Osteoporosis and Salt
Heavy exercisers need to take in extra salt to replace what they lose through sweat. Some people are concerned that this may cause osteoporosis.
As a general rule, taking extra salt causes the body to
retain extra fluid, which expands blood volume and increases blood
flow to the kidneys to increase loss of calcium in the urine. This
lowers blood calcium levels, so calcium has to be taken from bones
for replacement. Sodium salt also causes the kidney tubules to
lose more calcium. However, potassium blocks the exchange of
sodium for calcium in the kidneys and prevents calcium loss.
Eating calcium also prevents blood calcium levels from dropping so
there is no need for the bones to release extra calcium into the
bloodstream (Journal of the American College of Nutrition, June
2006).
Competitive athletes must eat large amounts of foods to take in enough
calories to fuel their muscles during exercise. A high salt intake in
athletes does not cause osteoporosis because they eat so much
food that contains calcium and potassium that the amount of salt
they take does not cause blood calcium levels to drop, so calcium
does not leach out of bones.
All fruits, vegetables, whole grains, beans and other seeds
are full of potassium. Most varied diets contain adequate
calcium, but if you decide to take a calcium supplement, be sure
you are also getting plenty of vitamin D. Because calcium blocks
the conversion of inactive vitamin D to active vitamin D, extra
calcium increases your needs for vitamin D.
Checked 9/29/08