Inclusion of Dairy Cheese In An 8‐day Controlled Dietary Intervention Prevents Sodium‐Induced Endothelial Dysfunction in the Cutaneous Microcirculation of Healthy Older Adults

Excess dietary sodium is associated with impaired vascular function and increased cardiovascular mortality. In controlled feeding studies, the inclusion of 3 daily servings of any dairy product improves blood pressure and measures of vascular health. Few studies have examined the inclusion of individual dairy products that contain both the beneficial bioactive dairy proteins and sodium. We recently demonstrated that single‐meal cheese consumption ameliorates acute sodium‐induced impairments in nitric oxide‐dependent vasodilation. However, controlled feeding studies examining the vasoprotective role of dairy cheese on sodium‐induced microvascular dysfunction are lacking. We hypothesized that (1) endothelium‐dependent vasodilation would be impaired by a high‐sodium diet compared to a low sodium diet, and (2) that a high‐cheese diet would preserve endothelium‐dependent vasodilation that is otherwise impaired by a high‐sodium diet. In a randomized, crossover study design, seven healthy older adults (63 ± 3 years; salt‐resistant: <10 mmHg increase in mean arterial pressure, 24 hour monitoring) with normal to elevated blood pressure completed 4 separate 8‐day controlled dietary interventions: 1) low‐sodium (LNa: 1500 mg sodium) diet devoid of dairy products, 2) low‐sodium high‐cheese diet (LNaC: 1500 mg sodium, 6 oz/d cheese), 3) high‐sodium (HNa: 5500 mg sodium) diet devoid of dairy products, and 4) high‐sodium high‐cheese diet (HNaC: 5500 mg sodium, 6 oz/d cheese). At the end of each dietary intervention, subjects participated in an intradermal microdialysis protocol in which one microdialysis fiber was inserted into the forearm skin for measurement of red cell flux (laser Doppler flowmetry) during local infusion of the endothelium‐dependent agonist acetylcholine (Ach; 10 −12 to 10 −1 M). Data were expressed as a percentage of maximum cutaneous vascular conductance (%CVC max ; 28 mM sodium nitroprusside, 43°C). Ach‐induced vasodilation was significantly attenuated during the HNa diet compared to the LNa diet (LNa: −5.06±0.20 M vs HNa: −3.22±0.63 M logEC 50 : p < 0.05). Conversely, Ach‐induced dilation during either the LNaC or HNaC diet was not different from the LNa diet (p > 0.05). These results demonstrate that increased dietary sodium intake impairs endothelium‐dependent dilation whereas the inclusion of cheese prevents sodium‐induced endothelial dysfunction in salt‐insensitive older adults. Support or Funding Information Supported by National Dairy Council This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .