Table 1.
Dietary isoflavone intake and urinary isoflavonoid excretion during the study†
| All (N=256) | BEAN1 (N=174) | BEAN2 (N=82) | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Baseline (all) |
Low soy (control) |
High soy (intervention) |
Baseline (all) |
Low soy (control) |
High soy (intervention) |
Baseline (all) |
Low soy | High soy | |
| Samples, N | 256 | 573 | 556 | 174 | 328 | 313 | 82 | 245 | 243 |
| Dietary isoflavone intake mg/day | 2.3 (0.3–7.4) | 0.2 (0.1–2.3) | 60.4 (49.8–74.6) | 2.7 (1.1–6.6) | 0.2 (0.1–4.3) | 56.9 (49.8–72.4) | 0.5 (0.1–31.3) | 0.2 (0.1–1.1) | 67.7 (48.5–85.3) |
| Urinary isoflavonoids nmol/mg creatinine | 0.4 (0.0–4.2) | 1.0 (0.0–4.4) | 32.4 (11.1–70.3) | 0.0 (0.0–4.1) | 0.9 (0.0–4.6) | 28.6 (8.4–63.6) | 0.9 (0.3–4.7) | 1.1 (0.3–4.2) | 44.2 (18.3–79.4) |
| Adherence to dietary intervention‡ | -- | 84% | 85% | -- | 83% | 87% | -- | 86% | 84% |
| Correlation coefficients between dietary isoflavone intake and urinary isoflavonoid excretion (p value) | |||||||||
| Low or high soy only | -- | 0.05 (p=0.20) | 0.06 (p=0.17) | -- | 0.07 (p=0.21) | 0.06 (p=0.30) | -- | 0.06 (p=0.35) | 0.01 (p=0.84) |
| Low and high soy | -- | 0.51 (p<0.0001) | -- | 0.49 (p<0.0001) | -- | 0.55 (p<0.0001) | |||
| Area under the receiver operating characteristic curve (p value)* | |||||||||
| Low or high soy only | -- | 0.565 (p=0.02) | 0.573 (p=0.03) | -- | 0.555 (p<0.001) | 0.537 (p=0.32) | -- | 0.618 (p=0.06) | 0.627 (p=0.01) |
| Low and high soy | -- | 0.850 (p<0.0001) | -- | 0.822 (p<0.0001) | -- | 0.899 (p<0.0001) | |||
†
Data are presented as median (lower - upper quartile) unless otherwise noted.
‡
Adherence to dietary intervention was defined using estimated dietary isoflavone intake (DII) from 24-hour dietary recalls as >40 mg/day during the high soy diet and <10 mg/day during the low soy diet.
*
P values and areas under the receiver operating characteristic curve were calculated in logistic regression models with log-transformed urinary isoflavonoid excretion as a continuous independent variable and dietary intervention (high-soy or low-soy diet) as a binary outcome variable.