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Background: The associations between dietary saturated fats and the risk of coronary heart disease (CHD) remain controversial, but few studies have compared saturated with unsaturated fats ...

Background Current guidelines recommend diet and lifestyle modifications for primary prevention and treatment of hypertension, but do not encourage dietary pulses specifically for lowering blood pressure (BP). To quantify the effect of dietary pulse interventions on BP and provide evidence for their inclusion in dietary guidelines, a systematic review and meta-analysis of controlled feeding trials was conducted. Methods MEDLINE, EMBASE, Cochrane Library, and CINAHL were each searched from inception through 5 May 2013. Human trials ≥3 weeks that reported data for systolic, diastolic, and/or mean arterial BPs were included. Two reviewers independently extracted data and assessed methodological quality and risk of bias of included studies. Effect estimates were pooled using random effects models, and reported as mean differences (MD) with 95% confidence intervals (CIs). Heterogeneity was assessed (χ(2) test) and quantified (I(2)). Results Eight isocaloric trials (n = 554 participants with and without hypertension) were included in the analysis. Dietary pulses, exchanged isocalorically for other foods, significantly lowered systolic (MD = -2.25 mm Hg (95% CI, -4.22 to -0.28), P = 0.03) and mean arterial BP (MD = -0.75 mm Hg (95% CI, -1.44 to -0.06), P = 0.03), and diastolic BP non-significantly (MD = -0.71 mm Hg (95% CI, -1.74 to 0.31), P = 0.17). Heterogeneity was significant for all outcomes. Conclusions Dietary pulses significantly lowered BP in people with and without hypertension. Higher-quality large-scale trials are needed to support these findings. Clinical trial registration NCT01594567.

Background: Dietary n−3 PUFAs are inversely associated with risk of sudden cardiac death (SCD); however, little is known about other fats and SCD. Furthermore, concerns have been raised that high n−6 PUFA intake may attenuate the benefits of n−3 PUFAs. Objective: We examined associations and selected interactions between dietary fatty acids, expressed as a proportion of total fat and SCD. Design: We conducted a prospective cohort study among 91,981 women aged 34–59 y from the Nurses’ Health Study in 1980. Over 30 y, we documented 385 SCDs. Results: In multivariable models, women in the highest compared with the lowest quintile of SFA intake had an RR of SCD of 1.44 (95% CI: 1.04, 1.98). Conversely, women in the highest compared with the lowest quintile of PUFA intake had an RR of SCD of 0.57 (95% CI: 0.41, 0.78). Intakes of n−6 and n−3 PUFAs were both significantly associated with a lower risk of SCD, and n−6 PUFAs did not modify the association between n−3 PUFAs and SCD. MUFAs and trans fats were not associated with SCD risk. After further adjustment for coronary heart disease (CHD) and CHD risk factors potentially in the causal pathway, the association between PUFAs and SCD remained significant, whereas the association for SFAs was no longer significant. Conclusions: Intake of PUFAs as a proportion of fat was inversely associated with SCD risk, independent of traditional CHD risk factors. These results support dietary guidelines to improve dietary fat quality by replacing intake of SFAs with n−6 and n−3 PUFAs.

Certain algae contain the (n-3) fatty acid DHA, yet the relation between algal oil supplementation and cardiovascular disease risk factors has not been systematically examined. Our objective was to examine the relation between algal oil supplementation and cardiovascular disease risk factors. We conducted a systematic review of randomized controlled trials published between 1996 and 2011 examining the relation between algal oil supplementation and cardiovascular disease risk factors and performed a meta-analysis of the association between algal oil DHA supplementation and changes in the concentrations of TG, LDL-cholesterol (LDL-C), and HDL-cholesterol (HDL-C). We identified 11 randomized controlled trials with 485 healthy participants that evaluated the relation between algal oil DHA supplementation and TG, LDL-C, and HDL-C. The median dose of algal DHA was 1.68 g/d. The pooled estimate for the change in TG concentration was -0.20 mmol/L (95% CI: -0.27 to -0.14), 0.23 mmol/L (95% CI: 0.16-0.30) for LDL-C, and 0.07 mmol/L (95% CI: 0.05-0.10) for HDL-C. DHA supplementation from algal oil, a marine source of (n-3) fatty acids not extracted from fish, may reduce serum TG and increase HDL-C and LDL-C in persons without coronary heart disease.

