Are artificial sweeteners bad for you? The truth about popular sugar replacers

Artificial sweeteners are often surrounded by questions and mixed messages, which can make it hard to know what to trust. You may wonder whether they raise your cancer risk, affect your memory or impact your weight. To help clear up the confusion, we’re breaking down what the research shows and what it means for your health.

What are artificial sweeteners?

Artificial sweeteners are manufactured sugar substitutes. They may be made from naturally occurring substances, such as a plant, herb or sugar itself. Artificial sweeteners are considered "intense sweeteners" because they are several times sweeter than regular sugar.

There are six artificial sweeteners approved by the Food and Drug Administration (FDA). The FDA has also established acceptable daily intakes of the approved sweeteners, which is much higher than anyone could possibly consume in one day.

These sugar substitutes are appealing because they contain almost no calories, and only a small amount is needed to create the same level of sweetness as sugar.

Artificial sweeteners are widely used in processed foods, such as:

• Soft drinks and other beverages
• Baked goods
• Candy
• Puddings and yogurts
• Canned foods
• Sweet spreads like jam

Types of artificial sweeteners

Here’s a list of FDA-approved artificial sweeteners, along with the recommended acceptable daily intake (ADI):

• Acesulfame K: A combination of organic acid and potassium. Unlike similar sweeteners, it is stable when heated, so many baked goods contain acesulfame potassium. (ADI 15 mg/kg)
• Advantame: A sweetener derived from aspartame that is heat-stable and approved for general use. (ADI 32 mg/kg)
• Aspartame: Approved as a general-use sweetener. Very little is needed since it contains such a high intensity of sweetness. (ADI 50 mg/kg)
• Neotame: Approved as a general sweetener, but rarely used in foods. (ADI 18 mg/kg)
• Saccharin: The oldest approved non-nutritive sweetener. It is approved as a food additive for gums, cosmetics and pharmaceuticals. (ADI is 15mg/kg)
• Sucralose: A derivative of the sucrose molecule. (ADI 5 mg/kg)

The FDA has identified three plant-based and fruit-based sweeteners as generally recognized as safe (GRAS), meaning they are not harmful based on a long history of safe use or scientific research:

These approved sweeteners include:

• Monk fruit
• Thaumatin
• Steviol glycosides from the stevia plant

Are artificial sweeteners bad for you?

So, are artificial sweeteners a good option? Let’s review the research on a few areas of concern.

Artificial sweeteners and cancer

Concerns regarding artificial sweeteners and cancer began in the 1970s when studies showed a link between saccharin and bladder cancer in laboratory rats. More recently, the World Health Organization’s International Agency for Research on Cancer (IARC) labeled aspartame as “possibly carcinogenic to humans.”

But this does not mean aspartame is actually linked to cancer.

The committee reported that there was no strong evidence from animal or human studies that aspartame causes harm. The IARC said that its conclusions were based on “limited evidence” of cancer in humans, specifically liver cancer.

The group also said that aspartame is safe to consume within the acceptable daily intake of 0-40 mg/kg body weight.

The National Cancer Institute also notes that studies looking at artificial sweeteners and cancer risk have shown mixed results with no consistent conclusions. This may be because many of these studies are epidemiological, meaning they observe patterns in large groups of people but can’t show what actually causes a condition.

Artificial sweeteners and cognitive decline

Another recent concern for artificial sweeteners is how they impact your brain health, specifically, if they cause your brain to age faster than it should.

This study looked at the intake of low- and no-calorie sweeteners (LNCS) and cognitive decline. The study assessed people’s memory, verbal fluency, processing speed (how fast your brain works) and executive function—the skills you use to plan, organize and focus.

The highest intake of LNCS was associated with a faster decline in cognitive function. People consuming the highest amount of artificial sweeteners were eating or drinking an average of 191 milligrams, or around 1 teaspoon per day.

Because it was an observational study, it cannot show cause and effect. Many factors can influence results, including age, diet, lifestyle and other health conditions.

For example, the link between LNCS and cognitive decline was stronger in people with diabetes. However, people who regularly use artificial sweeteners are also more likely to have obesity, diabetes or a lower-quality diet. These factors alone can increase the risk of cognitive decline, making it difficult to separate the effects of the sweeteners themselves.

