The sugar debate rages on and on, and along with each polemic attack on sugar, and stories of individuals experiencing life epiphanies emanating from cutting sugar from theirs diets altogether, hordes of people jump on the bandwagon and profess to give it up hence forth. But as impassioned as they are many of these people still enjoy, indeed crave, sweet flavours. The ‘healthy’ alternative sought is very often artificial sweeteners. But is this really a better alternative? Let’s find out.

war-on-sugar-main 

** Note: while I’d love to go into depths about the pitfalls of targeting one single food group or nutrient as the source of all our western societal lifestyle woes, I fear that I will get on my soap box and turn this already longish article into something resembling the crowning work of Russian author Leo Tolstoy about War, and Peace.

 

Introduction: what is “sugar”

Sugars are a simple form of carbohydrate, the basic substance which makes up most of the non-water content of any plant-based food, and one of the 4 macronutrients which make up the calorie content of any food (the other calorie-containing nutrients being Protein, Fat and Alcohol). Carbohydrates have 2 broad categories: simple (sugars) and complex. Imagine complex carbs as chains, and simple carbs as the individual links making up those chains.

A gram of sugar therefore has the same calorie content as a gram of complex carbohydrate (they are the same stuff after all). Incidentally, a gram of carbohydrate has the same calorie content as a gram of protein (4 calories).

Sugars are categorised as monosaccharides (meaning one unit, or chain link), disaccharides (meaning two), or oligosaccharides (small chains of 3 to 9 links). Anything longer than this is considered a polysaccharide, which might also be called complex carbs.

anatomy-carbohydrates

Examples of monosaccharides include fructose and glucose (both very common), and galactose. Two very common disaccharides are sucrose (table sugar, formed by a glucose unit bonded to a fructose unit) and lactose (a glucose unit linked to a galactose unit).

 

All the same stuff

Any complex carbohydrate or sugar eaten will break down into its constituent units in the small intestine, before those units are absorbed into the blood stream. (well almost any – starches and dietary fibre are types of carbohydrate which the body is not able to break down/digest – these substances ‘pass through’, which is why high fibre diets bulk up the faeces). Without getting on my soap box it is interesting when some anti-sugar proponents target specific types of sugar, like fructose. Given this is a major constituent to many types of carbs (and the ubiquitous table sugar), avoiding fructose, or blaming it for all of the problems, is a bit unrealistic. The point is that whatever form the carb is when you eat it, it will end up being broken into individual units before being absorbed into the blood. The complexity of the carbs only influences how slowly this occurs.

 

Not the same stuff

Most of our hormonal responses to sugar refer specifically to the monosaccharide glucose. Insulin secretions respond predominantly to blood glucose. Muscles and the liver utilise glucose preferentially when storing carbohydrate energy as glycogen. Finally, the brain and muscles prefer to use glucose as a major energy source. This is because glucose is a more stable molecule for deriving energy. The other monosaccharides are also utilised for energy but through longer, less efficient, and also more error prone, pathways. When we have the sugar debate we should keep this in mind because the different carb units are used in slightly different ways. In practice, however, glucose is so prevalent that we can usually approximate “sugar” with glucose.

 

 Problems with sugar and the introduction of sweeteners

Sugars move very quickly from the mouth to the blood stream (high GI) and cause sharp insulin responses, which can result in short lived satiety and therefore a poor ability to regulate one’s overall calorie intake. Over time, frequent sharp spikes in insulin can lead to “a worn out pancreas”. That is, the body becomes sluggish in its response to blood glucose levels, this is also known as insulin resistance, and ultimately diabetes. Note, and again, without jumping on the soap box, an equally bad outcome can occur if sugar is not present at all because the insulin response never gets a ‘workout’. Both of these effects are worsened if there is little or no physical activity present, and in the presence of ‘inflammation’ from chronic stress or some lifestyle condition like abdominal obesity.

Enter artificial sweeteners… well, not quite. Artificial sweeteners have been around for a while (e.g. used in the 1800s during sugar shortages). They became commercialised in the 1960s as people attempted to cut down on sugar in their diet. Not all sweeteners are the same (see below), but generally they all work by binding, often not quite perfectly, with the sweet taste receptors on your tongue. The imperfect binding is responsible for the sometimes odd or metallic after tastes.

