
  In her review of prospective cohort studies and controlled trials of manipulation of eating frequency published by 31 December 2012, Kant included four prospective cohort studies were identified - 2 of these included adults followed for 10 y and 2 followed  pre-adolescent / adolescent girls for 6 or10 y.
  
  

  

  Less Frequent Large(r) Meals & Caffeine - Proven Ways to Increase Your Energy Expenditure & Conserve Your Metabolic Rate While Dieting | more.

  As so often, the findings of the studies that were conducted with young subjects were contradictory.
  

  "Six controlled trials with adult subjects serving as their own controls found no significant changes in body weight due to manipulation of eating frequency interventions lasting 6–8 wk."

  In six additional intervention trials of 8–52 wk duration, free-living adults were counseled to change the eating frequency of self-selected food intake with no significant differences in weight loss attributable to eating frequency.
  
  Currently, the overwhelming majority of the available evidence does thus suggest that manipulation of eating frequency will not promote weight loss. The available scientific evidence is thus once more in conflict with common belief about "best practice", when it comes to losing weight - a "common belief", by the way that was, as so often, influenced by epidemiological data of which people simply don't understand that it cannot establish reliable causal relationships.
• Portion Size and Obesity - In their review of the contemporary literature on the effects of portion size on obesity and weight control, M. Barbara E. Livingstone and L. Kirsty Pourshahidi leave little doubt that "portion size has a powerful and proportionate effect on the amount of food consumed." (Livingstone. 2014).
  
  In spite of the fact that the positive effect of portion size on energy intake has been demonstrated for different types of foods and beverages, and is particularly pronounced with energy-dense foods, though, it is as of now not clear what types of interventions targeted at portion size are likely to be effective, in what settings, and among which target groups.
  

  

  Figure 2: You don't need to conduct a study to realize that portion sizes for foods and beverages - specifically the unhealthy ones - are ever-increasing (image from scienceinseconds.com)

  As the researchers point out, further research is thus urgently needed - specifically in view of the fact that the contemporary evidence indicates that the predisposition to overeat in response to large portions is pervasive and occurs regardless of demographic characteristics, such as socioeconomic status, age, body mass index, and sex. This is all the more true in view of the "secular trend toward greater availability of large portions. coupled with value-size pricing, effectively distorted consumption norms and perceptions of what is an appropriate amount to eat" (Livingstone. 2014).
• Variety and Palatability - Reasons We Get fat? As Fiona Johnson and Jane Wardle point out, "among the key characteristics of the Western obesogenic food environment is a highly palatable and varied food supply" (Johnson. 2014). At first, this sounds yummy and healthy. Unfortunately, the possibility to switch back and forth between a large variety of highly palatable salty and sweet junk food has been shown in both humans and animals to (a) have appetite stimulating effects, to (b) delay satiety, and to (c) promote excessive energy intake.
  
  

  

  Figure 3: When men are offered a sandwiches with identical or varied (4 different) fillings, they will consume significantly more if they are allowed to switch back and forth between the different fillings (Rolls. 1981).

  No wonder that the scientists found that there is a robust effect of food palatability and variety on short-term food intake, and increased variety and palatability also cause weight gain in animal models.
  

  "However, laboratory paradigms do not replicate the complexities of eating in a natural setting [...and t]here are substantial individual diffe- rences in susceptibility to the palatability effect and this may be a key determinant in individual vulnerability to weight gain" (Johnson. 2014).

  Or, put more simply, as long as we do not fully understand the pathways through which palatability and variety can affect eating, it is difficult to identify what helps those who can abstain from overeating maintain their weight and what we can do for those who fall for the temptations to help them stand the test of chocolate, chips, pizza and beer.

There are no simple solutions for complex problems: Obesity is a multifaceted problem. Against that background it's hardly surprising that the one thing all of the previously presented studies have in common is that none of them appears to offer a standalone solution to the obesity epidemic.

