Introduction
Materials and methods
Search strategy and study selection
Data extraction and assessment of the quality of included studies
Ref | Lead Author (publication year) | Location | RCT design | Sample size, (n) | Male participants, n (%) | Health status of study sample | Mean age, in years (SD)* | Duration | Characteristics of intervention arm | Characteristics of control arm | Overall risk of bias | Isocaloric diet | Different intake or background diet between arms |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
[56] | Abrahamsson et al. (1994) | Sweden | C | 31 | 0 (0) | Healthy female subjects | 26 (6.5) | Two 5-week periods | Oat bran | Wheat bran | SC | – | No |
[57] | Adamsson et al. (2015) | Sweden | P | 79 | 31 (39.2) | Mildly hypercholesterolemic and overweight subjects | 54.6 (10.8) | 12 weeks | Oat bran (porridge or muesli)—40 g per serving (corresponding to 3 g/d oat β-glucans) | Usual breakfast | SC | – | No |
[58] | Amundsen ÅL et al. (2003) | Sweden | C | 16 | 9 (56.3) | Hypercholesterolaemic subjects | 57 (7.9) | Two 3-week periods | OβGRE corresponding to 5 g/d oat β -glucans | Diet without OβGREs | SC | Yes | No |
[59] | Anderson et al. (1990) | USA | P | 14 | 14 (100) | Hypercholesterolemic subjects | 58 | 2 weeks | Oat bran (56 g/d) | Corn flakes (56 g/d) | H | Yes | No |
[60] | Anderson et al. (1991) | USA | P | 21 | 21 (100) | Hypercholesterolemic male subjects | 61 (2) | 3 weeks | Oat bran as cereal and muffins (110 g/d) | Wheat bran (40 g/d) | SC | Yes | No |
[61] | Anderson et al. (1984) | USA | P | 20 | 20 (100) | Hypercholesterolemic male subjects | Range (34–66) | 3 weeks | Oat-bran – 100 g/d of oat bran (dry wt.) served as cereals and oat bran muffins | Beans – diet containing 115 g of dried bean (dry wt.) | SC | Yes | No |
[62] | Ballesteros et al. (2015) | Mexico | C | 29 | 10 (34.5) | Subjects with type 2 diabetes | 53.5 (8.3) | 2 periods of 5 weeks | 40 g/d of oatmeal with 2 cups (472 mL) of lactose-free milk | One egg daily | SC | Yes | No |
[63] | Beck et al. (2010) | Australia | P | 56 | 0 (0) | Overweight female subjects | 37.4 (5.3) | 12 weeks | 2 MJ energy-deficit diets with high-fibre products with added OβGREs providing β-glucans at a moderate (5–6 g/d) and at a high (8–9 g/d) level | 2 MJ energy-deficit diets with high-fibre products and no oat OβGREs | L | Yes | No |
[64] | Berg et al. (2003) | Germany | P | 288 | 288 (100) | Male subjects with increased risk for coronary heart disease | 53.6 (6.3) | 4 weeks | Group 1: fat-modified diet (NCEP step 2) with caloric restriction to 1,000 kcal/d and in addition a daily intake of 35–50 g of oat bran Group 2: fat-modified diet (NCEP step 2) with caloric restriction to 1,000 kcal/d | Control group: age- and weight-matched normocholesterolemic overweight males; 1,000 kcal/d and only moderately fat-modified diet (NCEP step 1) | SC | No | Yes |
[65] | Biörklund et al. (2005) | Sweden | P | 89 | 44 (49.4) | Hypercholesteraemic subjects | 18–70 | 5 weeks | Beverage with 5 or 10 g β-glucans extract from oats or barley | Control beverage enriched with rice starch | H | No | Yes |
[66] | Biörklund et al. (2008) | Sweden | P | 43 | 19 (44.2) | Hyperlipidaemic subjects | 58 (8.2) | 8 weeks | Soup with OβGREs, providing 4 g/d oat β-glucans | Soup without OβGREs | SC | Yes | No |
