High blood pressure: Sodium may not be the culprit

97

Salt has long been vilified as the harbinger of hypertension. However, as research into the condition has delved deeper, it is becoming clear that the story is more complex. The latest study in this arena goes some way toward absolving sodium.
Following a raft of large-scale studies showing that a high salt intake leads to high blood pressure, the Dietary Guidelines for Americans set the recommended sodium intake at 2,300 milligrams per day. However, a new batch of studies are bringing this guideline into question, and researchers are now asking whether the relationship between hypertension and salt is so clear cut.
The latest research to probe sodium’s role in hypertension is presented today at the Experimental Biology 2017 meeting, taking place in Chicago, IL. Researcher Lynn L. Moore, an associate professor of medicine at Boston University School of Medicine in Massachusetts, completed the study with her team.
Moore and her team took data from 2,632 men and women aged between 30 and 64 years, who were part of the Framingham Offspring Study – an offshoot of the Framingham Heart Study. All participants had normal blood pressure at the start of the trial. Over the 16-year follow-up period, the researchers observed that the participants who consumed under 2,500 milligrams of sodium each day had higher blood pressure than those who consumed higher quantities of sodium.
The results seem counterintuitive. As the authors write: “While we expected dietary sodium intake to be positively associated with both SBP [systolic blood pressure] and DBP [diastolic blood pressure], the opposite was found.”
Although the findings appear to kick against the status quo, they are in line with other recent studies asking similar questions. Research has shown that there is a “J-shaped relationship” between cardiovascular risk and sodium. This means that low-sodium diets and very high-sodium diets both carry a higher risk of heart disease. Many people in the United States sit in the middle of this curve, where the cardiovascular risk is at its lowest.
“We saw no evidence that a diet lower in sodium had any long-term beneficial effects on blood pressure. Our findings add to growing evidence that current recommendations for sodium intake may be misguided.
The importance of dietary potassium is also underlined in this study.