Stevia a natural sweetener: an update based on the most recent evidence.

Although sugar is an inseparable part of the food we consume increased consumption of more than 10% of the total daily energy has been associated with dental carries and obesity. Nowadays, due to the increased incidence of obesity and diabetes, consumers and food manufacturers have an interest in the increased availability of foods with reduced caloric content by the use of artificial sweeteners which by definition are food additives that duplicate the effect of sugar in taste, containing less calories.

Stevia is derived from stevia rebaudiana Bertoni, a South American plant which has been used for centuries to sweeten herbal teas and other beverages. Stevia contains natural sweeteners, called steviol glycosides which contain stevioside and/or rebaudioside A as the principal sweetening components. It is important to highlight that steviol glycosides are low-calorie, high-intensity sweeteners which taste up to 300 times sweeter than sugar. In 1991, stevia import to the U.S. was banned by the Food and Drug Administration who claimed it as ‘unsafe food additive’. It remained banned until 1994 when it was approved as a dietary supplement. By 2010, sweeteners derived from stevia were permitted in several countries including China, Japan, South Korea, Mexixo, Austalia, New Zeeland, France, and Hong Kong and in 2011, the use of stevia was also approved by the European Union. The Joint FAO/WHO Expert Committee on Food Additives (JECFA) has established an acceptable daily intake of 0-4mg/kg body weight expressed as steviol which is equivalent to 12mg/kg body weight as rebaudioside A or 720mg for a 60kg woman or 840 for a 70kg man.

Steviol glycosides allow consumers to enjoy sweet taste without adding to the daily energy intake as they do not contain significant calories, thus may have the potential to play a role in the prevention and management of overweight and obesity. It is interesting to note that those with a rare genetic disease known as phenylketonuria can freely consume stevia as this sweetener is phenylalanine-free compared to other sweeteners like aspartame.

Studies looking on the effect of stevia consumption on blood pressure and blood glucose have shown that neither blood pressure nor blood glucose were affected making the conclusion that steviol glycosides are safe for use by individuals with heart disease and diabetes.

While the use of stevia was judged in the past due to its toxic effects, the most recent studies have shown that stevioside and rebaudioside A are not toxic nor carcinogenic.

Is stevia safe for everyone?

Although there is little evidence to date, some sub-groups of the population should avoid the consumption of stevia including children with atopic eczema and individuals suffering from auto-immune diseases or inflammation of the gastrointestinal tract. More research need to be done to draw better conclusions in these sub-groups of the population, however individuals with the above characteristics should discuss the use of stevia prior consumption.

The use of stevia sweeteners...

Stevia sweeteners are widely used by food companies and they are proposed to be used in a variety of foods and beverages like tea, coffee, soft drinks, tinned fruit and jams, ice-creams, cakes and alcoholic drinks.

Where can I get stevia?

Stevia sugar can be purchased at health food stores, natural product shops, pharmacists, and online.

How to use stevia?

Because stevia could be 300 sweeter than sugar attention should be given to the amount used so it is important to refer to the manufacturer’s instructions. As a guide, one tablespoon of sugar is equivalent to 1 and ¼ of teaspoons, and one teaspoon of sugar is about 3/8 teaspoon of stevia powder. Stevia can also be used in baking as stevia is stable at high temperatures.  Stevia has been shown to maintain a good stability for 2 hour up to 130 ºC but in higher than 140 ºC for  a prolong time it can loose its stability.