Background: Few studies have examined temporal trends in sodium intake in the US population. Collections of 24-h urine sodium excretions are reliable markers for dietary sodium intake. Objective: We examined temporal trends in 24-h urine sodium excretions to estimate temporal trends in sodium intake in the US population. Design: We performed a systematic search of English-language articles in MEDLINE for studies that reported collections of 24-h urine sodium excretions in the United States. We estimated mean urine sodium excretions over time for all studies and demographic subgroups. Results: We analyzed 38 studies, which dated from 1957 to 2003, and estimated a mean (±SE) 24-h urine sodium excretion per person of 3526 ± 75 mg Na. In a multivariate random-effects model with study year, sex, age, and race, the study year was not associated with any significant change in sodium excretions (coefficient = 154 mg Na · 24 h−1 · 10 y−1; 95% CI: −140, 448 mg Na · 24 h−1 · 10 y−1). In subgroup analyses, there was no significant temporal trend seen in male, female, black, or white study participants. Conclusion: Sodium intake in the US adult population appears to be well above current guidelines and does not appear to have decreased with time.

Background— With the exception of fish, few major dietary protein sources have been studied in relation to the development of coronary heart disease (CHD). Our objective was to examine the relation between foods that are major dietary protein sources and incident CHD. Methods and Results— We prospectively followed 84 136 women aged 30 to 55 years in the Nurses’ Health Study with no known cancer, diabetes mellitus, angina, myocardial infarction, stroke, or other cardiovascular disease. Diet was assessed by a standardized and validated questionnaire and updated every 4 years. During 26 years of follow-up, we documented 2210 incident nonfatal infarctions and 952 deaths from CHD. In multivariable analyses including age, smoking, and other risk factors, higher intakes of red meat, red meat excluding processed meat, and high-fat dairy were significantly associated with elevated risk of CHD. Higher intakes of poultry, fish, and nuts were significantly associated with lower risk. In a model controlling statistically for energy intake, 1 serving per day of nuts was associated with a 30% (95% confidence interval, 17% to 42%) lower risk of CHD compared with 1 serving per day of red meat. Similarly, compared with 1 serving per day of red meat, a lower risk was associated with 1 serving per day of low-fat dairy (13%; 95% confidence interval, 6% to 19%), poultry (19%; 95% confidence interval, 3% to 33%), and fish (24%; 95% confidence interval, 6% to 39%). Conclusions— These data suggest that high red meat intake increases risk of CHD and that CHD risk may be reduced importantly by shifting sources of protein in the US diet.

In individuals with chronic kidney disease, high-protein diets have been shown to accelerate renal deterioration, whereas low-protein diets increase the risk of protein malnutrition. Vegetarian diets have been promoted as a way to halt progression of kidney disease while maintaining adequate nutrition. We review the literature to date comparing the effects of animal and vegetable protein on kidney function in health and disease. Diets with conventional amounts of protein, as well as high-protein diets, are reviewed. The literature shows that in short-term clinical trials, animal protein causes dynamic effects on renal function, whereas egg white, dairy, and soy do not. These differences are seen both in diets with conventional amounts of protein and those with high amounts of protein. The long-term effects of animal protein on normal kidney function are not known. Although data on persons with chronic kidney disease are limited, it appears that high intake of animal and vegetable proteins accelerates the underlying disease process not only in physiologic studies but also in short-term interventional trials. The long-term effects of high protein intake on chronic kidney disease are still poorly understood. Several mechanisms have been suggested to explain the different effects of animal and vegetable proteins on normal kidney function, including differences in postprandial circulating hormones, sites of protein metabolism, and interaction with accompanying micronutrients.