[67] | Braaten et al. (1994) | USA | C | 30 | N.R | Hypercholesterolemic subjects | N.R | Two periods of 4 weeks | Oat gum with 2.9 g of β-glucans | Placebo (maltodextrin) | H | Yes | No |
[68] | Bremer et al. (1991) | New Zealand | C | 12 | 5 (41.7) | Hyperlipidaemic subjects | 53 (10) | 12 weeks | Oat bread—six slices daily for females and 10–12 slices daily for males | Wheat bread—six slices daily for females and 10–12 slices daily for males | SC | Yes | No |
[69] | Bridges et al. (1992) | USA | P | 20 | 20 (100) | Hypercholesterolemic male subjects | 61 (range 38–73) | 3 weeks | Oat bran 110 g/d (dry wt.), served as a bowl of hot cereal and oat-bran muffins | Wheat-bran diets provided 40 g/d wheat bran (dry wt.) served as a bowl of ready-to-eat cereal and wheat-bran muffins | SC | Yes | No |
[70] | Chang et al. (2013) | USA | P | 34 | 12 (35.3) | Overweight and obese subjects | 38.5 (11.3) | 12 weeks | β-glucans -containing cereal. One cereal pack (37.5 g) was prescribed to be mixed with 250 mL hot water twice daily | Placebo (cereal without β-glucans) | SC | No | Yes |
[71] | Chen et al. (2006) | USA | P | 102 | 41 (40) | Healthy subjects | 47.9 (8.4) | 12 weeks | 60 g of oat bran concentrate as a muffin and 84 g of oatmeal squares | 93 g of refined wheat as a muffin and 42 g of corn flakes | L | No | Yes |
[72] | Connolly et al. (2016) | England | C | 30 | 11 (36.7) | Subjects with glucose intolerance or mild to moderate hypercholesterolemia | 42 (N.R.) | Two 6-week periods | Whole grain oat granola cereal (45 g/d) | Non-whole grain breakfast; 45 g/d | SC | Yes | No |
[73] | Davy et al. (2002) | USA | P | 36 | 36 (100) | Overweight male subjects | 58 (8.6) | 12 weeks | 60 g oatmeal and 76 g oat bran ready-to-eat cold cereal and the wheat group consumed 5.5 g β-glucans | 60 g whole wheat cereals and 81 g frosted mini-wheats | SC | No | Yes |
[74] | De Souza et al. (2016) | Brazil | P | 132 | 44 (33.3) | Hypercholesterolemic subjects | 55.8 (10.6) | ~ 13 weeks | 40 g of oat bran | 40 g of corn starch and rice flour | SC | No | Yes |
[75] | Dubois et al. (1993) | France | P | 6 | 6 (100) | Normolipidemic male subjects | Range (20–27) | 2 weeks | Usual low-fibre diet and oat bran (40 g/d) | Usual low-fibre diet | SC | No | Yes |
[76] | Ferguson et al. (2020) | Australia | P | 72 | 27 (37.5) | Hypercholesterolemic subjects | 55.1 (1.4) | 6 weeks | Biscuits fortified with 2 g phytosterols (Group 1), 3 g β-glucans (Group 2) and 2 g phytosterols and 3 g β-glucans (Group 3) | Placebo (biscuit without phytosterols and β-glucans) | SC | Yes | No |
[77] | Geliebter et al., 2014 | USA | P | 36 | 18 (50) | Overweight subjects | 33.9 (7.5) | 4 weeks | Oat porridge or frosted cornflakes | No-breakfast | SC | Yes | No |
[78] | Gerhardt et al. (1998) | USA | P | 44 | 23 (52.3) | Moderately hypercholesterolemic subjects | 51.7 (1.5) | 6 weeks | Low-fat diet and oat bran; 84 g/d | Low-fat diet and rice starch placebo; 84 g/d | SC | Yes | No |
[79] | Guevara-Cruz et al. (2012) | Mexico | P | 67 | N.R | Subjects with metabolic syndrome | Range (20–60) | 8 weeks | Habitual diet reduced by 500 kcal and 22 g oats | Placebo: habitual diet reduced by 500 | H | No | Yes |
[80] | Gulati et al. (2017) | India | P | 69 | N.R | Mildly hypercholesterolemic subjects | 31.2 (6.6) | 4 weeks | 35 g of oats twice daily (total of 70 g/d) in the form of porridge (35 g of oats) for breakfast and a second serving of oats in the form of Upma (35 g of oats) in the afternoon | Usual diet | SC | No | Yes |
