Who should not use artificial sweeteners? A guide to dietary precautions

October 31, 2025 •

4 min read

According to the Food and Drug Administration (FDA), artificial sweeteners are generally safe for the public, but they are not universally recommended for everyone. The question of who should not use artificial sweeteners depends on a person's individual health conditions and life stage, as certain groups face specific health risks.

Quick Summary

This article outlines the specific health conditions and life stages that warrant caution or complete avoidance of artificial sweeteners, including metabolic disorders, gastrointestinal sensitivities, pregnancy, and early childhood, detailing the reasons behind these precautions.

Key Points

PKU patients must avoid aspartame: Due to a rare genetic disorder, individuals with Phenylketonuria (PKU) cannot process the phenylalanine in aspartame, leading to toxic buildup.
IBS sufferers should be wary of polyols: Sugar alcohols like sorbitol and mannitol, common in 'sugar-free' products, are fermentable carbohydrates (FODMAPs) that can cause significant digestive distress for those with IBS.
Artificial sweeteners require caution during pregnancy: Evidence on the safety of artificial sweeteners during pregnancy is mixed, with some studies suggesting a potential link to adverse outcomes like preterm birth, though more research is needed.
Avoid sweeteners for children under two: Health authorities advise against giving artificial sweeteners to very young children to protect their developing gut microbiome and prevent the formation of overly sweet taste preferences.
Long-term metabolic and heart risks: Emerging observational studies suggest a correlation between chronic, high-level artificial sweetener intake and an increased risk of metabolic syndrome and cardiovascular disease.
Focus on whole food sweetness: Instead of relying on artificial substitutes, a healthier long-term strategy is to reduce overall sugar cravings by opting for whole fruits and natural alternatives in moderation.

A Closer Look at Artificial Sweeteners

Artificial sweeteners, or non-nutritive sweeteners, are popular sugar substitutes designed to provide sweetness without the calories of sugar. They are commonly found in diet sodas, sugar-free products, and chewing gums. While regulatory bodies like the FDA deem them safe for general consumption within acceptable daily intake (ADI) levels, some research and clinical experience suggests specific populations should exercise caution or avoid them altogether.

Phenylketonuria (PKU)

Individuals with the rare genetic disorder, Phenylketonuria (PKU), are the most definitive group who must avoid specific artificial sweeteners.

Why aspartame is dangerous for PKU patients

PKU affects the body's ability to metabolize phenylalanine, an amino acid present in aspartame. Consumption of aspartame by someone with PKU can lead to a toxic buildup of phenylalanine, causing serious health issues. Therefore, products containing aspartame must include a warning label.

Gastrointestinal Sensitivities and IBS

Artificial sweeteners can trigger or worsen digestive symptoms, particularly for those with pre-existing issues like Irritable Bowel Syndrome (IBS). This is often due to sugar alcohols, also known as polyols, which include sorbitol, mannitol, and xylitol.

Polyols (Sugar Alcohols) and IBS

Polyols are poorly absorbed in the small intestine and are fermented by bacteria in the large intestine. This fermentation, combined with the osmotic effect of polyols, can cause bloating, gas, abdominal pain, and diarrhea. As fermentable carbohydrates (FODMAPs), polyols are a common trigger for IBS symptoms.

Pregnancy and Early Childhood

Health organizations like the American Academy of Pediatrics (AAP) provide guidance on artificial sweeteners for pregnant women and young children.

During pregnancy

Long-term studies on the effects of artificial sweeteners during human pregnancy are limited and have yielded mixed results. Some research has indicated a potential link between high intake of artificially sweetened drinks during pregnancy and increased risk of preterm delivery and higher offspring BMI.

For young children

The AAP advises against giving artificial sweeteners to children under two years old, emphasizing the need for nutrient-dense foods for growth. Early introduction of these sweeteners may negatively impact the developing gut microbiome and potentially lead to a preference for very sweet foods later in life.

Metabolic and Cardiovascular Concerns

Some research suggests a potential link between long-term, high intake of artificial sweeteners and increased risk of certain metabolic and cardiovascular issues.

Studies have observed correlations between regular consumption of artificially sweetened beverages and a higher risk of metabolic syndrome. Additionally, some observational studies have linked higher intake of these beverages to an elevated risk of stroke and coronary heart disease. Some sweeteners, like saccharin, may alter gut microbiota, potentially leading to impaired glucose tolerance and insulin resistance.

