Dietary black-grained wheat intake improves glycemic control and inflammatory profile in patients with type 2 diabetes: a randomized controlled trial

Figures & data

Figure 1 Flow diagram of the study.

Abbreviation: BGW, black-grained wheat.

Table 1 Nutritional composition of the BGW test foods

Food types	Energy, kcal/100 g	Protein, g/100 g	Fat, g/100 g	Carbohydrate, g/100 g	Dietary fiber, g/100 g	BGW, g/100 g
Steamed bun	965	16.6	1.6	37.2	4.9	49.6
Noodles	1,409	19.4	1.8	54.9	10.0	72
Kernels	1,448	11.1	1.1	71.4	2.7	24

Note: Data are expressed as the means ± SD (n=3).

Abbreviation: BGW, black-grained wheat.

Table 2 Characteristics of the subjects at baseline

Variable	BGW group (n=59)	Control group (n=51)	P-value
Male, n (%)	26 (44.1)	24 (47.1)	0.444
Age (years)	58.5±10.2	57.4±8.8	0.544
Duration of diabetes (years)	7 (0.3–20)	9 (0.3–20)	0.102
Family history of diabetes, n (%)	26 (44.1)	26 (51.0)	0.469
Diabetes medication use
No diabetes medication, n (%)	19 (32.2)	20 (39.2)	0.443
Oral medication only, n (%)	38 (64.4)	37 (72.5)	0.361
Insulin only, n (%)	5 (8.5)	2 (3.9)	0.329
Oral medication and insulin, n (%)	7 (11.9)	6 (11.8)	0.987
Antihypertensive agents	14 (23.7)	9 (17.6)	0.434
Lipid-lowering agents	3 (5.1)	6 (11.8)	0.202
Complications, n (%)	16 (27.2)	12 (23.5)	0.667
MetS (NCEP ATP III), n (%)	31 (52.5)	23 (45.1)	0.452
Overweight, n (%)	49 (83.1)	37 (72.5)	0.248
Hypertension, n (%)	29 (49.2)	21 (41.2)	0.446
Dyslipidemia, n (%)	46 (78.0)	36 (70.6)	0.390
Weight, kg	70.6±12.3	68.1±10.7	0.273
Height, cm	161.9±7.6	161.4±8.4	0.914
BMI, kg/m^2	26.8±3.4	26.1±3.2	0.281
Systolic blood pressure, mmHg	141.1±17.4	136.6±17.7	0.181
Diastolic blood pressure, mmHg	79.4±11.9	76.9±10.2	0.241

Notes: Data are expressed as the means ± SD for normally distributed variables, including age, weight, height and blood pressure; medians (IQR) for non-normally distributed variables, including duration of diabetes; or number (%) for categorical variables. Proportions were compared using Pearson’s χ² test, the means were compared using Student’s t-test, and medians were compared using the Wilcoxon’s signed-rank test. Overweight is defined as BMI ≥24 kg/m². Hypertension is defined as elevated blood pressure, having been diagnosed as hypertensive, or using antihypertensive agents. Dyslipidemia is defined as LDL cholesterol ≥3.3 mmol/L, reduced HDL cholesterol or elevated TG, having been diagnosed as dyslipidemic, or using lipid-lowering agents.

Abbreviations: BGW, black-grained wheat; BMI, body mass index; IQR, interquartile range; MetS, metabolic syndrome; NCEP ATP III, National Cholesterol Education Program Adult Treatment Panel III; TG, triglycerides; HDL, high-density lipoprotein; LDL, low-density lipoprotein.

Table 3 Daily energy and nutrient intake of the subjects at baseline and after a 5-week dietary intervention

