Influence of saturated fat and linolenic acid on the association between intake of dairy products and blood pressure

The Effect of Rice Bran Extract on Arterial Blood Pressure, Hepatic Steatosis, and Inflammation in Mice Fed with a High-Fat Diet

Background

Inflammation and hypertension are primary mechanisms involving in obesity-associated adverse effects of a high-fat diet. The aim of this study was to evaluate the effects of rice bran extract (RBE) on arterial blood pressure, hepatic steatosis, inflammation, and oxidative stress in high-fat diet (HFD)-induced obese mice.

Methods

Male ICR mice were divided into four groups, including a normal-diet control group, a high-fat diet (HFD) (60% kcal from fat) group, an HFD group treated with RBE (220 mg/kg/day), and an HFD group treated with 1100 mg/kg/day for eight weeks. Besides body weight and arterial blood pressure, we determined liver values of total cholesterol, triglyceride, as well as percent body fat, tumor necrosis factor-α (TNF-α), malondialdehyde (MDA), nuclear factor kappa-B (NF-κB), matrix metalloprotease-9 (MMP-9), cyclooxygenase-2 (COX-2), and mRNA endothelial nitric oxide synthase (eNOS).

Results

The HFD group had increased body weight, increased systolic and diastolic blood pressure, liver total cholesterol, triglyceride, NF-κB, COX-2 and MMP-9 protein levels, and decreased mRNA eNOS in the aorta. Mice of the HFD group receiving RBE had reduced diastolic blood pressure, as well as significantly decreased liver and serum TNF-α and MDA levels in the liver, and reduced NF-κB levels in both the liver and heart.

Conclusions

These results demonstrate that RBE decreases diastolic blood pressure, the liver lipid droplet accumulation, liver and myocardial NF-κB, myocardial COX-2 and MMP-9 protein levels, and oxidative stress. Moreover, RBE may improve endothelial function and may alleviate adverse health effects associated with obesity including obesity-associated hypertension.

Long-term yogurt consumption and risk of incident hypertension in adults

OBJECTIVE

To evaluate the relation between yogurt consumption as well as cheese, milk, and total dairy, and high blood pressure (HBP) in two Nurses' Health Study cohorts (NHS, n = 69 298), NHS II (n = 84 368) and the Health Professionals Follow-Up Study (HPFS, n = 30 512).

METHODS

NHS, NHS II, and HPFS participants were followed for incident HBP for up to 30, 20, and 24 years, respectively. Hazard ratios were calculated using time-dependent multivariate-adjusted Cox proportional hazards models. Pooled risk estimates were derived from fixed effects meta-analyses.

RESULTS

Participants consuming at least five servings per week (vs. <1 serving per month) of yogurt in NHS, NHS II, and HPFS had 19% (95% CI 0.75-0.87), 17% (95% CI 0.77-0.90), and 6% (95% CI 0.83-1.07) lower HBP risks, respectively. In pooled analyses of these cohorts, higher yogurt consumption was linked with 16% (95% CI 0.80-0.88) lower HBP risk; higher total dairy (3 to <6 vs. <0.5 servings/day), milk (2 to <6/day vs. <4/week) and cheese (1 to 4/day vs. <1/week) were associated with 16% (95% CI 0.81-0.87), 12% (95% CI 0.86-0.90), and 6% (95% CI 0.90-0.97) lower HBP risks, respectively. After controlling for BMI as a possible causal intermediate, total dairy, yogurt, milk, and cheese were associated with 13, 10, 8, and 8% lower HBP risks, respectively. The combination of higher yogurt intake and higher DASH ('Dietary Approaches to Stop Hypertension') diet scores was associated with 30% (95% CI 0.66-0.75) lower HBP risk compared with lower levels of both factors.

CONCLUSION

Higher total dairy intake, especially in the form of yogurt, was associated with lower risk of incident HBP in middle-aged and older adult men and women.

Dairy consumption, systolic blood pressure, and risk of hypertension: Mendelian randomization study

Objective To examine whether previous observed inverse associations of dairy intake with systolic blood pressure and risk of hypertension were causal.Design Mendelian randomization study using the single nucleotide polymorphism rs4988235 related to lactase persistence as an instrumental variable.Setting CHARGE (Cohorts for Heart and Aging Research in Genomic Epidemiology) Consortium.Participants Data from 22 studies with 171 213 participants, and an additional 10 published prospective studies with 26 119 participants included in the observational analysis.Main outcome measures The instrumental variable estimation was conducted using the ratio of coefficients approach. Using meta-analysis, an additional eight published randomized clinical trials on the association of dairy consumption with systolic blood pressure were summarized.Results Compared with the CC genotype (CC is associated with complete lactase deficiency), the CT/TT genotype (TT is associated with lactose persistence, and CT is associated with certain lactase deficiency) of LCT-13910 (lactase persistence gene) rs4988235 was associated with higher dairy consumption (0.23 (about 55 g/day), 95% confidence interval 0.17 to 0.29) serving/day; P<0.001) and was not associated with systolic blood pressure (0.31, 95% confidence interval -0.05 to 0.68 mm Hg; P=0.09) or risk of hypertension (odds ratio 1.01, 95% confidence interval 0.97 to 1.05; P=0.27). Using LCT-13910 rs4988235 as the instrumental variable, genetically determined dairy consumption was not associated with systolic blood pressure (β=1.35, 95% confidence interval -0.28 to 2.97 mm Hg for each serving/day) or risk of hypertension (odds ratio 1.04, 0.88 to 1.24). Moreover, meta-analysis of the published clinical trials showed that higher dairy intake has no significant effect on change in systolic blood pressure for interventions over one month to 12 months (intervention compared with control groups: β=-0.21, 95% confidence interval -0.98 to 0.57 mm Hg). In observational analysis, each serving/day increase in dairy consumption was associated with -0.11 (95% confidence interval -0.20 to -0.02 mm Hg; P=0.02) lower systolic blood pressure but not risk of hypertension (odds ratio 0.98, 0.97 to 1.00; P=0.11).Conclusion The weak inverse association between dairy intake and systolic blood pressure in observational studies was not supported by a comprehensive instrumental variable analysis and systematic review of existing clinical trials.