Although the association between red meat consumption and colorectal cancer (CRC) is well established, the association across subsites of the colon and rectum remains uncertain, as does time of consumption in relation to cancer development. As these relationships are key for understanding the pathogenesis of CRC, they were examined in two large cohorts with repeated dietary measures over time, the Nurses’ Health Study (n = 87,108 women, 1980–2010) and Health Professionals Follow-up Study (n = 47,389 men, 1986–2010). Cox proportional hazards regression models generated hazard ratios (HRs) and 95% confidence intervals (CIs), which were pooled by random-effects meta-analysis. In combined cohorts, there were 2,731 CRC cases (1,151 proximal colon, 816 distal colon, and 589 rectum). In pooled analyses, processed red meat was positively associated with CRC risk (per 1 serving/day increase: HR = 1.15, 95% CI: 1.01–1.32; P for trend 0.03) and particularly with distal colon cancer (per 1 serving/day increase; HR = 1.36; 95% CI: 1.09–1.69; P for trend 0.006). Recent consumption of processed meat (within the past 4 years) was not associated with distal cancer. Unprocessed red meat was inversely associated with risk of distal colon cancer and a weak non-significant positive association between unprocessed red meat and proximal cancer was observed (per 1 serving/day increase: distal HR = 0.75; 95% CI: 0.68–0.82; P for trend

Background: Evidence from controlled trials encourages the intake of dietary pulses (beans, chickpeas, lentils and peas) as a method of improving dyslipidemia, but heart health guidelines have stopped short of ascribing specific benefits to this type of intervention or have graded the beneficial evidence as low. We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) to assess the effect of dietary pulse intake on established therapeutic lipid targets for cardiovascular risk reduction. Methods: We searched electronic databases and bibliographies of selected trials for relevant articles published through Feb. 5, 2014. We included RCTs of at least 3 weeks’ duration that compared a diet emphasizing dietary pulse intake with an isocaloric diet that did not include dietary pulses. The lipid targets investigated were low-density lipoprotein (LDL) cholesterol, apolipoprotein B and non–high-density lipoprotein (non-HDL) cholesterol. We pooled data using a random-effects model. Results: We identified 26 RCTs ( n = 1037) that satisfied the inclusion criteria. Diets emphasizing dietary pulse intake at a median dose of 130 g/d (about 1 serving daily) significantly lowered LDL cholesterol levels compared with the control diets (mean difference −0.17 mmol/L, 95% confidence interval −0.25 to −0.09 mmol/L). Treatment effects on apolipoprotein B and non-HDL cholesterol were not observed. Interpretation: Our findings suggest that dietary pulse intake significantly reduces LDL cholesterol levels. Trials of longer duration and higher quality are needed to verify these results. Trial registration: ClinicalTrials.gov, no. NCT01594567.

Background Purified palmitoleic acid (16-1; omega-7) has shown lipid-lowering and anti-inflammatory benefits in open label, epidemiologic, and animal studies. Objective Our objective was to perform the first randomized controlled trial of purified palmitoleic acid supplementation in humans. Methods Adults with dyslipidemia and evidence of mild systemic inflammation (high-sensitivity C-reactive protein [hs-CRP] between 2 and 5 mg/L) were randomly allocated to receive either 220.5 mg of cis -palmitoleic acid (n = 30) or an identical capsule with placebo (1000 mg of medium chain triglycerides, n = 30) once per day for 30 days. Participants were asked to maintain their current diet. Serum lipids and hs-CRP were drawn at baseline and study completion. Results At 30 days, there were significant mean (95% confidence interval [CI]) reductions in CRP (−1.9 [−2.3 to −1.4] mg/L), triglyceride (−30.2 [−40.2 to −25.3] mg/dL), and low-density lipoprotein (LDL) (−8.9 [−12.0 to −5.8] mg/dL), and a significant increase in high-density lipoprotein (HDL) (2.4 [1.5, 3.3] mg/dL) in the intervention group compared with control. These changes equated to 44%, 15%, and 8% reductions in CRP, triglyceride, and LDL respectively, and a 5% increase in HDL compared with control. Conclusions Purified palmitoleic acid may be useful in the treatment of hypertriglyceridemia with the beneficial added effects of decreasing LDL and hs-CRP and raising HDL. Further study is needed to elucidate mechanisms and establish appropriate human doses.