If you are working out and dieting like a maniac and still not losing weight, you should revisit your self-torture.. ah training and nutrition regimen and make sure that you didn't already shut down your thyroid by overtraining and undereating | learn more.

Sugar-sweetened beverages are certainly a problem - artifically sweetened ones rather not. The availability of food and more specifically the availability of a high variety of highly palatable food contributes to the obesity epidemic as well - the issue of portion sizes is still not settled and myths that eating more frequently would help to lose weight are still propagated by the mainstream media.

Against that background it seems questionable, whether there's ever going to be a one-size-fits-it-all solution... but hey, maybe that's the solution! We probably just have to stop looking for the one-size-fits-it-all solution and start working towards personalized nutrition programs that evolve as you evolve, e.g. from ketogenic to low carb to moderate carb as you progressively lose weight.

References:

• Finkelstein et al. "Food Prices and Obesity: A Review." Adv Nutr. 5 (2014): 818-821.
• Gordon-Larsen, Penny. "Food Availability/Convenience and Obesity". Adv Nutr 5 (2014):809-817 
• Johnson, et al. "Variety, Palatability, and Obesity." Adv Nutr. 5 (2014): 851-859.
• Kant, Ashima K. "Evidence for Efficacy and Effectiveness of Changes in Eating Frequency for Body Weight Management." Adv Nutr 5 (2014): 822-828.
• Livingstone, et al. "Portion Size and Obesity." Adv Nutr. 5 (2014): 829-834.
• Mytton, Oliver T., Helen Eyles, and David Ogilvie. "Evaluating the Health Impacts of Food and Beverage Taxes." Current Obesity Reports (2014): 1-8.
• Pereira, A. P. "Sugar-Sweetened and Artificially-Sweetened Beverages in Relation to Obesity Risk."  Adv Nutr 5 (2014): 851-859.
• Rolls, Barbara J., et al. "Variety in a meal enhances food intake in man." Physiology & Behavior 26.2 (1981): 215-221.
• Stark, James H., et al. "Neighbourhood food environments and body mass index among New York City adults." Journal of epidemiology and community health 67.9 (2013): 736-742.

Stevia Kills Good Gut Bacteria - One Study Enough to Stop Using the Natural Sweetener? Probably Not in View of its Anti-Diabetes, Anti-LDL, Anti-Viral & Anti-Cancer Effects

Study indicates stevia kills healthy gut bacteria. So, how bad is it? Are the effects significant, will they have an impact on your overall health and does this mean you must not use stevia any longer?

A recent study from the Institute of Microbiology and Biotechnology at the University of Latvia in Riga shows the impossible: Stevia, the "natural" sweetener that's everybody's darling, could mess up your gut microbiome by killing large numbers of the beneficial Lactobacillus Reuteri bacteria in your tummy - exactly those bacteria of which several studies have shown that supplementing will help cure acute diarrhea in young children (Shornikova. 1997), is capable of reducing frequency and intensity of antibiotic-associated side-effects during eradication therapy for H. pylori. (Lionetti. 2006), confers broad-spectrum protection against disease in humans and animals (Casas. 2000), has cholesterol lowering effects (Jones. 2012) and much much more.

You can learn more about the gut & your health at the SuppVersity

Bugs Dictate What You Crave

Sweeteners & Your Gut

Foods, Not Ma- cros for the Gut

Lactulose For Gut & Health

Probiotics Don't Cut Body Fat

The Macrobiotic MaPi2.0 Diet

In view of the fact that it would appear as id Lactobacillus reuteri was clearly one of the "good guys" it seems that the results I. Denin a, P. Semjonovs, A. Fomina, R. Treimane and R. Linde report on their latest study in Letters in Applied Microbiology (Denin. 2014) were really bad news:

Figure 1: Influence of stevioside (a) and rebaudioside A (b) on biomass formation in Lactobacillus reuteri strains (24 h | Denin. 2014).

"In samples supplemented with stevia glycosides, the growth of all Lact. reuteri strains was slightly inhibited – however, a statistically significant concentration-dependent inhibitory effect was not observed for all strains (Fig. 1).

