Metabolic Syndrome and Milk Products
Several studies, including meta-analyses, indicate that milk products are associated with a reduced risk of developing metabolic syndrome.
Highlights
- Studies have shown that milk products (such as milk, yogurt and cheese) are inversely associated with the development of metabolic syndrome;
- Higher-fat dairy products do not appear to increase and may actually lower the risk of developing metabolic syndrome;
- Several milk nutrients and components appear to be responsible for the potential mechanisms underlying the protective effect of milk products against metabolic syndrome.
Synopsis
There is a growing amount of evidence on the role of milk products in preventing metabolic syndrome. In recent years, a number of studies and meta-analyses have demonstrated that higher intakes of milk products, including milk, yogurt and cheese, are associated with a significantly reduced risk of developing metabolic syndrome. Current evidence shows that higher-fat milk products are also associated with a lower risk of metabolic syndrome. Potential mechanisms appear to involve a variety of roles played by multiple dairy food components including: protein and bioactive peptides, vitamin D, calcium, potassium and magnesium, milk fat and conjugated linoleic acid.
Basic Facts on Metabolic Syndrome
Metabolic syndrome is also known as cardiometabolic syndrome, insulin resistance syndrome or syndrome X. It consists of a cluster of cardiometabolic risk factors that put an individual at increased risk for cardiovascular disease. In fact, metabolic syndrome is considered to be an important contributor to cardiovascular disease and type 2 diabetes.
In Canada, approximately 21% of adults aged 18 to 79 years have metabolic syndrome, according to the Canadian Health Measures Survey.1 The prevalence of metabolic syndrome increases with age and it is estimated that 39% of adults 60 to 79 years of age are affected.
As established by the international consensus guidelines of the International Diabetes Federation (IDF) in collaboration with the American Heart Association/National Heart, Lung, and Blood Institute (AHA/NHLBI), a diagnosis of metabolic syndrome is made when 3 out of the 5 following risk factors are present:2
Criteria for clinical diagnosis of metabolic syndrome2
(Diagnosis = 3 or more risk factors)
| Risk factors | Categorical cut points |
| Elevated waist circumference |
Population- and country-specific definitions (in Canada, established by Health Canada) ≥102 cm (men) |
| Elevated triglycerides (or drug treatment for elevated triglycerides) |
≥1.7 mmol/L |
| Reduced HDL-C (or drug treatment for reduced HDL-C) |
<1.0 mmol/L (men) <1.3 mmol/L (women) |
| Elevated blood pressure (or antihypertensive drug treatment or a history of hypertension) |
Systolic ≥130 mm Hg and/or diastolic ≥85 mm Hg |
| Elevated fasting glucose level (or drug treatment for elevated glucose) |
≥5.6 mmol/L |
The evidence
A 2018 meta-analysis of observational studies assessed the dose-response relationship between specific types of dairy foods and metabolic syndrome and its components. This analysis included a total of 29 cohort studies, 10 cross-sectional studies and 2 case-control studies.3
- The highest category of total dairy food consumption compared to the lowest was associated with a 25% reduced risk of metabolic syndrome.
- Each additional daily serving of dairy foods consumed was associated with a 9% reduced risk of metabolic syndrome.
- Each 200 g/day of milk was associated with a 13% reduced risk.
- Each 100 g/day of yogurt was associated with an 18% reduced risk.
- Higher total dairy food consumption was associated with a lower risk of metabolic syndrome components (elevated blood glucose, blood pressure, and triglycerides and low HDL-cholesterol).
- Each daily serving of milk was related to a 12% lower risk of abdominal obesity.
- Each daily serving of yogurt was related to a 16% lower risk of hyperglycemia.
A 2015 meta-analysis of observational studies assessed the effect of dairy consumption on the risk of developing metabolic syndrome. The analyses included 8 prospective cohort studies with a total of 31,944 participants.4
- The highest category of dairy consumption compared to the lowest was associated with a 15% reduced risk of metabolic syndrome.
- Higher consumption of milk and cheese was found to significantly reduce the risk of metabolic syndrome by 24% and 19%, respectively.
- Every additional serving of dairy products per day was associated with a 12% reduced risk of metabolic syndrome.
In another 2015 meta-analysis of 7 prospective cohort studies, the authors found that:5
- A higher intake of dairy products was associated with a 14% lower risk of developing metabolic syndrome;
- Milk was associated with a 25% decreased risk of metabolic syndrome;
- Every additional serving of dairy products per day was associated with a 6% decreased risk of metabolic syndrome.
Drehmer et al. investigated the association between different types of dairy products with varying fat content and metabolic syndrome. The analysis consisted of 9,835 subjects aged 35 to 74 years from the Brazilian Longitudinal Study of Adult Health, a prospective cohort study.6
- Dairy products, particularly full-fat dairy products, butter and yogurt, were associated with a reduced risk of metabolic syndrome.
- Associations seem to be mediated by dairy saturated fatty acids.
- Low-fat dairy products were not associated with metabolic syndrome risk.
Using data from the SUN (Seguimiento Universidad de Navarra) project, a prospective cohort study in Spain, the association between yogurt consumption and the incidence of metabolic syndrome was examined among 8,063 participants who had a minimum of 6 years of follow-up.7
- Higher yogurt consumption, particularly whole-fat, was associated with a 15% reduced risk of developing central adiposity.