[81] | He et al. (2004) | USA | P | 102 | N.R | Subjects with stage 1 hypertension or increased blood pressure | 47.7 (8.5) | 12 weeks | High fibre: group received a daily serving of 60 g oat bran concentrate as a muffin and 84 g oatmeal squares | Low fibre: 93 g of refined wheat as a muffin and 42 g corn flakes | L | No | Yes |
[82] | Hegsted et al. (1993) | USA | C | 11 | 10 (90.9) | Mildly hypercholesterolemic subjects | 37 (33.2) | Two periods of 3 weeks | 100 g/d oat bran | 100 g/d stabilized rice bran | SC | Yes | No |
[83] | Ibrugger et al. (2013) | Denmark | C | 14 | 6 (42.6) | Healthy subjects | 22.9 (2.1) | Four 3-week periods | Beverage of 3.3 g/d oat, barley, and barley mutant b-glucans’ extract of similar molecular mass | Control beverage | SC | Yes | No |
[84] | Johansson-Persson et al. (2014) | Sweden | C | 30 | 12 (34.3) | Healthy subjects | 58.6 (1.1) | Two 5-week periods | Oat bran beverage combined with a high-fibre diet, providing 4.4 g total dietary fibre per day (corresponding to 2.8 g β-glucans) | The rice beverage in the low-fibre diet provided 0.4 g fibre daily | SC | Yes | No |
[85] | Kabir et al. (2002) | France | C | 13 | 13 (100) | Subjects with type 2 diabetes | 59 (7.2) | Two 4-week periods | Low-glycaemic index breakfast period, the cereal used was based on extruded oat bran concentrate, apple, and fructose (muesli containing 3 g β-glucans). The bread used was pumpernickel | High-glycaemic index breakfast whole wheat grains and whole meal bread (wheat flour) | SC | Yes | No |
[86] | Karmally et al. (2005) | USA | P | 152 | 49 (32.2) | Healthy subjects | 49 (10.6) | 11 weeks | Ready-to-eat oat cereal (portion size: 45 g/d) | Corn Cereal | H | No | - |
[87] | Kashtan et al. (1992) | Canada | P | 84 | 50 (59.5) | Subjects with a history of previous polypectomy and volunteers with normal colon on colonic examination | 55.8 (13) | 2 weeks | Oat bran twice per day (88.4 g/d) | Wheat bran twice per day (73 g/d) | SC | Yes | No |
[88] | Keenan et al. (1991) | USA | C | 75 | 49 (65.3) | Healthy subjects | Range (20–70) | Three periods of 6 weeks | AHA Step I diet and oat bran, 28 g/d | AHA Step I diet and wheat bran | H | Yes | No |
[89] | Keenan et al. (2002) | USA | P | 18 | N.R | Hypertensive and hyperinsulinemic subjects | 44 (18) | 6 weeks | Oat cereals providing ~ 5.5 g/d of β-glucans | Low-fibre cereal (< 1 g/d total fibre) | SC | Yes | No |
[90] | Kerckhoffs et al. (2003) | The Netherlands | P | 48 | 21 (43.8) | Healthy subjects | 53 (13.9) | 4 weeks | Bread and cookies rich in β-glucans (~ 1.5 g/d) from > 5 g/d oat bran | bread and cookies rich in wheat fibre | SC | No | Yes |
[91] | Kirby et al. (1981) | USA | P | 8 | 8 (100) | Hypercholesterolemic subjects | Range (35–62) | 2 weeks | Diet containing 100 g of oat-bran daily, provided in form of muffins and cereals | Diet composed of commonly available foods | SC | Yes | No |
[92] | Kristensen et al. (2011) | Denmark | C | 24 | N.R | Healthy subjects | 25.2 (2.7) | Two periods of 2 weeks | Low-fibre diet and 102 g/d oat bran | Low-fibre diet | SC | Yes | No |