Comparing both the glycosides, the inhibitory effect of stevioside was more pronounced for strains 44 and 16, while the effect of rebaudioside A was more pronounced for strains 16 and 19. Statistically significant concentration-dependent inhib itory effect was observed for lactic acid and acetic acid synthesis. The decrease in lactic acid and acetic acid production was observed for both stevioside and rebaudioside A. [...] Although the inhibitory effect of stevioside on pH was observed at different stevioside concentrations, the effect was evident for all strains. Rebaudioside A had a more pronounced inhibitory effect on pH values of certain strains including Lact. reuteri 12, 16, 43 and 44" (Denin. 2014 | my emphasis).

The good news, however, is in the details: The inhibitory effect was "slight" (see quotation above) and the design of the study leaves it open, whether similar effects would occur in vivo and thus outside of a glycoside, stevioside and rebaudioside laden Petri dish.

Previous studies seem to refute significant effects of stevia on the human microbiome! In 2003, Gardana et al. found no effect of stevia on the make-up of human fecal cultures when they were incubated with either stevioside or rebaudioside A. Only the fact that bacteroides, i.e. the "enemies" of lactobacilli, were the most efficient in hydrolyzing Stevia sweeteners to steviol would suggest that there may be an overall effect on the human microbiome form stevia (ab-)use.

And while we have little in vivo evidence that stevia is bad for you, a brief review of the contemporary scientific literature on Stevia yields the following "proven" (mostly only in a handful, if not just a single study) benefits:

• Stevia has been implicated in diabetes and hyperlipidemia treatment and its effects on blood glucose levels are not a mere result of the corresponding reduction in sugar intake.

  

  Figure 2: Effects of stevia vs. diabetes drug Glibenclamide on blood glucose and lipid levels in diabetic rodents; data expressed relative to healthy control (Singh. 2014)

  In a recent rodent study that compared the effects of stevia against those of the often-prescribed diabetes-drug Glibenclamide, the natural sweetener outperformed the drug in many in its ability to reduce LDL and blood sugar and was not far off of what the Glibencamide did for the diabetic lab animals in terms of its effects on HDL and VLDL (see Figure 2).
  
  Previous human studies indicate that stevia extracts will also increase the increased 16 healthy human volunteers whose plasma glucose levels during an oral glucose tolerance tests were significantly lower after having consumed 5 grams of aqueous leave extract at regular 6-h intervals for 3 days (Curi. 1985).

  

  Figure 3: Effects of stevia and aspartame replacement of sucrose in test meals that were fed to obese and normal-weight volunteers on postprandial blood glucose levels (Anton. 2010)

  Moreover, in a more recent study by Anton et al. where stevia was compared to aspartame, it had the same beneficial effects on total energy intake and let to statistically significant reductions in postprandial glucose levels of both obese and lean study subjects (see Figure 3) that did not reach significance when the sucrose content of the test meal was replaced by aspartame.
• In-vitro stevia appears to have anti-cancer effects, as well. That's at least what studies by  Jayaraman et al. (2008) observed with stevia extracts. An effect that may be related to both it's anti-microbial, as well as its potent anti-oxidant activity (Tadhani. 2007) of the whole leaves and leave extracts of which Tahani et al. found that they contain significant effects of folic acid (52.18 mg/100 g) and vitamin C, as well as 130.76 μg catechin and 15.64 μg quercetin for leaves and 43.99 μg catechin and 1.57 μg quercetin for cellus at mg of water extracts, respectively.
  
  Furthermore, Tadhani et al.'s results showed that the leaf extracts contained higher amounts of free radicals, hydroxyl radicals and superoxide anion radical scavenging activities than those of the callus extracts or the anti-mutagenic effects Cariño-Cortés et al. report in their 2007 study. Whether anything similar can be observed with the white "stevia" powder that is used by most people to sweeten their foods is yet questionable - it's after all pure steviosid and thus devoid of all of the previously mentioned compounds.