- The combination of yogurt and fruit was associated with a reduced risk of developing metabolic syndrome.
In a prospective analysis of 1,868 adults aged 55 to 80 years from the PREDIMED (Prevención con Dieta Mediterránea) study, after 3 years of follow-up, the authors observed the following: 8
- Higher consumption of low-fat dairy was associated with a 23% reduced risk of metabolic syndrome;
- Yogurt intake (including whole-fat and low-fat) was associated with a 22% to 27% decrease in the risk of developing metabolic syndrome.
Potential mechanisms
Protein and bioactive peptides
Milk protein, especially whey protein, has been shown to improve body composition and to have a positive impact on muscle protein synthesis. Whey protein has also been shown to help control blood glucose levels.9
Furthermore, bioactive peptides in milk protein may help in reducing blood pressure through their angiotensin-converting-enzyme (ACE)-inhibiting action.9
Vitamin D
Several epidemiological studies have demonstrated that adequate vitamin D intake and status may be protective against metabolic syndrome. Many mechanisms have been proposed to explain how vitamin D may modulate cardiometabolic health. These include:10
- the reduction of dyslipidemia through the maintenance of calcium homeostasis;
- the stimulation of insulin production and release;
- the regulation of the renin-angiotensin-aldosterone system, which helps in blood pressure control.
Calcium, potassium and magnesium
Evidence suggests that calcium may improve the blood lipid profile through the potential mediation of fecal fat excretion.9
Additionally, calcium, potassium and magnesium in milk may help in the management of blood pressure by decreasing sodium retention through various mechanisms.9 Dietary calcium may help in the hormonal regulation of intracellular calcium, which favourably impacts blood pressure. Potassium also contributes by inhibiting proinflammation in vascular smooth muscle cells, reducing platelet aggregation and decreasing renal vascular resistance. Magnesium may also play a role in modulating intracellular calcium concentrations.
Milk fat and conjugated linoleic acid (CLA)
Milk fat appears to improve the ratio of HDL-cholesterol to total cholesterol. Saturated fatty acids present in milk fat may also have a neutral or beneficial impact on triglyceride levels.9
CLA has been shown to have many potential benefits on cardiometabolic health, particularly through its effects on plasma lipids and lipoproteins.9
Certain dairy fatty acids (e.g., 15:0 and 17:0), which are considered biomarkers of dairy/dairy fat intake, have been associated with a reduced risk of cardiovascular disease and type 2 diabetes.11,12,13
Conclusion
Current evidence suggests that milk products, including milk, yogurt and cheese, are associated with a reduced risk of developing metabolic syndrome.
Both higher-fat and lower-fat dairy foods may help to prevent metabolic syndrome.
More studies are needed to further clarify the mechanistic roles of milk components in preventing the development of metabolic syndrome.
References
- Statistics Canada. 2014. Metabolic syndrome in adults, 2012 to 2013. www.statcan.gc.ca. Accessed November 27, 2018.
- Alberti KG et al. Harmonizing the metabolic syndrome: a joint interim statement of the International Diabetes Federation Task Force on Epidemiology and Prevention; National Heart, Lung, and Blood Institute; American Heart Association; World Heart Federation; International Atherosclerosis Society; and International Association for the Study of Obesity. Circulation 2009;120:1640-1645.
- Lee M et al. Dairy food consumption is associated with a lower risk of the metabolic syndrome and its components: a systematic review and meta-analysis. Br J Nutr 2018;120:373-384.
- Kim Y and Je Y. Dairy consumption and risk of metabolic syndrome: a meta-analysis. Diabet Med 2015. doi: 10.1111/dme.12970.
- Chen GC et al. Dairy products consumption and metabolic syndrome in adults: systematic review and meta-analysis of observational studies. Sci Rep 2015;5:14606.
- Drehmer M et al. Total and full-fat, but not low-fat, dairy product intakes are inversely associated with metabolic syndrome in adults. J Nutr 2015. doi: 10.3945/jn.115.220699.
- Sayón-Orea C et al. Association between yogurt consumption and the risk of metabolic syndrome over 6 years in the SUN study. BMC Public Health 2015;15:170.
- Babio N et al. Consumption of yogurt, low-fat milk, and other low-fat dairy products is associated with lower risk of metabolic syndrome incidence in an elderly Mediterranean population. J Nutr2015;145:2308-2316.
- Rice BH et al. Dairy components and risk factors for cardiometabolic syndrome: recent evidence and opportunities for future research. Adv Nutr 2011;2:396-407.
- Muldowney S and Kiely M. Vitamin D and cardiometabolic health: a review of the evidence. Nutr Res Rev2011;24:1-20.
- Santaren ID et al. Serum pentadecanoic acid (15:0), a short-term marker of dairy food intake, is inversely associated with incident type 2 diabetes and its underlying disorders. Am J Clin Nutr 2014;100:1532-1540.
- Chowdhury R et al. Association of dietary, circulating, and supplement fatty acids with coronary risk: a systematic review and meta-analysis. Ann Intern Med 2014;160:398-406.
- de Oliveira Otto MC et al. Biomarkers of dairy fatty acids and risk of cardiovascular disease in the Multi-Ethnic Study of Atherosclerosis. J Am Heart Assoc 2013;2:e000092.
