What are Phytobezoars?
A bezoar is a tightly packed accumulation of partially digested or undigested foreign material that gets trapped within the gastrointestinal tract, most often in the stomach. The most common type is a phytobezoar, which is composed of indigestible plant materials such as cellulose, seeds, and fruit peels. For most healthy individuals, these fibrous foods pose no issue; however, people with certain risk factors are more susceptible to developing these dense masses. These factors include previous gastric surgery (like gastric bypass), reduced stomach acid (hypochlorhydria), or conditions causing delayed gastric emptying, such as diabetes.
The Role of High Fiber and Tannins
While a high-fiber diet is beneficial for many, it becomes a risk factor for bezoar formation in vulnerable individuals. The key components responsible for phytobezoar formation are the structural parts of plants—specifically, cellulose and lignin, and in some fruits, tannins. Plant fibers are difficult for the human digestive system to break down completely. When stomach motility is compromised or stomach acid is insufficient, these fibers can accumulate and form a mass.
In addition to fiber, certain fruits contain tannins, which are astringent compounds that can bind with and precipitate proteins in an acidic environment. This creates a dense, glue-like substance that acts as a binder for other food residues, significantly contributing to the formation of a hard, concrete-like bezoar.
Specific Foods Known to Cause Bezoars
Certain fruits and vegetables are more frequently implicated in phytobezoar formation due to their high content of indigestible fiber and tannins. These foods are particularly problematic for at-risk individuals, especially when not chewed thoroughly or prepared correctly.
Persimmons: The Most Common Culprit
Persimmons are uniquely notorious for causing bezoars, leading to the term "diospyrobezoars". This is because unripe or semi-ripe persimmons contain a high concentration of a specific tannin called shibuol. When exposed to stomach acid, this tannin polymerizes, creating a sticky coagulum that rapidly traps other food particles, fibers, and undigested materials. This results in a hard, difficult-to-dissolve mass, often requiring aggressive medical or surgical intervention.
Other High-Fiber Foods
Beyond persimmons, several other foods contribute to phytobezoar formation, especially if their skins, seeds, or fibrous stalks are consumed. These include:
- Fruits: Oranges (especially the membranes and pits), apples (with skin), figs, dates, raisins, and berries.
- Vegetables: Pumpkins, green beans, Brussels sprouts, celery, sauerkraut, leeks, and potato peelings.
- Seeds and Nuts: Flax seeds, sunflower seed shells, and various edible vegetable and fruit seeds.
- Legumes: In some cases, poorly chewed legumes can also contribute.
Comparison of High-Risk vs. Safer Food Preparations
For at-risk individuals, the preparation and form of food can dramatically influence the likelihood of bezoar formation. Here is a comparison of potentially problematic foods versus safer alternatives:
| Food Item | High-Risk Preparation (Avoid) | Lower-Risk Preparation (Safer) |
|---|---|---|
| Apples | Raw, unpeeled apples | Applesauce, peeled and cooked apples |
| Carrots | Raw, shredded carrots | Cooked until very soft, pureed carrots |
| Berries | Whole berries (especially with seeds) | Strained and pureed berry sauce or jam |
| Persimmons | Unripe or raw persimmons | AVOID entirely due to high tannin content |
| Pumpkin | Pumpkin pie filling or fibrous pumpkin flesh | Pureed pumpkin without added fiber |
| Beans/Legumes | Tough, fibrous husks or skins | Cooked until soft, with skins removed if possible |
Who is at Risk?
While what foods cause bezoars is a critical consideration, the risk is not equal for everyone. Several conditions and circumstances significantly increase susceptibility:
- Previous Gastric Surgery: Procedures like gastric bypass or partial gastrectomy alter the stomach's anatomy and function, reducing acid and motility, which are essential for breaking down food.
- Delayed Gastric Emptying (Gastroparesis): This condition, often associated with diabetes, autoimmune disorders, or certain medications, prevents the stomach from emptying food efficiently, allowing masses to form.
- Poor Mastication: Individuals with dentures, poor dentition, or those who simply do not chew their food thoroughly are at higher risk. Larger, un-chewed food fragments are more likely to aggregate.
- Hypochlorhydria: Low stomach acid levels compromise the digestive process, preventing the proper breakdown of food fibers.
- Behavioral Conditions: Psychiatric disorders like trichotillomania (compulsive hair pulling) can lead to the ingestion of indigestible materials, forming trichobezoars.
Dietary Strategies for Prevention
For those at risk, modifying diet and eating habits is the primary way to prevent bezoar formation.
Focus on Low-Fiber and Easily Digestible Foods
Rather than eliminating all fibrous foods, focus on low-fiber options and proper preparation. A gastroparesis-friendly diet emphasizes liquids and soft, low-fiber solids.
Chewing and Preparation Techniques
- Chew all food thoroughly, taking smaller bites.
- Choose cooked over raw fruits and vegetables, and cook them until very soft.
- Peel fruits and vegetables, and remove any seeds or tough membranes.
- Prioritize pureed and liquid forms of food, such as soups, smoothies, and applesauce.
Conclusion
While bezoars are rare, understanding what foods cause bezoars and the contributing risk factors is vital for prevention. Foods high in indigestible fiber, skins, seeds, and particularly persimmons, pose the highest risk for individuals with compromised digestive function. By adopting smart dietary strategies, such as thorough chewing and consuming softened, peeled foods, at-risk individuals can significantly reduce their risk of this serious gastrointestinal condition. Always consult a healthcare provider or a registered dietitian for personalized advice, especially following gastric surgery or if you have a pre-existing digestive disorder.
For further information on management strategies and risk factors, the University of Virginia's article on the subject provides a comprehensive overview: https://med.virginia.edu/ginutrition/wp-content/uploads/sites/199/2021/03/Bezoars-Mrach-2021.pdf.
