The Truth About Sweeteners: A Healthy Alternative or a Hidden Danger?

Sugar substitutes are substances used instead of sugar to provide a sweet taste in food and beverages. Their popularity stems from the desire to reduce calorie intake. Artificial and natural sweeteners allow people to enjoy sweetness without extra calories, which is especially appealing to those managing their weight, following a diet, or monitoring their body’s energy balance.

In addition, sugar substitutes help regulate blood glucose levels. People with diabetes often use them to avoid sharp spikes in blood sugar caused by regular sucrose. Some sweeteners have minimal impact on insulin response, making them a convenient alternative for controlling metabolic processes.

However, the popularity of sugar substitutes is influenced not only by their composition but also by marketing. Manufacturers actively use terms like “natural,” “healthy,” and “sugar-free”, creating the impression that these products are always safe. But scientific research provides mixed results. Artificial sweeteners do not always aid in weight loss, and some may disrupt gut microbiota, alter insulin levels, or even increase the risk of chronic diseases, including cancer.

Difference Between Natural and Artificial Sweeteners

Sugar substitutes fall into two main categories: natural and artificial. The primary differences between them are their origin, caloric value, and effects on the body.

Natural sweeteners are derived from natural sources such as plants and fruits. They are considered safer, have a lower glycemic effect compared to sugar, and sometimes offer additional health benefits. However, some may have a laxative effect when consumed in large quantities.

• Xylitol (E967) – sweetness 0.7–1.0 of sugar, protects tooth enamel, but is toxic to dogs.
• Sorbitol (E420) – sweetness 0.6 of sugar, commonly used in chewing gum, may cause digestive upset in large doses.
• Maltitol (E965) – sweetness 0.7–0.9 of sugar, partially absorbed by the body, can raise blood sugar levels.
• Erythritol (E968) – sweetness 0.6–0.8 of sugar, not absorbed, does not raise blood sugar, and is calorie-free.
• Stevia (E960) – sweetness 150–300 of sugar, contains no calories, but may trigger allergic reactions and contains oxalates.

Artificial sweeteners are synthetically produced and usually have high sweetness levels without calories. They are widely used in industry, but their long-term health effects are still under study.

• Aspartame (E951) – sweetness 200 of sugar, one of the most common, but controversial regarding safety.
• Sucralose (E955) – sweetness 600 of sugar, heat-stable, but may affect gut microbiota.
• Saccharin (E954) – sweetness 300–500 of sugar, one of the oldest sweeteners, may cause side effects in some individuals.
• Acesulfame-K (E950) – sweetness 200 of sugar, heat-stable, but requires limited intake.

Additional data on how sweeteners affect blood sugar, insulin, and body weight is provided below.

What Are the Known and Potential Risks of Sweeteners According to WHO and Ongoing Research?

Some sweeteners are approved for consumption, but this does not mean they are entirely safe. The WHO evaluates sweeteners based on long-term risks, such as cancer and metabolic disorders. However, research is ongoing, and several effects are still under investigation and not yet reflected in official guidelines.

Aspartame

• In 2023, classified by WHO as “possibly carcinogenic” (Group 2B), but considered safe within permitted doses.
• Found in popular drinks like Diet Coke, Coca-Cola Zero Sugar, and Pepsi Max.
• Possible side effects (under investigation):
  • Cognitive impairment (affecting neurotransmitters, anxiety, memory decline).
  • Linked to migraines – people with chronic headaches often report worsening symptoms.
  • Impact on serotonin levels – may worsen depression at high doses.

Sucralose

• Approved by WHO, but recommended for limited consumption.
• Possible side effects:
  • Disruption of gut microbiota – reduces beneficial bacteria.
  • Formation of toxic compounds when heated – potential effects on liver and DNA.
  • Influence on glucose metabolism – potential risk of prediabetic conditions.

Acesulfame-K

• Approved by WHO, but long-term effects are still being studied.
• Found in popular drinks like Diet Coke, Coca-Cola Zero Sugar, and Pepsi Max.
• Possible side effects:
  • Animal studies have shown effects on the thyroid gland.
  • Possible cognitive dysfunction, but data is limited.
  • Some studies suggest an increased cancer risk (though evidence is insufficient).