Adolescent diet may be etiologically relevant for colorectal carcinogenesis. We examined the association between meat and fish intakes during adolescence and the risk of colorectal adenomas later in life among 19,771 women participating in the Nurses' Health Study II. Subjects had completed a validated food frequency questionnaire in 1998 (when aged 34–51 years) about their diets during high school and subsequently underwent at least 1 lower-bowel endoscopy during the study period (1998–2007). During this period, 1,494 subjects were diagnosed with colorectal adenomas. Intake of red meat during adolescence was not associated with colorectal adenoma risk when comparing those in the highest versus lowest category of intake (odds ratio (OR) = 1.04, 95% confidence interval (CI): 0.81, 1.35). Similarly, intake of fish during adolescence was not associated with colorectal adenoma risk (OR = 0.96, 95% CI: 0.78, 1.17). Intake of poultry during adolescence was associated with a lower risk of total colorectal (OR = 0.80, 95% CI: 0.64, 0.99), distal (OR = 0.71, 95% CI: 0.51, 0.99), rectal (OR = 0.51, 95% CI: 0.29, 0.90), and advanced (OR = 0.60, 95% CI: 0.38, 0.93) adenomas. Replacement of 1 serving per day of red meat with 1 serving per day of poultry or fish was associated with 41% and 35% decreased risks for rectal adenomas and advanced adenomas, respectively. Our findings do not suggest an association between red meat intake during adolescence and colorectal adenomas later in life, but higher poultry intake during this time was associated with a lower risk of colorectal adenomas.

Background and Purpose— Few dietary protein sources have been studied prospectively in relation to stroke. We examined the relation between foods that are major protein sources and risk of stroke. Methods— We prospectively followed 84 010 women aged 30 to 55 years at baseline and 43 150 men aged 40 to 75 years at baseline without diagnosed cancer, diabetes, or cardiovascular disease. Diet was assessed repeatedly by a standardized and validated questionnaire. We examined the association between protein sources and incidence of stroke using a proportional hazard model adjusted for stroke risk factors. Results— During 26 and 22 years of follow-up in women and men, respectively, we documented 2633 and 1397 strokes, respectively. In multivariable analyses, higher intake of red meat was associated with an elevated risk of stroke, whereas a higher intake of poultry was associated with a lower risk. In models estimating the effects of exchanging different protein sources, compared with 1 serving/day of red meat, 1 serving/day of poultry was associated with a 27% (95% CI, 12%–39%) lower risk of stroke, nuts with a 17% (95% CI. 4%–27%) lower risk, fish with a 17% (95% CI, 0%–30%) lower risk, low-fat dairy with an 11% (95% CI, 5%–17%) lower risk, and whole-fat dairy with a 10% (95% CI, 4%–16%) lower risk. We did not see significant associations with exchanging legumes or eggs for red meat. Conclusions— These data suggest that stroke risk may be reduced by replacing red meat with other dietary sources of protein.

The appropriate manner of incorporating incident angina, coronary artery bypass surgery (CABG), percutaneous coronary intervention (PCI), diabetes, hypertension, and hypercholesterolemia, which may be both intermediate events and time-dependent confounders, into analyses of diet and coronary heart disease (CHD) is not clear. Using data from 72,266 women in the Nurses’ Health Study between 1984 and 2006, the authors examined the relation between report of intermediate events and change in cereal fiber intake and used different proportional hazards models to evaluate the association between cereal fiber and CHD. Cereal fiber intake increased significantly among participants who reported hypercholesterolemia (0.42 g/day; 95% CI: 0.34, 0.51 g/day) and diabetes (0.07 g/day with each additional 2-year increment; 95% CI: 0.01, 0.13 g/day). However, angina, CABG/PCI, and hypertension were not associated with a change in cereal fiber intake and thus were not important time-dependent confounders. Cereal fiber intake was inversely associated with risk of CHD in all proportional hazards models, but results varied modestly depending on the approach used to incorporate multiple measures of diet. Because stopping the updating of dietary variables when an intermediate event is diagnosed may lead to misclassification, future analyses should consider updating diet even after these diagnoses to best represent long-term intake. To best evaluate associations with incidence of disease, considerations should include the temporal trends in diet, changes in intake following intermediate events, and latency patterns. Sensitivity analyses can also be useful.

