Asia Pac J Clin Nutr. , 2020., 29(1):61-67. doi: 10.6133/apjcn.202003_29(1).0009.

Effects of flaxseed supplementation on functional constipation and quality of life in a Chinese population: A randomized trial.

Sun J Bai H Ma J et al.

Abstract

BACKGROUND AND OBJECTIVES: This prospective, randomized, controlled study aimed to evaluate the effects of flaxseed supplementation on functional constipation and quality of life in adult men and women in China. METHODS AND STUDY DESIGN: 90 subjects with functional constipation diagnosed by the Rome IV criteria were enrolled. Subjects were randomly assigned to receive either 50 g/day flaxseed flour with meals (n=60) or 15 mL/day of a lactulose solution on an empty stomach (n=30) every morning for 4 weeks. Wexner constipation scores, stool consistency according to the Bristol Stool Form Scale, and bowel habits (frequency of bowel movements/week, the time spent on defecation) were the primary outcomes. The change in Patient Assessment of Constipation Quality of Life score was the secondary outcome. RESULTS:  After 4 weeks, the bowel habits in both groups were significantly improved. The median Wexner constipation score decreased from 14 to 6.5 in the flaxseed group (p<0.001) and from 15 to 9 in the lactulose group (p<0.001). The median defecation frequency per week increased significantly (2 to 7 for flaxseed and 2 to 6 for lactulose, p<0.001 for both groups). The Patient Assessment of Constipation Quality of Life score decreased significantly (-1.34 and -0.66 for flaxseed and lactulose, respectively; p<0.001 for both groups). CONCLUSIONS:  Flaxseed flour is somewhat more effective at increasing defecation frequency than lactulose, improving bowel movements and promoting life quality of subjects with chronic functional constipation in the Chinese population.

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Key Points

Functional constipation can also be influenced by psychological and social factors, and increases with age. It can cause anxiety, discomfort, and even intestinal obstruction, leading to a decline in a patient’s quality of life. The present study was designed to investigate the effects of flaxseed supplementation on the frequency of bowel movements per week, time spent on defecation, Wexner scores (a measure of fecal incontinence), and quality of life in subjects with functional constipation. The aim was to understand the advantages of dietary treatment and to explore a comprehensive, effective, safe and convenient method for treating functional constipation. related to dietary habits.  Fifty grams of flaxseed contain 13.3 g of dietary fiber, which corresponds to about 50% of the recommended daily intake according to Chinese dietary reference intakes. The majority of the subjects in this study supplemented with flaxseed flour suffered from functional constipation for more than 10 years and had tried various treatments.

The results from this study showed that subjects taking flaxseed flour had less difficulty with bowel movements, less abdominal pain, and less failure of evacuation than the group taking lactulose. The increase in frequency of bowel movements per week was significantly higher with flaxseed flour than with lactulose. However, whereas the difference between lactulose and flaxseed flour was statistically significant, the clinical relevance of this difference may be limited (six bowel movements per week with lactulose and seven with flaxseed flour). Subjects in both treatment groups reported a reduction in hard stools. The flaxseed flour group had a higher proportion of normal stools than the lactulose group and a smaller proportion of watery stools. The PAC-QOL score reduction was also significantly larger in the flaxseed flour group than in the lactulose group, mostly because of a greater improvement in satisfaction. The study is limited by the relatively small number of participants and the fact that all subjects were recruited from a single city in China, limiting the generalizability of the results.  Compliance with the study protocol was very good in the flaxseed flour group. Flaxseed flour can be consumed in a variety of ways and is easy to add to the diet. This fact may have contributed to the very good compliance and indicates that flaxseed supplementation can have appeal in a wider population.