It's Sweet... But is it Safe?

CSPI’s 'Chemical Cuisine' Rates Artificial Sweeteners


Plump from holiday excesses, millions of Americans are making New Year's resolutions aimed at shedding pounds. For some of those people, a switch from regular soda to diet soda might be in the works. Nutritionists generally agree that sodas and other sugar drinks are leading culprits behind Americans' mushrooming waistlines and that virtually everyone would do well to reduce or eliminate their consumption.

But how safe are the diet drinks?

To help consumers assess the risks posed by diet soft drinks—and frozen desserts, table-top sweeteners, gums, and other artificially sweetened foods—the nonprofit Center for Science in the Public Interest has distilled the latest research into practical advice. What follows are CSPI's current ratings of artificial and natural no- and low-calorie sweeteners, excerpted from the group's Chemical Cuisine guide to food additives:


  • Acesulfame-potassium. Roughly 200 times sweeter than sugar, acesulfame-potassium, or ace-K, is used with aspartame in Coca-Cola Zero and Diet Pepsi. In the mid-calorie Pepsi Next, it is used with sucralose (and high-fructose corn syrup and sugar). Besides being used in foods, it is sold in packets under the Sweet One brand name. The manufacturer's safety studies of acesulfame-potassium conducted in rats in the 1970s were of mediocre quality, but suggested the ingredient might cause cancer. CSPI recommends avoiding ace-K.
  • Aspartame. This widely used artificial sweetener is also about 200 times sweeter than sugar and sometimes labeled with the brand name NutraSweet. Aspartame is the sole sweetener in Diet Coke and Diet Dr Pepper, and is the major sweetener used in Diet Pepsi (which also has ace-K). Three key studies funded by an independent lab (rather than by a maker of aspartame) found that the sweetener caused lymphomas, leukemias, kidney, and other cancers in rats and mice. That should be reason enough for the Food and Drug Administration to ban aspartame from the food supply, says CSPI. In addition, aspartame might cause headaches or other neurological symptoms in a small number of people. (But don’t believe most of the nonsense about aspartame on the Internet.) The group recommends that consumers avoid it.
  • Monk fruit extract (mogrosides). The monk fruit, a food consumed in China for centuries, contains super-sweet chemicals called mogrosides. Extracts of the fruit, which are 200 times sweeter than sugar, are being used in a smattering of foods and beverages. Monk fruit extract is sold in packages of Nectresse (along with some erythritol and a little sugar and molasses). Monk fruit extract is natural and may well be safe, but CSPI recommends caution because it has been poorly tested in animals.
  • Neotame. Neotame is a chemical cousin of aspartame, but about 40 times sweeter, meaning much less is needed to sweeten foods. One shortcoming, which may account for its scarcity in packaged foods, is that it has a somewhat different taste profile from sugar or high-fructose corn syrup. CSPI ranks it as safe, but notes that it has not been tested by independent researchers.
  • Saccharin. CSPI recommends that consumers avoid saccharin, the original artificial sweetener discovered in 1878. It is used in Sweet’N Low packets, Tab soda (which also now contains aspartame), and a few diet foods. Saccharin is over 300 times sweeter than sugar. In animal studies saccharin caused cancer of the bladder, uterus, ovaries, and other organs. Human studies have been inconsistent, but some found an association with higher cancer risk. In 1977, the Food and Drug Administration proposed banning saccharin, but Congress intervened and permitted its use with a warning notice. Congress killed the warning-notice requirement in 2000. Because of its bitter aftertaste, saccharin has generally been supplanted by aspartame and other newer and better-tasting artificial sweeteners.
  • Stevia leaf extract. This natural, high-potency sweetener—about 200 times sweeter than sugar—is extracted from the South American stevia plant (now also grown in the American west and in Southeast Asia). The purified sweetening agents are called rebiana, rebaudioside, reb A or D, or simply stevia leaf extract. As a table-top sweetener, it is sold as Truvia, Pure Via, and other brands. Coke, Pepsi, and other companies are experimenting with rebiana in beverages. CSPI says it is probably safe, but should be better tested (new additives are normally tested for long-term effects in two animal species; rebiana was tested in only one).
  • Sucralose. Sucralose, the key ingredient in Splenda, is made by reacting sugar with chlorine. It is about 600 times sweeter than sugar and widely used, often together with aspartame or ace-K, in foods and beverages. CSPI downgraded its rating of sucralose from "safe" to "caution" after the same lab that tested aspartame announced, though has not yet published, a study that found that sucralose caused leukemia in mice.
  • Sugar alcohols (erythritol, isomalt, lactitol, mannitol, sorbitol, xylitol, and others). Sugar alcohols (which don't contain sugar or alcohol) have about half as many calories as sugar (except for erythritol, which has one-twentieth as many). Too much can cause gastrointestinal distress, but otherwise they are safe.

