Dear Dr. Roach: I am a 75-year-old man in excellent overall health. Routine blood work recently showed an elevated potassium level of 5.6. For the most part, I follow a vegetarian diet, which includes a number of foods that happen to be high in potassium. I exercise regularly.
Two years ago, my level was 4.9. My cardiologist stopped my metoprolol, as he said that could have pushed up the potassium, and he felt that based on my routine tests, it was safe to stop it. I also stopped the 500-mg turmeric supplement I was taking, as a precaution. I take no other drugs.
I鈥檇 hate to have to give up bananas and the other fruits that contain potassium. Do you think the 5.6 level is cause for concern, and could you make a recommendation?
V.D.
A potassium level of 5.6 is still in the normal range in my hospital鈥檚 laboratory. Although metoprolol can raise potassium, it鈥檚 not one of the medicines that is very likely to do so, such as an ACE inhibitor or spironolactone. Some people just have a high normal potassium. Turmeric, on the other hand, has lots of potassium, so stopping that was reasonable.
Don鈥檛 worry too much about the potassium and keep up your diet, including fruits in moderation. I would recommend that you avoid salt substitutes, since they have very high amounts of potassium.
听
Dear Dr. Roach: I have hypothyroidism and am taking 50 mcg of Synthroid every day. I started this medication in 2001.
I became a vegan in 1990. I ate a lot of soy products, especially tofu. When I learned I had hypothyroidism, I was told soy was a big negative, so I immediately stopped eating soy products and added eggs and fish to my diet. Could soy be the reason why I am hypothyroid? Should I still stay away from soy products?
I also heard in the news that when taking Synthroid in the morning, you should wait at least one hour before drinking coffee. Is that something I should do? I have been drinking my coffee every morning right after I have taken my Synthroid pill.
S.C.
I also have read that soy protein can have adverse effects on thyroid metabolism. However, a 2006 review of 14 studies found soy has very little effect on metabolism in adults; however, because soy protein can decrease absorption of thyroid hormone (thyroxine, or T3), infants with congenital hypothyroidism are recommended not to take soy-based formula.
Eating lots of soy doesn鈥檛 cause hypothyroidism. Most cases are caused by an auto-immune response against the thyroid. I don鈥檛 think you need to avoid all soy protein, but keep to reasonable levels.
Other foods can decrease thyroid hormone absorption, but in most people the effect isn鈥檛 enough to be clinically relevant. However, you are on a small dose of thyroid hormone, so it could be affecting you. Waiting 30 to 60 minutes after breakfast improves absorption. The study looked at breakfast, not just coffee, but some experts recommend waiting after even coffee if your levels are low.
If you have been fine the way you have been taking it, by both symptoms and blood tests, I wouldn鈥檛 recommend changing.
Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to [email protected].
