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Back to Hypertension

Hypertension: Summary of Evidence

Data from several studies, such as systematic reviews and randomized-controlled trials including the landmark DASH diet study, have consistently demonstrated a beneficial association between milk product consumption and the prevention and management of hypertension.

Highlights

  • Milk products, including milk, yogurt and cheese, are protective against the development of hypertension;
  • The DASH diet is a recommended dietary pattern for controlling blood pressure that emphasizes fruits, vegetables, and milk products (milk, yogurt, cheese);
  • A DASH diet with high-fat dairy foods (milk, yogurt, cheese) is as beneficial to controlling blood pressure with similar or better control of blood lipids as a DASH diet with low-fat dairy foods;
  • Hypertension Canada recommends the DASH diet for the prevention and management of high blood pressure in at-risk individuals.

Introduction

The evidence suggests that consuming milk products has a beneficial effect on blood pressure. The potential mechanisms by which milk products may modulate blood pressure need to be elucidated, but there is evidence that several components of milk products may be involved, including:

  • Calcium,
  • Vitamin D,
  • Magnesium,
  • Potassium,
  • Phosphorous,
  • Milk protein, and
  • Bioactive peptides.

The Evidence

A 2016 systematic review of meta-analyses examined the relationship between the consumption of dairy products and the risk of cardiometabolic outcomes including hypertension.1 The findings were as follows:

  • Total dairy consumption is associated with a reduced risk of hypertension, based on high-quality evidence;
  • Low-fat dairy and milk consumption is associated with up to a 16% reduced risk of hypertension, based on moderate-quality evidence;
  • Consumption of regular-fat dairy and high-fat dairy, cheese, yogurt, and fermented dairy is not associated with hypertension, based on high- to moderate-quality evidence.

A 2012 dose-response meta-analysis of prospective cohort studies was conducted to examine the consumption of total dairy, low-fat dairy, high-fat dairy, and different types of dairy products in relation to hypertension incidence in the general population. This study included 57,256 adults aged 25 to 65 years and a follow-up of 5 to 15 years.2

  • The intake of total dairy products (low and high fat) was significantly associated with a risk reduction in hypertension, with a pooled relative risk of 0.97 (95% CI: 0.95-0.99) per intake of 200 g/d;
  • There was a significant inverse linear association between the consumption of milk and incident hypertension, with a pooled relative risk of 0.96 (95% CI: 0.94-0.98) per intake of 200 g/d;
  • Low-fat milk products were inversely associated with hypertension incidence, with a pooled relative risk of 0.96 (95% CI: 0.93-0.99) per intake of 200 g/d;
  • High-fat dairy, total fermented dairy, cheese, and yogurt were not significantly associated with hypertension incidence.

In a randomized, controlled crossover trial examining the impact of non-fat dairy products on blood pressure, 49 subjects underwent a high-dairy condition and a no-dairy condition for 4 weeks. Under the high-dairy condition, 4 servings of non-fat dairy products (milk, yogurt and cheese) were added to baseline dairy intakes.4 Under the no-dairy condition, dairy products were removed completely from the diet and 4 fruit product servings were added.3

  • After the high-dairy condition, mean pulse pressure decreased by 6 ± 1 mm Hg (p < 0.05);
  • After the no-dairy condition, mean pulse pressure increased by 2 ± 1 mm Hg (p < 0.05).

In another randomized, double-blind, placebo-controlled, crossover study, 34 subjects supplemented their diets with 2 servings of dairy products per day from 45 g of powdered buttermilk and 45 g of a placebo (4 weeks each).4

  • Systolic blood pressure was lower after supplementation with buttermilk than after supplementation with the placebo (mean difference: -2.6 mm Hg; = 0.009);
  • Diastolic blood pressure did not differ between treatments.

