Do Artificial Sweeteners Present Health Risks?

How safe are artificial sweeteners? It's a question that nags many dieters, diabetics and others trying to steer clear of sugar. The four low-calorie sweeteners in widespread use -- saccharin, aspartame, acesulfame potassium and sucralose -- have the Food and Drug Administration's blessing. But worries persist about adverse effects ranging from headaches to cancer. Before you sour on sweeteners -- or swear by them -- you need to understand the benefits and drawbacks of each.

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Saccharin, the oldest sugar substitute, is 300 times as sweet as sugar. It's found in Sweet 'N Low, the popular tabletop sweetener. After studies in the 1970s found it caused bladder cancer in rats, products containing saccharin had to carry warning labels. But subsequent research failed to confirm a risk to people. In 2000 the government removed saccharin from its list of cancer-causing substances. Still, some human research suggests (but doesn't prove) a link between heavy consumption -- six or more servings a day -- and cancer. Any increased risk is probably very small.

Aspartame, used in most diet drinks, is sold as NutraSweet and Equal. It's not as sweet as saccharin and is more expensive. Through the years, it has been blamed for a host of conditions, including brain tumors, seizures, birth defects, multiple sclerosis and lupus, though there's no evidence to back up these claims. Some people also report side effects such as headaches, dizziness and indigestion, but no one knows how widespread they are. The only proven risk is to the small number of people with conditions, such as advanced liver disease, that cause problems metabolizing phenylalanine, an amino acid in aspartame. They are the targets of required warning labels.

Acesulfame potassium is sold as Sunett and as the tabletop product Sweet One. In some products it's combined with other sweeteners. Unlike aspartame, it doesn't break down when heated, so it can be used for baking. It has been tested less thoroughly than aspartame, so researchers tend to know less about it.

Sucralose is made from sugar but is 600 times as sweet. Marketed as Splenda, it's found in some diet drinks and other products and is also ideal for baking. After five years on the U.S. market, sucralose hasn't been linked to any adverse health effects. The independent consumer group Center for Science in the Public Interest ranks sucralose as the safest of the four sweeteners.

Whatever sweetener you choose, don't consider it an excuse to indulge regularly in sweets. Even treats that are sugar-free still contain empty calories. If you find yourself guzzling diet drinks all day, try to cut back and go with water instead. Regardless of what some diet books say, don't feel compelled to replace all sugar with artificial sweeteners. Sugar isn't poison, and sugar substitutes are not a panacea. Both should be used the same way: in moderation.

Updated May 13, 2003