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The bittersweet truth about sugars and sweeteners

23/07/2019
The bittersweet truth about sugars and sweeteners

Why do you like sweet things?

Our ability to perceive sugar as sweet once ensured our survival as omnivores.

Sugar gave is the ability to identify plants with a high proportion of readily available energy - in the form of glucose[1].

Cats and many other carnivores, on the other hand, are not able to taste sweetness[2]. It simply didn't give them an evolutionary advantage, since they didn't have to eat plants with varying nutrient contents to survive.

 

Dangers of sugar in modern times?

But since the industrial production of large quantities of beet and cane sugar, the spread of sugar in our food has become rampant.

The fact that dopamine is released in the brain's reward center when sugar is consumed makes it difficult to avoid sugar. This also leads to sugar having addictive qualities[3].                      

A longterm overdose of sugar has already been associated with diseases ranging from obesity to type II diabetes[4] and cardiovascular disease[5].

The last revolution in sugar eventually gave us sweeteners: substances with a similar or enhanced sweetness that contain no or significantly fewer calories.

Is it possible that although they prevent some of the dangers of high sugar consumption, can sweeteners create new risks?

 

In a nutshell

What happens to sugar when we eat it?

Sugars are the building blocks of carbohydrates. The smallest version are monosaccharides, consisting of a single sugar molecule. One of them is glucose, which is used in our cells to produce energy.

In addition to monosaccharides, which also include fructose from fruit, disaccharides - such as lactose - are also found in common foods. They are chemical combinations of several sugar units. In order to be able to utilize them, they must be chemically broken down in the body.

Sugar is absorbed into the intestinal cells and transported into the bloodstream via the GLUT2 transporter. After a meal, the blood sugar level rises sharply, insulin is released and ensures that the sugar reaches the cells, where it is used to generate energy and transmit signals.

Insulin also stops the burning of fat so that glucose can be utilized first.

 

Why do some sweeteners contain less or no calories?

A distinction is made between sweeteners and sugar substitutes.

Sweeteners are many times sweeter than conventional sugar and can, therefore, be used in lower concentrations.

Sugar substitutes are just as sweet as sucrose but do not contain as many calories.

Both types are perceived as sweet by the taste buds because of their structure being similar to sugars. The binding to a receptor via hydrogen bonds is decisive for the sweet taste. The better a molecule can bind, the stronger the sweet taste.

 

Natural sugar sources

Sugar found in plants and natural products is present in a natural proportion to other molecules.

Natural (or unadded) sugar is not artificially highly concentrated; it is usually a mixture of glucose, fructose, and the disaccharide sucrose.

 

Fruits

Fruits contain a very high proportion of fructose. This has often been perceived as something very negative. Especially in the USA, the general population associates fructose with obesity and related diseases[6].

However, this does not concern the natural fructose from fruit, but high fructose corn syrup (HFCS), which is found as highly concentrated, added sugar in industrial food. Consumption of large quantities is associated with liver toxicity and other chronic diseases[7].

 

Honey

Before the industrial extraction of sugar from sugar beets or cane, honey was often the only sweetener.

Honey is 82%[8] sugar but is also enriched with minerals such as calcium and magnesium, trace elements, vitamin C and amino acids making it a complex natural food with more nutritional value than plain sugar.

 

Lactose/milk sugar

In people without lactose intolerance lactose is split into glucose and galactose. Since only monosaccharides can be absorbed through the intestinal wall. In the case of lactose intolerance, the unsplit lactose migrates further into the large intestine, where lactose digesting bacteria form gases and acids causing discomfort.

 

Industrial sugar

Industrial sugar production was initiated as early as 1801. Sucrose, the most commonly used form of sugar, has since been extracted from cane and sugar beet in large quantities ever since.

 

Sucrose

Common white sugar, obtained from sugar beet, is a disaccharide consisting of glucose and fructose. Our consumption has rapidly increased over the last century due to its spread into all food groups.

Excessive consumption has been shown to cause the onset of metabolic syndrome, a condition with symptoms such as:

  • high blood pressure
  • high blood triglycerides
  • insulin resistance
  • cardiovascular disease
  • diabetes
  • premature aging[9],[10].

The problem here is not the sugar itself, but the sheer amount of pure, concentrated sugar consumed in the western world which is associated with many chronic conditions.

 

Sweeteners and sugar substitutes

Most of these substances are so-called polyols - or sugar alcohols, obtained from fruits. Just like sugar, they have several hydroxide groups (or alcohol groups, i.e. compounds of hydrogen and oxygen) and are therefore perceived by us as sweet.

Since they are only absorbed very slowly or not at all in the intestines, they have a laxative effect. If too much is consumed, a large amount remains in the intestine, since it does not get through the intestinal wall and attracts water.