[93] | Laaksonen et al. (2005) | Finland | P | 72 | 36 (50) | Subjects with metabolic syndrome | 55.4 (6.8) | 12 weeks | Oat bread (made of 60% whole meal oat flour and 40% wheat flour) | Rye-pasta | SC | Yes | No |
[94] | Leadbetter et al. (1991) | USA | P | 40 | 20 (50) | Hypercholesterolemic subjects | Range (25–64) | 4 months | 30, 60 or 90 g/d oat bran | No supplementation | SC | Yes | No |
[37] | Leão et al. (2019) | Brazil | P | 154 | 41 (26.6) | Subjects with metabolic syndrome | 47.6 (12.6) | 6 weeks | Low-calorie diet plus oat bran (40 g/d) | A low-calorie diet | SC | No | Yes |
[10] | Li et al. (2016) | China | P | 298 | 155 (52) | Overweight subjects with type 2 diabetes | 59.5 (6) | 4 weeks | Diet with the same quantity of cereals replaced by 50 g and 100 g oats respectively | Low-fat and high-fibre diet | SC | No | - |
[95] | Liao et al. (2019) | Taiwan | P | 74 | N.R | Healthy and mildly hypercholesterolemic subjects | Range (35–70) | 10 weeks | Oat noodles containing 12 g of β-glucans | Wheat noodles | SC | No | Yes |
[96] | Liatis et al. (2009) | Greece | P | 41 | 23 (56.1) | Subjects with type 2 diabetes | 62.9 (9.1) | 3 weeks | Bread enriched β-glucans (providing 3 g/d β-glucan) | Bread without β-glucans | H | No | Yes |
[97] | Liu et al. (2011) | China | P | 120 | 60 (50) | Healthy subjects | N.R | 4 weeks | Either 4 capsules containing 1.6 mg of oat avenanthramides or 8 capsules containing oat avenanthramides-enriched extract (3.1 mg) | Placebo capsules (corn oil) or no treatment at all (control group) | H | No | No |
[98] | Lovegrove et al. (2000) | UK | P | 62 | 31 (50) | Healthy subjects | 56.6 (9.4) | 8 weeks | 20 g oat bran concentrate providing 3 g β-glucans | 20 g wheat bran | SC | No | No |
[99] | Maki et al. (2003) | USA | P | 112 | 49 (43.8) | Hypercholesterolemic subjects | 57.3 (9.5) | 6 weeks | Cereal, a snack bar and a beverage with 1.8 g oil–based phytosterols and 2.8 g/d β-glucans | Cereals, a snack bar and a beverage with less than 1 g β-glucans daily, and no oil–based phytosterols | SC | No | Yes |
[100] | Maki et al., (2007) | USA | P | 60 | 33 (55) | Subjects with elevated blood pressure | 59.7 (9.4) | 12 weeks | A ready-to-eat cold cereal made with oat bran, oatmeal and a powdered form of β-glucans | (1) A low-fibre ready-to-eat cold wheat-based cereal (2) a low-fibre hot cereal and (3) a control maltodextrin powder | SC | No | Yes |
[101] | Maki et al. (2010) | USA | P | 144 | 31 (21.5) | Healthy subjects | 48.9 (10.2) | 12 weeks | Energy deficit of 500 kcal/d and wholegrain oat cereals containing ~ 3 g/d β-glucans | Energy deficit of 500 kcal/d and low-fibre breakfast/snack foods | SC | No | Yes |
[102] | Martensson et al. (2005) | Sweden | P | 56 | 24 (42.9) | Moderately hypercholesterolemic subjects | 55 (9) | 3 weeks run-in, 5 weeks intervention | Fermented oat-based product (3–3.5 g/d native β-glucans) and oat-based product ropy which was co-fermented with an exopolysaccharide-producing strain (Pediococcus damnosus) | Fermented dairy-based product | SC | No | – |
[103] | Missimer et al. (2017) | USA | C | 50 | 24 (48) | Healthy subjects | 23.3 (3.1) | Two periods of 4 weeks | Oatmeal 35 g/d for breakfast | 2 eggs for breakfast, daily | SC | Yes | No |
[104] | Momenizadeh et al. (2014) | Iran | P | 60 | 21 (35) | Hypercholesterolemic subjects | 51.1 (9.3) | 6 weeks | Five servings of oat bread providing 6 g β-glucans | At least five servings of wheat bread | SC | No | Yes |
