Ketogenic diets, not for everyone

The adoption of low-carbohydrate diets can lead to weight loss in many patients. However, these now widespread diets also have the potential to exacerbate hypercholesterolemia.

The objective of this study is to display the potentially harmful effects of the ketogenic diet on cholesterol levels in patients with or without underlying hyperlipidemia.

We describe 5 patients who developed marked increases in plasma cholesterol on ketogenic diets and assessed whether they had a well-described underlying genetic hyperlipidemia.

Three out of 5 patients had extraordinary increases of blood cholesterol levels to over 500 mg/dL. The other 2 patients more than doubled their low-density lipoprotein cholesterol levels on a ketogenic diet. One patient had an APOE E2/E2 genotype. A higher burden of common genetic polymorphisms was found in 2 patients, with no major mutations found. No potential genetic cause was seen in a fourth patient, and the fifth patient had no genetic testing. Three patients, including the one who was most hypercholesterolemic, had a marked reduction in cholesterol after reverting to a more liberal diet. One refused to change his diet but had a satisfactory low-density lipoprotein cholesterol reduction on ezetimibe.

These cases should serve as a caution that high-fat low-carbohydrate diets have the potential to exacerbate or cause hypercholesterolemia in patients with or without underlying genetic hyperlipidemia.