Name: Agave nectar

What is it? A sweet syrup traditionally produced from a cactus-like plant. New methods of processing mean that it now bears little resemblance to the traditional product that, anecdotally, had health benefits. The product, including those claiming to be 'raw', is now a highly-refined syrup high in fructose. It is very similar to high fructose corn syrup, which is commonly found in carbonated drinks.

Found in? Available to purchase in a light or dark syrup, from health food shops and supermarkets.

Effect on general health: Agave is commonly marketed as a slow-release carbohydrate with a low glycaemic index. This is true as it contains mainly fructose and only low amounts of glucose. Although fructose doesn't raise blood sugar levels in the short-term, it can contribute to insulin resistance when consumed in large amounts. This can cause major increases in long-term blood sugar and insulin levels, strongly raising the risk of metabolic syndrome and type 2 diabetes.

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The liver metabolises fructose, but when overloaded it starts turning the fructose into fat globules, which raise blood triglycerides. Having a high level of triglycerides in your blood can increase your risk of heart disease.

Agave contains more calories than sugar (60 vs 48 calories per 3 tsp), but as it is sweeter you should use less.

Oral health impact: Fructose like sucrose is detrimental to oral health. Bacteria on tooth surfaces metabolise fructose to form acid, resulting in a fall in plaque pH and demineralisation. When the pH rises again to above 5.5 due to the dissipation of acid after about 20–30 minutes, enamel can be reformed and repaired with calcium and phosphate released from the saliva.

Advice for patients: The promotion of agave nectar as a natural and healthy product is unfounded. Its cost is much higher than sugar and there are no advantages in using it instead of sugar.

Agave is a sweetener to avoid as it has negative implications on health outcomes (both general and oral). If used, patients should be advised to maintain optimum oral hygiene through toothbrushing twice daily with fluoridated toothpaste and plaque control measures.

Find out more about the British Dietetic Association at: .

Coming up: Stevia.