Keynote Joint Annual Scientific Meeting of the Nutrition Society of NZ and the Nutrition Society of Australia

Dietary minerals, blood pressure, and heart disease – separating fact from fiction (379)

Lynn Moore 1
  1. Boston University, Boston, United States

High blood pressure is a major modifiable risk factor for cardiovascular and cerebrovascular diseases. Nonpharmacologic approaches to the prevention and management of CVD typically include weight loss, stress reduction, smoking cessation, exercise, and diet modification. Sodium restriction has been the primary dietary strategy for blood pressure management for many years. While average sodium consumption is approximately 3.5 g/day across many populations, current U.S., Australia, and New Zealand Dietary Guidelines recommend limiting sodium intake to 2.3 g/day for adults and most adolescents. U.S. Guidelines and some others suggests that some segments of the population, including blacks of any age, everyone over age of 50, and anyone with high blood pressure, diabetes or chronic kidney disease (~50% of the US population), should limit sodium intake to as low as 1.5 g/day. This talk will address a number of provocative questions about dietary sodium. For example, is current salt intake excessive for most individuals and would a lower level of intake generally be better? Would most people be healthier if they consumed less salt, or might salt restriction have unintended consequences on health outcomes such as lipid levels or insulin resistance? Is it even feasible to reduce sodium levels in the general population? Evidence for the effects of dietary sodium and sodium restriction on blood pressure and secondary vascular outcomes will be reviewed. The role of salt sensitivity and its interaction with patterns of dietary potassium intake have also emerged as important factors in dietary advice for the prevention of high blood pressure and related cardiovascular outcomes. In general, the roles of several dietary minerals on cardiometabolic risk seem to have been underestimated. For example, with its ability to affect vascular tone, potassium may play a much more important role in blood pressure regulation and cardiac functioning than has been previously appreciated. Calcium also has a controversial history. For many years, it was believed to be linked with blood pressure reduction but clinical trials have yielded results that are less than convincing. In the original DASH clinical trials, the calcium content of dairy was a major reason for its inclusion in the combined dietary intervention arm of the study. More recent evidence suggests that other factors in dairy may be responsible these beneficial effects instead. Finally, magnesium is a dietary mineral that may have significant impact on vascular health through the promotion of endothelium-dependent vasodilation and maintenance of normal cardiac electrophysiology. The direct effects of magnesium on blood pressure and other secondary cardiovascular outcomes will be reviewed. Dietary minerals are consumed as a part of an overall nutrient package. As a result, it is important that we look at those nutrient packages in an effort to understand the total effects of dietary sodium, potassium, calcium and magnesium on long-term health outcomes.

Funding source:  National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), the National Dairy Council in the U.S., the Dairy Council of California, USDA and Dairy Australia.