There were high hopes for stevia when it was approved for sale in 2012, but has it lived up to expectations? We take a closer look at the nutritional claims of stevia, find out where it can be found and ask whether it's a worthy alternative to sugar...
Commonly known as sweet leaf or sugar leaf, stevia rebaudiana is a widely grown plant, which belongs to the sunflower family, native to Central and South America. Studies have shown it to be a safe and natural, calorie-free sugar substitute and is commonly used to sweeten a number of foods and beverages. The compound responsible for the plant’s sweetness is a glycoside found in the plant's leaves. Steviol glycosides are said to be up to 300 times sweeter than sugar.
How it's used
Fresh leaves from the stevia plant can be used in hot or cold drinks or on their own as a herbal tea. The leaves are dried to form a powder, which can be used in baking - two tablespoons of stevia powder is the same as one cup of sugar. It is important to note however that stevia does not caramelise. Stevia-based sweeteners can be found in products including yogurts, chocolates and fizzy drinks.
With no calories, no sugar and no carbohydrates, stevia’s GI score is 0. Stevia was only approved for sale in the EU in 2012, and it was hoped it would prove useful for diabetics looking for a naturally derived, low-calorie sweetener.
In tests, pure stevia extract has been found to have no effect on blood glucose levels (and may even improve your bodies ability to metabolise glucose). Studies that have attempted to show that stevia can improve insulin sensitivity and benefit diabetes have not been conducted on humans as yet, but do show some promise.
However, pure stevia extract has a bitter aftertaste, which means that stevia-based sweeteners are often blended with other sugars and artificial sweetners to improve taste. By blending them with other sweetening ingredients such as dextrose, maltodextrin and sucrose, some stevia products are then capable of raising blood glucose levels. It is therefore important to read the labels on products which claim to be stevia.
Other research suggests stevia may be useful in the treatment of hypertension and management of Type 2 diabetes and it is recognised for have some anti-inflammatory properties. It contains no calories so it can be beneficial for weight loss with those looking for an alternative to sugar.
Is it better for you than sugar?
Unfortunately, many commercial stevia products are highly purified stevia extracts and are not always as healthy as some of their 'natural' labels would lead you to believe. Like with other sugar alternatives, it is the extraction and processing methods that change the properties of the whole leaf into something quite different.
In the sense that pure stevia doesn’t add calories, affect blood sugar or insulin levels, or contribute to tooth decay, it is a better choice than sugar. However, highly refined extracts perpetuate the desire for sweet-tasting foods and drinks and therefore over consumption is not recommended. As the long term effects of sweeteners are still unknown there is a clear need for further experimentation with respect to the metabolic processes involved.
This article was last reviewed on 25th March 2015 by nutritional therapist Kerry Torrens.
Jo Lewin works as a Community Nutritionist and private consultant. She is a Registered Nutritionist (Public Health) registered with the UKVRN. Visit her website at www.nutrijo.co.uk or follow her on Twitter @nutri_jo.
Whether you're looking for sweet substitutes, sugar-free baking guides or simply want to find out your recommended daily amounts find all the answers in our sugar hub:
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Have you tried stevia? Do you find it a useful alternative to sugar? We love to hear your thoughts...