Why Limiting Sodium Intake Can Impair Your Performance
Once upon a time back in the 90's, the government decided it would be a great idea to recommend low-fat diets to the general public based on the assumption that dietary fat makes you fatter.
No credit to overall caloric consumption was given. We later found out that this idea was very flawed and had adverse health effects. Recently, I was scrolling through Facebook and saw one of my colleagues repost an article that had a catchy title to draw the reader's attention (I'm not sharing the link because it deserves no attention). It was one of those articles about the foods you should never eat which are typically very extremist and case dependent. Here's a hint, watch out for those types of articles because they are filled with sensationalism. Within the comments of that Facebook post, a friend of mine mentioned the fact that people should watch their sodium intake because a high sodium diet could lead to hypertension.
I questioned why and asked for her definition of a "high sodium diet" so that they could shed some light on their logic. From my perspective, I wanted to understand her a little better. I try to understand where someone is coming from with a series of questions so I can meet them at their level of knowledge or comfort. But alas, sometimes people are too sensitive on the internetz.
What You Need to Know
Salt and sodium aren't exactly the same since salt is actually about 40% sodium and 60% chloride. If you've ever taken chemistry, you might recall that the sodium ion is positively charged and increases conductivity in nerve cells for communication between neurons which is how muscles are signaled to contract. For that reason, cutting sodium may not be the best choice for athletes or anyone that is regularly active. The National Dietary Guidelines established by the Institute of Medicine (IOM) recommends a daily salt intake of up to 2300mg (2.3g) for people ages 19-50. Even more interesting is that the American Heart Association (AHA) has dropped its recommendations from 2300mg to 1500mg!
Now let's be clear, there is a lot of data that points out reducing sodium intake could reduce hypertension but there are a lot of other very important variables to consider. Age, ethnicity, genetic factors, and dietary factors all have to be considered. The kidneys of a healthy person do a great job at regulating your fluid levels. If you are overly hydrated, you urinate more. If you are under hydrated, you hold onto fluid.
If you have an excessive sodium intake, your body pulls fluids from other tissues in an attempt to dilute the sodium, thus causing a rise in blood volume and pressure. Chronically elevated blood pressure from an increase in viscosity makes the heart have to work overtime to pump the thicker blood through the body which may cause a stroke, heart attack, kidney failure, or other health complications. Healthy kidneys balance this out through excretion of salty urine (sodium and water). Individuals with normal blood pressure have no need to restrict their sodium intake. However, those with higher than desired blood pressure may be more salt sensitive which would be cause for concern. A 2013 study concluded that a modest reduction in salt intake from 9g-12g to levels of 5g-6g would make improvements in BP, however, 3g-4g/day would be more ideal for the long term (1). More interestingly, one study in the Journal of the American Medical Association found that individuals with the highest death rates from CVD were those of low sodium diets and those with the higher sodium intake had the lowest death rates from CVD (2). Try this instead... Still worried about your sodium intake? Incorporate foods with potassium to balance out your sodium intake because they are both essential electrolytes used by the body to regulate blood pressure. Research indicates that a low potassium intake has the same detrimental effects on your blood pressure as a high salt diet.
In some cases, physicians will recommend that patients start incorporating more foods containing potassium to lower their blood pressure especially if they are resistant to making dietary modifications to lower salt intake. In fact, Americans and Canadians consume about half of the recommended 4.7g/day of potassium (3). Try balancing out your diet with potassium-rich foods from a wide variety of fruits, vegetables, and legumes.
For an extensive list of potassium containing foods, you can check out the list on page 104 here. What potassium-rich foods will you start to include in your regular diet? References • http://www.ncbi.nlm.nih.gov/pubmed/23633321 • http://www.ncbi.nlm.nih.gov/pubmed/21540421 • http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1125285/