How sugar alcohols affect metabolic health

You'll often see these sweeteners in low- or no-sugar foods, but are they a healthy replacement for natural sugar? Here’s what we know.

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You’ve likely seen foods labeled “sugar-free” or “no added sugar” while searching for healthy options in the grocery store, even in traditionally sweet foods like ice creams or candy. To provide a sweet taste without the sugar, food manufacturers often add alternative sweeteners such as sugar alcohols. 

Keep reading to find out what sugar alcohols are, how they are different from sugar, and the pros and cons of consuming them. 

What are Sugar Alcohols? 

Sugar alcohols, also known as polyols, are a type of carbohydrate that contain structural characteristics of both sugars and alcohols (although they don’t affect the body the same way that alcoholic beverages do). While most added sugar alcohols are manufactured, some like erythritol and sorbitol are also found in small amounts in certain fruits and vegetables. With between 1.5–3 calories per gram, they provide less energy than sugar (4 calories per gram). Manufacturers commonly add them to processed foods such as cookies, soft drinks, and chewing gum as a sugar substitute. 

What are the Different Types of Sugar Alcohols? 

There are eight sugar alcohols currently approved for use in the United States:

  • Lactitol
  • Sorbitol 
  • Erythritol 
  • Hydrogenated starch hydrolysates 
  • Isomalt 
  • Mannitol 
  • Maltitol 
  • Xylitol 

Xylitol, erythritol, and maltitol produce a flavor that resembles the taste of natural sugar. Erythritol is a food industry favorite because it minimally affects blood sugar levels, isn’t harmful to pets (as xylitol can be), and causes significantly fewer digestive problems than other sugar alcohols.

What’s the Difference Between Sugar and Sugar Alcohols?

Sugars are sweet-tasting carbohydrates containing carbon, hydrogen, and oxygen atoms. A single unit sugar molecule is called a monosaccharide (e.g., glucose, fructose, and galactose); monosaccharides can also join together to form double-unit sugar molecules called disaccharides (e.g., sucrose, lactose, and maltose). Sugar alcohols are structurally similar to sugar but contain a hydroxyl group instead of an aldehyde group.

Most of the sugar you eat is broken down into glucose and absorbed into the bloodstream,  causing a rise in blood sugar levels. In response, your pancreas releases insulin so glucose can enter cells to create energy. By contrast, most sugar alcohols pass through the gastrointestinal tract largely intact and are fermented by gut bacteria in the large intestine. This can cause bloating and digestive discomfort [more on that below].

Benefits of Sugar Alcohols 

  • Fewer spikes in blood sugar. Unlike regular sugar, sugar alcohols don’t cause significant blood sugar spikes. They’re a low glycemic index food that may only slightly raise blood sugar levels. 
  • Reduced dental risk. When you eat sugar, bacteria in your mouth break down the carbohydrates into acids that damage your tooth enamel. However, sugar alcohols do not contribute to tooth decay because they can’t be fermented by oral bacteria, making them a popular component of toothpaste and chewing gums. Look at the ingredients list on your toothpaste, and you’re likely to see xylitol, which may also combat tooth decay by preventing oral bacteria from adhering to teeth and interfering with their energy and acid production processes. 
  • Diversified microbiome. Certain sugar alcohols may contribute to a healthy microbiome by promoting the growth of beneficial bacteria. Xylitol can serve as a prebiotic, which helps feed probiotics to support gut health. 
  • Lower in calories. If you’re trying to manage your weight, sugar alcohols may help since they taste sweet but provide fewer calories than regular sugar. 

Adverse Effects of Sugar Alcohols?

Although the available evidence suggests that sugar alcohols are safe to consume in moderation, they can have adverse gastrointestinal effects. They are poorly absorbed and attract water via osmosis as they move through the gastrointestinal tract, which can cause bloating and diarrhea. They are also fermented by bacteria when they reach the large intestine, which produces gas and can lead to additional discomfort. These effects are particularly pronounced in people with irritable bowel syndrome (IBS). Erythritol appears to cause fewer digestive problems than other sugar alcohols because it’s a smaller molecule, which allows it to be better absorbed through the small intestine into the bloodstream before it’s eventually excreted into the urine.   

Conclusion

Limiting any form of sugar is essential for maintaining metabolic health. When used in moderation (generally up to 10-15 g/day), sugar alcohols are considered safe, lower-calorie alternatives. However, they can cause unwanted side effects when consumed excessively, and more research is needed to determine their long-term effects.

Another option is to use natural alternative sweeteners such as yacón syrup and monk fruit, which are less likely to cause digestive problems. You can also work to decrease your sweet cravings. Research shows that cravings dissipate within weeks when people cut back on carbs (including sugar).

It’s also important to remember that alternative sweeteners don’t give you a get-out-of-jail-free card when it comes to processed foods. Even those made with reduced-calorie sweeteners may still have a significant amount of calories, carbohydrates, fat, and unwanted additives. Always the best bet: stick with whole, unprocessed foods that don’t need a nutrition label.