A Randomized Placebo-controlled Trial of an Oral Preparation of High Molecular Weight Fucoidan in Patients with Type 2 Diabetes with Evaluation of Taste Sensitivity

Abstract

Background Fucoidan is derived from seaweed widely used in Japanese cuisine, but little is known about its influence on glucose metabolism. To obtain information about the physiological effects of fucoidan on glucose metabolism, the digestive system, and the gustatory system controlling taste sensation in patients with type 2 diabetes, we conducted a randomized, double-blind, placebo-controlled study. Methods Thirty patients with type 2 diabetes on diet therapy were recruited from an outpatient clinic (22 men and 8 women aged 59.10 ± 13.24 years, body mass index: 25.18 ± 3.88, hemoglobin A1c: 7.04 ± 1.24%). They were divided into 2 groups and underwent 2 interventions with a 4-week interval. One group received fucoidan for 12 weeks (a daily 60 mL test beverage containing 1,620 mg of fucoidan) and then placebo (60 mL) for the subsequent 12-week period, while the order was reversed in the other group. Evaluation was performed just before and after each intervention. Taste sensitivity was measured for 5 basic tastes by the filter paper disk method and food intake was evaluated with a validated diet questionnaire. Results No adverse events occurred during the study period. Despite no change of the diet, stool frequency increased during fucoidan intake (from 7.78 ± 4.64/week in Week 1 to 9.15 ± 5.03/week in Week 5, P < 0.001), and it increased more in lean subjects. In 11 subjects whose stool frequency exceeded the mean value, the thresholds for sweet, salty, bitter and umami tastes were significantly reduced (enhancement of sensitivity) after fucoidan intake. In 14 subjects with normal HOMA-IR (homeostatic model assessment of insulin resistance, < 2.5), hemoglobin A1c decreased after fucoidan intake (from 6.73 ± 1.00 to 6.59 ± 1.00%, P < 0.05), as did the fasting plasma level of GLP-1 (glucagon-like peptide-1, from 6.42 ± 3.52 to 4.93 ± 1.88 pmol/L, P < 0.05). Conclusion Sustained fucoidan intake led to alterations of gastrointestinal function, including increased stool frequency and enhanced taste sensitivity, which could contribute to better control of diabetes.

Quantifying the Effect of Supplementation with Algae and Its Extracts on Glycolipid Metabolism: A Meta-Analysis of Randomized Controlled Trials

“…From the electronic searches, 1409 potential literature citations and four additional records identified through other sources were identified. In the end, a total of 27 RCTs (30 trials) with 1221 participants were finally considered to be selected for the current meta-analysis [ 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 ]. The characteristics of RCTs included in the meta-analysis are summarized in Table 1 .…”

Nordic Seaweed and Diabetes Prevention: Exploratory Studies in KK-Ay Mice

“…Alginate, a polysaccharide distributed in the cell wall of brown algae, has beneficial effects on glucose metabolism [9]. Fucoidan, a sulfated polysaccharide also found in various species of brown algae, lowers alpha-glucosidase activity in vitro [10], blood glucose in db/db mice [11], and glycated hemoglobin and glucagon-like peptide-1 in type 2 diabetes patients [12]. The phlorotannin, dieckol, isolated from brown seaweed, was found to inhibit alpha-glucosidase activity in vitro [13], and to protect against the glucotoxicity-induced oxidative stress associated with diabetes [14,15], delay T2D development in a db/db mouse model [16], and reduce postprandial hyperglycemia in prediabetic subjects [17].…”

Fucoidan Structure and Its Impact on Glucose Metabolism: Implications for Diabetes and Cancer Therapy

“…Furthermore, fucoidan has been reported to alter gastrointestinal function, including bowel movements. In a study, where type 2 diabetes mellitus (T2DM) patients were enrolled, a high molecular weight fucoidan increased stool frequency and enhanced taste sensitivity, which favoured the management of T2DM [ 96 ]. In addition, fucoidan intake increases leptin levels, regulating energy balance by inhibiting hunger, and diminishes fat storage in adipocytes.…”