[105] | Noakes et al. (1996) | Australia | C | 23 | 13 (56.5) | Overweight, obese, dyslipidemic and/or hypertensive subjects | 51 (6.7) | Three periods of 4 weeks | Oat bran | Two control diets: high-amylose and low-amylose diet | SC | Yes | No |
[106] | Önning et al. (1999) | Sweden | C | 66 | 66 (100) | Moderate hypercholesterolemia | Mean age (62.6); Range (52–70) | Two periods of 5 weeks | Oat milk (0.75 L, daily) | Rice milk (0.75 L, daily) | SC | Yes | No |
[107] | Önning et al. (1998) | Sweden | P | 11 | 6 (54.5) | Healthy, non-smoking subjects | Range (23–54) | 4 weeks | Oat milk daily (0.75 L for females and 1 L for males) | Cow’s milk was a medium-fat milk (0.75 L for females and 1 L for males daily) | SC | Yes | No |
[20] | Pavadhgul et al. (2019) | Thailand | C | 24 | N.R | Hypercholesterolemic subjects | Range (30–60) | Two 4-week periods | 70 g of instant oat flakes (porridge) | 70 g instant white rice flakes (porridge) | SC | Yes | No |
[108] | Pins et al. (2002) | USA | P | 88 | 45(51.1) | Subjects with history of essential mild or moderate hypertension | 47.6 (16.1) | Three 4-week periods | 60 g Oatmeal and 77 g Oat Squares | 65 g wheat cereals and 81 g of rice- and corn-based breakfast cereals | SC | No | - |
[109] | Poulter et al. (1994) | UK | C | 59 | 17 (28.8) | Hypercholesterolemic subjects | 56.3 (2.5) | 2 periods of 4 weeks | Oat-based cereal (50 g) | Usual cereal without oat | SC | Yes | No |
[22] | Queenan et al. (2007) | USA | P | 75 | 25 (33.3) | Hypercholesterolemic subjects | 44.9 (12.9) | 6 weeks | 6 g/d concentrated β-glucans (powder form) | 6 g/d dextrose monohydrate (powder) | H | - | No |
[110] | Reyna-Villasmil et al. (2007) | Venezuela | P | 38 | 38 (100) | Mild to moderate hypercholesterolemic subjects | 59.8 (0.6) | 8 weeks | AHA Step II diet plus bread containing 6 g/d of oat-derived β-glucans | Same diet as the intervention arm plus whole-wheat bread providing 6 g/d of fibre | SC | Yes | No |
[111] | Robitaille et al. (2005) | Canada | P | 34 | 0 (0) | Normal cycling premenopausal overweight female subjects | 38.3 (7.5) | 4 weeks trial (2-week run-in phase) | 28 g/d of oat bran in form of oat bran-enriched muffins | No supplement | SC | No | No |
[112] | Romero et al. (1998) | Mexico | P | 46 | 46 (100) | Sedentary hypercholesterolemic male subjects | Range (20–45) | 8 weeks | Oat bran–100 g of cookies daily which is equivalent to 2.8 g of soluble fibre derived from oat bran | Wheat bran–100 g of cookies daily which is equivalent to 0.6 g of soluble fibre derived from wheat bran | SC | Yes | No |
[113] | Saltzman et al. (2001) | USA | P | 43 | 20 (46.5) | Healthy subjects | 44.6 (27.5) | 6 weeks | Hypocaloric diet and oats – 45 g/ (4.2 MJ dietary energy daily) | Hypocaloric diet without oat | SC | No | Yes |
[114] | Schweinlin et al. (2018) | Germany | P | 36 | 13 (36.1) | Obese subjects with NAFLD | 49.9 (10.3) | 2 + 10 weeks intervention | Powdered diet supplement containing 6 g oatmeal, enriched with 1,7 g β-glucans and 5 g oat fibre–3 × 30 g/d (2 weeks) and 2 × 30 g/d (10 weeks) | Low-glycaemic and insulinemic diet | SC | No | Yes |
[115] | Tabesh et al. (2014) | Iran | P | 60 | 21(35) | Hypercholesterolemic subjects | 51.1 (9.3) | 4 weeks | Hypocaloric diet with 150 g oat bread rich in β-glucan–corresponding to 18 g/d of β-glucans | Hypocaloric diet with 150 g wheat bread rich in wheat fibre, but no β-glucan | SC | No | Yes |