The Comparison of Dietary Behaviors among Rural Controlled and Uncontrolled Hypertensive Patients

Nutrition is a dominant peripheral factor in increasing blood pressure; however, little information is available about the nutritional status of hypertensive patients in Iran. This study aimed to compare nutritional behaviors of the rural controlled and uncontrolled hypertensive patients and to determine the predictive power of nutritional behaviors from blood pressure. This cross-sectional study was conducted on 671 rural hypertensive patients, using multistage random sampling method in Ardabil city in 2013. Data were collected by a 3-day food record questionnaire. Nutritional data were extracted by Nutritionist 4 software and analyzed by the SPSS 18 software using Pearson correlation, multiple linear regression, ANOVA, and independent t-test. A significant difference was observed in the means of fat intake, cholesterol, saturated fat, sodium, energy, calcium, vitamin C, fiber, and nutritional knowledge between controlled and uncontrolled groups. In the controlled group, sodium, saturated fats, vitamin C, calcium, and energy intake explained 30.6% of the variations in blood pressure and, in the uncontrolled group, sodium, carbohydrate, fiber intake, and nutritional knowledge explained 83% of the variations in blood pressure. There was a significant difference in the nutritional behavior between the two groups and changes in blood pressure could be explained significantly by nutritional behaviors.

Acute dairy milk ingestion does not improve nitric oxide-dependent vasodilation in the cutaneous microcirculation

In epidemiological studies, chronic dairy milk consumption is associated with improved vascular health and reduced age-related increases in blood pressure. Although milk protein supplementation augments conduit artery flow-mediated dilation, whether or not acute dairy milk intake may improve microvascular function remains unclear. We hypothesised that dairy milk would increase direct measurement of endothelial nitric oxide (NO)-dependent cutaneous vasodilation in response to local skin heating. Eleven men and women (61 (sem 2) years) ingested two or four servings (473 and 946 ml) of 1 % dairy milk or a rice beverage on each of 4 separate study days. In a subset of five subjects, an additional protocol was completed after 473 ml of water ingestion. Once a stable blood flow occurred, 15 mm-N G -nitro-l-arginine methyl ester was perfused (intradermal microdialysis) to quantify NO-dependent vasodilation. Red-blood-cell flux (RBF) was measured by laser-Doppler flowmetry, and cutaneous vascular conductance (CVC=RBF/mean arterial pressure) was calculated and normalised to maximum (%CVCmax; 28 mm-sodium nitroprusside). Full expression of cutaneous vasodilation was not different among dairy milk, rice beverage and water, and there was no effect of serving size on the total vasodilatory response. Contrary to our hypothesis, NO-dependent vasodilation was lower for dairy milk than rice beverage (D: 49 (sem 5), R: 55 (sem 5) %CVCmax; P<0·01). Acute dairy milk ingestion does not augment NO-dependent vasodilation in the cutaneous microcirculation compared with a rice beverage control.

A blend of sesame oil and rice bran oil lowers blood pressure and improves the lipid profile in mild-to-moderate hypertensive patients

BACKGROUND

Sesame oil and rice bran oil are known for their unsaturated fatty acids and antioxidants contents and have been reported to reduce the cardiovascular risk.

OBJECTIVE

To determine the effect of a blend of 20% unrefined cold-pressed lignans-rich sesame oil and 80% physically refined γ-oryzanol-rich rice bran oil (Vivo) as cooking oil in mild-to-moderate hypertensive patients.

METHODS

In this prospective, open-label dietary approach, 300 hypertensive patients and 100 normotensives were divided into groups as: (1) normotensives treated with sesame oil blend, (2) hypertensives treated with sesame oil blend, (3) hypertensives treated with nifedipine, a calcium channel blocker (20 mg/d), and (4) hypertensives receiving the combination of sesame oil blend and nifedipine (20 mg/d). Sesame oil blend was supplied to respective groups, and they were instructed to use it as the only cooking oil for 60 days. Resting blood pressure was measured at days 0, 15, 30, 45, and 60, whereas the fasting lipid profile was measured at days 0 and 60.

