Table 1.

Clinical trials investigating the efficacy of soybeans and pulses to improve insulin sensitivity.

Legume	Author	Study Design	Participants and Disease State/Condition	Intervention	Results
Soy (Glycine max. L.)	Llaneza et al. [5]	⋅Randomized (R), controlled, single-blinded (SB) ⋅Longitudinal study (24 months)	⋅Postmenopausal women (50–64 years old) ⋅Normal to obese body mass index (22.5 to 43.5 kg/m2)	⋅Control: physical exercise + Mediterranean diet ⋅Intervention: control + 80 mg soy isoflavone extract/day (ISO)	⋅ISO ↓ fat mass, fasting serum glucose & insulin, and HOMA-IR vs. baseline ⋅ISO ↓ fat mass, and HOMA-IR vs. control at 24 months ⋅ISO had greater ↓ effect on HOMA-IR, and fasting serum glucose & insulin in obese participants
	Choi et al. [17]	⋅R, double-blinded (DB), placebo-controlled (PC) ⋅12-week study	⋅Men and women (mean age range 43–53 years old) ⋅Overweight (body mass index 25.0–29.9 kg/m2) ⋅Mild hyperglycemia (fasting blood glucose 5.5–6.9 mmol/L)	⋅Placebo: 2 g starch capsules/day ⋅Positive control: 300 mg banaba extract/day (BE) ⋅Intervention: 2 g soybean leaf extract/day (SLE)	⋅No effect of interventions on body weight or body mass index ⋅SLE and BE ↓ body fat, blood glucose and HOMA-IR vs. placebo at 12 weeks
	Choquette et al. [18]	⋅R, DB, PC ⋅6-month study	⋅Postmenopausal women (50–70 years old) ⋅Overweight and obese (body mass index 28–40 kg/m2)	⋅Controls: Placebo capsules; Exercise (resistance and aerobic training 3×/week) + placebo capsules ⋅Interventions: 70 mg soy isoflavones/day (ISO); Exercise + ISO	⋅ISO, without exercise, improved fasting plasma insulin and HOMA-IR vs. baseline
	Fei et al. [19]	⋅R, controlled ⋅8-week study	⋅Pregnant women (single fetus) ⋅Gestational diabetes (diagnosed according to National Diabetes Data Group standard)	⋅Control: insulin (3×/day) ⋅Intervention: 10 g soybean oligosaccharides/day in water (SOGS) + insulin (3×/day)	⋅SOGS + insulin ↓ fasting plasma insulin and HOMA-IR vs. control group at 8 weeks ⋅SOGS + insulin ↓ total insulin dosage vs. control group
	Jamilian et al. [20]	⋅R, DB, PC ⋅12-week study	⋅Women (18–40 years old) ⋅Polycystic Ovary Syndrome	⋅Placebo: 50 mg capsules (composition not disclosed) ⋅Intervention: 50 mg soy isoflavones/day (ISO)	⋅ISO ↓ serum insulin and HOMA-IR vs. placebo at 12 weeks
	Ye et al. [27]	⋅R, DB, PC ⋅24-week study	⋅Pre- and post-menopausal Chinese women (30–70 years old) ⋅Impaired glucose regulation (fasting glucose 5.6–7.0 mmol/L, 2-h postprandial glucose 7.8–11.0 mmol/L, or newly diagnosed diabetes not requiring medication)	⋅Control: 10 g soy protein ⋅Interventions: control + 50 mg/day daidzein; control + 50 mg/day genistein	⋅No differences in fasting glucose or insulin levels ⋅No differences in insulin sensitivity
Beans (Phaseolus vulgaris L.)	Bourdon et al. [28]	⋅Cross-over (CO) ⋅3 × 6-h visits + 3 × 1–3 week washouts	⋅Men (21–45 years old) ⋅Healthy (body mass index 22.6–29.4 kg/m2)	⋅Control: instant rice and dry milk + test meal ⋅Intervention: 60 g white bean flakes + test meal	⋅No differences in fasting postprandial blood glucose or insulin levels between meals
	Nilsson et al. [21]	⋅R, CO ⋅2 × 3-h visits	⋅Men and women (mean age 24 ± 1 years old) ⋅Healthy (body mass index 22.5 ± 0.6 kg/m2)	⋅Evening meals: ⋅Control: 89 g white wheat bread (WB) ⋅Intervention: 101 g cooked Swedish brown beans ⋅Next-day: standardized breakfast	⋅Brown beans ↓ postprandial glucose and insulin incremental area under the curve (0–120 min) vs. WB ⋅No differences in fasting glucose and insulin concentrations between evening meals