 

Xylitol or birch sugar

This polyol is found in small amounts in fruit and vegetables. Xylitol has been a common sweetener in chewing gum for several decades because, unlike conventional sugar, it does not cause caries[11]. Unlike sucrose, this substance has no effect on blood sugar.

 

Aspartame

Aspartame is a sweetener. Although it has the same number of calories per gram as sugar, it is about 200 times sweeter[12], so smaller amounts can be used.

The European Food Safety Authority recognizes an amount of 40 mg/kg body weight/day as safe for the general population[13].

Again, there are no long-term studies on the effects of increased consumption of aspartame.

 

Stevia

This sweetener, derived from the leaves of the South American plant Stevia rebaudiana, is much sweeter than ordinary sucrose. The sugar-like substances responsible for it are called steviol glycosides.

Stevia was approved as a food additive in 2011[14] because it has been classified as safe for health in the EU. 

Blood pressure and blood sugar-lowering effects have been demonstrated for this non-caloric sweetener[15],[16]. However, it is still disputed whether stevia is really completely beneficial.         

 

Bittersweet conclusion    

According to the current state of research, sugar and sweeteners are of particular concern at higher concentrations. 

This is easy to understand because sugar-containing fruits were a very limited resource for our ancestors. They were only available a few months a year, in some climate zones not at all. Our body has not changed significantly since then and yet the consumption of sugary food has increased immeasurably.

 

What is important:

  • become aware of the amount of sugar in your daily diet
  • check nutritional information for additional sugar
  • make sure your main sources of sugar are natural

By increasing your intake of fruits high in natural sugar you also consume more antioxidants, vitamins, and minerals. Like that, sugar stops being the main reason you eat something and becomes more of a nice addition of flavor.                                                                                                  

 

 

[1] Gary K. Beauchamp, Why do we like sweet taste: A bitter tale?, Physiology & Behavior, Volume 164, Part B, 2016, Pages 432-437, ISSN 0031-9384, https://doi.org/10.1016/j.physbeh.2016.05.007.

[2] Peihua Jiang, Jesusa Josue, Xia Li, Dieter Glaser, Weihua Li, Joseph G. Brand, Robert F. Margolskee, Danielle R. Reed, Gary K. Beauchamp

Proceedings of the National Academy of Sciences Mar 2012, 109 (13) 4956-4961; DOI: 10.1073/pnas.1118360109.

[3] Wiss, David A et al. “Sugar Addiction: From Evolution to Revolution.” Frontiers in psychiatry vol. 9 545. 7 Nov. 2018, doi:10.3389/fpsyt.2018.00545

[4] Rippe, James M, and Theodore J Angelopoulos. “Relationship between Added Sugars Consumption and Chronic Disease Risk Factors: Current Understanding.” Nutrients vol. 8,11 697. 4 Nov. 2016, doi:10.3390/nu8110697.

[5] https://www.health.harvard.edu/heart-health/the-sweet-danger-of-sugar.

[6] Salwa W Rizkalla, Health implications of fructose consumption: A review of recent data, Nutrition & Metabolism20107:82, https://doi.org/10.1186/1743-7075-7-82.

[7] Lustig, R. H. J. Am. Diet. Assoc. 110, 1307–1321 (2010).

[8] https://fdc.nal.usda.gov/fdc-app.html#/?query=ndbNumber:19296.

[9] Lustig, R. H. J. Am. Diet. Assoc. 110, 1307–1321 (2010).

[10] Tappy, L., Lê, K. A., Tran, C. & Paquot, N. Nutrition 26, 1044–1049 (2010).

[11] K. K. Mäkinen: The rocky road of xylitol to its clinical application. In: Journal of Dental Research. Band 79, Nummer 6, Juni 2000, S. 1352–1355, PMID 10890712.

[12] https://www.efsa.europa.eu/de/topics/topic/aspartame.

[13] https://www.efsa.europa.eu/de/topics/topic/aspartame.

[14] Verordnung (EU) Nr. 1131/2011 der Kommission vom 11. November 2011 zur Änderung von Anhang II der Verordnung (EG) Nr. 1333/2008 des Europäischen Parlaments und des Rates hinsichtlich Steviolglycosiden. (PDF)Amtsblatt der Europäischen Union, L 295/205, 12. November 2011.

[15] M. S. Mélis: Influence of calcium on the blood pressure and renal effects of stevioside. In: Brazilian journal of medical and biological research = Revista brasileira de pesquisas medicas e biologicas. Band 25, Nummer 9, 1992, S. 943–949, PMID 1342842. 

[16] S. Gregersen, P. B. Jeppesen, J. J. Holst, K. Hermansen: Antihyperglycemic effects of stevioside in type 2 diabetic subjects. In: Metabolism: clinical and experimental. Band 53, Nummer 1, Januar 2004, S. 73–76, PMID 14681845.                                                 

 

X Katharina Hoffmann