[116] | Theuwissen et al. (2009) | The Netherlands | C | 42 | 20 (47.6) | Healthy subjects | 52 (11) | 2 periods of 4 weeks | β-glucan -containing muesli (4.8 g β-glucan) | Muesli without with 4.8 g fibre | SC | Yes | No |
[117] | Thongoun et al. (2013) | Thailand | C | 24 | 2 (8.3) | Hypercholesterolemic subjects | 51 (6.9) | 2 periods of 4 weeks | Oat bran 70 g (corresponding to 3 g β-gluans) | 70 g rice porridge | SC | Yes | No |
[23] | Tighe et al. (2010) | UK | P | 206 | 105 (51) | Healthy subjects | 51.8 (7.4) | 12 weeks intervention | 35–40 g whole meal bread plus 60–80 g of whole grain rolled oats daily | 70–80 g whole meal bread plus 30–40 g whole grain cereals or 3 servings of refined cereals foods, daily | SC | No | Yes |
[118] | Trinidad et al. (2004) | Philippines | C | 21 | 4 (19) | Mildly hypercholesterolemic subjects | 48.4 (4.6) | Four 2-week periods, separated by 2 weeks washout | 50 g organic oat bran flakes daily | 3 comparisons: 50 g corn flakes; 50 g cornflakes with 15% coconut flakes; 50 g 25% coconut flakes | SC | Yes | No |
[120] | Uusitupa et al. (1992) | Finland | P | 36 | 20 (55.6) | Hypercholesterolemic subjects | 47.8 (7.6) | 8 weeks | 29.8 g oat bran (corresponding to 10.3 g/d β-glucans) | 20.5 g/d wheat bran | SC | - | No |
[119] | Uusitupa et al. (1997) | Finland | P | 36 | 20 (55.6) | Hypercholesterolemic subjects | 47.8 (7.6) | 8 weeks | 29.8 g oat bran (corresponding to 10.3 g/d β-glucans) | 20.5 g/d wheat bran | H | - | No |
[121] | Van Horn L et al. (1991) | USA | P | 80 | 40(50) | Hypercholesterolemic subjects | 42.5 (12.9) | 8 weeks | Two packets (56.7 g/d dry wt.) of instant oats | Usual intake | SC | No | - |
[122] | Vuksan et al. (2017) | Canada | P | 58 | 18 (31) | Overweight and obese subjects with type 2 diabetes | 60 (2) | 26 weeks (6 months) | 25.7 g/d oat bran | 30 g/1000 kcal of ground Salba-chia | SC | No | Yes |
[123] | Wolever et al. (2010) | Canada | P | 367 | 210 (57.2) | Healthy subjects | 53.5 (9.1) | 4 weeks | Oat bran containing 3–4 g/d β-glucans | Wheat bran | L | No | Yes |
[124] | Zhang et al. (2012) | China | P | 166 | 65 (39.2) | Subjects with mild to moderate hypercholesterolemia | 53.2 (6.5) | 6 weeks | 100 g/d of instant oat cereal | 100 g/d of wheat flour-based noodles | SC | No | Yes |
Statistical analysis
Results
Included studies
Included studies | Participants | Study quality | Meta-analysis results | |||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Outcome | No. of unique studies | Follow-up duration, median (IQR), weeks | Total, no | Median sample size per intervention arm (IQR) | Age, median (IQR), years | No. of studies including healthy individuals, no. (%) | H | SC | L | WMD (95% CI) | I2 (%) | P value for heterogeneity |
Body morphology | ||||||||||||
BMI, kg/m2 | 5 | 5 (3.5;9) | 249 | 43 (37.5;65.5) | 42 (34.9;60.5) | 0 (0) | 1 | 4 | 0 | − 0.329 (− 0.634; − 0.025) | 55.6 | 0.060 |
Body weight, kg | 5 | 4 (3;12) | 250 | 41 (31;73.5) | 38.5 (27.1;58.8) | 1 (20) | 1 | 4 | 0 | − 0.943 (− 1.842; − 0.045) | 52.3 | 0.090 |
Waist circumference, cm | 3 | 4 (n.a.) | 144 | – | – | 0 (0) | 1 | 2 | 0 | − 1.058 (− 1.845; − 0.270) | 0.0 | 0.610 |
Body fat, % | 1 | – | – | – | – | – | – | – | – | – | – | |