Saccharin

• Previously considered a carcinogen, but WHO has revised this risk.
• Possible side effects:
  • Changes in gut microbiota.
  • Metallic aftertaste, digestive issues in some individuals.

Erythritol

• Officially approved by WHO.
• 2023 data suggests:
  • May increase the risk of thrombosis and cardiovascular disease.
  • Affects vascular responses, potentially raising stroke risk.

Xylitol, Sorbitol, Maltitol (polyols)

• Generally safe, but may cause a laxative effect in high doses.
• Possible side effects:
  • Impact on gut microbiota, especially with frequent use.
  • May trigger IBS (Irritable Bowel Syndrome) symptoms in sensitive individuals.

How Do Sweeteners Affect Blood Sugar, Insulin, and Weight?

In addition to potential risks, it’s important to understand how different sweeteners impact key metabolic processes.

Natural Sweeteners (Stevia, Monk Fruit)

• Blood Sugar Levels: have little to no impact on blood glucose.
• Insulin and Insulin Resistance: do not affect insulin sensitivity.
• Impact on Weight: zero calories, may aid in weight loss if they don’t trigger sweet cravings.

Natural Sugar Alcohols (Erythritol, Xylitol, Sorbitol)

• Blood Sugar Levels: cause minimal glucose increase, but high amounts can lead to digestive discomfort.
• Insulin and Insulin Resistance: may slightly raise insulin due to partial absorption.
• Impact on Weight: low-calorie, but can have a laxative effect in high doses.

Artificial Sweeteners (Aspartame, Sucralose, Saccharin)

• Blood Sugar Levels: do not raise blood sugar since they are not metabolized.
• Insulin and Insulin Resistance: some studies suggest potential impact on gut microbiota and insulin sensitivity.
• Impact on Weight: no calories, but may increase sweet cravings, leading to overeating.

Important! It was previously believed that sweeteners help with weight loss, but recent research shows some may actually increase appetite.

Where Are Sweeteners Most Commonly Found?

Sweeteners are added to many products, including those not obviously “diet” foods. They can be found in:

• Diet sodas: Diet Coke, Coca-Cola Zero Sugar, Pepsi Max
• Protein bars and powders
• Fat-free yogurts (fat removed, sweeteners added)
• Sugar-free gum and candies
• Prepared sauces, ketchup, mustard
• Medicines, cough syrups
• Low-calorie labeled baked goods, breads, crackers

Important! Even children’s products may contain sweeteners, especially vitamins and syrups.

What Are the Safest Sugar Substitutes?

The safety of sweeteners remains a subject of debate. However, there are a few options currently considered to be the most neutral for health. When choosing a sweetener, it’s important to consider its effect on blood sugar, insulin response, and overall health. Best choices for those aiming to avoid sugar spikes and insulin load:

• Berries – low in sugar and high in fiber, which slows absorption. Best options: raspberries, blueberries, blackberries (low glycemic index).
• Cinnamon and vanilla – enhance sweetness without sugar; cinnamon may also improve insulin sensitivity.
• Xylitol – has minimal effect on blood glucose and helps protect teeth by inhibiting cavity-causing bacteria.
• Erythritol – not metabolized by the body, does not raise blood sugar, does not affect metabolism, and is non-cariogenic.
• Stevia – natural, calorie-free, does not impact blood sugar or insulin levels, though it has a distinct taste.

Conclusion

Despite heavy marketing of sweeteners as a safe alternative to sugar, research shows they may not only be ineffective but also pose new health risks.

While sweeteners were once believed to aid weight loss, modern data suggest the opposite: they may increase cravings for sweets and promote overeating.

Ultimately, the best strategy is not to replace sugar but to reduce overall sweetness in the diet. There are no magical “safe” products — it’s our dependency on excessive sweetness that needs to change.

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World Health Organization (WHO): WHO advises not to use non-sugar sweeteners for weight control in newly released guideline

U.S. Food and Drug Administration (FDA): Aspartame and Other Sweeteners in Food

European Food Safety Authority (EFSA): Sweeteners