What is stevia? Have we found the zero-calories added sugar that can satisfy our sugar addiction with no side effects?
Most Western countries are experiencing a serious sugar problem. According to a study carried out by the Obesity Society in November 2014 it was found that added sugar consumption by American adults has increased by about 30% in the last three decades. The current average in South America is 130 grams per adult per day, in North and Central America 95 grams, in Western Europe about 101 grams and 90 grams in the Middle East. Equatorial and Southern Africa have the lowest average of 30 grams.
Adults and children from the Americas to Western Europe and Middle East must roughly halve the amount of sugar they consume according to the new 2015 World Health Organization guideline, which recommends a daily intake of roughly 50 grams of sugar (no more than 10% of total daily calories from sugars) for someone of normal weight. A further reduction to below 5% or roughly 25 grams (6 teaspoons) per day would provide additional health benefits.
We definitely “eat too much of it” as almost every health experts would say, we are surrounded by sugary foods and drinks! There are many different types of sugar, and some of these, such as glucose, fructose and lactose, occur naturally in fruits, vegetables and other foods. However, many of the foods we consume contain “added” sugars – sugar that we add or that has been added to a product to enhance the flavour. We can find them in soft drinks, cakes, pies, chocolate, fruit drinks, desserts… It is added sugars that have been cited as a contributor to many health problems: increased aging, increased risk of high blood pressure, increased risk of death from cardiovascular disease (CVD), obesity (in the US, more than a third of adults are obese, while the rate of childhood obesity has more than doubled in children and quadrupled in adolescents over the past 30 years) and even cancer.
What should we do then? Should we eliminate it from our diet, lower its consumption or replace it? Let’s have a closer look at the wide range of low or no calorie sugarlike extracts contained in sugar-free products.
The sugar substitute market was estimated to be worth $10.5 billion in 2012, according to an analysis by Markets and Markets research firm. And the market is growing. Just 18 percent of U.S. adults used low- or no-calorie sweeteners in 2000. In 2012, 24 percent of adults and 12 percent of children use the sugar substitutes, according to a review in the American Journal of Clinical Nutrition.
Some sugar substitutes are natural, while some others are synthetic: the latter are better known as artificial sweeteners (aspartame, sucralose, neotame, acesulfame potassium, saccharin, and advantame). Sugar substitutes are viewed as a healthier way to sweeten foods and beverages because, unlike refined sugar, they are low or even calorie-free. A smart use of non-nutritive sweeteners could help to reduce added sugars in our diet, therefore lowering the number of calories we eat. Reducing calories, in turn, could help to attain and maintain a healthy body weight, and thereby lower risks of heart disease and diabetes.
Recently, the use of stevia as a natural sweetener is catching more and more public interest. We can find it in sports drinks as well as in soft drinks, chewing gums, energy bars, teas, candies and other foods and beverage products. In addition, its sweet components are naturally occurring, which may further benefit consumers who prefer foods and beverages they perceive as natural.
To be more specific stevia is not a new substance by any means: its leaves has been used to sweeten tea by native tribes in Brazil and Paraguay for centuries. Nevertheless, Stevia became famous only in the early 1970s, when the substance was extracted and sold for commercial purposes.
What’s so special about it? And is it really the perfect sweetener we are looking for?
First of all let’s make things clear, when we talk about stevia we do not refer to the whole leaf but only to some of its glycosides. Steviol glycosides, the ones tested, contain no less than 95% of stevioside and/or rebaudioside A.
The plant has a very high sweetening capacity, its glycosides could be up to 300 or 400 times more sweet than sucrose (table sugar) with no caloric value whatsoever, which mean that these sweeteners may sweeten food and beverages in fewer calories than traditional sweeteners. These characteristics make it an interesting product for those looking to control weight or manage diabetes,it do not affect blood glucose or insulin response, which allows people with diabetes to consume a wider variety of foods and comply with a healthful meal plan. Moreover stevia was shown effective in lowering hypertension and hyperglycemia.
It was Moises S. Bertoni, an Italian botanist, who first described stevia in 1899 having initially been told some years before about a “very strange plant” known by indigenous Indians in the forests of Paraguay as kaa-he-e. In December of 1905 he observed: “The fact is that the sweetening power of kaa-he-e is so superior to sugar that there is no need to wait for the results of analyses and cultures to affirm its economic advantage.”
Well, as we can all imagine, this was not the case!
Stevia extract in its high purity form has been tested rigorously in more than 200 scientific studies and approved for human consumption by multiple major regulatory organizations such as SCF (Scientific Committee on Food), JEFCA (Joint FAO/WHO Expert Committee on Food and Additives), EFSA (European Food Safety Authority), FDA (Food and Drugs Administration) since 1984.
EFSA published on 10th April 2010 a panel in which it concludes that steviol glycosides are not carcinogenic, genotoxic or associated with any reproductive/developmental toxicity. It also establishes an ADI (average daily intake) for steviol glycosides, expressed as steviol equivalents, of 4 mg/kg bw(body weight)/day This restriction is based on the NOEL (non observable effect level) for stevioside of 970mg/kg bw per day (or 388 mg steviol equivalents/kg bw/day) in the 2-year study in rats, which was not associated with toxicity, taking into account a 100-fold uncertainty factor. Then, in November 2011, the European Commission authorized the use of steviol glycosides as a sweetener in foods and beverages.
On the other hand it should be pointed out that pure stevia extract has a bitter aftertaste, which means that stevia-based sweeteners are often 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, which claim to be stevia.
Just the same as other artificial sweeteners Stevia is still not recommended for use by nursing and pregnant women.
Another concern regards the fact that steviol glycosides exposures both in adults and in children suggest that it is likely that the ADI would be exceeded at the maximum proposed use levels. At high doses, steviol and stevioside are shown to exhibit weak mutagenic activity, gastrointestinal side effects such as nausea and stomach fullness.
For the time being, unlike steviol glycosides, long-term consumption of artificial sweeteners may have directly contributed to enhancing the exact epidemic that they themselves were intended to fight. According to a study, published in the journal Nature, these sweeteners may stll drive obesity and diabetes.
As we can deduce there is a clear need for further experimentation with respect to side effects associated with a long-term consumption of steviol glycosides and the metabolic process involved. And, at the same time, there is an urgent need for reducing drastically our sugar daily intake. If and when stevia will be proved to be the “perfect sweetener” as many supporters claim it to be, we will definitely enjoy our large slice of chocolate cake (baked with stevia extracts of course) drinking a soft drink without contributory factors for obesity, cardiovascular disease, and developing type 2 diabetes.
Too good to be true? Time will tell!