"We're most concerned about aspartame, because in several studies it caused multiple kinds of cancers in laboratory animals," said CSPI senior scientist Lisa Lefferts. "Based on those studies, the FDA should ban aspartame. If FDA has any doubts about that research, it should at least commission independent studies to settle the issue."

CSPI says that for most Americans, the increased risks of obesity, diabetes, and heart disease from consuming sugar drinks probably outweigh the risks posed by artificial sweeteners. Diet sodas may help some people lose weight, if those drinks replace full-calorie sodas—and if people don't replace the saved calories with extra calories at other times of day, the group says.

"The best beverage choices are water, seltzer, seltzer mixed with a little fruit juice, low-fat or fat-free milk, or unsweetened tea," Lefferts said.

CSPI's Chemical Cuisine is also available as a free smartphone app, and a hard-copy publication is available at

Non-calorie or Low-calorie Sweeteners Used in Some Popular Foods*

Coke Zero: Aspartame, Acesulfame-potassium
Crystal Light Peach Iced Tea Drink Mix: Aspartame, Acesulfame-potassium
Diet Coke: Aspartame
Diet Dr Pepper: Aspartame
Diet Mt. Dew: Aspartame, Acesulfame-potassium, Sucralose
Diet Pepsi: Aspartame, Acesulfame-potassium
Pepsi Next: Sucralose, Acesulfame-potassium (and High-Fructose Corn Syrup and Sugar)
Red Bull Sugar Free: Aspartame, Acesulfame-potassium
Sam's Choice Diet Cola (Wal-Mart): Aspartame
Tab: Saccharin, Aspartame
Vitaminwater Zero: Erythritol, Stevia Leaf Extract
Zevia Cola: Erythritol, Reb A (Stevia Extract), Monk Fruit Extract 

Light and Fit Strawberry Yogurt: Acesulfame-potassium, Sucralose
Nestle Coffee Creamer, Sugar Free French Vanilla: Sucralose, Acesulfame-potassium
Smuckers Strawberry Preserves, Sugar Free: Sucralose

Breyer's Vanilla Ice Cream, Sugar Free: Sorbitol, Sucralose, Acesulfame-potassium
Cool Whip Sugar Free Whipped Topping: Aspartame, Acesulfame-potassium
Enlightened Fudge Ice Cream Bars: Monk Fruit Extract, Erythritol
Jell-O Chocolate Sugar-Free Pudding: Aspartame, Acesulfame-potassium 
Jell-O Black Cherry Gelatin Snacks, Sugar Free: Aspartame, Acesulfame-potassium
Pillsbury Creamy Supreme Sugar Free Frosting: Maltitol Syrup, Isomalt, Sorbitol, Sucralose 
Popsicle Sugar Free Ice Pops: Aspartame, Acesulfame-potassium
Reese's Peanut Butter Cups Miniatures, Sugar Free: Sucralose
Swiss Miss Sensible Sweets Hot Cocoa Mix, Sugar Free: Acesulfame-potassium, Sucralose
Werther’s Original Candy Sugar Free: Acesulfame-potassium

Packaged Sweeteners
Equal Original, Aspartame, Acesulfame-potassium
Equal Next: Aspartame, Saccharin
NutraSweet: Aspartame
Monk Fruit in the Raw: Monk Fruit Extract
Nectresse: Erythritol, Sugar, Monk Fruit Extract, Molasses
Pure Via: Stevia Leaf Extract
Splenda: Sucralose
Sweet 'N Low: Saccharin
Truvia: Erythritol, Stevia Leaf Extract

Breathsavers Peppermint Mints, Sugar Free: Aspartame
Ricola Lemon Mint Throat Drops, Sugar Free: Aspartame, Isomalt
Stride Spearmint Sugar Free Gum: Sorbitol, Mannitol, Xylitol, Aspartame, Acesulfame-potassium
Walden Farms Honey Dijon Dressing, Sugar Free: Sucralose

*Not including dextrose, cellulose powder, or other bulking agents commonly used with high-potency sweeteners, but including erythritol.

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