Variable	BGW group (n=59)	Control group (n=51)	P-value
Energy, kcal
Baseline	1,834.16 (1,742.43 to 1,925.89)	2,032.43 (1,924.67 to 2,140.19)	0.034
5-weeks	1,735.33 (1,654.23 to 1,816.43)	1,854.10 (1,756.71 to 1,951.49)	0.154
Change from baseline	−98.83 (−189.13 to −8.53)	−178.33 (−291.76 to −64.90)	0.404
Protein, g
Baseline	37.72 (33.06 to 42.38)	38.97 (34.19 to 43.75)	0.594
5-weeks	45.04 (40.10 to 49.98)a	39.28 (35.08 to 43.48)	0.012
Change from baseline	7.32 (2.22 to 12.42)	0.31 (−4.66 to 5.28)	0.006
Protein, % of energy
Baseline	12.25 (11.43 to 13.07)	11.38 (10.65 to 12.12)	0.052
5-weeks	15.80 (15.09 to 16.51)a	12.55 (11.83 to 13.27)	<0.001
Change from baseline	3.55 (2.51 to 4.59)	1.17 (0.19 to 2.15)	<0.001
Fat, g
Baseline	57.30 (53.13 to 61.47)	62.65 (57.34 to 67.96)	0.253
5-weeks	51.92 (49.23 to 54.61)	54.34 (50.86 to 57.82)	0.443
Change from baseline	−5.38 (−9.32 to −1.44)	−8.31 (−13.73 to −2.89)	0.517
Fat, % of energy
Baseline	19.00 (17.64 to 20.36)	18.23 (17.05 to 19.41)	0.531
5-weeks	18.48 (17.62 to 19.34)	17.42 (16.53 to 18.31)	0.227
Change from baseline	−0.51 (−1.68 to 0.66)	−0.82 (−1.96 to 0.34)	0.815
Carbohydrate, g
Baseline	211.31 (194.52 to 228.09)	239.27 (223.73 to 254.81)	0.016
5-weeks	183.83 (171.28 to 196.38)	220.97 (204.36 to 237.58)	0.001
Change from baseline	−27.48 (−43.09 to −11.88)	−18.30 (−35.51 to −1.08)	0.431
Carbohydrate, % of energy
Baseline	68.63 (66.84 to 70.43)	70.44 (68.83 to 72.04)	0.134
5-weeks	64.42 (63.32 to 65.51)a	69.80 (68.38 to 71.22)	<0.001
Change from baseline	−4.22 (−5.99 to −2.44)	−0.64 (−2.47 to 1.20)	0.006
Dietary fiber, g
Baseline	11.93 (10.50 to 13.37)	13.26 (11.4 to 15.12)	0.263
5-weeks	20.49 (19.10 to 21.88)a	11.23 (10.12 to 12.33)a	<0.001
Change from baseline	8.55 (7.10 to 10.00)	−2.03 (−3.89 to −0.18)	<0.001
Cholesterol, mg
Baseline	313.07 (254.44 to 371.71)	261.78 (217.64 to 305.92)	0.159
5-weeks	347.90 (319.07 to 376.72)	328.99 (296.59 to 361.38)	0.386
Change from baseline	34.82 (−26.54 to 96.18)	67.21 (20.16 to 114.26)	0.397
Fatty acids, g
Baseline	41.83 (37.66 to 45.99)	45.73 (40.42 to 51.04)	0.253
5-weeks	36.57 (33.88 to 39.26)	38.28 (34.81 to 41.74)	0.443
Change from baseline	−5.26 (−9.20 to −1.31)	−7.46 (−12.88 to −2.03)	0.517

Notes: Baseline and 5-weeks data are expressed as means ± SD. Differences of variables between groups are analyzed using the Student’s t-test. Changes from baseline are expressed as means (95% CI) adjusted for sex, age, and BMI at baseline, and baseline values of relevant outcome variables. Differences of variables between groups are analyzed using the analysis of covariance (ANCOVA, generalized linear model) test.

a Difference is considered to be significant at P<0.05; within-group differences (baseline vs 5-weeks) are compared using the paired Student’s t-test if the between-group differences are significant.

Abbreviations: BGW, black-grained wheat; BMI, body mass index.

Table 4 Changes in metabolic parameters during the study period

Variable	BGW group (n=59)	Control group (n=51)	P-value
Glucose, mmol/L
Baseline	8.75 (8.16 to 9.34)	8.85 (8.10 to 9.60)	0.789
5-weeks	8.30 (7.86 to 8.74)	8.29 (7.59 to 8.98)	0.935
Change from baselineb	−0.41 (−0.78 to 0.04)	−0.57 (−0.96 to −0.18)	0.557
HbA1c, %
Baseline	7.13 (6.82 to 7.44)	7.08 (6.70 to 7.47)	0.894
5-weeks	6.79 (6.50 to 7.08)	6.90 (6.50 to 7.30)	0.623
Change from baselineb	−0.33 (−0.62 to 0.04)	−0.20 (−0.51 to 0.12)	0.537
GA, mmol/L
Baseline	18.05 (17.01 to 19.09)	18.54 (17.10 to 19.98)	0.524
5-weeks	16.06 (15.37 to 16.74)a	17.52 (16.26 to 18.78)a	0.034
Change from baselineb	−2.00 (−2.43 to −1.56)	−0.95 (−1.42 to −0.48)	0.002
Insulin, mU/L
Baseline	13.32 (10.89 to 15.76)	12.83 (9.30 to 16.36)	0.792
5-weeks	12.10 (10.45 to 13.75)	11.71 (8.69 to 14.74)	0.807
Change from baselineb	−1.13 (−2.69 to 0.43)	−1.27 (−2.95 to 0.41)	0.904
HOMA-IR, µU×mol/L^2
Baseline	1.54 (1.39 to 1.69)	1.36 (1.24 to 1.48)	0.535
5-weeks	1.43 (1.30 to 1.56)	1.34 (1.19 to 1.49)	0.135
Change from baselineb	−0.06 (−0.18 to −0.06)	−0.15 (−0.28 to −0.02)	0.303
hs-CRP, mg/L
Baseline	2.24 (1.41 to 3.06)	1.63 (0.99 to 2.27)	0.270
5-weeks	2.23 (1.00 to 3.46)	1.34 (0.89 to 1.80)	0.212
Change from baselineb	0.08 (−0.77 to 0.94)	−0.41 (−1.33 to 0.52)	0.448
TNF-α, pg/mL
Baseline	2.01 (1.93 to 2.09)	1.94 (1.88 to 2.00)	0.198
5-weeks	2.01 (1.92 to 2.10)	2.36 (2.21 to 2.52)a	0.003
Change from baselineb	0.01 (−0.10 to 0.12)	0.41 (0.29 to 0.53)	0.001
IL-6, pg/mL
Baseline	0.95 (0.79 to 1.10)	0.74 (0.70 to 0.78)	0.017
5-weeks	0.99 (0.84 to 1.13)	0.98 (0.85 to 1.11)a	0.957
Change from baselineb	0.06 (−0.05 to 0.17)	0.21 (0.09 to 0.33)	0.081

