The ketogenic diet is not a healthy diet: side effects do occur. Fortunately, most of the side effects are treatable or now even preventable. One side effect of the diet that still raises concern amongst neurologists, pediatricians and even parents is hyperlipidemia – namely high cholesterol and triglycerides. A well-done study from 2003 published in JAMA first formally studied this and revealed that total cholesterol and triglycerides about 50 mg/dl after 6 months (the total cholesterol increases from about 170 mg/dl to 220 mg/dl. It is also known that about 60% of children on the diet have elevations in their total cholesterol (>200 mg/dl).
The good news is that this elevation in cholesterol seems to go away. One interesting and reassuring aspect of this study was that by 12-24 months the abnormal values were returning to the results at the start of the diet. Another study of children on the diet for over 6 years found the same thing: cholesterol changes were not the primary concern (bone fractures, growth disturbance and kidney stones were)…the average total cholesterol of these children was 201 mg/dl (normal). Continuing this line of reason, in 2010 we studied children who had since stopped the ketogenic diet and their cholesterol values were normal today. If your child is having high cholesterol on the diet, lowering the ketogenic ratio, adding MCT oil or carnitine may help.
Despite the recent reassuring data, there is still a fear of the effects of even temporary increases in cholesterol and triglycerides. Parents are being warned to have cholesterol checked more frequently on the ketogenic diet than is probably necessary. Of high concern, some families of children with slight elevations of cholesterol are being told that the ketogenic diet would be unsafe and therefore is not an option.
The study by Christiana Liu RD and the ketogenic diet team from the Hospital for Sick Children in Toronto, Canada helps put that last concern to rest. Their study, entitled “Can children with hyperlipidemia receive ketogenic diet for medication-resistant epilepsy?” looked at the issue of children with high cholesterol before the diet and then what happens after the diet is started. Twelve children with elevated cholesterol levels were put on the diet (9 with classic ketogenic; 3 with MCT diet). Total cholesterol dropped right away and was normal by 6 months. Triglycerides took longer to decrease to normal (12 months), but still did. 75% of these children had their lipid values normalize by 12 months.
It is important to note that 3 of 12 children were put on the MCT diet, which may be better for cholesterol values. Also, they were prescribed a low saturated fat ketogenic diet (10% calorie intake), no trans fats, increased polyunsaturated fats, and sometimes omega-3 or carnitine. In addition, they excluded fatty meats, egg yolks, butter, lard, animal fat, cream, palm and coconut oil. Are all these dietary changes necessary for children with high cholesterol values at the start of the diet? That is unclear. It is also very important to note that 9 of 12 had family histories of high cholesterol – we always recommend parents check their own cholesterol values if their child tests high surprisingly.
This paper, even with its small numbers, hopefully helps to eliminate yet another road block to the ketogenic diet. It will be helpful to see what happens to adults with high cholesterol before (or during) the modified Atkins diet. We also hope to come up with better treatments for those patients in which dietary changes, carnitine, MCT oil do not lower their cholesterol values. Would statin medications help? Stay tuned!
Kwiterovich PO Jr, Vining EP, Pyzik P, Skolasky R Jr, Freeman JM. Effect of a high-fat ketogenic diet on plasma levels of lipids, lipoproteins, and apolipoproteins in children. JAMA 2003 Aug 20;290(7):912-20.
Patel A, Pyzik PL, Turner Z, Rubenstein JE, Kossoff EH. Long-term outcomes of children treated with the ketogenic diet in the past. Epilepsia. 2010 Jul;51(7):1277-82