Lectins

Lectins

Brief expert definition: What are Lectins, how do they work in the body, and how are they applied in sports nutrition.

Short answer: Lectins are proteins that can affect digestion and nutrient absorption, especially in athletes, if not properly processed. Practical advice: Always thermally process legumes for at least 10-20 minutes by boiling to deactivate active lectins and avoid gastrointestinal upset.

Lectins are a diverse group of proteins that reversibly bind to carbohydrates using specialized domains.

For a comprehensive overview, see the complete guide to proper nutrition — a foundational guide from the expert team at Sport Zona.

What are Lectins?

Lectins are a group of proteins found in foods that bind to sugars and can affect digestion and nutrient absorption in some people.

📖 Lectins

Lectins are a group of proteins that specifically and reversibly bind to carbohydrate structures, are found in plants, animals, and microorganisms, and can have both beneficial and anti-nutritional properties.

Lectins are a group of glycoproteins with exceptional diversity in their structure and functions. They are found in many different organisms – from viruses and bacteria to plants and animals, including the human body. The main characteristic that unites them is their ability to bind specifically and reversibly to carbohydrate structures without causing enzymatic changes in them. This ability is due to the presence of one or more specialized carbohydrate-binding domains.

In the plant world, lectins often play a role in defense against insects and pathogens, as well as in the accumulation and storage of nutrients. In animals, they participate in processes such as cell adhesion, immune function, and signal transduction. Although some lectins can exhibit toxic or anti-nutritional properties, especially when consumed raw and in large quantities, many of them are harmless or even beneficial when part of a balanced diet. Examples of foods rich in lectins include legumes, grains, and some types of vegetables.

How do Lectins work?

The mechanism of action of lectins is based on their specific binding ability to glycoproteins and glycolipids found on the surface of cells.

  • Participate in cell adhesion in animals
  • Have immunomodulatory effects in low doses
  • May have prebiotic properties
  • Support plant defense against pests

Disadvantages

  • Can alter intestinal permeability
  • Hinder nutrient absorption
  • Cause gastrointestinal upset in raw form
  • Activate immune response

The mechanism of action of lectins is based on their specific binding ability to glycoproteins and glycolipids found on cell surfaces. In the digestive tract, some resistant lectins can interact with the cells of the intestinal lining. This interaction can lead to a number of effects, depending on the specific lectin and its concentration. Possible mechanisms include:

  • Changes in intestinal permeability, which can allow the passage of unwanted substances.
  • Interference with nutrient absorption by binding to enzymes or transport proteins.
  • Activation of immune responses due to their recognition as foreign bodies by the immune system.
  • Disruption of hormonal balance by mimicking hormones or blocking receptors.

The effect of lectins is highly dependent on the dose and individual sensitivity. Importantly, most lectins in common foods are deactivated by cooking, soaking, sprouting, or fermentation, which reduces their potential negative effects to negligible levels.

Why are Lectins important for athletes?

  • Antinutrients — Lectins are often classified as a type of antinutrient due to their capacity to hinder nutrient absorption.
  • Whole foods — Many foods rich in lectins, such as legumes and grains, are also important whole foods with high nutritional value after proper processing.
  • Simple carbohydrates — Unlike simple carbohydrates, lectins are proteins that bind to polysaccharides and are not a source of quick energy.
  • Polyphenols — Similar to lectins, polyphenols are bioactive compounds in plants that can have both beneficial and (rarely) negative effects depending on the dose and processing.

Lectins are important for athletes because they can affect the digestion and absorption of macronutrients and micronutrients, which is crucial for recovery, energy, and performance. They can lead to gastrointestinal upset and reduced absorption of proteins and minerals if consumed raw or insufficiently processed.

For actively training individuals who consume legumes or grains daily, I recommend a minimum of 20 minutes of thermal processing by boiling to deactivate lectins and avoid digestive problems. — Petar Mitkov

Remember: Lectins are proteins that can affect digestion and nutrient absorption, but their negative effects are significantly minimized through proper thermal processing of foods.

Scientific Sources

  1. Review of legume lectins., 2000
  2. Lectins as bioactive proteins: A review of their role in health and disease., 2021
  3. Lectins: from basic science to practical applications in biomedicine and food science., 2020
  4. Anticancer activities of lectins (review), 2016

Expert Note from Sport Zona

From my practice, I notice that strictly avoiding lectins is rarely necessary for most trainees. Focusing on a balanced diet with whole foods is usually sufficient for achieving good health and performance. For a limited number of sensitive individuals, a personalized approach may be considered.

Frequently asked questions

What are lectins and where are they found?

Lectins are a group of proteins that bind to sugars and are found naturally in many foods, especially legumes, grains, and some vegetables. They are present in a wide range of organisms, including plants and animals.

How can lectins affect athletes?

Raw lectins can disrupt digestion and nutrient absorption, which is vital for athletes' recovery and energy. This can lead to gastrointestinal issues and reduced absorption of proteins and minerals.

Do lectins have side effects for athletes?

Some lectins, especially in raw or undercooked states, can cause gastrointestinal discomfort and compromise the gut barrier. This can lead to inflammation and delayed recovery after training.

How can the negative effects of lectins be reduced?

Properly cooking foods, such as boiling legumes, effectively deactivates most active lectins. This allows athletes to enjoy the benefits of these foods without worrying about their antinutritional effects.