Table 1.
Summary of the basic characteristics of included studies broken down by supplement.
| Supplement (Total Number of Studies) |
Type of Studies | Data | Sample Size | Population | Dose Range | Treatment Length Range |
|---|---|---|---|---|---|---|
| Vitamin C (n = 5) |
P: 1 (20%) CO: 4 (80%) |
Sys: 5 (100%) Dia: 4 (80%) |
Sys: 122 Dia: 114 |
Healthy: 4 (80%) General: 1 (20%) |
200–1000 mg/day | 2–52 weeks |
| Vitamin D (n = 29) |
P: 29 (100%) CO: 0 (0%) |
Sys: 29 (100%) Dia: 28 (96.6%) |
Sys: 4897 Dia: 4578 |
Healthy: 9 (31.0%) General: 8 (27.6%) Obese: 8 (27.6%) Postmenopausal: 4 (13.8%) |
200–8000 IU/day | 2–208 weeks |
| Vitamin E (n = 7) |
P: 5 (71.4%) CO: 2 (28.6%) |
Sys: 7 (100%) Dia: 5 (71.4%) |
Sys: 302 Dia: 240 |
Healthy: 6 (85.7%) Postmenopausal: 1 (14.3%) |
50–320 mg/day | 3–26 weeks |
| Calcium (n = 21) |
P: 20 (95.2%) CO: 1 (4.8%) |
Sys: 21 (100%) Dia: 21 (100%) |
Sys: 4534 Dia: 4525 |
Healthy: 12 (57.1%) General: 3 (14.3%) Obese: 3 (14.3%) Postmenopausal: 3 (14.3%) |
162–2000 mg/day | 4–208 weeks |
| Magnesium (n = 18) |
P: 14 (77.8%) CO: 4 (22.2%) |
Sys: 18 (100%) Dia: 18 (100%) |
Sys: 1575 Dia: 1575 |
Healthy: 11 (61.1%) Obese: 4 (22.2%) General: 3 (16.7%) |
212–636 mg/day | 4–26 weeks |
| Potassium (n = 12) |
P: 7 (58.3%) CO: 5 (41.7%) |
Sys: 12 (100%) Dia: 12 (100%) |
Sys: 1096 Dia: 1096 |
Healthy: 7 (58.3%) General: 5 (41.7%) |
24–100 mmol/day (938.4–3910 mg/day) |
3–26 weeks |
| Total (n = 87) | P: 71 (81.6%) CO: 16 (18.4%) |
Sys: 87 (100%) Dia: 83 (95.4%) |
Sys: 12,526 Dia: 12,128 |
Healthy: 44 (50.6%) General: 20 (23.0%) Obese: 15 (17.2%) Postmenopausal: 8 (9.2%) |
The number of parallel versus cross-over studies, number of studies reporting systolic and diastolic data, and number of each type of population is given in n (%), representing the frequency of findings. The denominator for this frequency is noted in the first column. Dosage and treatment length are given as ranges. P represents parallel trials, CO represents cross-over trials, Sys represents systolic blood pressure data, and Dia represents diastolic blood pressure data.