Background Associations between soy, dairy intakes and breast cancer risk are inconsistent. No studies exist with large numbers of dairy consumers and soy consumers to assess mutual confounding. Methods The study cohort contains 52 795 North American women, initially free of cancer, followed for 7.9 years (29.7% were Black). Dietary intakes were estimated from food frequency questionnaires and, for 1011 calibration study subjects, from six structured 24-h dietary recalls. Incident invasive breast cancers were detected mainly by matching with cancer registries. Analyses used multivariable proportional hazards regression. Results The participants (mean age of 57.1 years) experienced 1057 new breast cancer cases during follow-up. No clear associations were found between soy products and breast cancer, independently of dairy. However, higher intakes of dairy calories and dairy milk were associated with hazard ratios (HRs) of 1.22 [95% confidence interval (CI): 1.05–1.40] and 1.50 (95% CI 1.22–1.84), respectively, comparing 90th to 10th percentiles of intakes. Full fat and reduced fat milks produced similar results. No important associations were noted with cheese and yogurt. Substituting median intakes of dairy milk users by those of soy milk consumers was associated with HR of 0.68 (95% CI: 0.55–0.85). Similar-sized associations were found among pre- and post-menopausal cases, with CIs also excluding the null in estrogen receptor (ER+, ER-), and progesterone receptor (PR+) cancers. Less biased calibrated measurement-error adjusted regressions demonstrated yet stronger, but less precise, HRs and CIs that still excluded the null. Conclusions Higher intakes of dairy milk were associated with greater risk of breast cancer, when adjusted for soy intake. Current guidelines for dairy milk consumption could be viewed with some caution.

Scope Phytosterols are bioactive compounds in plants with similar cholesterol-lowering properties as vegetarian diets. However, information on phytosterol intake and plasma plant sterols among vegetarians is sparse. Methods and results We examined dietary intake and plasma concentration of plant sterols and cholesterol across five dietary patterns in the Adventist Health Study-2 Calibration Sub-study (n=861, 66% females, average age 61 y). To measure intake and plasma concentration of these compounds, we used 24-hour dietary recalls and gas-liquid chromatography-flame ionization detection, respectively. Mean (SD) total phytosterol and cholesterol intake were 363 (176) mg/d and 131 (111) mg/d; plasma β-sitosterol, campesterol, and cholesterol were 3.3 (1.7) μg/mL, 4.2 (2.3) μg/mL, and 1.9 (0.4) mg/mL, respectively. Total phytosterol intake was lowest among non-vegetarians (263 mg/d) and highest among vegans (428 mg/d) (P < 0.0001). Cholesterol intake was lowest among vegans (15.2 mg/d) and highest among non-vegetarians (124.6 mg/d) (P < 0.0001). Plasma plant sterols and cholesterol did not differ by diet. Cholesterol-adjusted plasma β-sitosterol and campesterol were significantly higher in Blacks than Whites, though no ethnic differences were observed in dietary intake of these plant sterols. Conclusion Dietary intake but not plasma concentration of plant sterols and cholesterol varies across distinct plant-based diets.

Background Excess visceral adiposity is associated with increased risk of cardiometabolic disorders. Short‐term well‐controlled clinical trials suggest that regular avocado consumption favorably affects body weight, visceral adiposity, and satiety. Methods and Results The HAT Trial (Habitual Diet and Avocado Trial) was a multicenter, randomized, controlled parallel‐arm trial designed to test whether consuming 1 large avocado per day for 6 months in a diverse group of free‐living individuals (N=1008) with an elevated waist circumference compared with a habitual diet would decrease visceral adiposity as measured by magnetic resonance imaging. Secondary and additional end points related to risk factors associated with cardiometabolic disorders were assessed. The primary outcome, change in visceral adipose tissue volume during the intervention period, was not significantly different between the Avocado Supplemented and Habitual Diet Groups (estimated mean difference (0.017 L [−0.024 L, 0.058 L], P =0.405). No significant group differences were observed for the secondary outcomes of hepatic fat fraction, hsCRP (high‐sensitivity C‐reactive protein), and components of the metabolic syndrome. Of the additional outcome measures, modest but nominally significant reductions in total and low‐density lipoprotein cholesterol were observed in the Avocado Supplemented compared with the Habitual Diet Group. Changes in the other additional and post hoc measures (body weight, body mass index, insulin, very low‐density lipoprotein concentrations, and total cholesterol:high‐density lipoprotein cholesterol ratio) were similar between the 2 groups. Conclusions Addition of 1 avocado per day to the habitual diet for 6 months in free‐living individuals with elevated waist circumference did not reduce visceral adipose tissue volume and had minimal effect on risk factors associated with cardiometabolic disorders. Registration URL: https://clinicaltrials.gov ; Unique identifier: NCT03528031.

