Yacon syrup (nectar)

What is it? Made from the roots of the Yacon plant, it has a caramel taste and is about half as sweet as honey.

Found in? Available from health food stores and online.

Effect on general health: Yacon syrup is composed of fructo-oligosaccharides (FOS), inulin and a small amount of glucose and fructose.

FOS is a soluble fibre virtually undigested by the human digestive system and by forming a gel, it provides beneficial bulk helping the movement of waste through the intestine.

Both FOS and inulin are prebiotics which means they provide a food source for the fermentation of beneficial bacteria in the gut. These friendly bacteria play a significant role in regulating the immune system, inhibiting the growth of disease-causing bacteria, digesting food and producing valuable vitamins.

Yacon syrup provides only about one third the calories of sugar, but as it is less sweet potentially more may be used. It has a very low glycaemic index, so beneficial in the regulation of blood sugar and insulin levels.

In the popular press it has been claimed to be a new 'miracle food' in weight loss treatment due to its lower calorie content, as well as its bulky nature making people feel fuller and satisfied. It also increases bowel transit time and increases defecation frequency, which may also play a role. Human trials are so far very limited and evidence is scarce.

Credit: ©Gary Ombler/Dorling Kindersley/Getty Images Plus

If Yacon syrup is taken in excess it can lead to abdominal pain, gas, bloating and diarrhoea. Maximum recommended daily consumption of Yacon syrup is about 20 g per day.

The quantity of beneficial constituents obtained by using Yacon syrup is limited by the amount consumed which means there may be minimal health benefits in everyday use.

Oral health impact: There have been no specific studies on Yacon syrup and oral health in humans. FOS are not cariogenic, but Yakon syrup also contains small amounts of the fermentable carbohydrates glucose and fructose.

There have also been reports of some of the FOS from Yacon being converted to fructose during food processing and when exposed to high temperatures (such as when baking). This increases the potential for cariogenicity.

Advice for patients: The adverse bowel effects of Yakon syrup limits its potential benefits. Although evidence is limited, it seems prudent to advise patients to pay full attention to oral hygiene if they are using the product.

Find out more about the British Dietetic Association at: www.bda.uk.com.

Coming up: Coconut (palm) sugar