The Prebiotic Benefits of Oligosaccharides

Jerusalem artichokes on a cutting board

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A healthy balance of gut bacteria can boost your immune system and contributes to overall health. Prebiotics such as oligosaccharides contributes to the growth and balance of beneficial gut bacteria.

You can get oligosaccharides in your diet by eating foods that are naturally rich in them, or that have had oligosaccharides added. Keep reading to learn more about how oligosaccharides contribute to health and where to find them.

What Are Oligosaccharides?

Oligosaccharides are a type of carbohydrate that falls between simple sugars (monosaccharides) and starches (polysaccharides). They are formed when three to 10 simple sugars are linked together. The human digestive system has difficulty breaking down many of these carbohydrates. These minimally-digested fibers act as prebiotics that ferment and feed good bacteria in the gut. Fructooligosaccharides and galactooligosaccharides are the two main types of oligosaccharides that act as prebiotics.

Some people follow a low-FODMAP diet—the O in FODMAP stands for oligosaccharides. While oligosaccharides are beneficial for most people, those with IBS or Crohn's disease may experience digestive symptoms when eating foods with oligosaccharides.

Benefits of Oligosaccharides

Oligosaccharides help promote the growth of healthy gut microflora. From there, bacteria that feed on fermentable carbohydrates produce many beneficial substances, including short-chain fatty acids (SCFAs) and specific B vitamins.

As the gut bacteria break down oligosaccharides, they produce SCFAs. Some early evidence suggests the bacteria could promote absorption of certain minerals, including calcium and magnesium, that escape the small intestine during digestion.

While research is ongoing, SCFAs likely provide many benefits both in the colon and the rest of the body. Specifically, butyrate may protect colon tissue from damage caused by conditions like colon cancer and ulcerative colitis.

At first, oligosaccharides were believed to be the main form of prebiotics, but it turns out that bacteria in the colon also feed on resistant starch and fermentable fiber. We now understand that a crucial digestive process is happening in the colon that influences the rest of the body.

Prebiotics are not to be confused with probiotics. While both terms relate to gut health, pre-and probiotics have different roles, health benefits, and sources; probiotics are the "good" bacteria in the gut. Prebiotics are a food source for those bacteria.

Prebiotic fiber is so beneficial for gut health because works to regulate bowel function while also stimulating the growth of beneficial bacteria, especially Bifidobacterium which is vital for health. Greater levels of good bacteria decrease the number of bad bacteria in the gut, balancing and enhancing the gut microbiome.

A healthy microbiome is related to lower levels of inflammation, and a better functioning immune system and metabolism. Prebiotic fibers, including oligosaccharides, also help regulate glucose metabolism. Since prebiotics are not reduced to simple sugars as some other forms of carbohydrates, they do not increase blood sugar.

There is no recommended daily intake for oligosaccharides. It is estimated that people in the United States obtain about 800 to 1000 milligrams daily, on average with a general recommendation of 2,000 to 3,000 milligrams per day to encourage healthy gut flora.

Oligosaccharides in Food

Small amounts of oligosaccharides occur naturally in many plants, including vegetables and fruit, grains, and legumes. Most oligosaccharides have a mildly sweet taste. Other characteristics, such as the mouthfeel they lend to food, have drawn the food industry's interest.

Many manufacturers are exploring oligosaccharides as a partial substitute for fats and sugars and a way to improve a product's texture. Due to these attributes, the amount of synthetically produced oligosaccharides present in food is on the rise.

Different oligosaccharides tend to produce different SCFAs—a good reason to eat a variety of oligosaccharide-containing foods.

Chicory root and Jerusalem artichokes—the root of a sunflower family member—have the most oligosaccharides. These substances are also found in onions—including leeks and garlic—asparagus, kale, cabbage, broccoli, legumes, jicama, and other plant foods. You also can find oligosaccharides in berries, pears, figs, bananas, nectarines, and watermelon as well as in wheat, rye, peans, and beans.

Non-Plant-Based Sources of Oligosaccharides

The most common oligosaccharide food additives are inulin and oligofructose. Protein bars, for example, feature inulin. Other brands also include inulin, though it's listed on the label as "chicory root fiber" because it can be derived from chicory.

Inulin is also available as an over-the-counter vitamin supplement you can purchase in health food stores or online. You can also get the prebiotic benefits of oligosaccharides by adding more fermentable fiber, including resistant starch, to your diet.

Oligosaccharides are also crucial for babies’ digestive health. They are present in breast milk and are added to infant formula.

Why Oligosaccharides Aren't Labeled As Fiber

While oligosaccharides do fall under the categories of both soluble fiber and fermentable fiber, they are not currently included under dietary fiber on food labels in the United States. One exception is inulin from chicory root, which may be listed as fiber on nutrition labels.

In response to a citizen's petition for the inclusion of synthetic carbohydrates on food labels under the product's dietary fiber content, the Food and Drug Administration proposed listing added oligosaccharides and other isolated or synthetic non-digestible carbohydrates (NDCs) on the labels. The change is still pending.

A Word From Verywell

Oligosaccharides are a prebiotic fiber that contribute to healthy gut bacteria growth. A healthy balance of gut bacteria leads to an improved microbiome. The overall health advantages of a flourishing microbiome are still being researched but include superior immune function, reduced inflammation, better metabolism, blood sugar regulation, and more.

You probably already get many oligosaccharides through your diet naturally, but if not, focus on getting a wide variety of whole grain, legumes, fruits, and vegetables. A nutrient dense diet high in these foods contributes to overall health in many ways, including providing plenty of prebiotic fiber.

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Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Rachel MacPherson, BA, CPT
Rachel MacPherson is a health writer, certified personal trainer, and exercise nutrition coach based in Montreal.