Question: I’m a 59 year old female with normal kidney function, according to lab tests. My problem is salt. I can’t eat even close to the RDA of salt without my body retaining fluid. I like to eat popcorn, but I always use a salt substitute. Do you know why this could be happening?

Dr. Hibberd's answer:
When the body retains too much salt, the excess salt causes the body to retain water. This water then leaks into the interstitial tissue spaces, where it appears as edema. Patients experiencing a disturbance in their ability to normally excrete salt may need to either be placed on a diet limited in salt and/or given diuretic medications (water pills). In the past, patients with diseases associated with edema were placed on diets very restricted in salt intake. With the development of new and very potent diuretic agents, this marked restriction in dietary salt intake is generally no longer necessary. These diuretics work by blocking the reabsorption and retention of salt by the kidneys, thereby increasing the amount of salt and water that is eliminated in the urine.
There is another condition called idiopathic edema which is a common disorder that occurs almost exclusively in women. It is characterized by salt retention in the absence of heart, kidney or liver disease. The swelling (edema) may be episodic or persistent. Swelling of the face, hands, and feet develops rapidly, frequently accompanied by headache, irritability, and depression, with weight gain. Your doctor will be the best person to advice you with the right diagnosis and treatment in your case.