Notes: Glucose, HbA1c, GA, insulin, and hs-CRP are normally distributed variables. The variables of HOMA-IR, TNF-α, and IL-6 are transformed by the natural logarithm. Baseline and 5-weeks data are expressed as the means (95% CI). Differences of variables between groups are analyzed using the Student’s t-test.

a Difference is considered to be significant at P<0.05; within-group differences (baseline vs 5-weeks) are compared using the paired Student’s t-test if the between-group differences are significant.

b Changes from baseline of glucose and inflammatory profiles are expressed as means (95% CI) adjusted for sex, age, and BMI at baseline, and baseline values of the relevant outcome variables. Differences of variables between groups are analyzed using the ANCOVA (generalized linear model) test.

Abbreviations: ANCOVA, analysis of covariance; BGW, black-grained wheat; GA, glycated albumin; HbA1c, glycated hemoglobin; HOMA-IR, homeostasis model assessment of insulin resistance; hs-CRP, hypersensitive-C-reactive protein; IL-6, interleukin-6; TNF-α, tumor necrosis factor-α.

Table 5 Effect of BGW intake on changes in metabolic parameters during the study period

Variable	No BGW (n=51)	Low BGW (n=29)	High BGW (n=30)
Glucose, mmol/L	−0.57 (−0.96 to −0.18)	−0.43 (−1.00 to 0.14)	−0.40 (−0.99 to 0.20)
HbA1c, %	−0.20 (−0.51 to 0.12)	−0.25 (−0.65 to 0.14)	−0.42 (−0.97 to 0.12)
GA, mmol/L	−0.95 (−1.42 to −0.48)^a	−1.20 (−1.80 to −0.60)^a	−2.65 (−3.65 to −1.66)^b
Insulin, mU/L	−1.27 (−2.95 to 0.41)	−0.98 (−3.26 to 1.29)	−1.53 (−3.96 to 0.89)
HOMA-IR, µU×mol/L^2	−0.15 (−0.28 to −0.02)	−0.02 (−0.21 to 0.18)	−0.12 (−0.29 to 0.05)
hs-CRP, mg/L	−0.41 (−1.33 to 0.52)	−0.40 (−1.22 to 0.43)	0.36 (−1.88 to 2.59)
TNF-α, pg/mL	0.41 (0.29 to 0.53)^a	−0.04 (−0.16 to 0.08)^b	0.04 (−0.05 to 0.13)^b
IL-6, pg/mL	0.21 (0.09 to 0.33)^a	0.11 (−0.06 to 0.28)^a,b	−0.03 (−0.18 to 0.12)^b

Notes: Glucose, HbA1c, GA, insulin, and hs-CRP are normally distributed variables. The variables of HOMA-IR, TNF-α, and IL-6 are transformed by the natural logarithm. No BGW, subjects do not eat BGW; Low BGW, intake of BGW is from 30 to 69 g/d; High BGW, intake of BGW is from 69 to 140 g/d; 69 g/d is the median of BGW intake in the BGW group. All data are mean (95% CI) adjusted for sex, age, BMI at baseline, and baseline values of the relevant outcome variables. Differences of change from baseline between groups are analyzed using the analysis of covariance (ANCOVAs, generalized linear model) test with post hoc analysis. Different superscript letters represent the statistical differences at P<0.05 among the groups.

Abbreviations: ANCOVA, analysis of covariance; BGW, black-grained wheat; GA, glycated albumin; HbA1c, glycated hemoglobin; HOMA-IR, homeostasis model assessment of insulin resistance; hs-CRP, hypersensitive C-reactive protein; IL-6, interleukin-6; TNF-α, tumor necrosis factor-α.