Q1. My doctor advised me to avoid potassium. I am suffering from high blood pressure and eat foods rich in this mineral. I am 72 years old. In my twenties I developed kidney stones, but they have not bothered me for many years. I am very careful with my diet, and I exercise and keep very active. Please explain the effect of potassium on my kidneys — is it really necessary that I give it up?
— Teresa, Japan
The kidney filters important ions from the bloodstream including sodium, potassium, and calcium. People with kidney dysfunction (mild or severe kidney failure) may not be able to handle potassium loads normally. Excessive amounts of potassium can accumulate in the bloodstream of patients with kidney failure and can lead to complications with the heart rhythms.
Medications used to lower high blood pressure may alter kidney function, which can raise potassium levels out of the normal range.
Thus, a physician may recommend a low-potassium diet depending on your level of kidney function, the type of medicines you are on for high blood pressure, and your baseline potassium level. Serial testing of potassium levels would be done to monitor and assess the effectiveness of the diet.
Q2. Can a person with chronic obstructive pulmonary disease (COPD) use diet pills, if they choose? It seems like my two inhalers, Advair and Spiriva, make me want to eat.
Yes, you can take diet pills if you have COPD. When I say diet pills, I'm referring to prescription drugs, like Meridia, Xenical ,and Phentermine. Meridia and Phentermine suppress appetite in the brain and have some side effects such as high blood pressure, palpitations, insomnia, and headache.
Xenical blocks up to 30 percent of fat calories from being absorbed. It is meant to be taken with a diet where no more than 30 percent of your calories come from fat. The more fat in your diet, the more fat that will be blocked from digestion, which can cause gastrointestinal distress such as flatus or oily stool. Xenical is also available over the counter in a lower dosage under the brand name Alli.
Q3. Why do we need potassium? What foods — other than bananas — are good sources of potassium?
— Susan, Florida
Potassium is needed to transport ions between cells — this is a major factor in metabolism and keeping your heart pumping the way it should. If you take medications that "waste" potassium, like diuretics (water pills), your body will excrete potassium in the urine. If this is the case, you need to make sure that you get enough postassium through your diet or take a potassium supplement. If you don't like bananas, don't worry, there is potassium in most fruits and vegetables.
A balanced diet — including potassium-rich fruits and vegetables — can guard against low potassium levels. For athletes who work out to exhaustion, it is sometimes important to take potassium supplements along with a salt replacement and drink a lot of water. However, for those who exercise moderately, a potassium replacement is probably not necessary.
Q4. Someone suggested that my potassium levels may be lower than they should be. What are the symptoms of low potassium? How much potassium should I take in daily, and how do I meet those requirements? Why is getting the proper amount of potassium important?
— Myron, Nevada
Potassium is an electrolyte that is important for normal function of the nervous system, muscles, kidneys, and adrenal glands, as well as for maintaining fluid balance. Low levels of potassium can cause weakness, confusion, muscular twitches, and arrhythmias (abnormal heart rhythms) that can be life-threatening. Most people who eat plenty of foods high in potassium (meats and fish; fruits such as bananas, apricots, and avocados; and vegetables such as spinach and potatoes) get enough in their daily diet. Athletes may need extra potassium during and after marathons or other demanding activities that cause loss of fluid and electrolytes. Other people who might need potassium supplementation are those on diuretics (aka water pills, typically used to treat high blood pressure) and other medications.
Q5. I've heard that vitamin A acetate can deplete minerals in bones. I take a multivitamin that contains vitamin A acetate — am I at risk for osteoporosis?
Vitamin A acetate is the typical form of vitamin A used in vitamin and mineral supplements. Vitamin A is needed for many reasons — it promotes good vision, immunity, and healthy skin, for example. In toxic doses it can make your bones brittle — among other effects — but these are doses in the range of 20,000 to 25,000 IU per day in adults and 10,000 IU per day in children. Check your multivitamin supplement for the dosage of vitamin A or beta-carotene — most multivitamins are dosed for vitamin A at well below the toxicity level and should not put you at risk for osteoporosis.
Q6. If you take diet pills for years and then stop, can you gain a lot of the weight back?
That depends. If you take diet pills for years and stop, you can indeed gain a lot of the weight back if you have not made permanent lifestyle changes with regard to diet and exercise. Prescription appetite suppressants signal the brain to make you feel less hungry, so if you stop taking them, your appetite will certainly come back.
Keep in mind that the purpose of diet pills is to help you shed pounds and feel confident that you can, in fact, lose weight; pills can also help you maintain weight loss. However, there is no shortcut to changing your lifestyle by increasing physical activity and/or decreasing caloric intake. If you don't burn more calories than you consume, there is no way to keep that weight off.
Q7. I had gastric bypass surgery and need to know if my diabetic and cardiac meds are being absorbed properly. None of my specialists nor my pharmacist seems to know for sure.
— Kimberly, Florida
The answer is yes. Following most gastric bypass surgeries, medications (as well as food) pass from the stomach directly into the jejunum, the part of the small intestine where most absorption takes place. The good news is that virtually all medications are adequately absorbed, as there are still many feet of small intestine remaining for that process to occur. Some medications are coated to avoid stomach upset or are time-released to dissolve in the small intestine, but even these medicines are adequately absorbed. You may occasionally see remnants of the pills (casings or coatings) in your stool, but rest assured that your body has most likely absorbed their contents.
I do recommend that patients who have had a gastric bypass have their iron and folic acid levels checked once a year, because these nutrients are primarily absorbed in the first part of the small bowel and may need to be supplemented if levels are low. Iron can be given by injection, as it can cause stomach upset at high doses after gastric bypass. Folic acid can be taken at high enough levels by mouth to overcome any deficiencies.
Learn more in the Everyday Health Diet and Nutrition Center.