Effects of cooking using multi-ply cookware on absorption of potassium and vitamins: a randomized double-blind placebo control study

Figures & data

Figure 1.  Design of the study. An initial screening visit was conducted 2 weeks prior to enrolment and randomization for 3 groups. Blood samples were collected before and after the periods of vegetable intake. Photo: Photos of all diets taken for 3 days; ★: vegetable delivery.

Table I.  List of vegetables supplied during the study.

1–3 Days		4∼7 Days		8∼11 Days		12∼14 Days
Item	g	Item	g	Item	g	Item	g
Spinach	400	Pumpkin	200	Komatsuna	150	Okra	100
Cabbage	500	Kidney bean	50	Okra	100	Broccoli	100
Green asparagus	100	Carrot	200	Broccoli	100	Potatoes	150
Carrot	50	Green asparagus	200	Bean sprouts	450	Komatsuna	300
Garlic	10	Paprika	110	Leek	50	Lotus	50
		Grape tomato	90	Garlic	20	Jew's mallow	250
		Spinach	150	Cabbage	500	Yam	100
		Bean sprouts	100	Pepper	50
		Garlic	10
		Potatoes	200
		Onion	100

Notes: The weight including vegetable skin. Participants were given to eat 350 g of vegetables per day.

Figure 2.  Trial profile.

Table II.  Comparison between the baseline and the data after vegetable intake.

	Group A (n 19 = 8:11)		Group B (n 22 = 8:14)		Group C (n 16 = 4:12)
	Baseline	2 Weeks	Baseline	2 Weeks	Baseline	2 Weeks
Age	20.4 ± 2.4		20.2 ± 1.9		20.9 ± 2.9
Body fat (%)	21.9 ± 7.7	20.5 ± 7.7**	24.6 ± 7.1	22.9 ± 6.4**	25.4 ± 6.0	24.0 ± 5.4^**
BMI (kg/m^2)	20.7 ± 2.2	20.7 ± 2.3	21.1 ± 2.0	20.9 ± 2.0	20.5 ± 1.8	20.5 ± 1.9
Systolic BP (mm Hg)	112.6 ± 13.8	110.9 ± 13.0	112.2 ± 8.0	111.4 ± 6.9	108.6 ± 10.3	101.8 ± 26.7
Diastolic BP (mm Hg)	62.8 ± 6.7	60.9 ± 7.6	62.2 ± 6.6	61.5 ± 6.4	62.4 ± 7.1	60.9 ± 7.2
Heart rate (bpm)	69.9 ± 11.7	67.1 ± 10.1	70.5 ± 7.1	72.4 ± 8.7	68.9 ± 10.9	68.4 ± 10.0
ALT (GPT) (U/l)	15.4 ± 5.9	14.4 ± 6.7	16.7 ± 10.4	12.6 ± 5.7**	14.8 ± 4.2	13.8 ± 4.4
AST (GOT) (U/l)	20.3 ± 5.3	19.5 ± 4.7	22.2 ± 14.7	18.0 ± 5.0	19.6 ± 4.8	19.3 ± 3.4
HDL (mg/dl)	71.1 ± 16.0	67.3 ± 16.8*	67.0 ± 15.8	62.4 ± 13.7*	70.9 ± 16.5	68.8 ± 11.3
LDL (mg/dl)	99.5 ± 31.9	89.6 ± 23.6*	98.3 ± 29.8	87.8 ± 23.1**	93.3 ± 26.6	94.0 ± 23.7
β-Carotene (μg/dl)	59.8 ± 45.8	74.4 ± 40.2**	43.4 ± 48.9	60.3 ± 43.9**	50.6 ± 33.6	48.0 ± 31.0
γ-GTP (U/l)	14.8 ± 3.4	14.1 ± 3.2	12.9 ± 5.0	12.5 ± 5.0	17.0 ± 5.9	16.4 ± 6.5
Insulin (μIU/ml)	5.4 ± 3.1	6.5 ± 5.7	6.7 ± 2.8	8.9 ± 8.5	8.3 ± 5.4	6.9 ± 4.1
Glucose (mg/dl)	91.5 ± 6.5	89.8 ± 6.9	94.0 ± 5.6	92.2 ± 8.5	91.1 ± 5.6	86.8 ± 7.3
HOMA-R	1.2 ± 0.8	1.5 ± 1.3	1.6 ± 0.7	2.1 ± 2.3	1.9 ± 1.4	1.5 ± 0.8
Vitamin C (μg/ml)	9.2 ± 1.6	11.0 ± 1.7**	9.8 ± 2.4	10.7 ± 2.0*	10.2 ± 2.1	9.9 ± 2.2
Ox-LDL (U/l)	101.5 ± 31.9	84.1 ± 19.7**	96.1 ± 25.3	88.2 ± 27.5	104.3 ± 65.0	89.1 ± 33.5
Total-C (mg/dl)	187.2 ± 39.0	168.8 ± 27.6**	179.7 ± 33.5	163.2 ± 30.4**	182.9 ± 38.0	177.1 ± 28.2
Total Hcys (nmol/ml)	8.5 ± 1.8	8.7 ± 1.9	11.5 ± 8.0	12.9 ± 12.7	9.1 ± 2.6	8.4 ± 2.0
Triglyceride (mg/dl)	50.0 ± 20.3	55.4 ± 23.2	57.7 ± 34.8	62.9 ± 52.8	57.6 ± 22.8	52.5 ± 21.7
Uric acid (mg/dl)	4.9 ± 0.8	4.6 ± 0.8	5.2 ± 0.7	5.1 ± 1.0	5.1 ± 0.9	5.0 ± 1.3
Folic acid (ng/ml)	5.6 ± 1.6	6.1 ± 1.7	5.6 ± 1.8	6.4 ± 2.2	6.0 ± 2.1	6.4 ± 2.4
Hs-CRP (ng/ml)	250.6 ± 447.6	292.0 ± 392.9	433.0 ± 1044.1	271.0 ± 448.7	422.6 ± 769.2	1489.9 ± 4691.1