The study also used food frequency questionnaires (FFQ) to assess dietary intake, which can be unreliable. The FFQ tool requires people to recall how often they eat specific foods over a period of time in order to determine their usual intake. These can be inaccurate, as people may not remember correctly or underestimate how much they actually ate.

If you’re concerned about your risk of cognitive decline, keep in mind that lifestyle factors, including a healthy diet, are one of the best ways to improve your memory and brain health.

The Alzheimer’s Association recommends the MIND diet. The diet includes:

• Leafy greens and other vegetables
• Berries
• Whole grains
• Poultry
• Fish
• Beans and legumes
• Nuts
• Extra virgin olive oil

The MIND diet also limits:

• Red and processed meats
• Butter
• Margarine
• Cheese
• Fried foods
• Sweets

Have a conversation with your doctor about ways to protect your brain as you age through healthy diet and lifestyle changes.

Artificial sweeteners and blood clots

Some people worry that artificial sweeteners may increase the risk of heart disease or blood clots.

Reducing added sugar is a recommended strategy to help prevent obesity and heart disease. The World Health Organization advises keeping added sugar to less than 10% of your total daily energy intake (the number of calories you eat in a day).

Based on current research, the long-term effects of artificial sweeteners on heart disease risk still need further research. At the moment, it’s difficult to take current research and turn it into concrete dietary guidelines.

A 2023 study researched erythritol, a common sugar alcohol, and found that people with the highest blood levels experienced more cardiovascular events like heart attacks and strokes. But erythritol is also made naturally in the body from glucose, and higher levels may reflect internal production (how much your body makes) rather than higher consumption from food and drinks.

Conditions such as prediabetes, diabetes, higher glucose intake and oxidative stress can all raise the body’s erythritol levels. This means that erythritol may be more of a marker of an underlying condition, rather than a cause.

Other studies have shown the benefits of erythritol, including reduced weight gain, antioxidant activity, protection of blood vessels from damage and lower levels of blood sugar. But findings from test tube and animal research don’t always translate to humans. More human trials are needed.

If you’re looking to reduce your risk of heart disease and stroke, focus on eating a diet full of whole foods. Instead of reaching for sugary foods and drinks, opt for fruits and vegetables that are naturally sweet to reduce added sugar in your diet. Talk to your doctor or dietitian if you need help building a sustainable diet that supports your heart health.

Will artificial sweeteners help me lose weight?

One of the main reasons people reach for artificial sweeteners is to aid in weight loss or weight management. Reducing overall daily intake of calories is challenging for most people, so replacing calories from sugary foods with zero-calorie sweeteners seems like an easy fix.

Some research suggests artificial sweeteners could lead to weight gain due to effects on the gut microbiome, cravings or sugar metabolism. However, many high-quality studies show that replacing sugar with artificial sweeteners reduces body weight.

Think about it this way. Sugar contains around 20 calories per teaspoon. The average American consumes an average of 17 teaspoons of sugar per day, according to USDA census data. If you replace the 17 teaspoons of sugar with a zero-calorie artificial sweetener, you should lose almost one pound in a week. Several studies have shown that people experience less hunger and therefore consume fewer calories when using artificial sweeteners. Since weight loss is created by achieving an overall daily calorie deficit, cutting out calories from sugar can help.

Keep in mind that if you rarely consume sweets or added sugars, then you won’t be reducing your daily calorie intake by including artificial sweeteners in your diet. Also, it doesn’t work if you replace the calories lost with other foods or bigger portions.

If you’re trying to lose weight, the best approach is to moderately reduce your daily calorie intake (by around 300-400 calories) and increase how many calories you burn through exercise (by around 200-300 calories expended). This balanced approach is easier to maintain long term.

Bottom line on artificial sweeteners

If your goal is to work toward eating a healthier, less processed diet, then choose whole foods, such as fruits and vegetables. Many are naturally sweet and have the added benefit of essential vitamins and minerals that your body needs every day. Whereas artificial sweeteners have no nutritional value.

However, if you’re trying to lose weight and you already regularly consume sugar sweetened beverages or other sugary foods, replacing them with artificially sweetened options is a good way to reduce your overall intake of calories.

If you have questions about how to build a sustainable plan for weight loss or make healthy changes to your diet, talk to your doctor or find a dietitian near you.