RESULTS

Significant reduction in blood pressure (systolic, diastolic, and mean arterial) from days 0 to 15, 30, 45, and 60 were observed in hypertensives treated with sesame oil blend alone (P < .001), nifedipine alone (P < .001), and combination of sesame oil blend and nifedipine (P < .001). Sesame oil blend with nifedipine-treated group showed greatest reduction in blood pressure. Total cholesterol, low-density lipoprotein cholesterol, triglycerides, and non-high-density lipoprotein cholesterol levels reduced, whereas high-density lipoprotein cholesterol levels increased significantly only in hypertensives treated with sesame oil blend alone and the combination of sesame oil blend and nifedipine (P < .001).

CONCLUSION

We demonstrate for the first time that using a blend of sesame oil and rice bran oil as cooking oil showed a significant antihypertensive and lipid-lowering action and had noteworthy additive effect with antihypertensive medication.

Dashing away hypertension: Evaluating the efficacy of the dietary approaches to stop hypertension diet in controlling high blood pressure

The dietary approaches to stop hypertension (DASH) diet has been developed and popularized as a non-pharmaceutical intervention for high blood pressure reduction since 1995. However, to date, a comprehensive description of the biochemical rationale behind the diet’s principal guidelines has yet to be compiled. With rising interest for healthy and reliable life-style modifications to combat cardiovascular disease, this review aims to compile the most recent and relevant studies on this topic and make an informed assessment as to the efficacy of and underlying mechanisms operant in the DASH diet. Specifically, the merits of lowering dietary intake of sodium and saturated fat, as well as increasing the intake of fruits, vegetables, fiber, and dairy, have been shown to attenuate hypertension individually. Upon review of this evidence, we conclude that the combination of dietary patterns proposed in the DASH diet is effective in attenuating high blood pressure. We also suggest that efforts to more widely implement adoption of the DASH diet would be beneficial to public health.

Effects of dairy protein and fat on the metabolic syndrome and type 2 diabetes

The incidence of the metabolic syndrome (MetS) and type 2 diabetes (T2D) is increasing worldwide. Evidence supports a negative relationship between the consumption of dairy products and risk of MetS and T2D. Dairy proteins are known to have a directly beneficial effect on hypertension, dyslipidemia, and hyperglycemia, but a detailed understanding of the underlying mechanisms is missing. It has been confirmed by observations that the insulinotropic effect of dairy proteins is associated with the amino acid composition; in particular branched-chain amino acids (BCAA) seem to be of vital importance. Dairy protein-derived peptides may also contribute to the insulinotropic effect via dipeptidyl peptidase-4 (DPP-4) inhibitory activity, and may lower the blood pressure (BP). The lipid metabolism may be improved by whey protein (WP), which acts to reduce the postprandial triglyceride (TG) response. The effect of dairy fat is much more controversial because of the potentially harmful effect exerted by saturated fatty acid (SFA) on metabolic health. Recent observations suggest less adverse effects of SFA on metabolic health than previous assumed. However, little is known about dairy lipid fractions belonging to the groups of monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), and phospholipids (PL). Dairy fat seems to act differently depending on the dairy product and the composition of macronutrients in the meal. Therefore, for a better understanding of the mechanisms behind the dairy protein and fat effect on MetS, we suggest that more human studies should be carried out to clarify the interactions of dairy protein and fat with macronutrients in the meal and other dairy components, such as micronutrients and microorganisms from fermented products.

An update on the cardiovascular pleiotropic effects of milk and milk products

Hypertension is a major risk factor in addition to atherosclerosis and type 2 diabetes mellitus for the development of coronary heart disease and strokes. Several prospective clinical studies have demonstrated a possible protective effect of milk and dairy product consumption on these conditions. The putative effects of milk and dairy products are possibly mediated through their mineral content of calcium, magnesium, potassium, and vitamin D. These dairy substances exercise their blood pressure-lowering effect either directly on the arterial wall by these minerals or indirectly through blockade of the angiotensin-converting enzyme (ACE) by the amino acids contained in the casein and whey of milk. The blockade of ACE results in the inhibition of production of angiotensin II, a potent vasoconstrictive peptide, and the prevention of degradation of bradykinin, a potent vasodilating peptide. For this concise review, a Medline search of the English language literature was conducted from 2006 to September 2012 and 16 pertinent papers were selected. The potential beneficial pleiotropic effects from these studies together with collateral literature will be discussed in this review.

Dairy and blood pressure: a fresh look at the evidence

The Dietary Guidelines for Americans, 2010 indicated there is moderate evidence for an association between the consumption of dairy foods and lower blood pressure in adults; however, it also stated that more evidence was needed, especially in clinical trials, to fully delineate a causal relationship. The purpose of this review is to provide background by examining the historical literature and the evidence reviewed by the 2010 Dietary Guidelines Advisory Committee, to examine the gaps in knowledge indicated by that committee, and to determine if recently published evidence is sufficient to elucidate or dismiss an association between dairy foods and blood pressure maintenance. Examination of the newly published literature, together with evaluation of the evidence as a whole, shows that the preponderance of evidence indicates dairy foods are beneficially associated with blood pressure; however, additional research is necessary to identify the mechanism of action of dairy foods. New evidence should come from carefully designed clinical trials that examine not only blood pressure outcomes but also the ability of dairy foods to affect the vasculature.