Traditional Asian fermented soy food products are associated with reduced cardiovascular disease risk in prospective studies, but few randomized controlled trials have been conducted in at-risk populations. The aim of this study was to investigate the effect of a commercial non-probiotic fermented soy product on blood lipids in adults with cardiovascular risk biomarkers. In a randomized, crossover, intervention study, 27 men and women (aged 29–75 y) exhibiting at least two risk factors, consumed two packets (12.5 g each) daily of a fermented powdered soy product, or an isoenergic control powder made from germinated brown rice for 12 weeks each. The consumption of the fermented soy product resulted in a significantly greater mean change from baseline (compared to the germinated rice, all p < 0.05) in total cholesterol of −0.23 mmol/L (CI: −0.40, −0.06) compared with 0.14 mmol/L (CI: −0.03, 0.31), respectively; and low density lipoprotein (LDL) cholesterol −0.18 mmol/L (CI: −0.32, −0.04) compared with 0.04 mmol/L (CI: −0.01, 0.018) respectively. This was accompanied by an increase in high density lipoprotein (HDL) cholesterol in the germinated rice group, a decrease in apolipoprotein B (ApoB) in the fermented soy group, and a between-treatment effect in apolipoprotein A1 (ApoA1); however, the ratio of the LDL:HDL and of Apo B:ApoA1 did not differ between the groups. The ratio of total cholesterol:LDL decreased in men in the fermented soy group (p < 0.001). Twenty-four-hour urine collection at the end of each treatment period resulted in an increased excretion expressed as a ratio in μmol/d between treatments of 10.93 (CI: 5.07, 23.54) for daidzein; 1.24 (CI: 1.14, 4.43) for genistein; and, 8.48 (CI: 4.28, 16.80) for glycitein, all p < 0.05. The fermented soy powder consumed by participants in this study without implementing other changes in their typical diets, decreased the total and LDL cholesterol, and may serve as a dietary strategy to manage blood lipids. The trial was registered at ClinicalTrials.gov as NCT03429920.

We evaluated the performance of a food frequency questionnaire (FFQ) in estimating phytosterol intake against multiple 24 hr dietary recalls (24HDRs) using data from 1,011 participants of the calibration sub-study of the Adventist Health Study-2 (AHS-2) cohort. Dietary assessments of phytosterol intake included a self-administered FFQ and six 24HDRs and plasma sterols. Plasma sterols were determined using the gas-liquid chromatography (GLC) flame ionization method. Validation of energy-adjusted phytosterol intake from the FFQ with 24HDR was conducted by calculating crude, unadjusted, partial, and de-attenuated correlation coefficients (r) and cross-classification by race. On average, total phytosterol intake from the FFQ was 439.6 mg/day in blacks and 417.9 mg/day in whites. From the 24HDRs, these were 295.6 mg/day in blacks, and 351.4 mg/day in whites. Intake estimates of β-sitosterol, stigmasterol, other plant sterols and total phytosterol from the FFQ had moderate to strong correlations with estimates from 24HDR (r=0.41 to 0.73). Correlations were slightly higher in whites (r=0.42 to 0.73) than in blacks (r=0.41 to 0.67). FFQ estimates were poorly correlated with plasma sterols as well as 24HDR versus plasma sterols. We conclude that the AHS-2 FFQ provided reasonable estimates of phytosterol intake and may be used in future studies relating phytosterol intake and disease outcomes.