A randomized trial of the effects of flaxseed to manage constipation, weight, glycemia, and lipids in constipated patients with type 2 diabetes.

Background: To compare the effects of baked flaxseed versus those who received a placebo on constipation symptom scores, weight, glycemic and lipid control in constipated patients with type 2 diabetes (T2D).

Methods: In a single-blinded, randomized controlled trial, 53 constipated patients with T2D with body mass index (BMI) 20.5-48.9 kg/m2 received either 10 g of flaxseed pre-mixed in cookies twice per day or placebo cookies for 12 weeks. The constipation symptom scores, BMI, fasting plasma glucose (FPG), glycosylated hemoglobin (HbA1c), and lipid profile were determined at the beginning and end of 4, 8, and 12-week period. Constipation was evaluated with a stool diary (ROME III).

Results: After the 12-week intervention, constipation symptom scores (2.46), weight (- 3.8 kg), BMI (- 1.5 kg/m2 ), FPG (- 26.7 mg/dl), cholesterol (- 37.3 mg/dl), triglycerides (- 10.4 mg/dl), LDLC (- 21.0 mg/dl), HDLC (4.7 mg/dl), cholesterol/ HDLC ratio (- 1.4 mg/dl) significantly decreased from baseline in the flaxseed group (all P -values < 0.05). The differences of absolute change of constipation symptom scores (2.46 vs. 0.41), weight (- 3.8 vs. 0.0 kg), BMI (- 1.5 vs.-0.1 kg/m2 ), FPG (- 26.7 vs.-1.9 mg/dl), >HbA1c (- 0.8 vs. 1.0%), cholesterol (- 37.3 vs. -10.4 mg/dl), LDLC (- 21.0 vs. -4.3 mg/dl), and HDLC (4.7 vs. -4.4 mg/dl) between the flaxseed and placebo groups were statistically significant (all P -values < 0.05). The compliance was good and no adverse effects were observed.

Conclusion: In constipated patients with T2D, flaxseed cookies used as a snack may be a useful tool for decreasing constipation symptoms, weight, glycemic and lipid levels.

Trial registration: irct.ir: IRCT20110416006202N2.