Comparison of Common Sweeteners for At-Risk Groups


Sweetener Type	Example (Brand Name)	Risk for PKU Patients	Risk for IBS/FODMAP	Risk for Pregnant Women	Risk for Children <2	Potential Metabolic/CVD Risk	Status for At-Risk Groups
Synthetic High-Intensity	Aspartame (NutraSweet, Equal)	High Risk: Contains phenylalanine, which is toxic for PKU patients.	Low, but some individuals report sensitivities.	Generally considered safe by FDA, but some clinicians advise caution due to mixed results on long-term effects.	Avoid (prohibited in infant formula).	Potential link to metabolic and neurobehavioral issues, but evidence is debated.	Avoid for PKU, Caution for other groups.
Synthetic High-Intensity	Sucralose (Splenda)	No Risk: Does not contain phenylalanine.	Moderate: Can alter gut flora and may exacerbate IBS symptoms in sensitive individuals.	Considered safe by regulatory bodies, but more long-term data needed on fetal development effects.	Avoid (lack of nutrient benefit).	Some studies link to gut flora changes, insulin resistance, and weight gain, but findings are mixed.	Caution for IBS, Limit for pregnant women and children.
Sugar Alcohol (Polyols)	Sorbitol, Mannitol, Xylitol	No Risk: Not metabolized into harmful substances.	High Risk: High FODMAP content often causes bloating, gas, and diarrhea.	Generally safe in moderation, but can cause digestive upset.	Avoid (can cause severe digestive issues).	Can raise blood sugar less than sugar, but high intake still contributes calories.	Avoid for IBS/sensitive gut.
Natural Low-Calorie	Stevia (Pure Via, Truvia)	No Risk: Does not contain phenylalanine.	Low, generally well-tolerated.	Limited human data, but generally recognized as safe (GRAS) by FDA.	Avoid (limited research).	May improve glucose tolerance and potentially has anti-diabetic properties.	Generally safer alternative.
Natural Low-Calorie	Monk Fruit	No Risk: No phenylalanine content.	Low, generally well-tolerated.	Generally recognized as safe (GRAS) by FDA, but limited research on pregnancy.	Avoid (limited research).	No significant impact on blood sugar, often a preferred alternative.	Generally safer alternative.

Managing Your Diet: Alternatives and Recommendations

For those who should limit or avoid artificial sweeteners, consider these alternatives and strategies:

Reduce overall sweetness: Gradually decrease reliance on all concentrated sweeteners, allowing your palate to adapt to less intense sweetness.
Use natural sweeteners in moderation: Options like dates, applesauce, pure maple syrup, and raw honey (avoid in infants under 1) can be used judiciously.
Prioritize whole fruits: Get sweetness from whole fruits, which also provide beneficial fiber, vitamins, and minerals.
Choose natural non-caloric options carefully: Stevia and monk fruit extracts are often better tolerated than synthetic options if a no-calorie sweetener is needed. Consult a healthcare provider or dietitian for personalized advice.

Conclusion

While artificial sweeteners can be a sugar alternative, they are not suitable for everyone. Individuals with PKU must strictly avoid aspartame, and those with IBS should be cautious with sugar alcohols. Pregnant women and parents of young children may also consider limiting or avoiding them due to potential risks and the importance of nutrient-rich diets for development. Focusing on reducing overall sweetness and choosing whole foods are generally healthier approaches. Always consult a healthcare professional before making dietary changes, especially with existing health conditions or during pregnancy.

For more dietary information, refer to reputable sources like the American Heart Association (AHA) or the American Diabetes Association (ADA).

Frequently Asked Questions

No, individuals with Phenylketonuria (PKU) must completely avoid aspartame. Their bodies lack the enzyme to metabolize phenylalanine, one of its components, and even small amounts can be harmful.

People with IBS often react poorly to sugar alcohols (polyols) like sorbitol because these are poorly absorbed and ferment in the large intestine. This process produces gas, bloating, and diarrhea.

Some individuals report fewer digestive issues with natural, high-intensity sweeteners like stevia and monk fruit extract. However, sensitivity varies, and some sugar alcohols like erythritol are generally better tolerated than sorbitol, but moderation is key.

While often marketed for weight management, long-term studies have shown mixed results, and some suggest they may paradoxically lead to weight gain, metabolic dysfunction, or a higher preference for sweet foods.

Yes, research indicates that some artificial sweeteners, including saccharin and sucralose, can alter the balance of gut bacteria and potentially lead to dysbiosis, which has been linked to metabolic issues.

Regulatory bodies typically say moderate use is safe, but some medical professionals advise caution due to conflicting research and limited long-term data on fetal effects. Avoiding them or using naturally-sourced alternatives is often recommended.

For those with a sensitive stomach, natural whole-food options like dates, berries, and applesauce are often a good choice. Plant-based sweeteners like pure stevia and monk fruit extract are also generally well-tolerated when used in moderation.

Always check the ingredient list on the product label. For aspartame, look for the 'PHENYLKETONURICS: CONTAINS PHENYLALANINE' warning. For polyols, check for ingredients ending in '-ol' such as sorbitol, xylitol, and mannitol.