Diet and blood pressure in 18-74-year-old adults: the French Nutrition and Health Survey (ENNS, 2006-2007)

OBJECTIVE

Dietary recommendations to reduce blood pressure (BP) have been widely disseminated. We investigated associations between dietary intake and BP in a national sample of adults living in France.

METHODS

The survey included 1968 18-74-year-old participants in the French Nutrition and Health Survey (Etude Nationale Nutrition Santé), a cross-sectional national multistage sampling study. Dietary intake and SBP and DBP were assessed using three 24-h recalls and three measurements, respectively. Mean dietary intake was compared across BP categories: previously diagnosed hypertensive and among undiagnosed optimal (SBP <120  mmHg and DBP <80  mmHg), intermediate and high (SBP ≥140  mmHg and/or DBP ≥90  mmHg) BP participants. After exclusion of previously diagnosed hypertensive participants, linear regressions were also carried out between dietary intake and SBP and DBP.

RESULTS

Eating habits of previously diagnosed hypertensive participants were not different from those of undiagnosed high BP participants, except higher milk consumption (P = 0.03) and lower seafood and alcohol intake (P < 0.03 and P = 0.002, respectively) in previously diagnosed hypertensive. After exclusion of them, dairy products (milk especially), fruit and vegetables, fiber and whole-grain food consumption were inversely and linearly associated with SBP (P < 0.04), whereas alcohol intake was positively associated with SBP (P < 10) and DBP (P = 0.005). Modification effect of sex was observed for saturated fatty acids intake (positive association with DPB in women) and calcium (negative association with SBP in men).

CONCLUSION

Adherence to nutritional recommendations still needs to be improved in hypertensive adults even if they are aware of their condition. In the rest of the population, proper habits regarding milk, fruit and vegetables, fiber and alcohol should decrease the risk of hypertension onset.

Safety of a probiotic cheese containing Lactobacillus plantarum Tensia according to a variety of health indices in different age groups

Safety of the probiotic Lactobacillus plantarum strain Tensia (DSM 21380) was tested in vitro, in semihard Edam-type cheese, in an animal model and after consumption of the probiotic cheese in double-blind randomized placebo-controlled human intervention studies with different age groups. The susceptibility of L. plantarum Tensia to 8 antibiotics, and the presence of tetracycline (tet M, S, O, K, L) genes and class 1 integron was assessed by applying epsilometer-test and PCR-based methods. Production of biogenic amines by the probiotic strain in decarboxylation medium containing 1% of l-histidine, l-glutamine, l-ornithine, l-arginine, or l-lysine and in cheese was tested by gas chromatography. The biosafety of L. plantarum Tensia was evaluated on National Institutes of Health-line mice fed cheese containing Tensia at a concentration of 9.6 log cfu/g for 30 consecutive days. In human intervention trials in adults and the elderly, the effects of different doses of Edam-type cheese and the probiotic bacterium on BW, gut functionality indices, and host metabolism were evaluated. The strain L. plantarum Tensia was susceptible to all tested antibiotics and did not possess the tetracycline resistance-determining genes tet(L), tet(S) and tet(O), nor did it contain the integron (Int1) gene. However, the strain was tet(K) and tet(M) positive. Lactobacillus plantarum Tensia did not produce potentially harmful biogenic amines, such as histamine or cadaverine. The amount of tyramine produced in the cheese environment during ripening and after 15 wk of storage was below the clinically significant content. In the animal model, no translocation of the administered strain or other microbes into the blood or organs of mice was detected. No harmful effect was observed on body mass index, inflammatory markers, or serum lipidograms during human intervention trials with different age groups at a daily dose of 10.3 or 8.17 log cfu/serving for 3 wk. No negative effect on gastrointestinal welfare was observed, but the consumption of 100g/d for 3 wk caused hard stools from the second week of the trial. The content of total lactobacilli increased in feces, and the presence of the ingested probiotic strain was confirmed after the consumption of cheese. Thus, L. plantarum strain Tensia is suitable for generally recognized as safe (GRAS) and qualified presumption of safety (QPS) criteria because it did not have any undesirable characteristics. The regular semihard Edam-type cheese (fat content of 26%) with the probiotic additive at a daily dose of 50 g or in excess (100g) and with a probiotic daily dose of 10 log cfu for 3 wk was safe.

Dairy intake, blood pressure and incident hypertension in a general British population: the 1946 birth cohort

PURPOSE

We aimed to examine the association between intake of different subgroups of dairy products and blood pressure and incident hypertension 10 years later, adjusting for confounding factors.

METHODS

We studied 1,750 British men and women from the 1946 British birth cohort from 1989 to 1999 (age 43 and 53 years, respectively). Diet was assessed by 5-day food diaries using photographs in the estimation of portion size. Systolic (sbp) and diastolic (dbp) blood pressure and prevalent hypertension were assessed at age 43 and 53 years. Linear regression and logistic regression were used to examine 10-year blood pressure levels and incident hypertension by baseline dairy intake.

RESULTS

There was a weak non-significant trend of a protective effect of total dairy intake on blood pressure and incident hypertension, but no evidence for a dose-response relationship (OR for incident hypertension: 0.88 (95% CI 0.68;1.14) 2nd vs. 1st tertile and 0.93 (95% CI 0.72;1.18) 3rd vs. 1st tertile). Higher intake of low-fat and fermented dairy was linked to a higher sbp but in a nonlinear manner. Adjustment for other dietary factors, health behaviours and BMI attenuated these associations.

