People with type 2 diabetes who are trying to bulk up on fiber may need to pay closer attention to their calcium intake as well, a small study suggests.

When 13 diabetics doubled their fiber intake, the study participants began to excrete less calcium in their urine - a sign that their body’s calcium absorption had declined, the researchers observed.

Fiber is known to help lower cholesterol, improve blood sugar control and maintain bowel regularity; and adults are advised to get roughly

25 grams or more each day.

But these latest findings suggest that poorer calcium absorption may the trade-off, the researchers report in the journal Diabetes Care.

“Because more calcium equals better bone health, we recommend that people on high-fiber diets talk to their physician about increasing their dietary calcium as well, in order to get the most benefit from both,” senior researcher Dr. Abhimanyu Garg, of the University of Texas Southwestern Medical Center in Dallas, said in a written statement.

He added that it is important to consult a doctor or dietitian first because excessive calcium can cause kidney stones.

The findings are based on 13 middle-aged and older adults with type 2 diabetes who each consumed 50 grams of fiber per day for 6 weeks, followed by 24 grams per day over another 6-week period.

Garg’s team found that when participants were on the higher-fiber diet, their calcium excretion declined. Some studies, the researchers note, have suggested that dietary fiber binds with certain minerals, forming “complexes” that cannot be absorbed.

Garg suggested that people try foods that provide both fiber and calcium, such as spinach, broccoli, figs, papaya, beans and artichokes.

SOURCE: Diabetes Care, online March 11, 2009.