*4.3. Seaweed Extract*

Sulfated xylorhamnoglucuronan-rich extract (SXRG84) from Ulva sp. 84 (PhycoDigest®Biobelly) was supplied by Venus Shell Systems Pty. Ltd. SXRG84 is an 80% pure proteoglycan extract containing 42% rhamnose, 20% glucose, and 5% xylose, as well as glucuronic and iduronic acids, and small amounts of galactose, mannose, and arabinose, with >16% sulfation and 15% protein. The molecular weight is above 600 kDa. The extract was approved for use in a clinical setting by the Australian Therapeutic Goods Administration (TGA) Clinical Trial Notification (CTN) (CT2015CTN021221) after assessment by the University of Wollongong Human Research Ethics Committee (approval CT13/002). No adverse events were recorded during the intervention.

For Study 1, dry milled extract was formulated into 2 g and 4 g doses per 8, opaque, 0 cellulosic, vegetarian capsules, with a milled brown rice additive that was also used for the placebo capsules. Milled dark seaweed residue (without glycans) was used in trace amounts (<1%) to make all treatments visually consistent. Six-week supplies of capsules at eight per day were allocated into jars in a three-stage double-blinding system, with the key held until post-data analysis from the clinical intervention. For Study 2, the formulation was the same as described above for Study 1 and the 2 g dose was used.

Participants ingested eight capsules throughout the day and recorded daily compliance, bowel movements, and flatulence. Self-assessment compliance charts were provided at commencement and were collected at the end of the study.
