TABLE 1.

Meta-analysis of the mean difference of blood pressure between beetroot-supplemented and control groups¹

	Number of studies	WMD (95% CI)	P value*	Q value	P value**	I2
Study duration, d
SBP
<14	26	−2.67 (−4.03, −1.31)	0.001	45.7	0.007	45.4
≥14	17	−5.11 (−6.63, −3.60)	0.001	9.30	0.90	0
DBP
<14	26	−0.91 (−1.65, −0.16)	0.017	18.8	0.81	0
≥14	17	−1.32 (−1.97, −0.68)	0.001	4.37	0.99	0
Dose of beetroot, mL/d
SBP
70 and 140	14	−2.37 (−4.52, −0.22)	0.03	18.0	0.15	28.0
250	18	−3.22 (−4.87, −1.58)	0.001	22.2	0.17	23.3
500	11	−4.78 (−5.81, −3.73)	0.001	8.93	0.53	0
DBP
70 and 140	14	−0.29 (−1.39, 0.79)	0.59	9.13	0.76	0
250	18	−1.48 (−2.69, −0.27)	0.016	5.54	0.99	0
500	11	−2.14 (−3.21, −1.09)	0.001	7.48	0.68	0
NO3 content of beetroot, mg/100 mL per day
SBP
<150	12	−4.63 (−5.74, −3.52)	0.001	11.6	0.38	5.70
151–249	14	−3.43 (−5.11, −1.76)	0.001	20.6	0.19	22.6
≥250	17	−2.37 (−4.52, −0.22)	0.030	18.0	0.15	28.0
DBP
<150	12	−2.11 (0.315, −1.07)	0.001	7.60	0.74	0
151–249	14	−1.50 (−2.74, −0.25)	0.018	5.53	0.99	0
≥250	17	−0.29 (−1.39, 0.79)	0.59	9.13	0.76	0
Types of placebo
SBP
NO3-depleted beetroot	27	−2.91 (−4.34, −2.54)	0.001	37.2	0.07	30.1
Others2	16	−4.57 (−5.55, −3.59)	0.001	14.5	0.48	0
DBP
NO3-depleted beetroot	27	−0.71 (−1.96, 0.14)	0.10	13.7	0.97	0
Others2	16	−2.10 (−3.08, −1.12)	0.001	9.79	0.83	0

¹To assess statistical heterogeneity, the I² statistic and Cochran’s Q statistic were used according to specific categories (low = 25%, moderate = 50%, and high = 75%) and significance level (P < 0.10), respectively. *, P for WMD; **, P for Q value. DBP, diastolic blood pressure; SBP, systolic blood pressure; WMD, weighted mean difference.

²Blackcurrant juice (n = 10), low-calorie juice (n = 5), and control diet for NO₃ (n = 1).