Blood lipids | ||||||||||||
Total cholesterol, mmol/L | 12 | 4.5 (3.3;7.5) | 589 | 38.5 (32.5;67.3) | 44.5(36.5;57.3) | 1 (8.3) | 1 | 11 | 0 | − 0.415 (− 0.607; − 0.223) | 96.1 | < 0.001 |
LDL, mmol/L | 12 | 4.5 (3.3;7.5) | 589 | 38.5 (32.5;67.3) | 44.5 (36.5;57.3) | 1 (8.) | 1 | 11 | 0 | − 0.286 (− 0.372; − 0.200) | 72.6 | < 0.001 |
HDL, mmol/L | 12 | 4.5 (3.3;7.5) | 589 | 38.5 (32.5;67.3) | 44.5(36.5;57.3) | 1 (8.3) | 1 | 11 | 0 | − 0.015 (− 0.041; 0.012) | 46.5 | 0.030 |
Triglycerides, mmol/L | 10 | 4.5 (3;9) | 466 | 42 (33.5;78.5) | 48.6(33.2;57.8) | 1 (10) | 1 | 9 | 0 | − 0.022 (− 0.096; 0.052) | 59.6 | 0.008 |
Glucose homeostasis | ||||||||||||
Glucose, mmol/L | 3 | 6 (n.a.) | 146 | – | – | 0 (0) | 1 | 2 | 0 | − 0.247 (− 0.357; − 0.136) | 47.29 | 0.150 |
HbA1c, % | 0 | – | – | – | – | – | – | – | – | – | – | |
Insulin, pmol/L | 2 | – | – | – | 0 (0) | 1 | 1 | 0 | − 22.33 (− 49.66; 4.95) | 66.0 | 0.090 | |
Blood pressure | ||||||||||||
Systolic blood pressure, mmHg | 5 | 8 (3.5;12) | 302 | 69 (37.5;79) | – | 0 (0) | 1 | 4 | 0 | − 0.56 (− 1.68; 0.56) | 33.8 | 0.200 |
Diastolic blood pressure, mmHg | 5 | 8 (3.5;12) | 302 | 69 (37.5;79) | – | 0 (0) | 1 | 4 | 0 | − 0.69 (− 1.59; 0.22) | 42.8 | 0.140 |
Meta-analysis of RCTs comparing oat supplementation interventions with the same intervention without oat product
Subgroup analysis, leave-one-out analysis and publication bias
Meta-analysis of RCTs comparing oat supplementation intervention combined with some type of dietary restriction versus the same dietary restriction alone
Included studies | Participants | Study quality | Meta-analysis results | |||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Outcome | No. of unique studies | Follow-up duration, median (IQR), weeks | Total, no | Median sample size per intervention arm (IQR) | Age, median (IQR), years | No. of studies including healthy individuals, no. (%) | H | SC | L | WMD (95% CI) | I2 (%)
| P value for heterogeneity |
Body morphology | ||||||||||||
BMI, kg/m2 | 6 | 4 (4–6.5) | 788 | 62 (30–79) | 59.5 (52.1–59.6) | 0 (0) | 1 | 6 | 0 | − 0.129 (− 0.256; − 0.002) | 40.0 | 0.130 |
Body weight, kg | 7 | 6 (4–10) | 739 | 24 (19–79) | 46.1 (37.4–59.5) | 2 (28.6) | 1 | 4 | 2 | − 0.171 (− 0.486; 0.143) | 39.2 | 0.110 |
Waist circumference, cm | 6 | 7 (4–11.5) | 706 | 31 (19–79) | 48.7 (37.4–59.5) | 0 (0) | 1 | 5 | 0 | 0.146 (− 0.438; 0.730) | 77.9 | < 0.001 |
Body fat, % | 2 | – | 384 | – | – | (0) | 0 | 2 | 0 | 0.316 (− 0.069; 0.701) | 69.8 | 0.040 |
Blood lipids | ||||||||||||
Total cholesterol, mmol/L | 8 | 6 (4–9) | 745 | 21 (16–72.5) | 55.3 (39.2–59.5) | 1 (12.5) | 1 | 6 | 1 | − 0.430 (− 0.556; -0.304) | 91.7 | < 0.001 |
LDL, mmol/L | 9 | 6 (4–10) | 804 | 22 (18.5–59.5) | 50.8 (37.4–59.5) | 2 (22.2) | 1 | 7 | 1 | − 0.260 (− 0.381; − 0.138) | 94.1 | < 0.001 |
HDL, mmol/L | 10 | 6 (4–9) | 958 | 23 (19–77) | 48.7 (37.4–55.0) | 2 (20) | 1 | 8 | 1 | − 0.054 (− 0.101; − 0.006) | 97.1 | < 0.001 |
Triglycerides, mmol/L | 13 | 6 (4–9) | 1,019 | 21 (17–66.5) | 49.9 (41.0–59.2) | 2 (15.4) | 1 | 12 | 0 | − 0.047 (− 0.141; 0.046) | 89.1 | < 0.001 |
Apo A, g/L | 2 | – | 178 | – | – | 0 (0) | 0 | 2 | 0 | 0.092 (0.042; 0.142) | 0.0 | 0.780 |
Apo B, g/L | 2 | – | 178 | – | – | 0 (0) | 0 | 2 | 0 | 0.066 (− 0.257; 0.390) | 97.1 | < 0.001 |
Glucose homeostasis | ||||||||||||