 

Sweeteners are not toxic, probably

Most sweeteners have undergone lifespan laboratory testing in rats, and short-term human studies for toxicity, metabolism, reproductive safety and pharmokenetic usage (what the body does to the drug during metabolism). No significant issues with their use has so far been identified from this perspective, although very heavy use (in excess of what is likely humanly possible) could be harmful, for instance, with some sweeteners being metabolised into methanol and others containing Chlorine. Reflecting this, there are Recommended Daily Intakes (representing maximum recommended amounts, not minimum required amounts) in place for most sweeteners. The toxicity of sweeteners has not been tested over a human lifespan, however – so we aren’t yet totally sure that there are harmful effects of long term sweetener use.

Examples of sweeteners include:

  • Sucralose (Splenda): 3 chlorine molecules (yes, chlorine) replace 3 hydroxol groups on the sucrose molecule. It passes through the body unabsorbed during digestion (comes out in urine) and contains no calories. Enjoys 50% of the sweetener market as it is stable at high temperatures, and therefore suitable for baking.

sucrose-vs-sucralose

  • Stevia: derived from a herb. It contains no calories and is unabsorbed by the body. There are several health claims as well as (contradictorily) possible concerns regarding potential carcinogenic properties, fertility issues, and carbohydrate metabolism with long-term use. There is currently insufficient data to “confidently” set tolerable upper limits or an RDI requirement. For this reason in the US it cannot be used in food production, but can be bought from chemists as an additive.
  • Aspartame (Equal): a chemical combination of 2 amino acids (protein building blocks) aspartic acid and phenylalanine, plus methanol. Contains four calories per gram. Not really suitable for baking – unstable at high temperatures.
  • Saccharin (Sweet’n Low): a combination of sodium, nitrogen and a hydrogen dioxide molecule and contains no calories. It passes through the body unabsorbed during digestion and is excreted in urine. In 1977 a US ban was placed on saccharin based upon animal research that suggested it was a weak bladder carcinogen. In the study, researchers administered unrealistically high doses of saccharin, equivalent to seven hundred cans of soft drinks or ten thousand tablets per day, every day, for a lifetime. In addition, the current research indicates the mechanism that causes cancer when high levels of saccharin are consumed is unique to male rats and not relevant to humans.
  • Sugar alcohols (xylitol): they are not a huge variation of a standard sugar molecule so they are still metabolised and converted into energy, though calorie content is much lower than straight sugar. Used in chewing gum and can cause gastrointestinal upset if consumed in large amounts.

 

Fewer calories, but are sweeteners healthy?

While studies (often part of government approval processes) indicate safety in the sporadic use of sweeteners in relation to toxicity, metabolism, reproductive safety and pharmokenetic usage, their usefulness or riskiness in relation to reducing energy intake, lowering/managing body weight and reducing/managing diabetes and other lifestyle diseases is much less clear. There is no doubt that replacing sugar in one’s diet with sweeteners, all other things being the same, will reduce caloric intake, but data does not suggest that this necessarily translates into lower weight and fewer health risks.

For instance, broad statistics do seem to draw a correlation between the increased use of artificial sweeteners and weight gain in the US population (see diagram) from (Yang, 2010). For many people, the adage “where there is smoke there is fire” would apply.

sweetner-vs-obesity

However, if you review the literature over the past 40 years there are equally credible studies which show that sweeteners are helpful (Raben & Richelsen, 2012), or have as yet unclear effects (Mattes & Popkin, 2009), (Brown, et al., 2010), (Pepino & Bourne, 2011), (Wiebe, et al., 2011) with regard to regulation of energy balance or other metabolic consequences.

The apparent contradiction is really the result of trying to draw general conclusions from studies which investigate very specific circumstances of sweetener use. Just some of the variables which have affected study results include:

  • How sweeteners were compared – e.g. to a diet were sugar was replaced, or to added to an otherwise healthy sugar controlled diet, or whether the sweetener or pre-study diet was itself controlled (e.g. for calories).
  • The variable being measured by the study: weight loss, weight gain, markers of diabetes (metabolic syndrome) or heart disease or treatment/management of diabetes or heart disease, and the risk factors associated with these diseases.
  • Whether the study was in animals or humans, adults or children, was short or long term, or was large or small. Large studies can be difficult to interpret because the results are often adjusted to allow for statistically significant differences in the baseline conditions (e.g. different genetics, race, sex, state of health, existing dietary habits, exercise status etc). These adjustments are different for every study depending on what researchers deem important in that case.
  • How the sweeteners are administered and in what quantities

