Sugar substitutes – stevia explained
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 that belongs to the sunflower family and is native to Central and South America. Studies have shown it to be a safe, naturally derived, calorie-free sugar substitute, and it's 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 – one teaspoon of stevia powder is about the same sweetness 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, sugar or 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 the ability of the body to metabolise glucose). Studies attempting to illustrate stevia's ability to improve insulin sensitivity and benefit diabetes are showing some promise, but it is too early to draw any firm conclusions.
However, because pure stevia extract has a bitter aftertaste, many stevia-based sweeteners are blended with other sugars and artificial sweeteners 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 that 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 its anti-inflammatory properties. When not blended with other sweeteners, stevia contains no calories, so it can be beneficial for weight loss and for 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 5 July 2019 by Kerry Torrens.
A qualified nutritionist (MBANT), Kerry Torrens is a contributing author to a number of nutritional and cookery publications including BBC Good Food magazine. Kerry is a member of the The Royal Society of Medicine, Complementary and Natural Healthcare Council (CNHC), British Association for Applied Nutrition and Nutritional Therapy (BANT).
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Have you tried stevia? Do you find it a useful alternative to sugar? We'd love to hear your thoughts...