Glycans: Definition, function, structure, foods, uses

Have you ever wondered what powers your body’s complex systems, from the immune response to cellular communication? Glycans, a group of essential sugars, play a pivotal role in these processes, yet they often go unnoticed in discussions about health and nutrition. 

Understanding glycans can unlock new perspectives on how to optimize your wellness strategy. These sugars are not only fundamental in the science of life but also in practical applications ranging from nutrition to disease prevention. 

This guide discusses importance of glycans, exploring their definition, function, structure, dietary sources, and uses. 

You’ll discover how integrating knowledge about glycans into your diet and lifestyle can contribute significantly to your health and well-being.

What are glycans?

Glycans, a crucial component of our biological makeup, are complex carbohydrates composed of sugar molecules bound together in chains [1]. 

Unlike proteins and DNA, which are defined by linear sequences of amino acids and nucleotides, respectively, glycans exhibit a staggering level of diversity in structure and function due to the ways their sugar units can be linked. 

This complexity allows glycans to participate in several biological processes, distinguishing them as a fundamental element in cellular communication, immune response, and the development of disease.

Biosynthesis and regulation

The creation and regulation of glycans, known as glycan biosynthesis, is a finely tuned process that occurs within cells [2]. 

Enzymes called glycosyltransferases play a pivotal role, adding sugars to proteins or lipids in a stepwise fashion. 

This biosynthesis is not template-driven like DNA or protein synthesis, making the diversity and complexity of glycan structures vast. 

Regulation of glycan synthesis is critical, as alterations in this process are associated with various diseases and autoimmune disorders.

The study of glycans and their biosynthesis offers exciting possibilities for health and medicine. 

As researchers uncover more about how glycans work and how we can manipulate their synthesis, the potential for new therapies and nutritional strategies grows. 

Glycans: Definition, function, structure, foods, uses

Forms of glycans

Glycans come in various forms, each serving distinct functions:

1. Glycoproteins – These are proteins covalently bonded to glycans, crucial for cell-to-cell recognition and signaling [3].

2. Glycolipids – Lipids attached to glycans, important for maintaining cell membrane stability and facilitating cell interaction.

3. Proteoglycans – Composed of a core protein and one or more glycosaminoglycan (GAG) chains, these are vital for the structural integrity of tissues and in cellular processes like growth and repair.

Understanding glycans is not just about adding another term to your health vocabulary; it’s about recognizing a fundamental component of biological processes that could revolutionize how you approach your health and wellness.

What is the function of glycans?

Cell-cell recognition and signaling

Glycans enable cells to identify and communicate with each other, facilitating essential processes like tissue growth, healing, and immune defense [4]. 

This signaling is not just about the presence or absence of glycans but also about their specific structures, which can convey different messages, influencing how cells respond to various stimuli.

Immune response modulation

The immune system’s ability to distinguish between self and non-self entities is crucial for defending against pathogens while avoiding autoimmunity. 

Glycans are at the heart of this discrimination process. They modulate immune responses by interacting with lectins (carbohydrate-binding proteins) on immune cells, guiding the immune system’s actions toward pathogens and away from the body’s own tissues [5].

Influence on pathogen interactions

Pathogens, including viruses and bacteria, often exploit glycans to invade host cells [6]. They can mimic host glycans to evade the immune system or bind to glycans on the surface of cells as a means of entry. 

Understanding these interactions opens the door to novel therapeutic strategies, such as vaccines and antiviral drugs that target these glycan-mediated pathways.

Role in the gut microbiome

Glycans are energy sources for beneficial gut bacteria, promoting a healthy microbiome composition [7]. This, in turn, impacts everything from nutrient absorption and digestion to immune function and even mood regulation. 

The intricate relationship between dietary glycans and the microbiome highlights the importance of diet in maintaining gut health and, by extension, overall well-being.

How do glycans shape our health and wellness?

At their core, glycans are composed of monosaccharides, simple sugars that combine in various ways to form complex carbohydrates. 

These building blocks are the foundation of glycan structures, which can vary immensely in size, shape, and composition. This diversity is not arbitrary; it is crucial for the specific roles glycans play in our bodies.

Glycans basic structure

Monosaccharides, such as glucose, galactose, and mannose, link together through glycosidic bonds to form complex glycans. 

The way these sugars combine—the sequence, the type of linkages, and the branching patterns—creates a vast array of possible structures. 

Each glycan has a unique composition and shape, determining its biological function. This structural complexity allows glycans to participate in various cellular activities, from signaling to structural support.

Diversity and specificity of glycan structures

The diversity of glycan structures is not merely for show; it underpins their specificity in biological functions. 

For example, the glycan structures found on the surface of cells can vary significantly from one cell type to another [8], enabling the immune system to distinguish between healthy cells and foreign pathogens. 

This specificity is also why certain viruses and bacteria can only infect specific cell types; they recognize and bind to particular glycan structures on the cell surface.

Why glycan diversity matters

The vast diversity of glycans and their precise roles in health and disease highlights the importance of glycobiology in medical research. 

Glycans are involved in nearly every biological process, from the development of the embryo to the functioning of the immune system. 

Their structures serve as key players in cell communication, pathogen recognition, and the modulation of immune responses. 

As we learn more about how glycans work, we unlock new possibilities for therapeutic interventions, ranging from vaccines to treatments for chronic diseases.

What foods boost your glycan intake?

When it comes to enhancing your health through diet, understanding which foods are rich in glycans can be a game-changer. 

Glycans, found in various foods, play critical roles in promoting gut health, supporting immune function, and facilitating cell communication. 

