Stevia, an extract from a shrub that grows in Brazil and Paraguay, is “natural.” But just because something is “natural” does not mean it is safe. Arsenic is natural. Poison ivy is natural.
What is far more important is the scientific data on stevia, or stevioside, the main ingredient in stevia. (The two terms are often used interchangeably.) We as consumers need to ask: Have sufficient studies been published on stevia to validate that it is safe?
Not Enough Research
Unfortunately, very few studies have been published. Because of inadequate data on the safety of stevia, the U.S. Food and Drug Administration (FDA) has not allowed the use of stevia in food, and describes it as an “unsafe food additive.” Since 1989, the FDA has rejected three industry requests to use stevia in foods and beverages.
Many other health organizations worldwide have also banned the use of stevia in foods until further data are published, including the World Health Organization, the European Union, and the Canadian Food Inspection Agency (Canada’s equivalent of the FDA).
The Scientific Committee on Food for the European Commission concluded that “there are no satisfactory data to support the safe use of these products [stevia plants and leaves].” (1)
In its review of stevioside, the World Health Organization Expert Committee on Food Additives stated there was inadequate data on the composition and safety of stevioside and therefore gave stevioside no acceptable daily intake. (2)
Moreover, the results from the few studies we do have are troubling. Stevioside may cause male reproductive problems, scientists from Japan concluded. When they fed male rats high doses of stevioside for 22 months, the rats produced fewer sperm, and there was an increase in cell proliferation in the testicles, which could cause infertility and other problems. (3)
And when researchers from Mahidol University in Bangkok fed female hamsters large amounts of a derivative of stevioside, the hamsters had fewer and smaller offspring. (4)
You’re probably not going to consume stevia in concentrations that the animals received, but we really don’t know at what point stevia may become toxic. Is it 10 teaspoons daily? 20 teaspoons? 50? We do know that Americans are quite capable of consuming many many teaspoons a day, especially if stevia were widely used in products like diet sodas. That is the FDA’s chief concern.
And yes, you can buy stevia, heavily promoted by U.S. supplement makers as a “natural” alternative to synthetic sweeteners, in “dietary supplement” form. But that’s only because safety rules for supplements are far looser than for foods, thanks to a law passed in 1994 (after intense lobbying by the supplements industry) that relaxed the rules for anything called a “dietary supplement.” The law is so relaxed, in fact, that all sorts of products, from hormones to dirt, can be sold with little or no science validating their safety.
“When it comes to supplements, it’s definitely a ‘buyer beware’ market out there,” warns Jeffrey Novick, MS, RD, Director of Nutrition at the Pritikin Longevity Center® & Spa.
Splenda: Adequately Tested
If you choose to use calorie-free sweeteners, “we prefer that you choose Splenda [brand name for sucralose]” advises dietitian Jeffrey Novick. Sucralose is sugar (sucrose) chemically combined with chlorine. It is calorie free because our bodies cannot burn sucralose for energy. In numerous studies on animals, sucralose passed all safety tests. It was approved for use in food by the FDA in 1998. For nearly a decade, it has been approved for use – and used widely – in more than 30 other countries worldwide.
Calorie-Free Sweeteners: Pritikin Program Recommendations
If you don’t need calorie-free sweeteners, don’t use them. They may undermine your attempts to follow the Pritikin Program because their high intensity of sweetness might mask the milder, lighter sweetness of foods like fruit, making it harder to recognize and appreciate the flavors of whole, nutrient-rich foods.
On the other hand, calorie-free sweeteners might actually improve your adherence to the Pritikin Program if using them helps you make better food choices. For example, if you’re more apt to eat oatmeal and strawberries when a little Splenda’s sprinkled on top, by all means, sprinkle the Splenda. Fiber- and nutrient-rich oatmeal and strawberries are a far better choice for breakfast than, say, bagels and low-fat cream cheese, or even egg-white omelettes.
Do what’s best for you. If you’re enjoying the fresh whole foods of the Pritikin Program without added sweeteners, that’s great. This is the gold standard.
If you need a little calorie-free sweetener, that’s fine, too. Just make sure you choose a sweetener scientifically documented to be safe, like Splenda. And don’t go overboard. We encourage you to limit your intake of calorie-free sweeteners to no more than 3 to 6 packets (3 to 6 teaspoons) daily.
3. J Food Hyg Soc Japan, 1985; 26: 169.
4. Drug Chem Toxicol, 1998; 21(2): 207.