  

  Figure 1: Several natural constituents of the stevia plant, including steviosides, which are the naturally sweet agents in stevia have potent anti-viral activity against Epstein-Barr virus; values in brackets
  represent % of untreated control dish (Konoshima. 2002)

  Another possible anti-cancer mechanism may be related to stevia's ability to kill viruses like the Epstein-Barr virus that has been implicated in the pathogenesis of Burkitt’s lymphoma, Hodgkin’s disease, non-Hodgkin’s lymphoma, nasopharyngeal carcinoma, and lymphomas, as well as leiomyosarcomas arising in immunocompromised individuals.in humans (Thompson. 2014).

Against that background it seems questionable that the new evidence of negative effects on allegedly healthy gut bacteria (just want to remind everyone that we have no clue what the optimal gut microbiome would look like) is significant enough to have us all reconsider our use of tiny amounts of stevia as a sweetener in our foods.

Read more about the effects artificial sweeteners have on the microbiome in a prevoius article | go ahead!

Interim conclusion: While I am not all too scared that stevia will mess with my gut microbiome in a way that makes me sick, fat and what not, I truly believe that the effects of artificial sweeteners on the make-up and density of the human gut microbiome is still massively under-researched - and that in spite of the fact that it could have a significant effect on the health of us all.

As s SuppVersity reader you will also be aware that this is not a stevia-specific effects. Only recently I have written about similar effects for a bunch of artificial sweeteners - an article I can only recommend to anyone who hasn't read it yet | Comment on Facebook.

References:

• Anton, Stephen D., et al. "Effects of stevia, aspartame, and sucrose on food intake, satiety, and postprandial glucose and insulin levels." Appetite 55.1 (2010): 37-43.
• Casas, Ivan A., and Walter J. Dobrogosz. "Validation of the probiotic concept: Lactobacillus reuteri confers broad-spectrum protection against disease in humans and animals." Microbial ecology in health and disease 12.4 (2000): 247-285. 
• Curi, R., et al. "Effect of Stevia rebaudiana on glucose tolerance in normal adult humans." Brazilian journal of medical and biological research= Revista brasileira de pesquisas médicas e biológicas/Sociedade Brasileira de Biofísica 19.6 (1985): 771-774.
• Deniņa, Ilze, et al. "The influence of stevia glycosides on the growth of Lactobacillus reuteri strains." Letters in applied microbiology 58.3 (2014): 278-284. 
• Gardana, Claudio, et al. "Metabolism of stevioside and rebaudioside A from Stevia rebaudiana extracts by human microflora." Journal of agricultural and food chemistry 51.22 (2003): 6618-6622. 
• Jayaraman, Sathishkumar, Muthu Saravanan Manoharan, and Seethalakshmi Illanchezian. "In-vitro antimicrobial and antitumor activities of Stevia rebaudiana (Asteraceae) leaf extracts." Tropical Journal of Pharmaceutical Research 7.4 (2008): 1143-1149.
• Jones, M. L., C. J. Martoni, and S. Prakash. "Cholesterol lowering and inhibition of sterol absorption by Lactobacillus reuteri NCIMB 30242: a randomized controlled trial." European journal of clinical nutrition 66.11 (2012): 1234-1241.
• Konoshima, Takao, and Midori Takasaki. "Cancer-chemopreventive effects of natural sweeteners and related compounds." Pure and applied chemistry 74.7 (2002): 1309-1316.
• Lionetti, E., et al. "Lactobacillus reuteri therapy to reduce side‐effects during anti‐Helicobacter pylori treatment in children: a randomized placebo controlled trial." Alimentary pharmacology & therapeutics 24.10 (2006): 1461-1468.
• Shornikova, Aino-Vieno, et al. "Lactobacillus reuteri as a therapeutic agent in acute diarrhea in young children." Journal of pediatric gastroenterology and nutrition 24.4 (1997): 399-404.
• Singh, Sunanda. "Antidiabetic, Antidyslipidymic and Antioxidative potential of methanolic root extract of Stevia rebaudiana (Bertoni) on Alloxan induced Diabetic Mice Sunanda Singh and Veena Garg Department of Bioscience and Biotechnology, Banasthali Vidyapeeth, Banasthali, Rajasthan, India." (2014). 
• Tadhani, M. B., V. H. Patel, and Rema Subhash. "In vitro antioxidant activities of Stevia rebaudiana leaves and callus." Journal of Food Composition and Analysis 20.3 (2007): 323-329. 
• Thompson, Matthew P., and Razelle Kurzrock. "Epstein-Barr virus and cancer." Clinical Cancer Research 10.3 (2004): 803-821.