On the balance of all of the literature, here is what is STRONGLY suggested (Swithers, 2013):

  • Increased health risks and no reduction in health risks

A bank of recent studies, taken together, suggest a link between consumption of artificially sweetened beverages (note: a very specific use of sweeteners in one’s diet, not clear whether this applies to use of sweeteners generally) and a variety of negative health outcomes, including increased risk of being overweight and obesity, diabetes, and cardiovascular events 

[for example, see footnote 1], especially in adults. In none of these studies was consumption of artificially sweetened beverages associated with significantly decreased risk; and in an interventional study (replacing sugar sweetened beverages with artificially sweetened beverages) there was no improvement in fasting glucose as a result of the substitution whereas there was when water was used. This general pattern of findings emerged across studies that varied widely in design, methodology, and population demographics.

  • No reverse causality

There is generally a refutation of various studies which suggest that increased health risks and generally poorer health in people using sweeteners is actually due to overweight people turning to sweeteners in an attempt improve their diet. These studies say these people already had elevated health risks before they started using sweeteners, which means these risks are not related to the use of sweeteners. However, statistical control analysis (adjusting for baseline health) has concluded that this “reverse causality” does not plausibly account for the increased risk in all studies.

  • There could be a place for sweeteners in very controlled conditions

Physiological responses that typically occur following consumption of sugar (e.g. insulin release, fat storage) are not elicited by artificial sweeteners or are of much smaller magnitude. There is good evidence that sweeteners do not raise blood glucose levels in people with diabetes when substituted for added sugar. In this way, sweeteners used as part of a controlled intervention into diabetes, most particularly the management of blood sugar levels and insulin sensitivity, can be effective.

  • But sweeteners can lead to poorer health outcomes in uncontrolled conditions

Sweet tastes are known to evoke numerous physiological responses that help to maintain energy homeostasis by signalling the imminent arrival of nutrients into the gut and by facilitating the absorption and utilization of energy contained in food (Smeets, et al., 2010). When these physiological responses are elicited on a regular basis, with no corresponding calorie intake, the body is tricked. A learned behaviour emerges where a given physiological response to sweetness is associated with fewer calories, and therefore the body stimulates hunger more strongly to compensate  (Davidson, et al., 2011). The body essentially loses its ability to turn off hunger in response to a perceived level of sugar, interpreted as sweetness. If sugar is still present in the diet, the body will demand more of it. It is also possible, though not yet proven, that this occurs in relation to carbohydrates generally, not just sugars.

  • Sweeteners can lead to a perverse form of reasoning about one’s diet

Behavioural studies have shown that the use of sweeteners can often create a sense that a person had made a healthy choice which grants permission to over consume other ‘non-healthy’ foods (Chandon, 2012).

  • Too much sweetness is probably not a good thing

It is possible that artificial sweeteners, when used to augment the number of sweet foods in a person’s diet as opposed to simply replacing sugars already present, often “justifiable” because they contain no calories, encourages sweet cravings and dependence. Repeated exposure to sweetness (or other flavours) trains flavour preference and will result a preference for more and more intense forms of that flavour (Liem & de Graaf, 2004). This is a dangerous problem when they body given the availability of sugar and how easily it can creep into the diet even while endeavouring to use sweeteners.

 

Conclusion

Sweeteners can useful in controlled environments and in specifically targeting health disorders such as type 2 diabetes. But their use is fraught with risks ranging from altered body physiology, to warped cognitive processes, to exposure to as yet unquantified toxicity effects if your use is long term. Therefore, their use as a general substitute for sugar in the diet is probably inferior to simply reducing sugar intake. I made a point of the short sightedness of targeting sugar as the sole cause of health issues at several points in the article but I should qualify this by saying that in many people’s diets, a reduction of sugar intake (along with calories generally, and an increase in exercise) is totally warranted. To wind back our desire for sugar we need to realise that flavour preference is a learned behaviour (see the final point above); it can be unlearned through gradual but systematic reduction of that flavour in the diet.