In the original landmark randomized controlled Dietary Approaches to Stop Hypertension (DASH) Diet Study, the impact of dietary patterns on blood pressure was examined. After following a control diet for 3 weeks, 459 adults were randomized to 1 of 3 of the following diets, which differed primarily in their content of fruit and vegetables and milk products:5,6

  • Control diet (typical of most Americans): 0.5 servings/d milk products and 2.6 servings/d fruit and vegetables;
  • Fruit and vegetable diet: 8 to 10 servings/d fruit and vegetables; 0.3 servings/d milk products;
  • Combination (DASH) diet: c~3 servings of milk products, in addition to the 8 to 10 servings of fruit and vegetables per day;
    • The milk products in the combination (DASH) diet included ~30 g of regular-fat cheese;
    • Sodium was constant for all diets at ~3,000 mg/d;
    • The dairy-enriched combination diet (DASH diet) had twice the impact as the fruit and vegetable diet, reducing systolic blood pressure by 5.5 mm Hg and diastolic blood pressure by 3.0 mm Hg (p < 0.001) more than the control diet;5 about 50% of the magnitude in these reductions could be ascribed to the milk products per se in the diet.7

A recent randomized, crossover, controlled trial examined the effects of substituting full-fat for low-fat dairy foods in the DASH diet. In total, 36 hypertensive subjects followed a control diet, a standard DASH diet, and a higher-fat lower-carbohydrate modification of the DASH diet (High Fat-DASH) for 3 weeks each.

The High Fat-DASH diet was similar to the standard DASH diet, except that non-fat and low-fat dairy was substituted with full-fat milk, cheese, and yogurt, increasing saturated fat from 8% to 14%, and that sugars were reduced (mostly from fruit juices) by 12% of the total energy intake.8

  • Systolic and diastolic blood pressures were comparably reduced in the DASH and High Fat-DASH groups (reduction of ~2.8-3.4 mm Hg compared to control, p < 0.0001);
  • Plasma triglycerides, VLDL concentrations, and LDL peak diameter were significantly lower in the High Fat-DASH group compared to the standard DASH group.

This study provides high-level evidence that consuming full-fat dairy, as part of a modified DASH diet, reduces blood pressure with similar or better control of blood lipids compared to a standard DASH diet.

Several health authorities recommend the DASH diet. Hypertension Canada recommends the DASH diet for the prevention and management of hypertension in individuals with hypertension and normotensive individuals at increased risk.9,10 Similarly, in its guidelines for the year 2000, the American Heart Association also recommended the DASH diet for heart health.11

Interested in learning more? Watch this webinar with Dr. Sally Chiu from Touro University.

Potential Mechanisms

Although the mechanisms by which milk products may modulate blood pressure remain to be fully elucidated, calcium is thought to be one of the main nutrients responsible for the impact of milk products on blood pressure control.7

Vitamin D, because of its importance in calcium absorption, may also play a role in the management of blood pressure. Additionally, low vitamin D status has been shown to increase blood pressure by activating the renin-angiotensin-aldosterone system, which leads to vasoconstriction and sodium and water retention.12

Potassium intake appears to be involved in blood pressure regulation. An increase of 750 to 1,000 mg/d of potassium can decrease blood pressure by 2 to 3 mm Hg, based on several observational studies.13

It has also been shown that whey protein found in milk products may reduce systolic blood pressure in hypertensive individuals.14

Bioactive peptides have been shown to have an angiotensin-1-converting enzyme (ACE) inhibitory effect, a key process in blood pressure control.7 They may also have antioxidant properties and may increase nitric oxide production, both of which may help reduce blood pressure.15 Bioactive peptides are formed by either the digestion of casein and whey protein (the main proteins in milk products) or the lactobacilli fermentation of milk (for instance during cheese making). In fact, antihypertensive peptides have been reported to be present in various types of cheese.16

Other studies have found that certain milk-derived peptide combinations also have hypotensive effects via the modulation of endothelin-1 release by endothelial cells.9 A meta-analysis of milk tripeptides on blood pressure indicated that milk-derived tripeptides have hypotensive effects in individuals with prehypertension and hypertension.17

Conclusions

There is consistent evidence to support a beneficial relationship between milk product consumption and blood pressure control.

