Dietary Factors

Dietary Considerations for Reducing Kidney Stones

Kidney stones are painful and common complications in IBD, particularly in patients who have had intestinal surgery. IBD patients are at risk for the most common types of stones -- those composed of either calcium oxalate or uric acid crystals. The following are some considerations in reducing the risk for stones:

• The most important dietary recommendation is to increase fluid and restrict sodium intake.
• Limiting protein is recommended for reducing kidney stones. However, people with IBD with frequent diarrhea are protein deficient. Sufficient protein, particularly in children with IBD, is very important and should be weighed against any risk for stones.
• Patients should increase intake of potassium-rich foods (bananas, watermelon, cantaloupe, oranges, tomatoes, beans).
• Patients should try to correct any dietary habits that cause acidic or alkaline imbalances in the urine that promote stone formation.
• Many kidney stones are formed from calcium-oxalate stones. Patients should avoid or limit intake of oxalate-rich foods, such as beets, beet tops, black tea, chenopodium, chocolate, cocoa, dried figs, ground pepper, lamb quarters, lime peel, nuts, parsley, poppy seeds, purslane, rhubarb, sorrel, spinach, and Swiss chard. A high calcium diet does not appear to increase the risk for kidney stones as long as it also contains plenty of fluids and dietary potassium and phosphate. Importantly calcium is associated with protection against colon cancer and osteoporosis -- two conditions that are associated with IBD.
• Patients who have stones associated with short-bowel syndrome should restrict their intake of fat as well oxalates. In such cases, calcium may bind to unabsorbed fat instead of to oxalates, which increase oxalate levels.

The general recommendations for avoiding kidney stones need to be tailored to the dietary requirements of IBD. Patients should work with their doctors to develop an individualized plan.

Probiotics and Prebiotics

Researchers are currently investigating bacteria (called probiotics) and specific foods (called prebiotics) that are metabolized by these bacteria, and the compounds they produce (called synbiotics). Some evidence suggests that alone or in combination, they may have significant benefits in the intestine.

• Probiotics are bacterial strains that by themselves may provide a barrier against harmful bacteria, possibly through various mechanisms such as excreting certain acids (lactate, acetate) that inhibit harmful bacteria or compete with them for nutrients. It has been suggested that probiotics may help maintain remission in patients with IBD. The specific bacterial strains that might be beneficial, however, are not fully known. The most well-known probiotics are the lactobacilli strains, such as acidophilus, which are found in yogurt and other fermented milk products. Others, however, may prove to be more important, such as bifidobacteria and GG lactobacilli. Other probiotics that may be beneficial for patients with IBD include lactobacilli rhamnosus, casel, plantarium, bulgaricus, and salivarius, and also Enterococcus faecium and Streptococcus thermophilus.
• Prebiotics are specific non-digestible molecules called fructo-oligosaccharides (FOS), which stimulate the growth of probiotics. FOS are found in many foods, including Jerusalem artichokes, onions, salsify, bananas, honey, garlic, and leeks. (However, some of these foods can irritate the intestine in patients with IBD.)