By Dr. Bill Misner Ph.D.
A real and present danger
Approximately six out of every ten persons with blood pressure elevated above 120/80 can blame too much sodium in their diet! There is no Required Daily Amount (RDA) for sodium because our diets are ample. An adequate amount of sodium for adults is between 250-500 mg/day. The Tolerable Upper Intake Level (UL) for healthy adults is 2,300 mg/day.[A] The 2005 Dietary Guidelines for Americans recommends an upper limit of 1,500 mg/day for people over 50 and 1,200 mg/day for those over 70. The average American adult consumes 4,000 mg/day.[B] Too much dietary sodium wears on the human body and may result in disease onset in time.
A high-sodium diet raises serum sodium, a condition known medically as hypernatraemia or hypernatremia. Some researchers believe that only sodium chloride (table salt) is associated with toxicity issues [Wester 1986]. Others argue that too much sodium from the diet is associated with congestive heart failure (CHF), hypertension, stroke, gastric ulcers, cataracts, stomach cancer, osteoporosis, and migraines. CHF patients are advised to reduce their consumption of sodium. (Approximately 57% of CHF patients have elevated muscle sodium levels.)
Researchers believe that sodium elevates blood pressure and is therefore implicated in hypertension [Gordon 1995, Haddy 1995]. This aspect of sodium is still being debated; some researchers believe that sodium has high-sodium diet raises serum sodium, a condition known medically as hypernatraemia or hypernatremia. Some researchers believe that only sodium chloride (table salt) is associated with toxicity issues [Wester 1986]. Others argue that too much sodium from the diet is associated with congestive heart failure (CHF), hypertension, stroke, gastric ulcers, cataracts, stomach cancer, osteoporosis, and migraines. CHF patients are advised to reduce their consumption of sodium. (Approximately 57% of CHF patients have elevated muscle sodium levels.)
Researchers believe that sodium elevates blood pressure and is therefore implicated in hypertension [Gordon 1995, Haddy 1995]. This aspect of sodium is still being debated; some researchers believe that sodium has been falsely "blamed" for hypertension and that the true cause is the chlorine component of sodium chloride. Essential hypertension generally does not occur in societies following diets that provide less than 3,000 mg of sodium (presumably sodium chloride) per day. [C] Hypertension incidence begins to rise with sodium intake exceeding 3,000 mg per day.
In congestive heart failure, the activation of the renin-angiotensinaldosterone system causes sodium retention, and the secondary hyperaldosteronism may result in elevated intracellular sodium via a direct permeability effect on the cell membrane. In 297 CHF patients (previously treated with diuretics), 12% were found to have abnormally high blood sodium levels and 57% had excessive muscle sodium.
Excess dietary sodium may also be associated with an increased risk of:
- Stroke [Nagata 2004]
- Gastric ulcers [Sonnenberg 1986]
- Cataracts [Tavani 1996]
- Stomach cancer [Joossens1996]
- Osteoporosis (by accelerating the loss of calcium from the bones) [Devine 1995, Evans1995, Matkovic 1995, Sellemeyer 2002]
- Migraines [Brainard 1976, Campbell 1951]
Most foods in nature do not contain large amounts of sodium. Humans add sodium for taste and shelf-life preservation if the food is packaged and stored for purchase or preparation. HN
