What are sugar alcohols and how does erythritol differ?
Erythritol is a type of sugar alcohol, or polyol, a carbohydrate that tastes sweet but is metabolized differently than sugar. Sugar alcohols are known for causing digestive issues because they are poorly absorbed in the small intestine. This leaves unabsorbed particles to travel to the large intestine where gut bacteria can ferment them. This fermentation process can lead to gas, bloating, and other unpleasant symptoms. Additionally, the presence of these poorly absorbed substances can create an osmotic effect, pulling water into the large intestine and causing a laxative effect.
What sets erythritol apart from other common sugar alcohols like xylitol, maltitol, and sorbitol is its superior absorption rate. The small intestine absorbs approximately 90% of ingested erythritol before it reaches the large intestine. The remaining 10% is not readily fermented by gut bacteria. Because so little of it reaches the colon, and because what does get there is poorly fermented, erythritol is significantly less likely to cause digestive upset compared to its counterparts. However, this does not mean it is completely free of risk.
The digestive mechanism behind erythritol's side effects
Despite its high absorption rate, erythritol can still trigger digestive problems in certain situations. The primary factor is the amount consumed. When large quantities of erythritol are ingested at once, the small intestine's capacity to absorb it can be overwhelmed. The excess then travels to the colon, where it can cause issues.
This leads to two main mechanisms for gastrointestinal distress:
- Osmotic effect: Unabsorbed erythritol in the large intestine draws water into the bowels, which can cause loose stools and diarrhea.
- Bacterial fermentation: While minimal compared to other sugar alcohols, the small amount of erythritol that reaches the colon can still be fermented by gut bacteria, producing gas. This can result in bloating, cramping, and flatulence.
Individual tolerance plays a huge role. Some people's systems are more sensitive to sugar alcohols than others. Furthermore, those with pre-existing digestive conditions, such as Irritable Bowel Syndrome (IBS), may be particularly susceptible to adverse effects, even from smaller amounts.
How much erythritol is too much?
Determining a precise threshold for digestive side effects is difficult due to individual variability. However, research and expert opinions provide general guidelines. A 2007 study found that a single dose of 50 grams of erythritol significantly increased reports of nausea and stomach rumbling, while lower doses (20-35g) were better tolerated. The European Food Safety Authority (EFSA) suggests an acceptable daily intake (ADI) of 0.5 grams per kilogram of body weight to minimize laxative effects, but notes that many can tolerate higher amounts. Spreading consumption throughout the day, rather than in a single large dose, can also help. For many, consuming more than a few tablespoons at once may cause symptoms.
Managing erythritol digestive issues
If you experience digestive problems with erythritol, several strategies can help you manage your intake and minimize discomfort:
- Start with small amounts: Introduce erythritol-containing foods gradually to allow your digestive system to adjust and to find your personal tolerance level.
- Spread out consumption: Instead of eating a large quantity at once, distribute your intake of sugar-free products throughout the day.
- Read ingredient labels: Be aware of how much erythritol is in a serving, as well as the presence of other sugar alcohols like maltitol or xylitol, which are more likely to cause issues.
- Pair with other foods: Consuming erythritol as part of a meal can slow its absorption and may reduce the likelihood of side effects compared to having it on an empty stomach.
- Consider alternatives: If you continue to experience problems, consider other non-sugar sweeteners like stevia or monk fruit, which do not cause fermentation in the gut.
Erythritol vs. other sugar alcohols: A comparison
To illustrate why erythritol is generally better tolerated, here is a comparison with xylitol, another popular sugar alcohol.
| Feature | Erythritol | Xylitol |
|---|---|---|
| Digestive Tolerance | Generally high, even at larger doses. Least likely to cause issues compared to other polyols. | Moderate. More likely to cause bloating, gas, and diarrhea, especially at high doses. |
| Absorption | About 90% absorbed in the small intestine. | About 50% absorbed in the small intestine. |
| Fermentation | Minimal fermentation by gut bacteria in the colon. | Significant fermentation by gut bacteria in the colon. |
| Osmotic Effect | Less pronounced, as most is absorbed before it reaches the large intestine. | More pronounced, drawing water into the large intestine and causing a laxative effect. |
| Taste | About 70% as sweet as sugar with a cooling aftertaste. | Roughly equal to sugar in sweetness. |
The low FODMAP diet and erythritol
For individuals following a low FODMAP diet, erythritol presents a nuanced case. While it is a polyol, and polyols are generally high FODMAP, erythritol's high absorption rate has led Monash University to classify it as low FODMAP. However, some nutritionists still recommend limiting or avoiding it during the elimination phase of the diet. This is because it can still cause problems for some people, and it can also increase fructose malabsorption. As with any food, listening to your body's specific response is the best course of action.
Conclusion
While erythritol is a common and popular sugar substitute, particularly in keto and low-carb products, it is not without potential digestive side effects. For most people, these issues only occur with excessive intake, and erythritol is far better tolerated than other sugar alcohols like xylitol or maltitol due to its higher absorption rate. However, those with sensitive digestive systems, such as IBS, may need to be more cautious. By being mindful of dosage, starting with small amounts, and distributing consumption throughout the day, most can enjoy the sweetness of erythritol without the bloating, gas, or diarrhea. Listening to your body and consulting a healthcare provider or registered dietitian is the best way to determine your personal tolerance and ensure digestive comfort.
Visit the Monash University website for more information on erythritol's FODMAP status.
