Saturday, 6 December 2008

Sugar, Sugars and Sweeteners - Spotlight on Xylitol

Summary
Alternative Names
Chemistry and Origins
Classification
Regulation
Where it can be Found
Taste, Calories and Digestion
Health Implications and Safety
Other Information
My Opinion
Introduction
As part of the Definitive Guide to Sugar, Sugars and Sweeteners, each month I will try to cover one in detail so that eventually the guide becomes a one-stop shop for all you ever wanted to know...
Summary
Xylitol is found in a number of fruits, vegetables and plants, such as plums and mushrooms. It is used worldwide, most commonly to sweeten chewing gums and dental products, as it does not cause damage to teeth. It is seen as a healthy alternative to sucrose because it has fewer calories and a reduced effect on blood sugar. There are currently no known serious health effects from consuming xylitol.
Alternative Names
Birch Sugar
Chemistry and Origins
Xylitol was first used in Finland during the second world war because of sugar shortages. The Finns extracted the xylitol from the plentiful birch trees found in Finland. After the war, people noticed a marked reduction in tooth decay amongst those who has been using xylitol instead of sugar. Further research into its benefits led to wider adoption later in the 20th century and more industrialised production.

Xylitol is one of four isomers of 1,2,3,4,5-pentapentanol. It's molecule is achiral, which means it can be superimposed on its mirror image.
Classification
Xylitol is a sugar alcohol and therefore classed as a natural sweetener.
Regulation
Xylitol was approved by the FDA (America's Food and Drug Administration) in 1963 for 'special dietary uses' and in 1986, recognized as a 'safe sweetener'. Xylitol is approved throughout Europe for various dietary, pharmaceutical, and cosmetic uses. It has also been approved by a variety of other organisations including the Joint Expert Committee on Food Additives (JECFA), the UK Ministry of Agriculture, Fisheries and Foods (MAFF) in 1994, at national level in more than 40 EU countries and in 1997 by the Japanese Ministry of Health and Welfare.
Where it Can be Found
In nature, xylitol can be found in small amounts in a variety of plants, most commonly fruit, berries, vegetables and mushrooms. Examples are raspberries, yellow plums and strawberries. It is also found in corn husks oats and the birch tree.

As an additive, xylitol is most commonly used in chewing gum, but is also found in many dental and pharmaceutical products, some of which include xylitol for its medicinal properties. However, increasingly it is being used as a general sweetener for food and drink. As well as being used as an additive by manufacturers, it can be bought in large amounts in the same way as sucrose (sugar) and is being used domestically for baking or to sweeten food and drink.
Taste, Calories and Digestion
Weight for weight, Xylitol is just as sweet as sucrose (sugar) and has a very similar, though slightly menthol taste. However, it contains only two thirds of the calories. Only a small proportion is absorbed through the small intestine and converted to glucose in the liver. The slowness of absorption means that the majority moves down to the lower intestine, where it is metabolised by friendly bacteria into short-chain fatty acids. These are mostly returned to the liver for oxidation, providing energy. As a consequence, xylitol has a negligible or zero effect on blood glucose levels and has been widely used for many years in diabetic diets.
Health Implications and Safety
The only reported negative effect of xylitol consumption is that of gastric discomfort and upset when large amounts are consumed. This is a symptom associated with a number of the sugar alcohols and broadly speaking is a consequence of their partial digestion.

However, a number of claims for the positive health effects of Xylitol have been made:

Teeth: as well as providing a non-damaging alternative to other sweeteners, xylitol is also believed to actively prevent tooth decay by helping teeth to re-mineralise.

Bones: research conducted on rats suggests that dietary xylitol can improve bone density, pointing to the possibility of its use to treat osteoporosis.

Infection: xylitol has been seen to increase the neutrophil activity - these are the white blood cells involved in fighting many bacteria. Xylitol chewing gum has been successfully used to treat ear infections, which is believed to be a result of anti-bacterial properties combined with the beneficial effects of regular chewing and swallowing.

ADI (Acceptable Daily Intake)
A collaboration between the Food and Agricultural Organisation (FAO) and the World Health Organisation (WHO) has recommended that no daily limit be placed on xylitol consumption. This means there is no ADI specified, which is the safest category for a food additive.
Other Information
Domestically, xylitol can be used in same quantity as sucrose (sugar) in food and drink. It dissolves quickly, mixes easily, and is heat-stable for cooking or baking. However, unlike sucrose, it does not caramelise.
My Opinion
Xylitol appears to tick all the boxes - it's not bad for the teeth, does not create blood sugar highs and lows, has fewer calories and even has some medicinal properties; and at present there is no evidence of harm.

So if you need some sweetness in your life and fruit is not enough, I guess this would be the least bad option. Okay, it might not be zero calories like many of the artificial alternatives, but it clearly trumps them by virtue of the absence of scare stories.

However, when it comes down to it, you don't know what you don't know: who's to say in 20 years we won't discover that regular ingestion of xylitol causes some kind of health problem? Admittedly, it was discovered around the same time as aspartame, which is associated with many supposed side-effects and worrying studies. So even though it has had just as long to be investigated, xylitol is not implicated in the same way. Whether this is a function of increased safety or differing levels of scrutiny is not clear.

Final thought, then: consuming anything in amounts that differ significantly from the diet we evolved to eat has the potential to have long term effects, so I would suggest that even this apparently benign sweetener should be used occasionally rather than installed as a household regular.

Summary
Alternative Names
Chemistry and Origins
Classification
Regulation
Where it can be Found
Taste, Calories and Digestion
Health Implications and Safety
Other Information
My Opinion

See Also:
Sugar, Sugars and Sweeteners: The Definitive Guide

5 comments:

Chris - Zen to Fitness said...

Great article, I always keep a bag of Xylitol on hand and will occasionally add some to a black coffee with cream when I feel like a treat. Otherwise I rarely use the stuff. Its cheap and effective definitely worth having in a Paleo pantry....

My Year Without said...

Love your detailed account of this ambiguous sweetener, especially your opinion at the end. Xylitol is interesting to me, as are the other sugar alcohols, not including maltitol, which makes me sick every time I ingest it.

I have not used xylitol in any recipes, but I'm curious what it would be like...I enjoy it in the natural gums I chew.

Methuselah said...

My Mum is actually going to try cooking with this over Christmas - before going paleo she used to make a great apple crumble. She's going to see whether she can replicate this with chestnut flour, coconut oil and xylitol. If it's any good I might just post the recipe!

Son of Grok said...

It all sounds good and dandy but I will still pass. A piece of fruit is usually enough to satisfy any craving for something sweet for me. Like you said, who knows what info will pop up in 20 years? Fruit is a natural safe bet ;-)

The SoG

Health Test Dummy said...

Since going 'Primal' I have not had the need for many sweet things, but when I treat the family or want to indulge a bit, I will use Xylitol. It's the only one that I find has a ZERO after-taste. In fact, when I use it in my coffee, my teeth feel cleaner than when I used to drink my sugary coffee.

I'm still a 'sweets' fan and this stuff is just too awesome of a sugar substitute to give up in my baking.

I will be attempting to make the switch to Erythritol, however, due to the fact that, although I tolerate it just fine, my husband and kids get horrific diarrhea EVEN when consuming very small amounts :-(

Great article, thanks!

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