The evidence to date indicates that a higher intake of milk products may protect against the development of hypertension. The DASH diet, which emphasizes fruits and vegetables and milk products (milk, yogurt, cheese), is recommended by health authorities for the prevention and management of hypertension.

More studies, including randomized controlled trials, are needed to better understand the mechanisms by which milk products exert their beneficial effect on blood pressure.

References

1. Drouin-Chartier JP et al. Systematic review of the association between dairy product consumption and risk of cardiovascular-related clinical outcomes. Adv Nutr 2016;7:1026-1040.

2. Soedamah-Muthu SS et al. Dairy consumption and incidence of hypertension: a dose-response meta-analysis of prospective cohort studies. Hypertension 2012;60:1131-1137.

3. Machin DR et al. Hypotensive effects of solitary addition of conventional nonfat dairy products to the routine diet: a randomized controlled trial. Am J Clin Nutr 2014;100:80-87. doi: 10.3945/ajcn.114.085761.

4. Conway V et al. Effect of buttermilk consumption on blood pressure in moderately hypercholesterolemic men and women. Nutrition 2014;30:116-119. doi: 10.1016/j.nut.2013.07.021.

5. Appel LJ et al. A clinical trial of the effects of dietary patterns on blood pressure. DASH Collaborative Research Group. N Engl J Med 1997;336:1117-1124.

6. Karanja NM et al. Descriptive characteristics of the dietary patterns used in the Dietary Approaches to Stop Hypertension Trial. DASH Collaborative Research Group. J Am Diet Assoc 1999;99:S19-S27.

7. German JB et al. A reappraisal of the impact of dairy foods and milk fat on cardiovascular disease risk. Eur J Nutr 2009;48:191-203.

8. Chiu S et al. Comparison of the DASH (Dietary Approaches to Stop Hypertension) diet and a higher-fat DASH diet on blood pressure and lipids and lipoproteins: a randomized controlled trial. Am J Clin Nutr 2016;103:341-347.

9. Khan NA et al. The 2008 Canadian Hypertension Education Program recommendations for the management of hypertension: part 2 - therapy. Can J Cardiol 2008;24:465-475.

10. Mosca L et al. Evidence-based guidelines for cardiovascular disease prevention in women: 2007 updateCirculation 2007;115:1481-1501. doi: 10.1161/CIRCULATIONAHA.107.181546.

11. Krauss RM et al. AHA Dietary Guidelines: revision 2000: a statement for healthcare professionals from the Nutrition Committee of the American Heart AssociationCirculation 2000;102:2284-2299.

12. McGrane MM et al. Dairy consumption, blood pressure, and risk of hypertension: an evidence-based review of recent literature. Curr Cardiovasc Risk Rep 2011;5:287-298.

13. Houston MC and Harper KJ. Potassium, magnesium, and calcium: their role in both the cause and treatment of hypertension. J Clin Hypertens (Greenwich) 2008;10:3-11.

14. Fekete ÁA et al. Whey protein lowers blood pressure and improves endothelial function and lipid biomarkers in adults with prehypertension and mild hypertension: results from the chronic Whey2Go randomized controlled trial. Am J Clin Nutr 2016;104:1534-1544.

15. Beltrán-Barrientos LM et al. Mechanistic pathways underlying the antihypertensive effect of fermented milk with Lactococcus lactis NRRL B-50571 in spontaneously hypertensive rats. Nutrients 2018;10. pii: E262. doi: 10.3390/nu10030262.

16. Choi J et al. Bioactive peptides in dairy products. Int J Dairy Technol 2011;65. doi: org/10.1111/j.1471-0307.2011.00725.x.

17. Xu JY et al. Effect of milk tripeptides on blood pressure: a meta-analysis of randomized controlled trials. Nutrition 2008;24:933-940.

Keywords: hypertension , blood pressure , dash diet , sodium , american heart association , hypertension canada


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