In the BDJ this month is a specially commissioned feature on sugar and common sugar alternatives from the viewpoint of Elaine Gardner of the British Diabetic Association. I commend the BDJ for creating this article but I also have some criticisms of it so I have decided to air my views and create one page really delving deep into sugar and collecting other useful resources in this field. Hopefully this can help others to lead more stable lives without the highs and lows associated with refined sugars and enable you to give more complete advice to your patients by expanding on the limited knowledge given to undergraduates on this topic so vital to dental health.
Sugar is metabolised by oral bacteria such as streptococcus mutans, releasing acid as a by product and over time this puts you at risk of dental caries.
This is the line that is taught to dental students throughout the world and indeed it is true, but is also a massive oversimplification of a vital part of dental health. And in my experience almost nothing is taught in dental schools about how sugar impacts on general health and on mental capabilities. The aim of this post is to expand on this topic which is so vital to understand to both provide better care for our patients and to allow us to take better care of our own bodies.
"Sugar" is a term for a select group of carbohydrates and within that group are various different molecules each of which are metabolised differently both by oral bacteria and your body.
Each of the following molecules are the basic building blocks of the more complex sugars discussed later. They all have the same chemical composition of C6H12O6 but in different arrangements.
"Glucose" is the form of sugar that circulates in your blood. Many foods naturally contain Glucose but often either in combination with other sugars (e.g. Honey is predominately glucose and fructose) or as part of a long chain "complex carbohydrate" e.g. Starch in potatoes is a chain of lots of Glucose molecules. The Glyacaemic index (GI) of pure Glucose is 100.
"Fructose" is naturally found in most fruit. Glycaemic index of 25.
"Galactose" is found in dairy products combined with glucose to form lactose. Glycaemic index of 25.
"Sucrose" (Table sugar aka refined sugar although other sugars can also be refined) is a combination of a molecule of Glucose and Fructose. Derived from sugar cane or sugar beet and used in most commercial confectionary and baking. GI of 65.
"Lactose" as explained earlier is a combination of Glucose and Galactose found in dairy products. GI of 45.
"Maltose" is a combination of 2 Glucose molecules. Found in any foods related to the word malt e.g. Beer and many grain based foods. GI of 105.
There are other various polysaccharide sugars but these are generally only a small part of our diets.
Sugar and Tooth Decay
Some of these sugars are metabolised readily by oral bacteria thereby dropping the oral pH below the critical level when enamel and dentine start to demineralise. The critical pH varies depending on the abundance of phosphate and calcium in the environment but for enamel is about 5.5 and for dentine is about 6.5. Sucrose, Glucose and Fructose are metabolised easily by oral bacteria. These molecules are broken down providing energy for the bacteria to function and releasing lactic acid thereby reducing the pH putting tooth surface at risk. However lactose is not fermentable by oral bacteria hence the reason dairy products are often recommended as part of a diet to maintain a healthy dentition.
It is this relationship between dietary sugars and plaque pH that is so critical to caries formation and the reason why gum manufacturers like Wrigley's even mention it in their adverts. Although be warned that while chewing sugar free gum does indeed help to minimise the impact of low oral pH, many of these gums do themselves contain artificial sweeteners that you need to be mindful of. More about that later.
Sugar and general health
Just as some sugars affect oral pH more than others, some sugar molecules are more readily metabolised by your body resulting in a greater impact on your blood sugar level. This is illustrated by the glycaemic index of a food. The higher the number, the greater the impact on your blood sugar level although sometimes this can get confusing because some foods classed as healthy have a higher GI than some with a bad reputation. A better idea can be gained from considering the glycaemic load which combines GI and the amount of carbohydrate of a food. Foods that raise your blood sugar quickly will often also only give you a short burst of energy which is followed by a deep crash leaving you feeling sluggish and also resulting in a massive dive in your mental function as the brain requires so much more energy than almost any other of your organs. Some scientists believe our brains consume over 20% of the total energy allowance of our body. The opening chapters of Dave Asprey's book Head Strong are very good at explaining this topic and he has some good dietary advice although personally I feel that you may need to keep an open mind over some of his more extreme ideas.
Over a long period of time, regular consumption of a lot of high GI foods can mean that your body becomes intolerant to insulin and then the problem is compounded because it can't regulate your blood sugar level properly, putting you at risk of diabetes and rapid weight gain.
There are other serious risks that have been associated with sugar too with a very worrying trend showing that a high sugar diet massively increases your risk of developing a whole host of cancers. One part of the current theory is that because cancer cells require a lot of energy to divide, a high blood sugar level allows them easy access to an excess of fuel to drive even faster division and thus spread at an alarming rate.
It is for all these reasons and more that I am now a lot more mindful of the food I put into my body and am on a drive to almost completely eradicate refined sugars from my diet. This isn't always easy and I openly admit that I wouldn't be able to do this without my wife sharing this passion and helping to educate me about much of this over the last year. However I cannot stress highly enough how powerful this can be. The gradual shift in my diet this year over to one with much less free sugar and much richer in good fats and organic produce has allowed my mind and body to function at a much higher level.
The various names for sugar
Food manufacturers often add sugar to foods in a variety of forms so sometimes it is difficult to know whether the food you are eating contains refined sugars. Below are some of the various names given to sugars, some of which are refined, some are not. But all should be avoided where possible or eaten only in moderation:
High-fructose corn syrup (HFCS)
I had been thinking of writing about sugar for a while now but the final spark came from reading an article in the current BDJ which I have linked to below. I commend the BDJ for commissioning this article but I do have some constructive criticisms of it that I would like to share:
1) It seems extremely positive about artificial sweeteners such as sucralose. This worries me seeing as there is a history of controversy that many artificial sweeteners may have terrible health effects. For instance, even though a big review of lots of studies concluded in setting a safe level for various sweeteners there are many renowned scientists who still publicly express grave concerns about a wide variety of potential side effects. Did you know that the scientists that first created Sucralose weren't trying to make a sweetener? They were in fact attempting to make a pesticide!
2) The article says very little about coconut sugar and what it does say isn't clear. While coconut sugar is still cariogenic and does raise blood sugar levels, its glycemic index is significantly less than that of refined sugar (35 for coconut sugar vs 65 for table sugar) so it makes a very good substitute for baking etc. This omission is surprising seeing as the article was written by a member of the British Diabetic Association.
3) It is very positive about Xylitol, Stevia and Yacon syrup and I agree that they have potential as a sugar replacement, however personally I believe their relatively recent introduction to our diets means that we do need to be mindful of potential long term effects of their use in high doses that we may not be aware of yet.
Here is the BDJ article:
If you would like to find out more about these ideas please have a look at some of the content below. Of particular note I would recommend you look at the content by the American nutritional expert Dr Axe. He provides a very good guide on all the options available to you for reducing your refined sugar intake by choosing better alternatives. I will aim to add extra links here as I find other useful guides:
WHO guide to sugar intake
Dr Axe guide to sugar in your diet
Dr Axe guide to sugar alternatives
The current NHS guide to artificial sweeteners
A really interesting article about the role of sugar in cancer growth promotion
Soon I will share with you my thoughts on why giving yourself a diet diary can be one of the most powerful things you do for your overall health. And by sharing my own diet diary hopefully I will show you that a diet with minimal sugar doesn't mean depriving yourself.
Dr Chris Harper