Key Summary Points
· Recent findings in the European Heart Journal highlight potential cardiovascular risks associated with xylitol, a low-calorie sweetener used in various food and beverage products.
· Xylitol, a sugar alcohol, is commonly used as a sugar substitute in items like chewing gum, candies, and drinks, as well as naturally occurring in small amounts in fruits and vegetables.
· The study involved multiple steps, including observational cohort studies, a human consumption experiment, and laboratory tests, to assess the impact of xylitol on cardiovascular health.
· Higher levels of xylitol were linked to an increased risk of major adverse cardiovascular events and blood clot formation in the study participants.
· The research indicated that xylitol consumption could elevate platelet reactivity, potentially leading to clot formation that may contribute to heart attacks or strokes.
· More research is needed to explore the cardiovascular safety concerns associated with xylitol consumption further.
What is Xylitol
Xylitol is a sugar alcohol, also known as a polyol, widely used as a sweetener. While it occurs naturally in small amounts in fruits (such as strawberries) and vegetables, it is primarily produced industrially from plant materials like birch bark or corn cobs. Xylitol is commonly found in sugar-free desserts, gum, candies, toothpaste, and mouthwash.
In Europe, xylitol (designated as E967) has been approved by the European Commission as a food additive. This approval permits its use in various products including jams, marmalades, spreads, chewing gum, and baked goods.
Considerations Regarding the Study Findings
· Xylitol levels in the blood of participants were likely from endogenous production rather than dietary intake, as samples were collected after fasting.
· The study did not collect data on participants’ dietary habits, making it challenging to isolate the impact of xylitol intake on cardiovascular risk.
· While the study identified associations between xylitol levels and cardiovascular events, it did not establish causation.
· The study population consisted of high-risk individuals, potentially limiting the generalizability of the findings to the broader population.
· The research focused solely on xylitol and did not extend to other sweeteners, emphasizing the need for individual assessment of different sweetener types.
Regulatory Perspective and Dietary Recommendations
· Xylitol is approved for use as a sweetener in the European Union, and its risk assessment is under review by the European Food Safety Authority.
· The importance of maintaining a healthy and balanced diet with minimal added sugars is highlighted by regulatory bodies like the EFSA and WHO.
· Sweeteners like xylitol can aid in reducing overall sugar intake in the diet while still enjoying sweet-tasting foods.
Decoding the Study Behind the Headlines
The published paper presents a complex study, but understanding its key steps is crucial. The researchers used a stepwise approach: starting with two observational cohort studies, followed by a human consumption experiment and laboratory tests.
Initially, they analyzed blood samples from 1,157 participants undergoing cardiac evaluations. They found that individuals with higher levels of a compound suspected to be xylitol had a 63% higher risk of major adverse cardiovascular events (such as heart attacks, strokes, or death) over three years compared to those with lower levels. However, they couldn’t definitively identify this compound as xylitol.
To resolve this, they developed more specific methods to quantify xylitol levels. In a second group of 2,149 people, they confirmed that higher blood xylitol levels were linked to increased risks of major cardiovascular events and blood clot formation (thrombosis).
Next, they examined the effects of consuming xylitol. When 10 healthy volunteers ingested 30 grams of xylitol, it led to increased platelet reactivity (a greater tendency to clot) within 30 minutes, returning to baseline within 4-6 hours.
Finally, in vitro (cell) and animal studies showed that xylitol enhanced platelet aggregation and adhesion, promoting clot formation. In mice, xylitol also shortened the time required for blood clots to form.
The researchers concluded that further research is necessary to fully examine the potential cardiovascular safety concerns associated with xylitol consumption.
Important Factors in Understanding the Study’s Results
1. Xylitol Levels and Dietary Intake: In the cohort studies, blood samples were taken after participants had fasted overnight. This suggests that the xylitol levels detected were likely not related to recent dietary intake but rather to natural production by the body. The half-life of xylitol in the blood is about 13 minutes, and levels return to baseline within 4-6 hours after consumption. Thus, the observed cardiovascular risks were likely associated with endogenous (internally produced) xylitol rather than dietary xylitol.
2. Lack of Dietary Data: The cohort studies did not collect information on participants’ dietary intake. Many factors in diet can influence cardiovascular risk, such as high sodium intake, low fruit consumption, or low intake of whole grains. Without dietary data, it is difficult to determine if the observed associations between xylitol levels and cardiovascular events were influenced by xylitol intake or other dietary habits.
3. Causation vs. Correlation: Observational cohort studies cannot prove causation. The researchers supplemented their findings with cell and animal studies to explore possible mechanisms by which high xylitol levels might increase cardiovascular risk. Although these experimental studies showed that xylitol promotes clot formation in test tubes and mice, they do not conclusively prove that xylitol causes increased cardiovascular risk in humans. More long-term research is needed to establish a causal link between xylitol consumption and cardiovascular health.
4. Study Population: The participants in the cohort studies were patients undergoing cardiac risk assessments and thus were at high risk for cardiovascular events. This population may not be representative of the general population, as their risk factors might differ. Additionally, the human experimental study included only 10 volunteers, which limits the generalizability of the findings.
5. Specificity to Xylitol: This study specifically focuses on xylitol and its potential cardiovascular effects. The findings are not necessarily applicable to other types of sweeteners, which have different chemical compositions and metabolic effects. While the study suggests that other sugar alcohol sweeteners might have similar effects, each sweetener needs to be individually assessed for its potential health impacts.
Official Views on Xylitol: Regulatory Perspectives
The European Commission has approved xylitol (E967) as a sweetener for use in various products within the European Union, including jams, marmalades, spreads, chewing gum, and baked goods. The European Food Safety Authority (EFSA) is currently reassessing the risk of xylitol in foods based on new data that has emerged since its initial approval.
EFSA recommends minimizing the intake of added and free sugars as part of a healthy and balanced diet. The World Health Organization (WHO) advises that free sugars should make up no more than 10% of a person’s daily energy intake, ideally less than 5%. Sweeteners like xylitol can help reduce sugar intake while still allowing for the enjoyment of sweet foods.
References
1. Witkowski et al., (2024) Xylitol is prothrombotic and associated with cardiovascular risk. European Heart Journal, ehae244, https://doi.org/10.1093/eurheartj/ehae244
2. Safety evaluation of low/no calorie sweeteners https://www.sweeteners.org/wp-content/uploads/2024/06/isa-safety_evaluation-factsheet-2024_en.pdf
3. Commission Regulation (EU) No 1129/2011 of 11 November 2011 amending Annex II to Regulation EC No 1333/2008 of the European Parliament and of the Council by establishing a Union list of food additives. https://www.efsa.europa.eu/en/topics/topic/food-additives
4. World Health Organization. (2015). Guideline: sugars intake for adults and children. World Health Organization. 5. EFSA Food Additives https://www.efsa.europa.eu/en/topics/topic/food-additives
6. EFSA Sweeteners Safety and Evaluation https://www.efsa.europa.eu/en/topics/topic/sweeteners