 

Addendum

Be aware that you don’t always have to “taste” sweetness for sugar to be present. Many of the processed food products we eat has sugar content similar to fruit (which is 8-15 grams per 100 grams), but quite often salt is added to mask the sweetness. The sugar makes us want to eat more, but the salt keeps the flavour savoury.

By the way – the comparison to fruit should not be interpreted as a direction to cut fruit from the diet. Fruit is a great source of fibre and vitamins, contains no salt and is packed with water, which helps with our overall hydration efforts. When compared to processed products of similar sugar content, which are often dehydrated and fully or partially stripped of the natural fibre and vitamin content of its ingredients, fruit is a far better choice. Nonetheless, it is recommended that we only need around 2 serves of fruit per day. In looking to reduce our taste preference for sweetness there are far more numerous and far poorer dietary choices to target than fruit.

 

 

Works Cited

Brown, R. J., De Banate, M. A. & Rother, K. I., 2010. Artificial sweeteners: a systematic review of metabolic effects in youth. Int J Pediatr Obes., Issue 5, p. 305–312.

Chandon, P., 2012. How package design and packaged-based marketing claims lead to overeating. Appl Econ Perspect Policy, Issue 31, p. 7–31.

Davidson, T. L., Martin, A. A., Clark, K. & Swithers, S. E., 2011. Intake of high-intensity sweeteners alters the ability of sweet taste to signal caloric consequences: implications for the learned control of energy and body weight regulation. Q J Exp Psychol (Hove), Issue 64, p. 1430–1441.

Liem, D. G. & de Graaf, C., 2004. Sweet and sour preferences in young children and adults: role of repeated exposure. Physiol Behav, Issue 83, p. 421–429.

Mattes, R. D. & Popkin, B. M., 2009. Nonnutritive sweetener consumption in humans: effects on appetite and food intake and their putative mechanisms. Am J Clin Nutr., Issue 89, p. 1–14.

Pepino, M. Y. & Bourne, C., 2011. Non-nutritive sweeteners, energy balance, and glucose homeostasis. Curr Opin Clin Nutr Metab Care, Issue 14, p. 391–395.

Raben, A. & Richelsen, B., 2012. Artificial sweeteners: a place in the field of functional foods? Focus on obesity and related metabolic disorders. Curr Opin Clin Nutr Metab Care, Issue 15, p. 597–604.

Smeets, P. A., Erkner, A. & de Graaf, C., 2010. Cephalic phase responses and appetite. Nutr Rev, Issue 68, p. 643–655.

Swithers, S. E., 2013. Artificial sweeteners produce the counterintuitive effect of inducing metabolic derangements. Trends Endocrinol Metab., 24(9), pp. 431-441.

Wiebe, N. et al., 2011. A systematic review on the effect of sweeteners on glycemic response and clinically relevant outcomes. BMC Med, Issue 9, p. 123.

Yang, Q., 2010. Gain weight by “going diet?” Artificial sweeteners and the neurobiology of sugar cravings: Neuroscience 2010. Yale J Biol Med, Issue 83, p. 101–108.

 

[footnote 1]

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Dhingra R, et al. Soft drink consumption and risk of developing cardiometabolic risk factors and the metabolic syndrome in middle-aged adults in the community. Circulation. 2007;116:480–488.

Lutsey PL, et al. Dietary intake and the development of the metabolic syndrome: the Atherosclerosis Risk in Communities study. Circulation. 2008;117:754–761.

Nettleton JA, et al. Dietary patterns and incident cardiovascular disease in the Multi-Ethnic Study of Atherosclerosis. Am J Clin Nutr. 2009;90:647–654.

Fagherazzi G, et al. Consumption of artificially and sugar-sweetened beverages and incident type 2 diabetes in the Etude Epidemiologique aupres des femmes de la Mutuelle Generale de l’Education Nationale-European Prospective Investigation into Cancer and Nutrition cohort. Am J Clin Nutr. 2013;97:517–523.

de Koning L, et al. Sugar-sweetened and artificially sweetened beverage consumption and risk of type 2 diabetes in men. Am J Clin Nutr. 2011;93:1321–1327.

Bhupathiraju SN, et al. Caffeinated and caffeine-free beverages and risk of type 2 diabetes. Am J Clin Nutr.2013;97:155–166.

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