Villi are microscopic, finger-like projections that line the inner surface of the small intestine. Despite their small size, they play an enormous role in your body’s ability to absorb nutrients from the food you eat. Each villus is covered in specialized cells designed to extract vital nutrients and transfer them into the bloodstream for use throughout the body.

When villi become damaged, your digestive efficiency can suffer, leading to malnutrition and other serious health concerns. In this guide, we’ll explore the anatomy, function, and importance of villi—and how you can protect them through diet and lifestyle.

Anatomy Of The Villi

Where Villi Are Located
The small intestine is a coiled, narrow tube measuring over 20 feet long, connecting the stomach to the large intestine. Villi emerge from the inner lining of the small intestine’s walls, specifically the mucosal layer, where they maximize contact with digested food (chyme) passing through the intestinal tract.

Structure And Composition
Each villus is made up of epithelial cells and supported by connective tissue and a network of capillaries and lymphatic vessels. The key types of epithelial cells found in villi include:

  • Enterocytes: Responsible for nutrient absorption

  • Goblet Cells: Produce mucus that lubricates and protects the intestinal wall

  • Tuft Cells: Detect chemical signals in the gut and coordinate immune responses

  • Enteroendocrine Cells: Secrete hormones that regulate digestive processes and cell turnover

Size And Surface Area
A typical villus measures between 0.4 and 1 millimeter in length. Despite their tiny size, villi significantly increase the absorptive surface area of the small intestine. When combined with microvilli—smaller structures on the surface of enterocytes—the surface area of the intestine expands by up to 100 times, enhancing nutrient absorption.

Crypts And Cell Regeneration
Between each villus lies a depression called a crypt, where new epithelial cells are generated. These cells migrate upward to the tip of the villus, where they eventually shed, ensuring that the intestinal lining is continually renewed every 3–5 days.

Functions Of The Villi

Nutrient Absorption
The main job of the villi is to absorb nutrients from the digested contents in the small intestine. Villi extract:

  • Vitamins (A, D, E, B12)

  • Minerals (including iron and calcium)

  • Amino acids and fatty acids

  • Carbohydrates and sugars

  • Water and electrolytes

Their elongated shape and cellular makeup make them uniquely suited for this task. The single-layer cell structure allows for rapid transfer of nutrients into blood vessels and lymphatic channels.

Mucus Secretion
Goblet cells located in the villi secrete mucus, which coats the intestinal lining. This mucus protects the villi from digestive enzymes and acids while facilitating smooth movement of food through the gut.

Immune Support
Villi also serve as a defense mechanism. Immune cells are embedded near the base and tips of villi, helping detect and neutralize harmful pathogens. Tuft cells and lymphocytes help initiate immune responses to protect the intestine from infections and inflammation.

Cellular Turnover
Continuous regeneration of epithelial cells from crypts ensures the structural integrity of the intestinal lining. This rapid cell turnover helps maintain optimal digestive function and allows the intestine to recover from minor injuries or infections quickly.

Conditions That Damage Villi

When villi become inflamed, blunted, or flattened, their ability to absorb nutrients is compromised. This condition is known as villous atrophy and can lead to severe malnutrition and health complications.

Celiac Disease

Gluten-Induced Immune Response
Celiac disease is an autoimmune condition where the immune system attacks the villi in response to gluten—a protein found in wheat, barley, and rye. This leads to inflammation and eventual flattening of the villi, severely impairing nutrient absorption.

Common Symptoms Include:

  • Bloating and abdominal pain

  • Chronic diarrhea or constipation

  • Fatigue and weakness

  • Weight loss or poor growth (in children)

  • Nausea and vomiting

  • Foul-smelling or oily stools

A gluten-free diet is currently the only effective treatment to prevent further damage and promote healing of the villi in people with celiac disease.

Inflammatory Bowel Disease (IBD)

Two Main Types Of IBD:

  • Crohn’s Disease: Can affect any part of the gastrointestinal tract and may result in patchy villous damage

  • Ulcerative Colitis: Primarily affects the colon but can indirectly lead to malabsorption when inflammation is severe

IBD is believed to result from an abnormal immune response to gut bacteria, causing chronic inflammation that can erode the intestinal lining.

Lymphoma

Intestinal Lymphoma And Villi Damage
Some types of non-Hodgkin lymphoma target the lymphatic tissue within the intestines, where villi are located. These cancers can lead to structural changes or destruction of the villi and compromise digestion.

Symptoms May Include:

  • Swollen lymph nodes

  • Night sweats

  • Unexplained weight loss

  • Fever and fatigue

  • Persistent digestive symptoms

Early detection and treatment can improve outcomes and help limit intestinal damage.

Medications That May Harm Villi

Several prescription and over-the-counter drugs can negatively affect intestinal health, including:

  • NSAIDs (e.g., ibuprofen): Known to irritate the digestive tract lining

  • Chemotherapy agents (e.g., methotrexate): May inhibit cell regeneration in the villi

  • Immunosuppressants (e.g., azathioprine): Can impair healing and immune surveillance

  • Mycophenolate mofetil: Often used after organ transplants but may cause gastrointestinal side effects

Consult with your healthcare provider before stopping any prescribed medications.

Infections That Affect Villi

Common Culprits Include:

  • Giardia: A parasite that infects the intestines and causes watery diarrhea, cramping, and malabsorption

  • H. pylori: A bacterium that causes gastritis and may contribute to intestinal inflammation

  • HIV: Can directly damage the small intestine and increase vulnerability to other gut infections

Proper diagnosis and treatment are essential to prevent long-term damage.

Diagnostic Tools For Villous Health

If you experience symptoms of nutrient deficiency or digestive discomfort, your provider may use the following to assess villi health:

Evaluation Methods:

  • Physical examination: To detect bloating, tenderness, or abnormalities

  • Blood tests: To check for deficiencies and markers of celiac disease or infection

  • Stool tests: To detect parasites or digestive enzyme deficiencies

  • Endoscopic biopsy: Tissue samples taken during an endoscopy to observe villi under a microscope

  • Genetic testing: Used to confirm predisposition to celiac disease

Early detection of villous atrophy can prevent complications and guide dietary or medical interventions.

How To Protect And Support Healthy Villi

Caring for your digestive tract helps maintain the integrity of your villi. Here are simple ways to preserve their function:

Dietary Tips:

  • Eat fiber-rich foods: Whole grains, fruits, and vegetables promote gut motility

  • Stay hydrated: Water supports nutrient transport and prevents constipation

  • Avoid ultra-processed foods: Limit saturated fats and sugars

  • Take probiotics if advised: They can help maintain gut microbiota balance

  • Go gluten-free if needed: Essential for those with celiac disease

Lifestyle Habits:

  • Exercise regularly: Physical activity improves gut circulation and reduces inflammation

  • Manage stress: Chronic stress can trigger digestive issues and affect the immune system

  • Limit NSAID use: Choose alternatives when possible to reduce intestinal irritation

A Quick Review

Villi are essential structures that ensure your body absorbs vital nutrients from the foods you eat. They line the small intestine with a dense, brush-like covering that maximizes surface area and facilitates efficient digestion and absorption.

When villi are damaged, your body’s ability to extract nutrients diminishes, leading to symptoms like fatigue, digestive discomfort, and malnutrition. Conditions such as celiac disease, IBD, infections, or certain medications can harm villi. Fortunately, maintaining a balanced diet, staying hydrated, exercising, and treating underlying conditions can help support villous health and overall digestive wellness.