CONCLUSIONS

Total dairy intake and specific dairy subgroups were not associated with blood pressure and incident hypertension among a representative sample of British adults after adjustment for confounding factors.

Self-perceived lactose intolerance results in lower intakes of calcium and dairy foods and is associated with hypertension and diabetes in adults

BACKGROUND

Self-perceived lactose intolerance may result in adverse dietary modifications; thus, more studies are needed to understand the prevalence of self-perceived lactose intolerance and how it relates to calcium intake and selected health conditions.

OBJECTIVE

The objective was to examine the effects of self-perceived lactose intolerance as it relates to calcium intake and specific health problems that have been attributed to reduced intakes of calcium and dairy foods in a nationally representative multiethnic sample of adults.

DESIGN

This was a cross-sectional study in a national sample of 3452 adults. The relation between self-perceived lactose intolerance, calcium intakes, and physician-diagnosed health conditions was analyzed by using linear regression analyses.

RESULTS

Of the total sample, 12.3% of respondents perceived themselves to be lactose intolerant. The age-adjusted prevalence of self-perceived lactose intolerance was 7.8% for non-Hispanic whites, 20.1% for non-Hispanic blacks, and 8.8% for Hispanics. Respondents with self-perceived lactose intolerance had significantly lower (P < 0.05) average daily calcium intakes from dairy foods than did those without self-perceived lactose intolerance. A significantly higher (P < 0.05) percentage of respondents with self-perceived lactose intolerance than of respondents without self-perceived lactose intolerance reported having physician-diagnosed diabetes and hypertension. The odds of self-reported physician-diagnosed diabetes or hypertension decreased by factors of 0.70 and 0.60, respectively, for a 1000-mg increase in calcium intake from dairy foods per day.

CONCLUSIONS

Self-perceived lactose-intolerant respondents had a significantly lower calcium intake from dairy foods and reported having a significantly higher rate of physician-diagnosed diabetes and hypertension.

Dairy Consumption, Blood Pressure, and Risk of Hypertension: An Evidence-Based Review of Recent Literature

Hypertension is a major risk factor for development of stroke, coronary heart disease, heart failure, and end-stage renal disease. In a systematic review of the evidence published from 2004 to 2009, the 2010 Dietary Guidelines Advisory Committee (DGAC) concluded there was moderate evidence of an inverse relationship between the intake of milk and milk products (dairy) and blood pressure. This review synthesizes results from studies published over the past year on the relationship between dairy intake, blood pressure, and hypertension risk. The influence of dairy micronutrients including calcium, vitamin D, potassium, and phosphorous on blood pressure and incident hypertension is examined. Emerging research on bioactive dairy peptides is also reviewed. Lastly, recent evidence on effects of dairy fat content on blood pressure and hypertension risk, and the impact of inclusion of low-fat dairy in dietary patterns is also investigated.

Associations between dairy consumption and body weight: a review of the evidence and underlying mechanisms. Nutr Res Rev. 2011;24:72-95. [PMID: 21320381 DOI: 10.1017/s095442241000034x]

As the incidence of obesity is reaching 'epidemic' proportions, there is currently widespread interest in the impact of dietary components on body-weight and food intake regulation. The majority of data available from both epidemiological and intervention studies provide evidence of a negative but modest association between milk and dairy product consumption and BMI and other measures of adiposity, with indications that higher intakes result in increased weight loss and lean tissue maintenance during energy restriction. The purported physiological and molecular mechanisms underlying the impact of dairy constituents on adiposity are incompletely understood but may include effects on lipolysis, lipogeneis and fatty acid absorption. Furthermore, accumulating evidence indicates an impact of dairy constituents, in particular whey protein derivatives, on appetite regulation and food intake. The present review summarises available data and provides an insight into the likely contribution of dairy foods to strategies aimed at appetite regulation, weight loss or the prevention of weight gain.

A systematic review and meta-analysis of elevated blood pressure and consumption of dairy foods

Hypertension is a public health priority in developed countries and worldwide, and is strongly associated with increased risk and progression of cardiovascular and renal diseases. A systematic review and meta-analysis were conducted to examine the association between dairy food intake during adulthood and the development of elevated blood pressure (EBP), specifically comparing the association of EBP with consumption of low-fat dairy foods versus high-fat dairy foods, as well as cheese versus fluid dairy foods (milk or yogurt). Seven databases were searched and five cohort studies selected for inclusion, involving nearly 45,000 subjects and 11,500 cases of EBP. Meta-analysis of consumption of dairy foods and EBP in adults gave a relative risk (RR) of 0.87 (95% confidence interval (CI) 0.81-0.94). Separation of high- and low-fat dairy foods, however, indicated a significant association with low-fat dairy foods only (RR of 0.84 (95% CI 0.74-0.95)). Additional analyses showed no association between EBP and cheese, although fluid dairy foods were significantly associated with a reduced development in EBP (RR of 0.92 (95% CI 0.87-0.98)). Little heterogeneity was observed among the data presented. This meta-analysis supports the inverse association between low-fat dairy foods and fluid dairy foods and risk of EBP. Understanding these relationships can aid in the development of public health messages involving dairy foods, and supports current recommendations.

