Small Bowel Water Content (SBWC)

Small Bowel Water Content (SBWC) is a key parameter for understanding small intestinal function and its disorders[4]. It represents the balance between secretion and absorption processes in the small intestine. SBWC can be measured non-invasively using magnetic resonance imaging (MRI) techniques, which have allowed for accurate assessment in both healthy individuals and those with various gastrointestinal conditions[1]. In healthy individuals, the average fasting SBWC is approximately 82 mL (with a standard deviation of 65 mL), showing high variability between individuals[1]. SBWC is influenced by various factors including: 1. Age: There is a small decline in fasting SBWC with advancing age in healthy volunteers[1]. 2. Food intake: Eating significantly affects SBWC, with different responses to different types of foods: - High-fat meals cause marked increases in SBWC - Fiber (both viscous and particulate) increases SBWC - After a mixed liquid/solid meal, SBWC initially decreases due to rapid nutrient-driven fluid absorption, then increases later[2] 3. Distribution: Most of the total volume of liquid in the small intestine is found in fewer, larger pockets (>20 mL in size), which account for over 45% of the total volume[6][7]. 4. Disease states: SBWC is altered in various conditions: - Increased in untreated celiac disease (202 mL, compared to 82 mL in healthy individuals)[1] - Reduced in fasting and postprandial states in patients with irritable bowel syndrome with diarrhea (IBS-D)[2] - Abnormal responses to meals in cystic fibrosis and IBS-D[1] Normal stool consists of approximately 75% water and 25% solid matter (dead bacteria, indigestible food, and inorganic substances)[3]. Changes in SBWC can affect transit time through the digestive system and ultimately impact stool consistency and bowel habits. SBWC serves as a valuable biomarker indicating the balance of secretion and absorption in health and disease and can be used to assess the impact of treatments on gastrointestinal function[1].

Other names

Small intestinal water contentSmall intestinal fluid volumeSmall bowel fluid content