Sodium has important roles in the body including balancing fluid levels inside and outside of cells. It is naturally found in certain meats, shellfish and milk but is also commonly added to foods. Sodium is found in the highest amount in processed foods and condiments. These foods are a mjor contributor to excess sodium consumption most Americans now have. This high sodium may increase the risk of chronic diseases such as hypertension, heart disease, and stroke. Most heart healthy diets include sodium lowering steps but some wonder if lowering sodium too much can cause other problems.
A systematic review wanted to examine the benefits of decreasing sodium intake for blood pressure and cardiovascular disease and look for potential adverse effects. The review, published in British Medical Journal, found that reducing sodium intake can decrease blood pressure, and reduce the risk of stroke or fatal heart attack.
About the Study
The systematic review included 14 cohort studies and 42 randomized trials. The studies and trials tracked sodium intake and the development of heart disease, stroke or death. The following outcomes were noted:
- In participants that reduced their sodium intake, systolic blood pressure was lowered by 3.39 mm Hg and diastolic blood pressure lowered by 1.54 mm Hg.
- Participants with sodium intake less than 2 grams per day had lower blood pressure reading than participants with sodium intake at or above 2 grams per day to (3.47 mm Hg lower in systolic and 1.81 mm Hg lower in diastolic).
- Higher sodium intake was associated with an increased risk of stroke, death from stroke, or death from heart disease.
- Lower sodium intake was not associated with harmful side effects like kidney dysfunction or increased blood lipids.
- There was no clear link between sodium levels and the development of heart disease or overall death.
How Does this Affect You?
A systematic review is considered a reliable form of research because it creates a large pool of data from many studies. Higher number of participants means the results are more likely to be true and not due to chance. But, the review is only as reliable as the studies that make it up. In this case, there are several high quality randomized trials which are considered a very reliable form of research. The cohort studies are observational studies which can not determine cause and effect but simply point out potential relationships which may make the overall outcomes a little less reliable. These studies also showed fairly small changes in blood pressure numbers. Lowering salt in the diet was not a cure but an important addition to overall effort to lower blood pressure risks.
High sodium consumption does appear to be associated with higher blood pressure and increased blood pressure is a known risk factor for stroke and heart disease. Seek out healthy options for your diet to get a low amount of sodium. Most get excess sodium from processed foods rather than from adding salt to their meals. Be aware of these foods and limit them in your diet. Opt for fresh fruits and vegetables and other whole foods when possible. If you have a chronic health condition, talk to your doctor or dietitian about a dietary plan to help you find the right balance.
- Reviewer: Brian Randall, MD
- Review Date: 06/2013 -