Glucose, mmol/L | 9 | 8 (6–11.5) | 717 | 21 (17.5–77) | 54.4 (40.0–59.5) | 1 (11.1) | 0 | 9 | 0 | 0.021 (− 0.155; 0.198) | 92.2 | < 0.001 |
HbA1c, % | 3 | – | 343 | – | – | 0 (0) | 0 | 3 | 0 | − 0.423 (− 0.483; -0.364) | 0.0 | 0.760 |
Insulin, pmol/L | 4 | – | 208 | – | – | 1 (25) | 0 | 4 | 0 | 11.325 (− 4.220; 26.870) | 68.7 | 0.010 |
Blood pressure | ||||||||||||
Systolic blood pressure, mmHg | 5 | 6 (5–8) | 654 | 30 (20.7–44) | – | 1 (20) | 1 | 4 | 0 | 0.170 (− 2.168; 2.508) | 88.3 | < 0.001 |
Diastolic blood pressure, mmHg | 5 | 6 (5–8) | 654 | 30 (20.7–44) | – | 1 (20) | 1 | 4 | 0 | − 1.154 (− 2.030; -0.278) | 55.9 | 0.060 |
Subgroup analysis, leave-one-out analysis and publication bias
Meta-analysis of RCTs comparing oat supplementation intervention versus heterogeneous control arms
Outcome | Included studies | Participants | Study quality | Meta-analysis results | ||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
No. of unique studies | Follow-up duration, median (IQR), weeks | Total, no | Median sample size per intervention arm (IQR) | Age, median (IQR), years | No. of studies including healthy individuals, no. (%) | H | SC | L | WMD (95% CI) | I2 (%) | P value for heterogeneity | |
Body morphology | ||||||||||||
BMI, kg/m2 | 13 | 6 (4.5–8) | 862 | 25 (19.7–39.7) | 53.2 (49.4–56.2) | 2 (15) | 1 | 12 | 0 | − 0.014 (− 0.220; 0.192) | 76.8 | < 0.001 |
Body weight, kg | 8 | 4 (3–9) | 344 | 12 (10.7–28) | 58.6 (43–62) | 1 (12.5) | 0 | 8 | 0 | 0.118 (− 0.513; 0.749) | 0.0 | 0.920 |
Waist circumference, cm | 7 | 6 (4–13) | 618 | 30.5 (24–66) | 51.1 (33.9–55.8) | 1 (14.3) | 0 | 7 | 0 | 0.124 (− 1.412; 1.660) | 95.8 | < 0.001 |
Body fat, % | 3 | – | 149 | – | – | 0 (0) | 0 | 3 | 0 | 1.020 (− 1.957; 3.998) | 92.3 | < 0.001 |
Blood lipids | ||||||||||||
Total cholesterol, mmol/L | 28 | 5 (3.7–8) | 1,922 | 24 (18–44.5) | 53 (47.9–56.9) | 6 (21.4) | 3 | 25 | 0 | − 0.267 (− 0.385; -0.149) | 99.0 | < 0.001 |
LDL, mmol/L | 26 | 5 (4–8) | 1,823 | 25 (16.5–47.2) | 53 (48.1–56.6) | 6 (46.1) | 3 | 23 | 0 | − 0.163 (− 0.216; − 0.109) | 95.4 | < 0.001 |
HDL, mmol/L | 27 | 5 (4–8) | 1,652 | 25 (18–48) | 53 (48.1–56.6) | 5 (18.5) | 3 | 24 | 0 | 0.002 (− 0.022; 0.025) | 95.7 | < 0.001 |
Triglycerides, mmol/L | 26 | 5 (4–8) | 1,802 | 24 (16.5–47.2) | 53 (48.4–57.3) | 4 (15.4) | 3 | 23 | 0 | − 0.084 (− 0.153; − 0.015) | 98.7 | < 0.001 |
Apo A, g/L | 6 | 6 (5–8) | 634 | 36.5 (19.7–74.5) | 51.8 (48–54.5) | 1 (16.7) | 1 | 5 | 0 | − 0.005 (− 0.029; 0.018) | 89.0 | < 0.001 |
Apo B, g/L | 6 | 7 (5–11.7) | 777 | 50 (20–7) | 51.8 (49.0–52.8) | 1 (16.7) | 1 | 5 | 0 | − 0.031 (− 0.052; -0.010) | 98.8 | < 0.001 |
Glucose homeostasis | ||||||||||||
Glucose, mmol/L | 15 | 6 (4–10) | 1,142 | 21.5 (18.2–79) | 59 (37.4–59.5) | 1(6.7) | 0 | 15 | 0 | − 0.009 (− 0.064; 0.045) | 93.6 | < 0.001 |
HbA1c, % | 2 | – | 113 | – | – | 0(0) | 0 | 2 | 0 | − 0.076 (− 0.321; 0.169) | 87.7 | 0.004 |
Insulin, pmol/L | 10 | 12 (5–12) | 644 | 20 (12–36) | 49.4 (41.7–55) | 2 (20) | 1 | 9 | 0 | − 0.641 (− 4.218; 2.935) | 82.7 | < 0.001 |
Blood pressure | ||||||||||||
Systolic blood pressure, mmHg | 7 | 6 (4–8) | 618 | 48 (19–66) | 51.1 (33.9–55.8) | 1 (12.5) | 0 | 7 | 0 | 0.547 (− 0.564; 1.657) | 85.3 | < 0.001 |
Diastolic blood pressure, mmHg | 7 | 6 (4–8) | 618 | 48 (19–66) | 51.1 (33.9–55.8) | 1 (12.5) | 0 | 7 | 0 | 0.357 (− 1.210; 1.925) | 96.8 | < 0.001 |