Artificial Sweeteners Mess W/ Gut Biome & Induce Insulin Resistance in Rodents - What about Man? Plus: Sucralose & Saccharin, Not Aspartame Induce the Effect

Could diet coke really be more obeso- genic than regular coke? there is no experimental evidence to prove that and still the mainstream interpretation of the latest rodent study in Nature says just that.

In contrast to some other experts, I believe in the usefulness of rodent studies as preliminary, easily available way to investigate general physiological processes. Still, when I look at a study that has to use germ-free mice to produce an effect, I begin to doubt that the results are relevant for someone with an intact gut microbiome (no matter if it's "perfectly healthy", or not).

Before I go on with my criticism of a recently published study in Nature (Suez. 2014), I would suggest we'll first take a look at study design and outcome, to make sure not just Steven and Conor, both of whom asked my opinion on the study on Facebook, know what we are talking about.

You can learn more about sweeteners at the SuppVersity

Unsatiating Truth About Artif. Sweeteners?

Will Artificial Sweeteners Spike Insulin?

Sweeteners & the Gut Microbiome Each is Diff.

Sweeter Than Your Tongue Allows!

Stevia, the Healthy Sweetener?

Sweeteners In- crease Sweet- ness Threshold

Suez et al. claim that their study, a 10-week study in the course of which germ-free mice (no bacteria in the gut at the onset of the study) were fed standard chow and supplied with unlimited access to

• saccharin (artificially), sucralose or aspartame sweetened drinking water,
• naturally sweetened drinking water with either sucrose or glucose as a sweetener, or
• plain water as a control,

would demonstrate that the consumption of commonly used non-caloric artificial sweeteners (NAS) formulations, in this case , drives the development of glucose intolerance through induction of compositional and functional alterations to the intestinal microbiota. In that, they probably rightfully point out that

"[...t]hese NAS-mediated deleterious metabolic effects are abrogated by antibiotic treatment, and are fully transferrable to germ-free mice upon faecal transplantation of microbiota configurations from NAS-consuming mice, or of microbiota anaerobically incubated in the presence of NAS," (Suez. 2014)

but they don't tell the reader without full-text access that the negative effects occurred only in four of the animals, were saccharin- and sccralose exclusive and did not occur with the often (falsely) derided sweetener aspartame (see Figure 1, right hand side).

Figure 1: Changes in the bacterial make-up (left) and consequences for the glycemic response after 11 weeks on regularly or artificially sweetened drinking water and antibacterial treatment (Suez. 2014).

Scientific fraud? No, I would rather say a clever way to draw everyone's freakin' attention to a problem that (even if it exists), is not one of all artificial sweeteners and maybe not even be one everyone is susceptible to.
You, as a SuppVersity reader know that this is not the first study to show significant effects of alternative sweeteners on the gut microbiome of the host.

Previous experimental evidence shows that NAS promote, not hinder weight loss | learn more

Experimental evidence vs. observational statistics: As a SuppVersity reader you will also remember that experimental evidence from human studies shows that "Artificial Sweetened Foods Promote, Not Hinder Fat(!) Loss. 1.2kg Body Fat in 70 Days By Eating Artificially Sweetened Products." In the corresponding study by Sørensen et al. I wrote about in May 2014, the artifical sweetener group also had lower hunger ratings, and higher fat oxidation rates compared to the subjects on sucrose sweetened diets. Similar results have been reported by Chen et al. in a study, where subjects replaced part of their regular SSB consumption with diet drinks (Chen. 2009) and de Ruyter et al. who recorded sign. reductions in fat and weight gain in youths after masked replacement of regular SSBs with diet coke & co (de Ruyter. 2012).