Dietary fatty acids and the risk of hypertension in middle-aged and older women

Dietary intake of various fats may have different effects on blood pressure. We conducted a prospective cohort study to examine the association between intake of subtype and individual fatty acids (FAs) and the risk of developing hypertension among 28 100 US women aged ≥39 years and free of cardiovascular disease and cancer. Baseline intake of FAs was assessed using semiquantitative food frequency questionnaires. Incident hypertension was identified from annual follow-up questionnaires based on self-reported physician diagnosis, medication use, and blood pressure levels. A total of 13 633 women developed incident hypertension during 12.9 years of follow-up. After adjusting for demographic, lifestyle, and other dietary factors, intake of saturated FAs, monounsaturated FAs, and trans-unsaturated FAs (trans FAs) was positively associated with the risk of hypertension. The multivariable relative risks and 95% CIs of hypertension in the highest compared with the lowest quintile of intake were 1.12 (1.05 to 1.20) for saturated FAs, 1.11 (1.04 to 1.18) for monounsaturated FAs, and 1.15 (1.08 to 1.22) for trans FAs. After additional adjustment for body mass index and history of diabetes mellitus and hypercholesterolemia, these associations were attenuated and remained statistically significant only for trans FAs (relative risk in the highest quintile: 1.08; 95% CI: 1.01 to 1.15). Intake of polyunsaturated FAs, including ω3 and ω6 polyunsaturated FAs, was not significantly associated with the risk of hypertension. In conclusion, higher intake of saturated FAs, monounsaturated FAs, and trans FAs was each associated with increased risk of hypertension among middle-aged and older women, whereas only association for trans FAs remained statistically significant after adjustment for obesity-related factors.

Milk products, insulin resistance syndrome and type 2 diabetes

A growing body of evidence suggests an inverse relationship between calcium and vitamin D status and dairy food intake and the development of the insulin resistance syndrome (IRS) and type 2 diabetes mellitus (t2DM). Observational studies show a consistent inverse association between dairy intake and the prevalence of IRS and t2DM. In a systematic review of the observational evidence, the odds for developing the IRS was 0.71 (95% CI, 0,57-0.89) for the highest dairy intake (3-4 servings/d) vs. the lowest intake (0.9-1.7 servings/d). Few interventional studies have been conducted to evaluate the effects of dairy food intake on the management of prevention of IRS or t2DM. Intervention studies that have examined the independent effects of dairy intake on specific metabolic components of the IRS including blood pressure and obesigenic parameters have shown favorable effects that support the observational findings albeit the results have been less consistent. Many metabolic and dietary factors appear to influence the degree to which dairy affects IRS metabolic parameters including calcium and vitamin D intake status, BMI, ethnicity and age. Overall, the intake of low-fat dairy products is a feature of a healthy dietary pattern which has been shown to contribute to a significant extent to the prevention of IRS.

Milk products, dietary patterns and blood pressure management

High blood pressure (BP) is a major risk factor for heart disease, stroke, congestive heart failure, and kidney disease. Inverse associations between dairy product consumption and systolic blood pressure (SBP) and diastolic blood pressure (DBP) have been observed in cross-sectional studies; some studies, however, have reported an inverse association with only one BP parameter, predominantly SBP. Randomized clinical trials examining the effect of calcium and the combination of calcium, potassium and magnesium provide evidence for causality. In these studies, reductions in BP were generally modest (-1.27 to -4.6 mmHg for SBP, and -0.24 to -3.8 mmHg for DBP). Dairy nutrients, most notably calcium, potassium and magnesium, have been shown to have a blood pressure lowering effect. A low calcium intake increases intracellular calcium concentrations which increases 1,25-dihydroxyvitamin D(3) and parathyroid hormone (PTH), causing calcium influx into vascular smooth muscle cells, resulting in greater vascular resistance. New research indicates that dairy peptides may act as angiotensin converting enzyme (ACE) inhibitors, thereby inhibiting the renin angiotensin system with consequent vasodilation. A growing evidence base shows that dairy product consumption is involved in the regulation of BP. Consequently, inclusion of dairy products in a heart healthy diet is an important focal point to attain BP benefits.

Inverse association between dairy intake and hypertension: the Rotterdam Study

BACKGROUND

Little is known about the effect of different types of dairy food products on the development of hypertension.

OBJECTIVE

The objective was to determine whether the incidence of hypertension in older Dutch subjects is associated with intake of dairy products.

DESIGN

We examined the relation between dairy intake and incident hypertension in 2245 participants of the Rotterdam Study aged > or =55 y with complete dietary and blood pressure data, who were free of hypertension at baseline (1990-1993). Blood pressure was reexamined in 1993-1995 and in 1997-1999. Hazard ratios (HRs) with 95% CIs for 2- and 6-y incidence of hypertension were obtained in quartiles of energy-adjusted dairy intake, with adjustment for age, sex, BMI, smoking, educational level, dietary factors, and intake of alcohol and total energy.

