The Study: A Standard Lipid Panel Is Insufficient for the Care of a Patient on a High-Fat, Low-Carbohydrate Ketogenic Diet

 Overview: This article is a case study and examines laboratory findings in a young male patient who adopted a keto diet to help manage his inflammatory bowel disease.

Subsequent changes in his blood lipid profiles which might traditionally have been thought to be adverse are analyzed by the author and with discussion as to how such changes might actually be representative of physiological improvement.

 Key Points: 

A.    High fat/low carb (aka “ketogenic”) diets have become widely popular in recent years. 

B.     Benefits of “keto” diets have been claimed for both weight loss and a wide range of health disorders. 

C.     Ketogenic diets run contrary to decades of mainstream nutritional thought which has promoted low fat/high carb diets as the key to reducing serum cholesterol levels and consequently improving cardiovascular health. 

D.    Consequently, many health care providers now find an increasing number of their patients eating in ways that are not only contrary to their own professional training but also challenging to understand clinically using standard laboratory analysis. 

E.     The study is useful because it highlights how traditional lipid panels can “lead to misleading conclusions” and that “more nuanced” analysis should be considered to better understand what is happening on low carb/high fat diets.   

F.      Standard lipid panels tend to focus primarily only on total cholesterol, high density cholesterol (HDL-C) , low density cholesterol (LDL-C) and triglycerides despite the fact that we now know all LDL-C and HDL-C particles are not created equal and differences in the size and characteristics of various lipoprotein particle types are critical to better understand what is actually happening with the patient.   

G.    Within one week of commencing the high fat/low carb diet the patient experienced dramatic improvement of his G.I. symptoms and his fecal calprotectin level dropped from 123 to 19 (normal is less than 50). Eight months later he had still not experienced any further flare-ups of his colitis. This is a remarkable recovery but this is where the story really begins.  

H.    One week prior to starting the diet the patient had a subfractionated lipid panel done which was repeated after seven months on the low carb/high fat diet.  

I.       Several “alarming changes” were noted on the follow up study: 1) total cholesterol increased by 290 mg/dl (from 160 to 450),  2) LDL-C (traditionally considered to be “bad cholesterol”) increased from 95 to 321 mg/dl and 3) LDL-P (LDL particle count) increased from 1143 to 2259.  If merely taken at face value these changes would likely be interpreted as a substantial increase in risk of atheroslcerosis, but it is here that a closer look at the subfractionation results is informative.   

J.       On the positive side there was improvement in HDL-C (traditionally considered to be “good cholesterol” and having known anti atherosclerotic and antioxidant properties) from 48-109 mg/dl. Note that this increase alone accounts for 61 mg of the 290 mg increase (21%) in total cholesterol mentioned in section I above. 

K.    Not only did the total amount of HDL-C more than double, but the patient’s large HDL particle count (that portion of the total HDL-C which is made up of large HDL particles) jumped from 5699 to “a remarkable” 12,080 nmol/L. High counts of Large HDL particles are strongly predictive of reduced cardiovascular risk. 

L.     Also on the positive side, even though there was a dramatic increase in the LDL particle count, the subfractionation analysis indicated that almost all of the increase was due to an increase in large LDL particles. Current thinking is that much of the risk attributable to increased LDL cholesterol comes from small, dense, oxidized LDL particles, which can more easily penetrate the endothelium of the arteries and perpetuate the buildup of arterial plaque.  

M.   Finally, the article discusses other, more nuanced, interpretations of additional blood factors. The interested reader is referred to the full text for more discussion.   

Author’s Conclusions: The patient’s ketogenic diet resulted in positive changes for his ulcerative colitis but was also associated with an ostensibly adverse change in his serum lipid profile. A deeper analysis “revealed that many parameters might, in fact, be positive.” 

Reviewer's Comments: We rarely review case studies because of the low quality of the evidence but this article was of particular interest to me. Over the last year I have been eating a high fat/low carb diet and have lost 60+ lbs. Like the patient in this case study, I have also experienced a number of changes in my lipid profiles which might be considered adverse. I am currently trying to better understand the nature of these changes and adopting a wait and see approach. Currently I feel great and aside from my LDL and total cholesterol, all other markers appear to be much improved. Good evidence regarding the effect of changes in lipid profiles in low carb diets on cardiovascular risk remains scant but larger scale studies are in the making. I hope to review more on this subject as they become available.  

Reviewer:  Mark R. Payne DC

Reference:  Norwitz N, Loh V. A Standard Lipid Panel Is Insufficient for the Care of a Patient on a High-Fat, Low-Carbohydrate Ketogenic Diet Frontiers in Medicine. 2020 7:97 Published online 202 April 15. PMID: 32351962; PMCID: PMC7174731 

Link to Abstract: https://pubmed.ncbi.nlm.nih.gov/32351962/

Link to Full Text: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7174731/