In April 2014, I already wrote about a corresponding study by Daly et al. which found that "[d]ietary supplementation with lactose or artificial sweetener enhances swine gut Lactobacillus population abundance," and shows that this effect can be beneficial, as well (at least atm, we still believe that lactobacilli were among the "good guys").

Table 1: Human gut-associated microbial species capable of metabolizing fructose, sugar alcohols, artificial sweeteners (left) and rare sugars and host metabolism and potential implications of consuming various dietary sugar compound (right; HFCS = high fructose corn syrup | Payne. 2014)

Likewise earlier this year, Payne et al. (2014) published a review on the gut microbial adaptation to dietary consumption of fructose, artificial sweeteners and sugar alcohols and the implications for host–microbe interactions contributing to obesity (see Table 1), which suggests both, positive and negative effects depending on the type of sweetener that's used. In this context, it's yet worth mentioning that previous reviews of the literature clearly indicate that the role of artificial sweeteners in the gastrointestinal tract in humans vs. rodents may be fundamentally different (Brown. 2012).

Accordingly, the results Suez et al. present in their latest paper would hardly be considered significant evidence of the existence of a similar problem in human beings, if there weren't the results of an on-going study the scientists are doing. A study that clearly indicates that "similar NAS-induced dysbiosis and glucose intolerance in healthy human subjects." (Suez. 2014)

Alright, but there is one caveat: The previously mentioned human study, the data of which has unfortunately not yet been published has a built-in selection bias with the subjects that meet the criterion of long-term NAS consumption usually being those who have all the reason, namely weight problem, to avoid sugar-sweetened products.

Table 2: Data from the unpublished ongoing observational human study by the same researchers -- Correlates of chronic sweetener (ab-)use; In red: parameters directly related to glycemic control (Suez. 2014)

Still, the significant positive correlations between NAS consumption and several metabolic-syndrome-related clinical parameters (Table 1), including increased weight and waist-to-hip ratio (measures of central obesity); higher fasting blood glucose, glycosylated haemoglobin (HbA1C%) and glucose tolerance test (GTT, measures of impaired glucose tolerance), and elevated serum alanine aminotransferase (ALT, measure of hepatic damage that is likely to be secondary, in this context, to non-alcoholic fatty liver disease) are unquestionably disconcerting and should make us all revisit the amount and frequency with which we are using artificial sweeteners, if the results are eventually corroborated by experimental, not observational, evidence.

Ah, and did the other Internet sources you looked at mention that only saccharine and sucralose, but no allegedly worst of all artificial sweeteners, aspartame, lead to changes in glucose homeostasis? No, well I thought so and I guess they didn't mention either that less than 50% of the mice even developed measurable decreases in insulin tolerance, right? In that case, the fact that stevia has anti-microbial properties (Goyal. 2010; Subudhi. 2010) and could thus also mess with the gut microbiome, wasn't mentioned either, right? Comment on Facebook!

References:

• Brown, Rebecca J., and Kristina I. Rother. "Non-nutritive sweeteners and their role in the gastrointestinal tract." The Journal of Clinical Endocrinology & Metabolism 97.8 (2012): 2597-2605.
• Chen, Liwei, et al. "Reduction in consumption of sugar-sweetened beverages is associated with weight loss: the PREMIER trial." The American journal of clinical nutrition 89.5 (2009): 1299-1306.
• Daly, Kristian, et al. "Dietary supplementation with lactose or artificial sweetener enhances swine gut Lactobacillus population abundance." British Journal of Nutrition 111.S1 (2014): S30-S35.
• de Ruyter, Janne C., et al. "A trial of sugar-free or sugar-sweetened beverages and body weight in children." New England Journal of Medicine 367.15 (2012): 1397-1406. 
• Goyal, S. K., and R. K. Goyal. "Stevia (Stevia rebaudiana) a bio-sweetener: a review." (2010).
• Payne, A. N., C. Chassard, and C. Lacroix. "Gut microbial adaptation to dietary consumption of fructose, artificial sweeteners and sugar alcohols: implications for host–microbe interactions contributing to obesity." obesity reviews 13.9 (2012): 799-809.
• Sørensen, Lone B., et al. "Sucrose compared with artificial sweeteners: a clinical intervention study of effects on energy intake, appetite, and energy expenditure after 10 wk of supplementation in overweight subjects." The American journal of clinical nutrition (2014): ajcn-081554. 
• Subudhi, E., et al. "In vitro antimicrobial study of plant essential oils and extracts." Int. J. Microbiol 8.1 (2010): 1-6.
• Suez et al. "Artificial sweeteners induce glucose intolerance by altering the gut microbiota." Nature (2014). Ahead of Print.

Artificial Sweetened Foods Promote, Not Hinder Fat(!) Loss. 1.2kg Body Fat in 70 Days By Eating Artificially Sweetened Products. Lower Hunger, Higher Fat Oxidation vs. Sucrose

Artificial sweeteners - Could they really be less toxic and obesogenic than half of the blogosphere has it? The study at hand suggests so, but its significance is limited..

The recently posted SuppVersity Classic "Sweet, But Not Innocent!? The Fattening Effects of the Non - Nutritive Sweeteners Erythritol & Aspartame Are On Par With Equally Sweet Sugar Water" (read more) has gotten quite some attention on Facebook, against that background I suppose that today's SuppVersity article will, once more inflame passions. The use of artificial sweeteners as dieting aids is after all highly controversial within the health and fitness community.

If you've read my previous reviews of the corresponding papers, you will yet be aware that there is not a single human study to confirm that any of the "classic" artificial sweeteners (sucralose, aspartame & co) would have negative effects on the loss of body and fat mass during dietary restriction - an still you hear and read corresponding claims on almost every virtual corner of the blogosphere.

You can learn more about sweeteners at the SuppVersity

Unsatiating Truth About Sweeteners?

Will Artificial Sweeteners Spike Insulin?

Sweeteners & the Gut Microbiome Each is Diff.

Sweeter Than Your Tongue Allows!

Stevia, Much More Than Sweet?

Sucralose Raises Cholesterol in Diabetics!?

In this respect, the latest paper by Lone B Sørensen, Tatjana H Vasilaras, Arne Astrup, and Anne Raben is no exception. What is extraordinary, though, is that it describes a relatively tightly controlled single-blind 10-week parallel design study that provides convincing evidence that the association between artificial sweetener consumption and obesity that has been observed in epidemiological studies would be a good example to explain the term "reverse causation" [fat people buy diet products vs. diet products make lean people fat].

In the said study, 24 healthy, overweight subjects had to consume a specific minimum amount of either sucrose-sweetened or artificially sweetened foods and drinks daily.

"The subjects were assigned to 3 different levels of supplements according to their initial body weight: level 1, 2, or 3 corresponding to 60–75, 75–90, and.90 kg, respectively. The minimum intake of the experimental diet was regulated by the sucrose intake and corresponded to a sucrose intake of 125 g/d (level 1), 150 g/d (level 2), and 175 g/d (level 3). This corresponded to a total EI from sucrose supplements of 2.74, 3.29, and 3.83 MJ/d, respectively."

The sweetener group received an equivalent amount (by weight) of foods and drinks, which resulted in an average EI of 694, 832, or 971 kJ/d at levels 1, 2, and 3, respectively. The artificial sweetener content of the intervention diet was 54% aspartame, 23% cyclamate, 22% acesulfame K, and 1% saccharin.

