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