RESULTS

Risk of hypertension after 2 y of follow-up (664 incident cases) was inversely associated with dairy product intake. After adjustment for confounders, HRs (95% CIs) were 1.00, 0.82 (0.67, 1.02), 0.67 (0.54, 0.84), and 0.76 (0.61, 0.95) in consecutive quartiles of total dairy product intake (P for trend = 0.008). Corresponding HRs for low-fat dairy products were 1.00, 0.75 (0.60, 0.92), 0.77 (0.63, 0.96), and 0.69 (0.56, 0.86) (P for trend = 0.003). Analysis of specific types of dairy products showed an inverse association with milk and milk products (P for trend = 0.07) and no association with high-fat dairy or cheese (P > 0.6). After 6 y of follow-up (984 incident cases), the associations with hypertension were attenuated to risk reductions of approximately 20% for both total and low-fat dairy products between the extreme quartiles of intake (P for trend = 0.07 and 0.09, respectively).

CONCLUSION

Intake of low-fat dairy products may contribute to the prevention of hypertension at an older age.

The effect of low-fat versus whole-fat dairy product intake on blood pressure and weight in young normotensive adults

BACKGROUND

Epidemiologic and experimental studies suggest that higher intake of dairy products could be associated with lower risk of hypertension and obesity. Differences in nutrient composition of distinct dairy products suggest that their effect on these outcomes might be heterogeneous. However, little experimental research has examined the potentially different effects of low- and whole-fat dairy products on blood pressure (BP) and weight change. The present study aimed to assess whether supplementing diets with low- or whole-fat dairy products would differentially affect BP levels and weight.

METHODS

A randomised crossover trial in 45 normotensive volunteers (18-24 years old, 49% female) was conducted. Participants alternatively received 3.5 servings/day of whole-fat or low-fat dairy products (milk and yogurt) in addition to their usual diet during two 8-week periods, with a 4-week washout period between both interventions. Weight and BP were measured at the beginning and end of each intervention.

RESULTS

Whole-fat dairy supplementation significantly increased systolic BP [2.1 mmHg, 95% confidence interval (CI) = 0.1-4.0, P = 0.04] and weight (1.0 kg, 95% CI = 0.5-1.5, P = 0.0002), but not diastolic BP (P = 0.34). Weight and BP did not change significantly after the low-fat dairy intervention (P > 0.10). There were no significant differences in the effect of low-fat or whole-fat dairy products on BP (P > 0.60), but whole-fat dairy increased weight significantly compared to low-fat dairy (1.2 kg, 95% CI = 0.5-1.8, P = 0.0007).

CONCLUSIONS

In a young nonhypertensive population, dietary supplementation with whole-fat dairy products, compared to low-fat dairy, was associated with weight gain. No differential effects were observed for levels of BP.

Dairy intake, blood pressure, and incident hypertension in a general Dutch population

Diet and lifestyle are important for maintaining a healthy blood pressure (BP). The role of dairy in the prevention of hypertension, however, is not yet clear. We studied the relation of dairy intake with BP in 21,553 Dutch participants aged 20-65 y who did not use antihypertensive medication. In addition, the risk of hypertension was examined in 3454 of these participants with a 5-y follow-up. Dairy consumption was assessed at baseline (1993-1997) using a semiquantitative FFQ that included 178 foods and beverages. Baseline BP and odds ratios (OR) (95% CI) for incident hypertension were calculated in categories of energy-adjusted dairy intake with adjustment for age, sex, socioeconomic status, BMI, smoking, alcohol use, and dietary intakes. Participants had a median intake of 344 g/d (approximately 2.3 servings) for total dairy and 174 g/d (approximately 1.2 servings) for low-fat dairy. Mean BP was 120/76 mm Hg. Intake of total dairy, specific dairy groups (i.e. low-fat, high-fat, fermented) and dairy products (i.e. cheese, yogurt) were not consistently related to BP. Of 3454 participants who were followed, 713 developed hypertension. The risk of hypertension tended to be inversely related to low-fat dairy intake, with multivariate OR (95% CI) of 1.00, 0.78 (0.61, 1.00), 0.81 (0.63, 1.03), and 0.82 (0.64, 1.06; P-trend: 0.24) in consecutive quartiles. We conclude that variations in BP in a general middle-aged Dutch population cannot be explained by overall dairy intake. A beneficial effect of low-fat dairy on risk of hypertension, however, cannot be excluded, which warrants further investigation in prospective population-based studies.

The Mediterranean diet and incidence of hypertension: the Seguimiento Universidad de Navarra (SUN) Study

The Mediterranean diet is receiving increasing attention in cardiovascular epidemiology. The association of adherence to the Mediterranean diet with the incidence of hypertension was evaluated among 9,408 men and women enrolled in a dynamic Spanish prospective cohort study during 1999-2005. Dietary intake was assessed at baseline with a validated semiquantitative food frequency questionnaire, and a 9-point Mediterranean diet score was constructed. During a median follow-up period of 4.2 years (range, 1.9-7.9), 501 incident cases of hypertension were identified. After adjustment for major hypertension risk factors and nutritional covariates, adherence to the Mediterranean diet was not associated with hypertension (the hazard ratio was 1.10 (95% confidence interval (CI): 0.81, 1.41) for moderate adherence and 1.12 (95% CI: 0.79, 1.60) for high adherence). However, it was associated with reduced changes in mean levels of systolic blood pressure (moderate adherence, -2.4 mm Hg (95% CI: -4.0, -0.8); high adherence, -3.1 mm Hg (95% CI: -5.4, -0.8)) and diastolic blood pressure (moderate adherence, -1.3 mm Hg (95% CI: -2.5, -0.1); high adherence, -1.9 mm Hg (95% CI: -3.6, -0.1)) after 6 years of follow-up. These results suggest that adhering to a Mediterranean-type diet could contribute to the prevention of age-related changes in blood pressure.