No low fat allowed: Some of the artificially sweetened products were low fat, so the subjects in the sweetener group were given additional butter or corn oil to keep the fat intake in the 2 intervention diets as similar as possible.

In the sucrose group, ~70% of the sucrose came from drinks (average: ~1.3 L/d), and ~30% came from solids foods. About 80% by weight of the supplements were beverages, and ~20% by weight were solid foods. The beverages consisted of several soft drinks and fruit juices, and the solid foods consisted of yogurt, marmalade, ice cream, and stewed fruit.

The products were handed to all participants at the University without informing them about the specific content of sucrose and artificial sweeteners in the supplemented products was unknown to the subjects - all thought, they were consuming products with artificial sweeteners. Otherwise, they were advised to to consume their habitual diet ad libitum. And guess what happened!?

Figure 1: Changes in body weight and fat mass (kg) and energy intake (in MJ) during breakfast, lunch and dinner measured on the one day all subjects had to spend in a metabolic ward (Sorensen.2014).

Yep, you already saw it, the sugar victims (sucrose sweetened products) got fat, while the subjects who had been supplied with artificially sweetened products saw small, bus significant improvements in their body composition without deliberately restricting their energy intake (Remember: all subjects thought that they were consuming zero calorie products).

The reason? Well, take a look at the left hand side of Figure 1. The subjects in the sucrose group did what some people claim would happen, if you consume artificially sweetened products: They ate more! Why? Well, because they were hungrier. Significantly hungrier; and that in spite of their 22% higher energy intake.

Figure 2: The satiety response at lunch was (non significantly) less sustained in the sucrose group (full circles) compared to the artificial sweetener group (open circles) during the subjects visit at the metabolic ward (Sorensen. 2014).

Especially after lunch, the satiety effects were significantly less sustained than in the artificial sweetener group (see Figure 2). What is interesting, though, is the fact that unlike its consequences and the perceived fullness and prospective food consumption (not shown in Figure 2), the satiety difference did not reach statistical significance.

Figure 3: 24h fatty acid oxidation after 10 weeks on diets with sucrose or artificially sweetened add-ons (Sorensen. 2014)

The data in Figure 1 did already tell you: The net effect of the satiety differences was a significantly higher energy intake (+22%) that was not fully compensated by the ca. 6% higher total 24h energy expenditure of the subjects in the sucrose group.

In concert with the reduced fatty acid oxidation rates (see Figure 3) the remaining energy surplus of approx. 1,000kcal (that's the mere mathematical difference of total 24h energy expenditure during the stay at the metabolic ward and the corresponding energy intake) was obviously more than enough to fatten the subjects up.

There is one impor- tant reason why I still recommend to be careful with any kind of sweetener (inclu- ding stevia) and that's the fact that they won't help people get rid of their extra-sweet tooth. A "tooth" which is in many cases the reason they ran into weight problems in the first place. And a tooth that is rather going to get more, not less sugar hungry if you are adding stevia, sucralose or aspartame to whatever foods you eat.

Putting the results into perspective: What this study does confirm is that artificially sweetened products can help average healthy non-dieting, non-overweight individuals lose weight. What it does not confirm is that artificially sweetened products will help obese people lose weight or ward off further weight gain in an ad libitum diet scenario such as the one at hand.

If we go one step further and extend our skepticism from a potential subject- to a potential duration-specific effect, we still don't know if the chronic consumption of artificially sweetened products wouldn't have negative effects on what some people call the "energy intake gauge". Or, put differently, whether the constant exposure to no-calorie foods with an extreme sweetness would not - in the long term - reduce the satiety the subjects in the artificial sweetener group obviously felt after consuming their diet products. If that was the case, the "energy deficit" would disappear and the short term benefits would eventually turn against you.

References: 

• Sørensen, Lone B., et al. "Sucrose compared with artificial sweeteners: a clinical intervention study of effects on energy intake, appetite, and energy expenditure after 10 wk of supplementation in overweight subjects." The American journal of clinical nutrition (2014): ajcn-081554.