Science Meets Fitness & Exercise
Sodium and the Diet
Sodium (Na+) is both a friend and a foe within the sphere of diet and health. Sodium found commonly in salt (sodium chloride) is an important electrolyte. Electrolytes are substances that become ions in solution and attain the capacity to conduct electricity. The human body relies on balanced electrolyte content for normal function of the cells and organs. However, too much sodium can have negative effects on the functionality of the kidneys and cause them to retain water which in turn can cause increases in blood pressure. Other detrimental factors concerned with high sodium intake could be ‘increased left ventricular mass, the incidence of strokes, a stiffness of conduit arteries, and activity of resistance arteries’ (Wardener and MacGregor, 2002).
So how much salt should an individual consume daily in order to maintain balanced sodium content without negatively affecting the roles of the kidneys? Wardener and MacGregor (2002) assert that ‘The human race is genetically programmed to consume less than 1 g of salt per day’. However, as they also point out, ‘in most human populations, the diet contains 6 to 12 g of salt per day’. This is corroborated by Marcelo et al (2015) who stated ‘Currently, salt intake in the general population is ten times higher than that consumed in the past and at least two times higher than the current recommendation. Indeed, a salt-rich diet increases cardiovascular morbidity and mortality’.
The daily RDA for sodium is around 2.3g (2300mg) which equates to around 1 teaspoon of salt. Let us look at how much sodium certain foods contain so we can determine how much sodium our diets contain. Below is a table of some foodstuffs and their sodium content.
Salt Should Be Used Minimally in a Healthy Diet
To place the sodium ‘conundrum’ into perspective; if you were to have a typical full English breakfast in the morning with two rashers of bacon, one pork sausage, two fried eggs, some beans and tomatoes and two slices of toast you will have already consumed approximately 2250mg (2.25g) of sodium. This is just below 100% of the RDA for sodium. Any sodium consumed above this intake would be considered excessive and detrimental to a healthy diet.
What can you do to reduce your sodium intake? Read food labels carefully and determine exactly how much sodium you are consuming. When you buy foods look for low sodium alternatives. Do not add salt to meals for seasoning. Use other flavours such as pepper, garlic, ginger or chili to give your food taste. Ensure that your diet always allows you to fall below the RDA for sodium intake. Applying all of these strategies is an investment in your long-term health.
One last factor that must be considered is the environment. Remember that when you are in humid hot environments your salt RDA will potentially rise due to the sodium you are losing through the sweating process. It is just as important to make sure you are getting enough salt as it is to ensure you are not consuming to much salt!
References
Marcelo P.B., Rodrigues S.L., Mill J.G. (2015) High Salt Intake As A Multifaceted Cardiovascular Disease: New Support From Cellular And Molecular Evidence. Heart Failure Reviews.
Wardener, H.E. and MacGregor, G.A. (2002) Sodium and Blood Pressure. Current Opinion in Cardiology. 17(4):360-7.
To place the sodium ‘conundrum’ into perspective; if you were to have a typical full English breakfast in the morning with two rashers of bacon, one pork sausage, two fried eggs, some beans and tomatoes and two slices of toast you will have already consumed approximately 2250mg (2.25g) of sodium. This is just below 100% of the RDA for sodium. Any sodium consumed above this intake would be considered excessive and detrimental to healthy diet.