Table 2.

Study assay, study characteristic, source, and content and bioactivity.

Study Assay	Study Characteristics	Source and Content	Bioactivity	References
Intervention trial	Diet with large amount of seaweed 417 male Japanese T2DM 65 years or older	Total vegetable intake	↓ HbA1c, Tg, waist circumference	[120]
		>150 g of daily total vegetable	↓ HbA1c
		>200 g of total vegetable intake	↓ Serum Tg ↓ HbA1c
		Green vegetable intake	↓ Body mass index, Tg, waist circumference
Double blind, randomized, placebo-controlled crossover study	23 participants 19–59 year old	Blend of Ascophyllum nodosum and Fucus vesiculosus	↓ Insulin concentrations ↑ Insulin sensitive	[215]
Randomized Crossover Trial	26 participants	Undaria pinnatifida (4 g, dry alga) + Rice (200 g)	↓Postprandial glycemia ↓ Insulin levels	[176]
Randomized crossover study	12 participants	70 g Mekabu(sporophylls of Undaria pinnatifida)	↓ Postprandial glycemia ↓ Glucose area under the curve	[178]
Randomized controlled trial	12 overweight, healthy males. Aged 40 year	Ascophyllum nodosum enriched bread (4%)	↓ Energy intake	[182]
In vitro assay	Brown marine algae from Eastern Canada.	Fucoidan extracted from Ascophyllum nodosum	Inhibit α-glucosidade and α-amylase activities	[179]
Mouse model and human hepatic cells	Male C57BL/6J mice 12 weeks	Food additive carrageenan (E-407) Drinking water (10 mg carrageenan/L) HepG2 Cells (1 mg carrageenan/L × 24 h)	↓ Glucose tolerance ↑ Insulin resistance Inhibit insulin signalling	[183]
In vivo assay	Male Wistar rats 16 weeks	Lota-Carrageenans from Sarconema filiforme (5%, last 8 weeks)	↓ Body weight ↓ Abdominal and liver fat Improve symptoms of high-carbohydrate, high-fat diet-induced metabolic syndrome.	[185]
Randomized controlled trial	10 healthy male volunteers, studied on three occasions	Agar (2.0 g)	↓ Delay gastric emptying No effect on the postprandial glucose response	[187]
Randomized controlled trial	76 obese patients with type 2 diabetes 12 weeks	Agar (180 g) + Traditional Japanese food	↓ HbA1c, ↓ Visceral fat area, subcutaneous fat area, total body fat, ↓ Insulin area under the curve after oral glucose tolerance test ↓Total cholesterol p.	[188]
In vitro and in vivo assay	Normal C57/BL6 mice 4 weeks	Laminarin (50 mg/mL)	↑ GLP-1 secretion and c-Fos protein expression in STC-1 cells	[189]
In vivo assay	Adult male Wistar rats	Sodium alginate from Laminaria angustata. Natural and three water-soluble low-molecular weight	Natural and 50 and 100 kDa molecular weights of alginates: ↓ Glucose tolerance ↓ Cholesterol excretion	[190]
In vitro and vivo assay	Wistar rats	Calcium alginate	Inhibited α-glucosidase activity in vitro Suppression postprandial increase of blood glucose	[193]
Randomized controlled trial	48 overweight or obese participants 10 days	Sodium alginate from Laminaria digitata	No effect on gastric motor functions, satiation, appetite, or gut hormones	[195]
Randomized placebo-controlled trial	176 participants 5 weeks	Fiber supplements of alginate + balanced 1200 Kcal diet	↓ Body weight	[196]
In vitro and in vivo assay	IEC-6 cell line Male db/db mice	Fucoidans from eleven species of brown algae	Specially from Fucus vesiculosus: ↓ α-glucosidase activity ↓ Fasting blood glucose ↓ HbA1c	[203]
In vitro assay	Human colonic carcinoma Caco-2 cells	Five brown species of alga	Cold water and ethanol extracts of Ascophyllum nodosum: ↓ α-glucosidase activity	[206]
In vitro assay	3T3-L1 cells	Fucoidan from Undaria pinnatifida Several concentrations	↑ Glucose uptake ↓ Lipolysis ↓ Expression of PPARϒ	[208]
In vivo assay	Diabetic KK-A(y) mice 5 weeks	Polyphenols from Ecklonia kurome (0.1%)	↓ α-glucosidase and α-amylase activity ↓ Postprandial blood glucose ↑ Glucose tolerance ↓ Fasting blood glucose ↓ Insulin levels	[212]
In vivo assay	Male diabetic KK-A(y) mice 5 weeks	Polyphenols (Phlorotannins) from Ecklonia stolonifera (0–1%)	↓ Increase in plasma glucose ↓ Increase in lipid peroxidation in plasma	[213]
In vivo assay	Male Wistar rats	Ascophyllum nodosum and Fucus vesiculosus extract (10% polyphenols) (7.5 mg/kg body weight)	↓ α-glucosidase and α-amylase activity ↓ Postprandial blood glucose	[214]
Double-blind, placebo-controlled, randomised croos-overal trial	38 healthy adults (Asian and non-Asian)	Polyphenol-rich Fucus vesiculosus extract (500–200 mg)	↑ Risk of insulin resistance among Asian populations	[215]
In vivo	Rat model of type 2 diabetes	Sargassum polycystum, alcohol (150 and 300 mg kg (−1) body weight) water extract (150 and 300 mg Kg (−1))	↓ Blood glucose ↓ HbA1c levels ↑ Response to insulin	[216]
In vivo	Obese murine model 10 weeks	Fucoxanthin-rich Undaria pinnatifida (Wakame) lipids (carotenoid)	↓ Alterations in lipid metabolism and IR induced by a HF diet	[217]
In vitro assay	Insulin-resistant HepG2 cells	Fucosterol from Ecklonia stolonifera	↑ Glucose uptake ↑ Insulin resistance by down regulating expression of PTP1B ↑ Insulin signaling pathway	[218]
In vivo assay	Growing Zucker fa-fa rats 8 weeks	Modified AIM-93 diets containing 30% of freeze-dried skid surimi formulated with glucomannan (30%) or with glucomannan plus Spirulina (30%) without added cholesterol	↓ Hyperglycemia (glucomannan + Spirulina), ↑ Adiponectin/leptin ratio in adipose tissue increase	[221]

HbA1C, glycosylated haemoglobin; Tg, triglycerides; GLP-1, serum glucagon-like peptide-1; PPARϒ, peroxisome proliferator-activated receptor ϒ. Arrows ↑ or ↓ indicates significantly more or less than control, respectively.