Red meat consumption has been consistently associated with an increased risk of type 2 diabetes mellitus (T2DM). However, whether changes in red meat intake are related to subsequent T2DM risk remains unknown.To evaluate the association between changes in red meat consumption during a 4-year period and subsequent 4-year risk of T2DM in US adults.Three prospective cohort studies in US men and women.We followed up 26,357 men in the Health Professionals Follow-up Study (1986-2006), 48,709 women in the Nurses' Health Study (1986-2006), and 74,077 women in the Nurses' Health Study II (1991-2007). Diet was assessed by validated food frequency questionnaires and updated every 4 years. Time-dependent Cox proportional hazards regression models were used to calculate hazard ratios with adjustment for age, family history, race, marital status, initial red meat consumption, smoking status, and initial and changes in other lifestyle factors (physical activity, alcohol intake, total energy intake, and diet quality). Results across cohorts were pooled by an inverse variance-weighted, fixed-effect meta-analysis.Incident T2DM cases validated by supplementary questionnaires.During 1,965,824 person-years of follow-up, we documented 7540 incident T2DM cases. In the multivariate-adjusted models, increasing red meat intake during a 4-year interval was associated with an elevated risk of T2DM during the subsequent 4 years in each cohort (all P .001 for trend). Compared with the reference group of no change in red meat intake, increasing red meat intake of more than 0.50 servings per day was associated with a 48% (pooled hazard ratio, 1.48; 95% CI, 1.37-1.59) elevated risk in the subsequent 4-year period, and the association was modestly attenuated after further adjustment for initial body mass index and concurrent weight gain (1.30; 95% CI, 1.21-1.41). Reducing red meat consumption by more than 0.50 servings per day from baseline to the first 4 years of follow-up was associated with a 14% (pooled hazard ratio, 0.86; 95% CI, 0.80-0.93) lower risk during the subsequent entire follow-up through 2006 or 2007.Increasing red meat consumption over time is associated with an elevated subsequent risk of T2DM, and the association is partly mediated by body weight. Our results add further evidence that limiting red meat consumption over time confers benefits for T2DM prevention.

Red meat consumption has been associated with an increased risk of chronic diseases. However, its relationship with mortality remains uncertain.We prospectively observed 37 698 men from the Health Professionals Follow-up Study (1986-2008) and 83 644 women from the Nurses' Health Study (1980-2008) who were free of cardiovascular disease (CVD) and cancer at baseline. Diet was assessed by validated food frequency questionnaires and updated every 4 years.We documented 23 926 deaths (including 5910 CVD and 9464 cancer deaths) during 2.96 million person-years of follow-up. After multivariate adjustment for major lifestyle and dietary risk factors, the pooled hazard ratio (HR) (95% CI) of total mortality for a 1-serving-per-day increase was 1.13 (1.07-1.20) for unprocessed red meat and 1.20 (1.15-1.24) for processed red meat. The corresponding HRs (95% CIs) were 1.18 (1.13-1.23) and 1.21 (1.13-1.31) for CVD mortality and 1.10 (1.06-1.14) and 1.16 (1.09-1.23) for cancer mortality. We estimated that substitutions of 1 serving per day of other foods (including fish, poultry, nuts, legumes, low-fat dairy, and whole grains) for 1 serving per day of red meat were associated with a 7% to 19% lower mortality risk. We also estimated that 9.3% of deaths in men and 7.6% in women in these cohorts could be prevented at the end of follow-up if all the individuals consumed fewer than 0.5 servings per day (approximately 42 g/d) of red meat.Red meat consumption is associated with an increased risk of total, CVD, and cancer mortality. Substitution of other healthy protein sources for red meat is associated with a lower mortality risk.