Can keto diet contribute to atrial fibrillation?

DEAR DR. ROACH: My husband, age 67, recently was diagnosed with atrial fibrillation. He began feeling very weak, and got dizzy every time he stood. We both had started on the keto diet together about a week prior. I’m a registered nurse. After taking his blood pressure and finding it to be very low for him, I thought he was dehydrated. I fed him extra carbs and lots of fluids, but nothing changed. So we went to the emergency room.

After a few tests and an EKG, he was diagnosed and admitted to intensive care, where he ate a regular diet. I asked the hospital doctor if being in ketosis could cause atrial fibrillation, and he thought that ketosis makes the body more acidic so maybe, but he wasn’t sure. He was put on a blood thinner and metoprolol, and sent home the next day to continue on a regular diet.

The following day, he began having chest pain, sweating and shortness of breath, so we went back to the emergency room. More tests ruled out a heart attack, and when his heart converted back to a normal rhythm, he was sent home until his stress test. He remained on a regular diet and hasn’t had any more symptoms since then, and also passed his stress test.

His doctor cut his metoprolol down and has kept him on the blood thinner. Do you have any thoughts on ketosis causing atrial fibrillation? The keto diet is very popular right now, and I am concerned for friends who may want to try it. — L.S.

ANSWER: The ketogenic diet uses very low amounts of carbohydrates to create a condition called “ketosis,” where the body has ketones in the blood and urine. This can lead to rapid weight loss; however, there is not general acceptance of the diet from the standpoint of overall health, especially in long-term use.

The effect of a ketogenic diet on blood acid is complex, but briefly, the blood pH does not change appreciably in people on a ketogenic diet, because the body has powerful ways of regulating pH. Worse still, the terminology is confusing: ketones do lead to “acidosis” but not a low pH (which is called “acidemia”).

The connection with atrial fibrillation is not clear. An early study noted that several people developed atrial fibrillation during diet-induced ketosis; however, I could not find a well-done study to support or refute a connection. Your husband’s ordeal does raise suspicion, however, that there may be a link. Still, atrial fibrillation is common, and it may have nothing to do with the diet.

DEAR DR. ROACH: I’m an 87-year-old woman and have been taking thyroid pills for many years. What would cure this condition? I try to eat healthy, but is there something I should get more of or avoid? — J.B.

ANSWER: By far, the most likely thyroid condition requiring daily medicine in older women is autoimmune thyroiditis, also called Hashimoto’s. Diet is neither a cause nor a cure: The condition is caused by your body’s own immune system attacking the thyroid gland in the neck, initially causing too much thyroid hormone to be released, then a long period of low thyroid levels in the blood. Symptoms of low thyroid include fatigue, constipation, dry skin and voice changes when severe.

Although many people will get better on their own from autoimmune thyroid disease, most people take replacement thyroid hormone long-term. Blood levels usually are tested yearly but some people may need more frequent checks to make sure the dose is right.

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