Intake of milk fat, reflected in adipose tissue fatty acids and risk of myocardial infarction: a case–control study

Abstract

Objective: To study the association between content of fatty acids from milk fat (14:0, 15:0 and 17:0) in adipose tissue and risk of a first myocardial infarction (MI). Design and subjects: A case-control study with 99 patients and 98 population controls both men and postmenopausal women, age 45-75 year. Adipose tissue fatty acids were determined by gas-liquid chromatography. Results: The content of 14:0, 14:1, 15:0, 17:0 and 17:1 were all significantly higher in adipose tissue of controls than of the patients. Age and sex adjusted odds ratios (OR) for MI were significantly reduced with increasing quartiles of 14:0, 14:1, 15:0 and 17:1 in adipose tissue, but except for 15:0 (OR ¼ 0.36, 95% CI 0.13-0.99), the trend was no longer significant after further adjustment for waist-to-hip ratio, smoking and family history for coronary heart disease. Correlations between 14:0 and 15:0 in adipose tissue, and waist-to-hip ratio were significantly negative (r ¼ À0.22 for both, Po0.01). Conclusion: Our study suggests that intake of dairy fat or some other component of dairy products, as reflected by C15:0 as marker in adipose tissue, may protect persons at increased risk from having a first MI, and that the causal effects may rely on other factors than serum cholesterol. Keywords: pentadecanoic acid; myristic acid; heptadecanoic acid; milk fat; coronary heart disease; biological markers IntroductionPopulations with a high intake of saturated fat are shown to have a high mortality of coronary heart disease (CHD) (Renaud and Lanzmann-Petithory, 2001). This is one reason why intake of milk fat has been considered an important factor related to the high incidence of CHD in western countries. A large number of metabolic studies have shown that the saturated fatty acids lauric (12:0), myristic (14:0) and palmitic acid (16:0) increase serum total and LDL cholesterol (Kris-Etherton and Yu, 1997). It has been difficult, however, to demonstrate a clear relationship between intake of saturated fat and risk of cardiovascular disease in large observational studies. A significant positive association was found in two prospective studies (McGee et al., 1984;Kushi et al., 1985), but in others, weak or no association were found (Garcia-Palmieri et al., 1980;Gordon et al., 1981;Shekelle et al., 1981;Kromhout and de Lezenne, 1984;McGee et al., 1984;Kushi et al., 1985;Ascherio et al., 1996;Hu et al., 1997;Pietinen et al., 1997 HDL ratio, serum triglycerides and blood pressure, associated with dairy products (Smedman et al., 1999;Mennen et al., 2000;Pereira et al., 2002), andElwood et al. (2004), suggesting that consumption of milk products may be associated with a small reduction in risk of heart disease and stroke.Pentadecanoic acid (15:0) and heptadecanoic acid (17:0) are characteristic for milk fat. They are synthesized by the bacterial flora in the rumen of ruminants (Wu and Palmquist, 1991), and cannot be synthesized in the human body. Another fatty acid, 14:0, is mainly present in milk fat. In most human tissues, the substrate specificiti...

Milk fat biomarkers and cardiometabolic disease

“…The correlations were weaker when food intake was assessed by food frequency questionnaire (FFQ) compared with repeated food records [5]. Notably, dairy intake was more strongly correlated with adipose 15 : 0 than 17 : 0 [5,6,10,11], showing a clear dose–response relationships between intake and 15 : 0 [11]. In adipose tissue, the mean or median proportions of 15 : 0 range from 0.19 (Costa Rica) to 0.39 (Norway) and for 17 : 0 from 0.21 to 0.34 [5,6,10,12–14].…”

Intake of dairy fat and dairy products, and risk of myocardial infarction: A case–control study

“…Use of biological markers may represent a more accurate measure of intake than FFQ, and our previously reported results showed that the OR for MI were significantly reduced with increasing quartiles of 15:0 in adipose tissue even after adjustment for lifestyle factors (Biong et al 2006). This suggests that the intake of dairy fat or some other component of dairy products, as reflected by C15:0 as a marker in adipose tissue, may possibly protect persons at increased risk from having a first MI.…”

“…Previously, Biong et al (2006) have used these data to show that intake of dairy fat or some other component of dairy products, as reflected by C15:0 as a marker in adipose tissue, is associated with reduced risk of myocardial infarction (MI). In the present analyses the same data have been used to assess whether this reduced MI risk may be reflected in the self-reported intake of different food items (food frequency questionnaire [FFQ]), in particular different dairy products*and, if so, what kind of dairy products.…”

Molecular and Biotechnological Advances in Milk Proteins in Relation to Human Health

“…Two Swedish studies have shown that cardiovascular risk factors were negatively associated with intake of milk fat [42,43]. A Norwegian study suggests that intake of dairy fat or some other component of dairy products, as reflected by C15:0 as marker in adipose tissue may protect persons at increased risk from having a first myocardial infarction (MI), and that the causal effects may rely on other factors than serum cholesterol [44]. It has been shown that 34 grams dairy fat per day gives no negative effect on odds ratio for myocardial infarction [45].…”

“…Accordingly milk and milk products contribute substantially to the dietary intake of oleic acid in many countries. In Norway about a quarter of the average intake of oleic acid comes from milk and milk products [40][41][42][43][44][45][46]. Oleic acid is considered to be favourable for health, as diets with high amounts of monounsaturated fatty acid will lower both plasma cholesterol, LDL-cholesterol and triacylglycerol concentrations [48], and replacement of saturated fatty acids with cis-unsaturated fatty acids reduces risk for coronary artery disease [24].…”