Notes: n = men: women. Values are means ± SD. HOMA-R: insulin resistance = insulin × glucose/405. Ox-LDL, oxidized LDL; Total-C, total cholesterol; Total Hcys, total homocysteine; Hs-CRP, high-sensitive C-reactive protein. Significantly different from the baseline (*P < 0.05, **P < 0.01, two-side paired t-test).

Table III.  Change from the baseline to the data after vegetable intake.

	Group A (n 19 = 8:11)	Group B (n 22 = 8:14)	Group C(n 16 = 4:12)
Body fat (%)	− 1.41 ± 1.81	− 1.67 ± 1.07	− 1.34 ± 1.71
BMI (kg/m^2)	− 0.06 ± 0.47	− 0.12 ± 0.31	− 0.08 ± 0.45
Systolic BP (mm Hg)	− 1.68 ± 7.75	− 0.82 ± 7.79	− 6.88 ± 25.84
Diastolic BP (mm Hg)	− 1.95 ± 7.43	− 0.68 ± 5.38	− 1.56 ± 6.11
Heart rate (bpm)	− 2.84 ± 10.19	1.86 ± 7.19	− 0.44 ± 8.97
ALT (U/l)	− 1.05 ± 5.18	− 4.05 ± 6.35	− 0.94 ± 4.77
AST (U/l)	− 0.84 ± 4.56	− 4.23 ± 12.63	− 0.25 ± 2.70
HDL-C (mg/dl)	− 3.84 ± 7.49	− 4.55 ± 10.03	− 2.13 ± 7.72
LDL-C (mg/dl)	− 9.89 ± 17.35	− 10.55 ± 14.99	0.69 ± 12.77
β-Carotene (μg/dl)	14.55 ± 21.82^†	16.90 ± 15.76^††	− 2.59 ± 17.21
γ-GTP (U/l)	− 0.79 ± 2.12	− 0.36 ± 1.33	− 0.63 ± 1.67
Insulin (μIU/ml)	1.16 ± 3.39	2.16 ± 7.54	− 1.43 ± 6.53
Glucose (mg/dl)	− 1.63 ± 6.09	− 1.77 ± 8.12	− 4.25 ± 8.79
HOMA-R	0.25 ± 0.78	0.56 ± 2.08	− 0.45 ± 1.63
Vitamin C (μg/ml)	1.81 ± 1.79^†	0.93 ± 2.00	− 0.32 ± 2.96
Ox-LDL (U/l)	− 17.42 ± 25.18	− 7.86 ± 29.82	− 15.19 ± 58.72
Total-C (mg/dl)	− 18.37 ± 23.96	− 16.55 ± 17.84	− 5.81 ± 19.15
Total Hcys (nmol/ml)	0.23 ± 0.95	1.49 ± 5.11	− 0.67 ± 1.31
Triglyceride (mg/dl)	5.37 ± 27.60	5.23 ± 48.78	− 5.13 ± 14.40
Uric acid (mg/dl)	− 0.26 ± 0.56	− 0.10 ± 0.55	− 0.09 ± 0.76
Folic acid (ng/ml)	0.50 ± 1.12	0.77 ± 1.76	0.34 ± 1.76
Hs-CRP (ng/ml)	41.42 ± 353.57	− 162.00 ± 1178.16	1067.21 ± 4824.67

Notes: n = men:women. Values are means ± SD. HOMA-R: insulin resistance = insulin × glucose/405. ox-LDL, oxidized LDL; Total-C, total cholesterol; Total Hcys, total homocysteine; Hs-CRP, high-sensitive C-reactive protein. Significantly different from Group C at week 2 (^†: P < 0.05, ^††: P < 0.01).

Table IV.  Comparison between the baseline and the 24 U data after vegetable intake.

	Group A (n 16 = 7:9)		Group B (n 15 = 4:11)		Group C (n 14 = 3:11)
Urine	Baseline	2 Weeks	Baseline	2 Weeks	Baseline	2 Weeks
8-OHdG (μg/day)	3.7 ± 2.1	3.8 ± 2.0	3.5 ± 1.4	3.9 ± 1.6	4.6 ± 1.4	3.9 ± 1.7
Na/K	3.7 ± 2.0	2.6 ± 0.9^*	3.8 ± 1.7	3.1 ± 1.6	3.2 ± 1.2	3.5 ± 2.0
NaCl (g/day)	7.8 ± 4.2	7.7 ± 4.0	8.2 ± 4.0	7.4 ± 3.2	7.2 ± 2.3	7.3 ± 2.7
K (g/day)	1.6 ± 0.9	2.0 ± 1.1^**	1.5 ± 0.5	1.6 ± 0.4	1.6 ± 0.6	1.6 ± 0.8

Notes: n = men:women. Values are means ± SD. 8-OhdG, 8-hydroxy-2′-deoxyguanosine. Significantly different from the baseline (*P < 0.05, **P < 0.01, two-side paired t-test). The analysis only as for the success in 24 U collection.