Does Stevia Cause Cancer?

Stevia is a natural sugar substitute made from the leaves of the stevia plant. It has been used in South America since the 16th century to sweeten tea and other beverages. Because it is essentially free of calories and carbohydrates, stevia often is considered a healthful alternative to table sugar. However, this hasn't always been the case.

Due to safety concerns, the Food and Drug Administration (FDA) banned stevia in 1991. Today, purified extracts from stevia leaves are allowed and commonly used in the United States. Still, concern that stevia is unsafe and may cause cancer still exists.

This article will discuss the current research on stevia and examine any potential links to cancer.

The Stevia Plant

The term "stevia" refers to a natural sweetener and sugar substitute derived from the leaves of the Stevia rebaudiana plant. Its use dates back thousands of years, when people of South American native cultures used the plant's leaves to enhance the flavor of beverages and treat various health conditions, including diabetes, high blood pressure, and obesity.

Stevia leaves are estimated to be 150–400 times sweeter than sugar. Despite tasting sweet, some users report it has a licorice-like aroma and slightly bitter aftertaste.

Although purified stevia extracts are "generally recognized as safe" (GRAS)—an FDA designation to categorize chemicals or substances added to food considered safe by experts if used as intended)—stevia leaves and crude stevia extracts are not permitted for use as sweeteners and do not have GRAS status.

The Sweetener

Stevia sweeteners are made by harvesting and drying stevia leaves, which are then steeped in hot water. After many stages of filtering and separating to diminish the bitter aftertaste, the purified stevia extract can be sold commercially. Purified stevia extract must be composed of at least 95% steviol glycosides.

There are many different steviol glycosides responsible for giving stevia its sweet taste. Rebaudioside A, or reb-A, is one of the most common steviol glycosides found in foods and beverages today.

Stevia is available in several forms, including liquid, powder, and granules. Most stevia products combine steviol glycosides with other ingredients such as dextrose, maltodextrin, and erythritol.

For example, the popular sugar substitute Truvia is made with stevia leaf extract (reb-A), erythritol, and natural flavors. Stevia in the Raw packets are made with stevia leaf extract (reb-A) combined with dextrose.

Stevia can be substituted for sugar during baking. It is also commonly found in the following products:

• Soft drinks
• Chewing gum
• Baked goods
• Desserts
• Candy
• Yogurt
  

Steviol Glycosides

There are 11 main steviol glycosides in the stevia plant. These include:

• Rebaudiosides A, B, C, D, E, and F
• Stevioside
• Rubusoside
• Steviolmonoside
• Steviolbioside
• Dulcoside A

Stevia leaves primarily contain rebaudioside A and stevioside. Reb-A is the most sought-after compound in the stevia plant because it is the sweetest and the least bitter out of all glycosides.

In some test-tube studies, steviol glycosides have been reported to have mutagenic effects. This means they may cause permanent changes in genetic material. However, results have been inconsistent and appear not to be tied to the daily use of stevia as a sweetener.

Generally Recognized as Safe

High-purity steviol glycosides including reb-A, stevioside, reb-D, or steviol glycoside mixtures are GRAS.

Because of increasing consumer demand for a natural, zero-calorie sweetener, major food-and-beverage industry giants pushed for FDA approval of stevia. In 2008, Cargill and Merisant notified the FDA that their natural sweetener rebiana (reb-A) should have GRAS status and submitted evidence verifying its safety. Both companies received a "no objection letter" from the FDA.

However, many experts advise against the use of nonnutritive sweeteners like stevia during pregnancy because not enough studies exist that demonstrate their long-term effect on offspring.

Additionally, the use of low-calorie sweeteners like stevia while breastfeeding may lead to an increased risk of vomiting in breastfed infants.

According to the FDA, there is not enough information to verify the safety of stevia leaf and crude stevia leaf extracts. Therefore, they are not approved for use as sweeteners in the United States.

What the Research Says

Despite an extensive database of scientific evidence demonstrating the safety of stevia, some people understandably remain skeptical.

Here's a look at what the latest research says on the subject.

Can Stevia Cause Cancer?

One study found that, at high dosages, stevioside was shown to have weak mutagenic activity (the presence of a substance that causes changes in genetic material). However, the dosage necessary for this to happen is equivalent to that of 3,000 cups of coffee. Researchers concluded the genetic toxicity of stevia to be safe as long as it is used in ordinary amounts.

A review of 372 studies found that short-term use of stevia did not result in an increased risk of cancer.

Moreover, the American Cancer Society also considers the amount of stevia and other nonnutritive sweeteners often used in our diets to be safe. 

Can Stevia Help Fight Cancer?

Although more solid research is needed to determine the potential health benefits of stevia, some studies suggest the sweetener has anti-cancer properties.

One recent review suggests that, in combination with a healthy diet, stevia may aid in cancer prevention and complement ongoing therapy.

The review found that stevia may:

• Play a role in cancer prevention because it minimizes glucose levels in the blood
• Help fight inflammation and protect against oxidative stress that can lead to tumor development
• Inhibit the growth of cancer cells
• Speed up the death of cancer cells

Again, more research is needed on human subjects before any stevia products can be used to treat or prevent cancer.

Important Considerations

Eating too much added sugar can lead to high blood pressure, inflammation, weight gain, fatty liver disease, and obesity. It can also increase the risk of a heart attack or a stroke. Choosing a nonnutritive sweetener like stevia may be a good option to help reduce the amount of sugar in your diet.

Overall, most studies suggest that consuming stevia in moderate quantities is safe and does not cause cancer. There are also studies that highlight the potential for stevia to have health benefits.

However, it is important to note that some of the studies that highlight the benefits of stevia consumption are funded by the stevia industry. This can lead to biased results.

Some people may also experience unpleasant side effects after consuming stevia. For example, one study found that some participants who were given stevia experienced nausea, abdominal fullness, muscle pain, and weakness. Symptoms resolved after one week.

Summary

Stevia is a natural sweetener that is commonly found in low-calorie foods and beverages. Although stevia was once banned in the United States by the FDA, purified stevia extracts are now considered safe. When used in normal amounts, stevia can be a good low-calorie alternative to table sugar.

There is no solid evidence that purified stevia extracts can cause cancer. However, stevia leaves and stevia crude extract should not be used due to the uncertainty surrounding their safety. Stevia may even be a beneficial component of a cancer treatment or prevention regimen, but more research is needed to determine this.

A Word From Verywell

Based on the current scientific evidence available, stevia is safe for use. It may even be beneficial because it can lower your total daily calories and the amount of sugar you take in.

As long as you're using stevia in amounts below the recommended daily guidelines, it should pose no health risks. Always ask your healthcare provider any questions you may have regarding the safety of any food and drink additive, including stevia.