Oligosaccharides, or “oligos,” are carbohydrates recognized for their role in human health. Found naturally in many plant-based foods, they contribute to our nutritional well-being. Understanding these unique carbohydrates can show how certain foods support overall health, especially by influencing the digestive system. This article defines oligosaccharides, identifies their natural sources, and explains their health benefits.
The Building Blocks: What Exactly Are Oligosaccharides?
Oligosaccharides are carbohydrates made of a few simple sugar units, called monosaccharides, linked in a chain. The “oligo” prefix means “few,” reflecting their structure of typically three to ten monosaccharide units. This short-chain structure differentiates them from single-unit monosaccharides like glucose, and from larger polysaccharides such as starch.
Oligosaccharides resist digestion by human enzymes in the upper gastrointestinal tract. Instead of being absorbed quickly like simple sugars, they travel largely intact to the lower digestive system. This resistance allows them to perform their beneficial functions. The specific arrangement of these units determines each oligosaccharide’s unique properties.
Diverse Forms and Their Natural Homes
Several types of oligosaccharides exist in nature, each with distinct sources. Fructooligosaccharides (FOS) are a common type, primarily composed of fructose units. They are abundant in fruits and vegetables like onions, garlic, asparagus, bananas, and artichokes.
Galactooligosaccharides (GOS) are another group, formed from galactose units. GOS are present in legumes, such as beans and lentils, and some dairy products. Human Milk Oligosaccharides (HMOs) are a significant category found exclusively in human breast milk. HMOs are the third most abundant solid component in human milk, after lactose and lipids.
The Health Benefits of Oligosaccharides
Oligosaccharides primarily benefit human health as prebiotics. They selectively stimulate the growth of beneficial bacteria in the colon, such as Bifidobacteria and Lactobacilli. Since human enzymes cannot break them down, oligosaccharides serve as a fermentable food source for these gut microorganisms. This fermentation produces short-chain fatty acids (SCFAs), important for colon health and broader systemic effects.
Consuming oligosaccharides can improve digestive function, reducing issues like constipation and bloating by promoting a balanced gut microbiota. Beyond gut health, oligosaccharides may also modulate the immune system. By fostering a healthy gut environment, they indirectly support immune responses, as many immune cells reside in the gut.
Incorporating Oligosaccharides into Your Diet
You can increase oligosaccharide intake by including a variety of foods in your diet. Many common fruits and vegetables are excellent natural sources. For example, fructooligosaccharides are found in chicory root, Jerusalem artichokes, and leeks. Legumes like chickpeas and lentils provide galactooligosaccharides.
While whole foods are the preferred way to get these compounds, supplements are also available. These often contain concentrated FOS or GOS. If considering supplements, consult a healthcare professional to determine the appropriate dosage and ensure it aligns with your health needs.