Table 1.
Possible effects of dietary factors on BC risk.
| Study | Results | Reference | |
|---|---|---|---|
| Fruits, vegetables | Meta-analysis (15 prospective studies) | RR = 0.89 (95% CI, 0.80–0.99, p = 0.67) fruits + vegetables; highest vs. lowest intake RR = 0.92 (95% CI, 0.86–0.98, p = 0.36) fruits; highest vs. lowest intake RR = 0.99 (95% CI, 0.92–1.06, p = 0.26) vegetables; highest vs. lowest intake |
[25] |
| Prospective study (75,929 women, 38–63 years, 24 years follow-up) | RR = 0.82 (95% CI, 0.71–0.96, p = 0.01), 2 servings/week of total berries RR = 0.69 (95% CI, 0.50–0.95, p = 0.02), 1 serving/week of blueberries RR = 0.59 (95% CI, 0.37–0.93, p = 0.02), 2 servings/week of peaches/nectarines |
[26] | |
| Prospective study (31,000 women, 36–64 years, 11.25 years follow-up) | HR = 0.70 (95% CI, 0.57–0.86, p = 0.0001) leafy vegetables, highest vs. lowest quintile HR = 0.75 (95% CI, 0.60–0.94, p = 0.01) fruiting vegetables, highest vs lowest quintile no association with fruit |
[27] | |
| Red meat | Meta-analysis (13 cohort, 3 case-control, 2 clinical trials) | RR = 1.06 (95%CI, 0.99–1.14) unprocessed red meat, highest vs. lowest intake RR = 1.09 (95%CI, 1.03–1.16) processed red meat, highest vs. lowest intake |
[28] |
| Cohort study (262,195 women, 7 years follow-up) Meta-analysis |
HR = 1.21 (95% CI, 1.08–1.35, p = 0.001), >9 g/day processed red meat RR = 1.09 (95% CI 1.03–1.15, p = 0.662), >9 g/day processed red meat in post-menopausal women RR = 0.99 (95% CI 0.88–1.10, p = 0.570), >9 g/day processed red meat in pre-menopausal women |
[29] | |
| Dietary Fat | Randomized controlled trial (48,835 post-menopausal women, 8.1 years follow-up) | HR = 0.91 (95% CI, 0.83–1.01, NS) intervention group vs. control group | [30] |
| Meta-analysis (cohort + case-control studies) | RR = 1.091 (95% CI, 1.001–1.184) cohort PUFA RR = 1.042 (95%CI, 1.013–1.073) case-control total fat RR = 1.22 (95% CI, 1.08–1.38) case-control PUFA |
[31] | |
| Systematic review (18 studies) | 45–78% increased risk of death with increased intake of trans fats | [32] | |
| EPIC study (337,327 women, 11.5 years follow-up) | HR = 1.20 (95% CI, 1.0–1.45, p = 0.05), highest vs. lowest quintile of total fat intake (ER+PR+ BC) HR = 1.2 (95% CI, 1.09–1.52, p = 0.009), highest vs. lowest quintile of saturated fat intake (ER+PR+ BC) HR = 1.29 (95% CI, 1.01–1.64, p = 0.04), highest vs. lowest quintile of saturated fat intake (HER2− BC) |
[33] | |
| Meta-analysis (6 cohort studies + 3 case-control studies) | RR = 1.29 (95% CI, 1.06–1.56), highest vs. lowest cholesterol intake | [34] | |
| Dairy products | Pooled analysis (8 prospective cohort studies) (351,041 women, 15 years follow-up) | NS | [35] |
| Meta-analysis (18 prospective cohort studies, n = 1,063,471) | RR = 0.91 (95% CI, 0.80–1.02, p = 0.003), milk consumption RR = 0.85 (95% CI, 0.76–0.95, p = 0.01), highest vs. lowest total dairy food |
[36] | |
| Meta-analysis (22 cohort + 5 case-control studies) | RR = 0.90 (95% CI, 0.83–0.98, p = 0.111), highest vs. lowest dairy products RR = 0.91 (95% CI, 0.83–0.99, p = 0.991), yogurt consumption RR = 0.85 (95% CI, 0.75–0.96, p = 0.121), low-fat dairy consumption |
[37] | |
| Carbohydrate, Glycaemic Index | Meta-analysis (19 prospective studies) | RR = 1.04 (95% CI, 1.00–1.07, p = 0.19), 10 units/d for glycemic index RR = 1.01 (95% CI, 0.98–1.04, p = 0.07), 50 units/d for glycemic load RR = 1.00 (95% CI, 0.96–1.05, p = 0.01), 50 g/d for carbohydrate intake |
[38] |
| Soy products, isoflavones | Meta-analysis (14 case-control + 7 cohort studies) | RR = 0.75 (95% CI, 0.59–0.95, p = 0.023), soyfood intake RR = 0.81 (95% CI, 0.67–0.99), isoflavone intake |
[39] |
| Meta-analysis (1 cohort + 7 case-control studies) | OR = 0.71 (95% CI, 0.60–0.85, p = 0.023), highest vs. lowest soy intake in Asians OR = 0.88 (95% CI, 0.78–0.98, p = 0.60), moderate vs. lowest soy intake in Asians OR = 1.04 (95% CI, 0.97–1.11, p = 0.42), highest vs. lowest soy isoflavone intake in Western populations |
[40] | |
| Meta-analysis (18 prospective studies) | RR = 0.89 (95% CI, 0.79–0.99, p = 0.001), highest vs. lowest isoflavone intake (RR = 0.76, 95% CI: 0.65–0.86, p = 0.136 in Asian population; RR = 0.97, 95% CI: 0.87–1.06, p = 0.083 in Western population) | [41] |
RR: multivariable-adjusted relative risk; HR: adjusted hazard ratio; OR: odds ratio; CI: confidence intervals; NS: not significant; PUFA: poly unsaturated fatty acids; ER: estrogen receptor; PR: progesterone receptor; HER2: human growth factor-neu receptor; BC: breast cancer; EPIC: European Prospective Investigation into Cancer and Nutrition.