Low-fat dairy products and blood pressure: follow-up of 2290 older persons at high cardiovascular risk participating in the PREDIMED study

High blood pressure (BP) has been ranked as the most important risk factor worldwide regarding attributable deaths. Dietary habits are major determinants of BP. Among them, frequent intake of low-fat dairy products may protect against hypertension. Our aim was to assess the relationship between low-fat dairy product intake and BP levels and their changes after 12-month follow-up in a cohort of asymptomatic older persons at high cardiovascular risk recruited into a large-scale trial assessing the effects of Mediterranean diets on cardiovascular outcomes. Data from 2290 participants, including 1845 with hypertension, were available for analyses. Dairy products were not a specific part of the intervention; thus, data were analysed as an observational cohort. Dietary information was collected with validated semi-quantitative FFQ and trained personnel measured BP. To assess BP changes, we undertook cross-sectional analyses at baseline and at the end of follow-up and longitudinal analyses. A statistically significant inverse association between low-fat dairy product intake and systolic BP was observed for the 12-month longitudinal analysis. In the longitudinal analysis, the adjusted systolic and diastolic BP were significantly lower in the highest quintile of low-fat dairy product intake (-4.2 (95% CI -6.9, -1.4) and -1.8 (95% CI -3.2, -0.4) mmHg respectively), whereas the point estimates for the difference in diastolic BP indicated a modest non-significant inverse association. Intake of low-fat dairy products was inversely associated with BP in an older population at high cardiovascular risk, suggesting a possible protective effect against hypertension.

The evidence for dietary prevention and treatment of cardiovascular disease

During the past few decades numerous studies have reported the atherogenic potential of saturated fatty acids, trans-fatty acids, and cholesterol, and beneficial effects of fiber, phytostanols/phytosterols, n-3 fatty acids, a Mediterranean diet, and other plant-based approaches. The purpose of this article is to provide a comprehensive and systematic review of the evidence associated with key dietary factors and risk of cardiovascular disease-an umbrella term encompassing diseases that affect the heart and blood vessels, including coronary heart disease, coronary artery disease, dyslipidemia, and hypertension-in conjunction with the work of the American Dietetic Association Evidence Analysis Library review on diet and lipids, updated with new evidence from the past 2 years. The criteria used and results cited provide scientific rationale for food and nutrition professionals and other health professionals for counseling patients. Details of these searches are available within the American Dietetic Association Evidence Analysis Library online (http://adaevidencelibrary.com). Potential mechanisms and needs for future research are summarized for each relevant nutrient, food, or food component.

The role of calcium in peri- and postmenopausal women: 2006 position statement of The North American Menopause Society

OBJECTIVE

To update the evidence-based consensus opinion published by The North American Menopause Society (NAMS) in 2001 on the role of calcium in peri- and postmenopausal women.

DESIGN

NAMS followed the general principles established for evidence-based guidelines to create this document. A panel of clinicians and researchers acknowledged to be experts in the field of calcium and women's health was enlisted to review the previous position statement and data published since then, compile supporting statements, and make recommendations. Their advice was used to assist the NAMS Board of Trustees in publishing this position statement.

RESULTS

Adequate calcium intake (in the presence of adequate vitamin D status) has been shown to reduce bone loss in peri- and postmenopausal women and reduce fractures in postmenopausal women older than age 60 with low calcium intakes. Adequate calcium is considered a key component of any bone-protective therapeutic regimen. Calcium has also been associated with beneficial effects in several nonskeletal disorders, primarily hypertension, colorectal cancer, obesity, and nephrolithiasis, although the extent of those effects has not been fully elucidated. The calcium requirement rises at menopause. The target calcium intake for most postmenopausal women is 1,200 mg/day. Adequate vitamin D status, defined as 30 ng/mL or more of serum 25-hydroxyvitamin D (usually achieved with a daily oral intake of at least 400 to 600 IU), is required to achieve the nutritional benefits of calcium. The best source of calcium is food, and the best food source is dairy products. High-quality calcium supplements (taken in divided doses) are alternative sources for women unable to consume enough dietary calcium. There are no reported cases of calcium intoxication from food sources, and cases associated with supplements are rare (high intake levels of 2,150 mg/day have resulted in a 17% increase in renal calculi in one recent study, but not others). Because no accurate test to determine calcium deficiency exists, clinicians should focus instead on encouraging women to consume enough calcium to meet the recommended levels.

CONCLUSIONS

The most definitive role for calcium in peri- and postmenopausal women is in bone health, but, like most nutrients, calcium has beneficial effects in many body systems. Based on the available evidence, there is strong support for the importance of ensuring adequate calcium intake in all women, particularly those in peri- or postmenopause.