What we commonly refer to as table salt is made up of two elements (sodium and chlorine) and known as sodium chloride. Though a high sodium intake is associated with adverse health effects, a small amount is required to maintain normal bodily functions. Unfortunately, with an increased reliance on processed and convenience foods, sodium intake in American diets is dangerously high.
What is sodium?
Sodium is responsible for proper functioning of muscles and nerves and helps regulate fluid balance in the body1. Sodium is added to food for a number of reasons including: curing meat, improving consistency, retaining moisture, enhancing flavor and increasing shelf life2.
Sources of Sodium
Sodium is found in a wide variety of foods with content ranging from innocuous in fruits and vegetables to extreme in processed and convenience foods. Though a common image of sodium is the salt shaker, the FDA says 75% of sodium comes from packaged and restaurant foods while only 11% comes from salt added to food when cooking or eating2.
The vast majority of sodium intake comes from processed foods, not the salt shaker or home cooking. Sodium intake is much higher in individuals who rely on processed foods compared to those who prepare their own meals. Examples of processed foods include: frozen, ready to eat meals, fast food (pizza, hamburgers, fries, burritos) and pre-made ready to eat grocery store meals (fried chicken, sandwiches, chicken wings).
The Institute of Medicine (IOM) creates recommendations for all nutrients based on gender, age and other health considerations such as pregnancy and lactation status. The IOM has two separate recommendations for sodium: adequate intake (AI) and tolerable upper intake level (UL).
Adequate intake (AI) is "a mean intake which appears to sustain a desired indicator of health." Tolerable upper intake level (UL) is defined as "the maximum intake that is unlikely to pose risks of adverse health effects in health individuals3." In other words, AI is a goal, UL is the highest amount you should consume.
On average, Americans consume ~3,300 milligrams of sodium per day2. The AI for sodium is 1,500 milligrams per day for males and females over the age of nine4. The UL for sodium is 2,300 milligrams per day for males and females over the age of fourteen4. The average American consumes more than twice the AI and almost 50% above than the UL of sodium per day.
As a reference, a Big Mac from McDonald's contains 970 mg of sodium and a side of medium fries contains 190 mg (1,160mg when eaten together; almost 100% of the AI)5. Diets relying on processed foods are extremely high in sodium.
Effects of Excessive Dietary Sodium
High sodium levels lead to hypertension (high blood pressure), increased risk of cardiovascular disease and stroke4. One study concluded, "1.65 million deaths from cardiovascular causes that occurred in 2010 were attributed to sodium consumption above a reference level of 2.0 g [2,000mg] per day6." Another study found, "the totality of evidence suggests that most people will likely benefit from reducing sodium intake" in terms of a reduced risk of stroke and fatal heart disease7.
Ways to Decrease Sodium Intake
There are plenty of small steps and comprehensive strategies to lower sodium intake. Because 75% of sodium comes from processed or restaurant foods, eliminating, or at least reducing reliance on these products, greatly reduces sodium intake. Other ways to reduce sodium intake include: cooking instead of eating out, avoiding canned items or other foods which rely on sodium as a preservative, using non-sodium flavor enhancers (pepper, garlic, onions) and utilizing fresh ingredients.
The DASH (dietary approaches to stop hypertension) diet was developed as a comprehensive strategy to reduce sodium intake and reverse hypertension. The DASH eating plan emphasizes (among other steps) buying fresh, frozen or no salt added canned vegetables, using fresh rather than processed meats, consuming low or no sodium versions of products and limiting flavor packets or mixes8.
The Bottom Line
The evidence is clear: an increased sodium intake leads to high blood pressure and an elevated risk of cardiovascular disease, stroke and kidney failure. The vast majority of dietary sodium comes from processed foods. Decreasing reliance on these convenience foods lowers sodium intake and reduces the risk of sodium-related health issues.
- Sodium. (n.d.). Retrieved March 22, 2016, from https://www.nlm.nih.gov/medlineplus/sodium.html
- Sodium in Your Diet: Use the Nutrition Facts Label and Reduce Your Intake. (2016, March 11). Retrieved March 22, 2016, from http://www.fda.gov/Food/ResourcesForYou/Consumers/ucm315393.htm
- New Report Recasts Dietary Requirements For Calcium. (1997, August 13). Retrieved March 22, 2016, from http://www8.nationalacademies.org/onpinews/newsitem.aspx?RecordID=5776
- Dietary Reference Intakes: Electrolytes and Water. (n.d.). Retrieved March 22, 2016, from http://www.nationalacademies.org/hmd/~/media/Files/Activity Files/Nutrition/DRIs/DRI_Electrolytes_Water.pdf
- McDonald's USA Nutrition Facts for Popular Menu Items. (n.d.). Retrieved March 22, 2016, from http://s3.amazonaws.com/us-east-prod-dep-share-s3/dna/pushlive/nutritionfacts.pdf
- Mozaffarian, D. (2014). Global Sodium Consumption and Death from Cardiovascular Causes. New England Journal of Medicine, 371, 624-634. Retrieved March 22, 2016, from http://www.nejm.org/doi/full/10.1056/NEJMoa1304127
- Aburto, N. (2013). Effect of lower sodium intake on health: Systematic review and meta-analyses. British Medical Journal. Retrieved March 22, 2016, from http://www.bmj.com/content/346/bmj.f1326.long
- Salt. (2014, August 21). Retrieved March 22, 2016, from http://www.cdc.gov/salt/reduce_sodium_tips.htm