More sodium and lower sodium intake associated with lower cardiovascular disease risk

According to Harvard T.H., lower sodium intake and greater potassium intake are associated with lower risk of developing cardiovascular disease (CVD). Researchers at the Chan School of Public Health.

The methodological shortcomings in previous observational studies have led to confusion about the extent to which reducing current levels of sodium in the diet can increase CVD risk. This study combined high-quality participant data from six cohort studies where sodium was measured using the most reliable method of measurement, multiple 24-hour urine samples. Our results will help determine the role of sodium as an important risk factor for CVD. They reveal that a lower intake of sodium is associated with lower CVD risk in the majority of populations including those from the United States.

Yuan Ma, first author, research scientist, Department of Epidemiology, Harvard Chan School

The study was published online November 13, 2021 in the New England Journal of Medicine.

Sodium, one of the constituents of table salt, is naturally found in some foods, however large amounts of sodium are frequently added to packaged, processed and prepared food items. The U.S. Food and Drug Administration recently released new voluntary guidance encouraging the food industry to gradually reduce sodium–which has been linked in previous studies to elevated blood pressure in commercially manufactured food items in the coming two and two-and-a-half years.

Potassium has an opposite impact on the body. It helps relax blood vessels and increase sodium excretion while decreasing blood pressure. You can find potassium in a variety of foods, including fruits, leafy greens and beans, in addition to dairy foods and starchy vegetables, such as winter squash.

According to the study authors, the relationship between sodium intake and CVD risk has been debated. The vast amount of data, including those from randomized studies, have consistently proven that as daily sodium intake increases, so does blood pressure and, as blood pressure rises also increases the risk of CVD. A few cohort studies have shown that a lower intake of sodium is associated to a higher chance of developing CVD. The studies used methods that were susceptible to measurement errors, such as spots urine or 24-hour samples, which aren’t reliable for estimating the individual’s usual sodium intake.

The study was a pooled analysis of six cohort studies that included the Health Professionals Follow-up Study and the Nurses Health Study. The researchers examined the individual excretion of sodium and potassium and the prevalence of CVD, which includes coronary heart disease and stroke. Multiple urine samples over the course of 24 hours were used to evaluate the intake of sodium. These samples were taken from more that 10,000 healthy adults who had been keeping track of CVD events for almost nine years. 571 cardiovascular events were recorded during the study cohort.

After accounting for a wide range of risk factors for cardiovascular disease The researchers found that a higher intake of sodium as determined by a variety of samples of urine collected over 24 hours, was significantly associated with higher cardiovascular risk in a dose-response way with a daily intake of between 2,000 and 6,000 mg. Every 1,000 mg per day increase in sodium excretion was associated with an 18% increase in risk of CVD. For each 1,000 mg daily increase in potassium excretion the risk of developing cardiovascular disease was 18% lower. In addition the higher ratio of potassium to sodium was associated with an increase in risk of cardiovascular disease. These associations were similar across all subgroups, regardless of age, sex status as well as baseline hypertension weight, or length of time of follow-up.

Frank Hu, Fredrick J. Stare Professor of Nutrition and Epidemiology and chair of Harvard Chan School’s Department of Nutrition, said, “This study highlights the importance of using reliable biomarkers to assess the level of sodium consumed by people regularly and determine the connection with cardiovascular risk.” He was the lead author of the study. “The results provide additional support for public health strategies including regulations, food labeling, and promoting healthy eating patterns to lower sodium intake and increase potassium intake.”

Journal reference:

Ma, Y., and. (2021) 24-Hour Urinary Sodium and Potassium Excretion and Cardiovascular Risk. New England Journal of Medicine.

Content Source:

Gemma Wilson

Gemma is a journalism graduate with keen interest in covering business news – specifically startups. She has as a keen eye for technologies and has predicted quite a few successful startups over the last couple of years.

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