Table 1.

Summary of human trials on effects of algae consumption on glucose homeostasis and satiety.

Study population	Study design	Algae	Method of administration	Intervention	Duration	Study outcomes (Glucose and Satiety)	References
Healthy volunteers, 19–56 years, M/F, n = 38	Double-blinded, randomized 3-way crossover trial	F. vesiculosus (brown seaweed)	Capsules	Intervention 1: 500 mg F. vesiculosus Intervention 2: 2000 mg F. vesiculosus Control: 2000 mg cellulose placebo Study meal of 50 g available carbohydrate (white bread)	Acute postprandial study (2 h post-meal)	No effects on glucose or insulin. Asian participants had consistently ↑ insulin responses.	Murray et al. (126)
Healthy volunteers, 19–59 years, M/F, n = 23	Double-blinded, randomized 2-way crossover trial	A. nodosum and F. vesiculosus (brown seaweed)	Capsules	Intervention: 500 mg algae blend 1-week washout Control: 500 mg placebo Study meal of 50 g available carbohydrate (white bread)	Acute postprandial study (3 h post-meal)	↓ insulin and ↑ insulin sensitivity. No differences in glucose.	Paradis et al. (127)
Healthy volunteers, 20–50 years, M/F, n = 20	Blinded, randomized 3-way crossover trial	L. digitata (LD) and U. pinnatifida (UP) (brown seaweed)	Whole seaweed salads	5,000 mg of LD or UP or an energy-adjusted control meal containing pea protein.	Acute postprandial study (3 h post-meal)	↓ glucose, insulin, and C-peptide following LD and UP intake in participants <63 kg, after adjustment for body weight. LD and UP ↓ hunger and ↑ satiety but did not affect subsequent food intake.	Zaharudin et al. (128)
Overweight, otherwise healthy volunteers, 18–65 years, M, n = 12	Single-blinded, 2-way crossover trial	A. nodosum (brown seaweed)	Algae-enriched bread	Intervention: 100 g toasted bread enriched with 4% A. nodosum Control: 100 g toasted standard whole meal bread (0% A. nodosum) Both meals were consumed with scrambled eggs	Acute postprandial study (4 h post-meal)	↓ subsequent food intake. No changes in glucose.	Hall et al. (129)
Healthy volunteers, 18–45 years, M/F, n = 28	Double-blinded, prospective, randomized, 2-way crossover, pilot study	A. nodosum (brown seaweed)	Capsules	Intervention: Capsules containing 1,000 mg Garcinia cambogia (G. cambogia), 400 mg A. nodosum and 40 mg L-carnitine in total for 1 week 1-week washout Control: Placebo capsules similar in weight, color, and size to intervention for 1 week	2 weeks (excluding 1-week washout)	↓ hunger and satiety; ↑ fullness and preference for sweet foods.	Mayer et al. (130)
Type 2 diabetes mellitus patients, 40–70 years, M/F, n = 20	Randomized controlled trial	Sea mustard (also known as wakame or U. pinnatifida, a brown seaweed) and sea tangle	Pills	Intervention: 48 g algae/day Control: No supplementation	4 weeks	↓ fasting glucose and 2-h postprandial glucose. No changes in HbA1c.	Kim et al. (82)
Participants with at least 1 symptom of the metabolic syndrome, men (47.4 ± 9.9 years), women (45.6 ± 12.2 years), M/F, n = 27	Double-blinded, 2-way crossover study	U. pinnatifida (brown seaweed)	Capsules	Group 1: 1 month of maltodextrose placebo followed by 1 month of 4,000 mg/day algae Group 2: 1 month of 4,000 mg/day algae followed by 1 month of 6,000 mg/day algae	8 weeks	No changes in glucose, insulin, or HOMA-IR.	Teas et al. (131)
NAFLD patients, 20–50 years, M/F, n = 55	Double-blinded, randomized, controlled clinical trial	C. vulgaris (green microalgae)	Tablets	Intervention: 1,200 mg/day C. vulgaris + 400 mg/day Vitamin E Control: Placebo tablets +400 mg/day Vitamin E	8 weeks	↓ glucose. No significant changes in insulin and HOMA-IR.	Ebrahimi-Mameghani et al. (132, 133)
Hypercholesterolemia patients, 20–60 years, M/F, n = 103	Double-blinded, randomized, controlled and parallel-group comparison trial	P. palmata (red seaweed)	Capsules	Intervention: 2000 mg/day P. palmata Control: Placebo capsules	8 weeks	No differences in glucose, glycated albumin, insulin, or HOMA-IR.	Takase et al. (134)
Type 2 diabetes mellitus patients, 20–65 years, M/F, n = 84	Double-blinded, randomized controlled trial	C. vulgaris (green microalgae)	Capsules	Intervention: 1,500 mg/day C. vulgaris Control: 1,500 mg/day placebo	8 weeks	No changes in glucose, insulin, HbA1c or HOMA-IR.	Hosseini et al. (135)
Intervention: Non-insulin dependent diabetes mellitus (NIDDM) patients, mean age: 47.8 years, M/F, n = 15 Control: Healthy volunteers, Mean age: 53.4 years, M/F, n = 7	Controlled clinical trial	Spirulina (blue-green algae; species not specified)	Tablets	Intervention: 2000 mg/day Spirulina Control: Not supplemented with Spirulina	8 weeks	↓ glucose	Mani et al. (136)
At-risk group: Volunteers with high risk of diabetes or hyperlipidemia, > 20 years, M, n = 17 Healthy group: Healthy volunteers, > 20 years, M, n = 16	Clinical trial	C. pyrenoidosa (green microalgae)	Tablets	Both groups took 8,000 mg/day of Sun Chlorella A	12 weeks (excluding 4-weeks follow-up)	↓ glucose; no changes in insulin.	Mizoguchi et al. (137)
NAFLD patients, 35–70 years, M/F, n = 54	Randomized open-label clinical trial	C. vulgaris (green microalgae)	Tablets	Intervention: 1,200 mg/day C. vulgaris + 750 mg/day metformin +200 mg/day Vitamin E Control: 1,250 mg/day metformin +200 mg/day Vitamin E	12 weeks	↓ HbA1c and HOMA-IR in intervention group. ↓ glucose in control group.	Panahi et al. (138)
Pre-diabetic volunteers, 20–60 years, M/F, n = 80	Double-blinded, randomized, clinical trial	Ecklonia cava (brown seaweed; referred hereafter as E. cava)	Tablets	Intervention: 1,500 mg/day dieckol-rich extract from E. cava Control: 1,500 mg/day placebo	12 weeks	↓ glucose	Lee et al. (139)
Overweight or obese prediabetic volunteers, 18–70 years, M/F, n = 56	Double-blinded, randomized, parallel clinical trial	A. nodosum and F. vesiculosus (brown seaweed)	Capsules	Intervention: 500 mg/day brown algae extract Control: 500 mg/day placebo Both groups also received individualized nutritional advice for moderate weight loss	12 weeks	No effect on glucose; ↓ C-peptide at 120 min-OGTT.	Vodouhè et al. (140)