Let’s explore some of the best sources of dietary glycans and how to integrate them into your daily diet for maximum health benefits.

Fruits and vegetables

These are nature’s bounty when it comes to glycans. Apples, bananas, onions, garlic, and leeks are particularly rich in fructo-oligosaccharides (FOS) [9], a type of glycan that promotes healthy gut bacteria. 

Similarly, legumes such as lentils and chickpeas contain galacto-oligosaccharides (GOS) [10], known for their prebiotic effects.


Not only are mushrooms a culinary delight, but they are also packed with beta-glucans [11], a form of glycans that has been shown to enhance immune defense mechanisms. 

Incorporating varieties like shiitake, maitake, and reishi into your meals can boost your intake of these beneficial compounds.

Seaweeds and algae

These sea vegetables are excellent sources of sulfated polysaccharides, unique glycans with potent antiviral and immune-modulating properties. 

Adding seaweed to your soups, salads, or sushi rolls not only enriches the flavor but also your glycan intake.

Seaweeds and algae
Photograph: Aleruana/Envato

Human breast milk

For infants, human breast milk is the ultimate source of complex glycans, particularly human milk oligosaccharides (HMOs) [12], which play a crucial role in developing the infant gut microbiome and immune system. 

While adults can’t tap into this source directly, understanding its importance underscores the value of glycans right from the start of life.

How to incorporate glycan-rich foods into your diet?

  1. Start your day with a smoothie that includes bananas or apples for a quick glycan boost.
  2. Add onions and garlic to your cooking for both flavor and a healthy dose of FOS.
  3. Experiment with different types of mushrooms in your meals for a delicious way to consume beta-glucans.
  4. Explore the world of seaweeds by incorporating them into your meals as salads, soups, or snacks.

How can glycans enhance your health?

From nutritional supplements to innovative therapies, the application of glycans is reshaping our approach to health maintenance and disease treatment.

Let’s look into how glycans are being utilized across various health sectors and their potential to revolutionize future healthcare innovations.


Nutritional supplements enriched with glycans, such as fructo-oligosaccharides (FOS) and galacto-oligosaccharides (GOS), offer a promising avenue for enhancing gut health and boosting the immune system. 

These supplements act as food for beneficial gut bacteria, fostering a healthy gut microbiome. A balanced microbiome is essential for optimal nutrient absorption, efficient digestion, and a robust defense against pathogens [13]. 

Incorporating glycan-based supplements into your daily regimen could be a simple yet effective strategy to support your digestive health and immune resilience.

Therapeutic applications

The therapeutic potential of glycans is vast and varied. Researchers are exploring glycans’ ability to block harmful pathogens from attaching to human cells, offering a new way to prevent infections [14]. 

Biotechnology and pharmaceuticals

The biotechnology and pharmaceutical industries are at the forefront of translating glycan research into practical solutions. 

Glycan-based biomarkers are emerging as crucial tools for the early detection of diseases and autoimmune disorders. 

Furthermore, the advent of glyco-engineered drugs, which involve tweaking the glycan structures on proteins, is improving treatment efficacy and safety. These advancements promise more targeted and tolerable therapies for patients.

Are glycans good for you?

Glycans are crucial for effective immune responses, facilitating cell-to-cell communication, and ensuring the proper functioning of proteins. 

Their presence in the gut, in the form of dietary fibers, also supports the growth of beneficial bacteria, contributing to a healthy microbiome. 

This, in turn, can enhance nutrient absorption, bolster your immune system, and even impact your mood positively.

Moreover, the therapeutic potential of glycans is immense. Research indicates that certain glycans may help prevent infection by blocking pathogen adhesion to human cells. 

Additionally, their role in developing new cancer therapies — by making cancer cells more recognizable to the immune system — is a promising avenue for future treatments.

However, the beneficial effects of glycans depend on the balance and types of glycans present in your body and diet. 

For instance, while some dietary glycans support health by feeding beneficial gut bacteria, others, especially those in processed foods, can contribute to inflammation and disease.

Incorporating natural, glycan-rich foods into your diet — like fruits, vegetables, legumes, and whole grains — is a straightforward way to harness the health benefits of glycans. 

Such dietary choices can promote a healthy gut, support immune function, and may even protect against certain diseases.

Closing thoughts

Understanding glycans and their impact on health has opened new doors to wellness and disease prevention. 

These complex carbohydrates are more than just sugars; they are vital players in the body’s cellular communication, immune function, and gut health. 

Embracing a diet rich in glycan-containing foods can lead to improved health outcomes and may offer protection against various diseases. 

Now is the time to consider the role of glycans in your diet and health regimen. Explore glycan-rich foods, stay informed about the latest research, and take proactive steps towards harnessing the benefits of glycans for your well-being.


Are glycans prebiotics?

Yes, certain types of glycans function as prebiotics. These specific glycans promote the growth of beneficial gut bacteria, supporting a healthy microbiome and contributing to overall digestive health and immune function.

Do humans have glycans?

Yes, humans have glycans. These complex carbohydrates are found on the surfaces of cells and within bodily fluids, playing crucial roles in cellular communication, immune response, and the structural integrity of tissues.

Are glycans carbohydrates?

Yes, glycans are carbohydrates. They consist of complex chains of sugar molecules and play vital roles in cellular processes, including cell signaling, immune response, and the structural integrity of cells and tissues.

What is another name for glycans?

Another name for glycans is complex carbohydrates or polysaccharides. These terms refer to the intricate chains of sugar molecules that are essential for various biological functions, including cellular communication and immune system regulation.


Photograph: Maryna Olyak/Shutterstock
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