	Reverri et al. [22]	⋅R, controlled, cross-over (CO) ⋅3 × 5-h visits + 3 × 1-week washouts	⋅Men and women (mean age 49 ± 14 years old) ⋅Metabolic syndrome (body mass index 32.2 ± 5.7 kg/m2; insulin resistant)	⋅Controls: fibre-matched meal (FM) and antioxidant-matched meal (AM; 300 mg grape seed extract supplemented) ⋅Intervention: black bean meal (BB)	⋅No difference in postprandial blood glucose levels between meals ⋅BB ↓ plasma insulin vs. controls
Beans (Phaseolus vulgaris L.) and Peas (Pisum sativum L.)	Winham et al. [29]	⋅R, CO, 33 × block design ⋅3 × 8-week arms + 2 × 2-week washouts	⋅Men and women (22–65 years old) ⋅Moderately insulin resistant (fasting insulin ≥ 15 µU/mL and ≤50 µU/mL)	⋅Control: ½ cup canned sliced carrots/day ⋅Interventions: ½ cup canned pinto beans; ½ cup canned black-eyed peas	⋅No difference in fasting blood glucose and insulin levels ⋅No difference in HOMA-IR
Peas (Pisum sativum L.)	Marinangeli & Jones [23]	⋅R, SB, CO ⋅3 × 4-week arms + 3 × 4-week washouts	⋅Men and women (mean ages 51.8 ± 12.3 and 52.3 ± 10.0 years old, respectively) ⋅Overweight (body mass index 25–40 kg/m2) ⋅Hypercholesterolemic	⋅Control: white wheat flour muffins ⋅Intervention: whole pea flour (WPF) or fractioned pea flour (FPF) muffins; 50 g dried yellow peas/day	⋅No change in body weight ⋅No differences in postprandial blood glucose levels ⋅WPF and FPF ↓ fasting plasma insulin and HOMA-IR vs. control
Chickpeas (Cicer arietinum L.)	Johnson et al. [24]	⋅R, SB, CO ⋅3 × 175-min visits + 3 × 7-day (minimum) washouts	⋅Men and women (mean age 32 ± 2 years old) ⋅Healthy (body mass index 24.7 ± 0.8 kg/m2)	⋅Control: 3–4 toasted slices of white bread (WB) ⋅Interventions: 3–4 toasted slices of chickpea bread (CB) or extruded chickpea bread (EXB)	⋅CB and EXB ↓ incremental plasma glucose concentrations at 90 min and 120 min, respectively, vs. WB ⋅CB ↑ serum insulin incremental area under the curve vs. WB
	Nestel et al. [25]	⋅Acute study: 3 × 3-h visits ⋅Long-term study: R, CO, 2 × 6-week arms	⋅Men and women (acute study mean age 62 ± 6 years old; long-term study mean age 57 ± 8 years old) ⋅Healthy (acute study body mass index 26.5 ± 3.8 kg/m2; long-term study body mass index 25.6 ± 3.2 kg/m2)	⋅Acute study ⋅Control: white bread ⋅Interventions: cooked, mashed chickpeas (200 g) or wheat cereal with wheat bran ⋅Long-term study ⋅Interventions: chickpea-foods (from 140 g canned chickpeas) or wheat-based foods	⋅Acute study: Chickpea treatment ↓ postprandial plasma glucose levels vs. wheat and control treatments at 30 and 60 min; chickpea treatment ↓ fasting plasma insulin levels and HOMA-IR vs. wheat and control treatments ⋅Long-term study: No differences in fasting plasma glucose or insulin levels or HOMA-IR
	Pittaway et al. [26]	⋅CO ⋅20-week study (4 weeks regular diet + 12 weeks intervention + 4 weeks regular diet)	⋅Men and women (30–70 years old) ⋅Overweight (mean body mass index 26.3 ± 4.8 kg/m2) ⋅Mildly hypercholesterolemic (mean fasting serum total cholesterol 6.5 ± 1.4 mmol/L) ⋅Normoglycemic	⋅Control: regular diet ⋅Intervention: average 119 g canned chickpeas/day (Chickpea diet)	⋅Chickpea diet ↓ fasting serum insulin and HOMA-IR vs. regular diet after 12 week intervention

Abbreviations: ↓, decrease; ↑, increase; AM, antioxidant-matched; BB, black bean meal; BE, banaba extract; CB, chickpea bread; CO, cross-over; DB, double-blind; EXB, extruded chickpea bread; FM, fibre-matched; FPF, fractioned pea flour; HOMA-IR, homeostasis modelling assessment—insulin resistance; ISO, soy isoflavones; PC, placebo-controlled; R, randomized; SB, single-blind; SLE, soy leaf extract; SOGS, soybean oligosaccharides WB, white bread; WPF, whole pea flour.