One of the most common hesitations many people have when it comes to embarking on a ketogenic diet is the concern that the diet will result in dangerously high cholesterol. You may worry that eating a higher fat diet will increase your serum cholesterol and, in turn, increase your risk for developing heart disease. Fortunately, this concern is often incorrect and eating a higher fat diet may actually decrease your bad cholesterol and risk for various types of heart disease.

What is Cholesterol 

Cholesterol is a substance made by the liver or consumed in the diet from animal-based products.  Whether you consume food with high cholesterol or not, your liver will continue to produce cholesterol.  

Cholesterol is necessary for multiple physiological processes:

·       Cholesterol is a critical structural element in certain tissues such as your brain and nervous system. It is estimated that around 25% of your cholesterol can be found in the brain. In fact, higher saturated fat intake and high cholesterol levels are associated with better mental function in old age!

·       Cholesterol also acts as a transport molecule to shuttle fat soluble nutrients into cells so that they can be utilized appropriately.

·       Cholesterol serves as an essential building block for progesterone, estrogen, testosterone, cortisol and Vitamin D.

·       Cholesterol is vital in the building and integrity of cellular walls

A few types of fatty structures made by the body and found in many foods make up cholesterol molecules. It is essential to proper homeostasis (normal functioning of the human body and the cellular constructs within), because the body employs it for so many functions. Without cholesterol, the body would be incapable of adequate and optimal cellular development and intercellular communication.

Not all cholesterol is created equal and there are a number of different types of cholesterol made and utilized by the body. The ones you hear most about are those discussed in your typical lipid (cholesterol) test and include

·       Triglycerides

·       High-density lipoprotein (HDL)

·       Low-density lipoprotein (LDL)

·       Total Cholesterol (this includes both LDL and HDL cholesterol)

Triglycerides

Triglycerides are directly influenced by the intake of carbohydrate-rich foods and not associated at all with the ingestion of dietary fat. These molecules are also typically associated with increased body-fat percentages, particularly in individuals who carry most of their fat in the belly area. Studies of prognostic data (long-term risk of poor outcomes) have shown that high levels of triglycerides play a key role in the development of and worsening of coronary artery disease. High levels of triglycerides in the blood are thought to be a sign of poor metabolism. Poor metabolism, or metabolic disorders, are associated with obesity, diabetes, heart disease and cancer. Often times, elevated triglycerides are a byproduct of insulin resistance.

A ketogenic diet typically has a positive effect on reducing triglycerides as you significantly reduce your carbohydrate consumption.  The normal range for triglycerides is considered under 1.7 mmol/L

HDL

HDL (high density lipoprotein), known as “good” cholesterol, is associated with decreased risk for coronary atherosclerosis (heart disease) and therefore is seen to reduce risk of heart attack and even stroke. The ideal HDL range is typically above 1.0 mmol/L for men and above 1.3 mmol/L for women.

LDL

LDL (low-density lipoprotein), is the part of the lipid panel that is blamed for coronary disease, strokes, and other issues surrounding atherosclerosis throughout the body. Normal LDL, is considered when results show less than 3.4 mmol/L. However, if you have been diagnosed with coronary disease or diabetes, your cardiologist will likely aim to get this even lower. There is significant nuance with LDL though and it may not be quite the demon it has been purported to be.

Total Cholesterol

The “total cholesterol” value fund on your lipid panel is fairly unhelpful in determining whether or not you are at risk for coronary disease or if your “bad” cholesterol is too high. Total cholesterol includes both HDL and LDL.  However, according to most healthcare institutions, the target for acceptable cholesterol levels is less than 5.2 millimoles per litre (mmol/L) and more than 6.2 mmol/L is considered high. Unfortunately, cardiovascular outcomes have not changed for the better by lowering that value.

Most lipid panels do not include VLDL (very low-density lipoprotein) and do not differentiate the LDL particle into its two primary sizes (large and small particle). This is very important and particle size matters immensely.

LDL Particle Size

Identifying the LDL particle size gives a better risk analysis for atherosclerosis (a disease in which plaque builds up inside your arteries). Research has concluded that large particle LDL is not associated with coronary artery disease, while small particle LDL has a very strong association with the development of coronary artery disease.

You may wonder why you have not heard of your LDL particle size or why it has not been evaluated and discussed. Cost can play a role in this as evaluation of different types of LDL can be expensive and these tests are not available freely in Canada. Conventional thinking assumes that by simply lowering your total LDL, you should lower small-particle concentration and therefore decrease risk for coronary disease. This theory is not as supportive of health outcomes as one may think and patients with well-controlled lipid panels on statin therapy with serum-LDL concentrations within normal ranges continue to develop and experience a worsening of existing coronary artery disease.

80% of the cholesterol in the human body is manufactured by the liver and is not impacted by the intake of food, including dietary fat. The remaining 20% may be influenced by dietary fat intake and the intake of other macronutrients, such as carbohydrates. This may not apply to individuals diagnosed with congenital hypercholesterolemia (a disorder that causes LDL levels to be very high).

Individuals with this diagnosis have fewer cholesterol receptors, and, consequently have more free-floating cholesterol in the bloodstream. In these individuals, the serum cholesterol will be slightly more influenced by their dietary choices. However, an individual with normally functioning cholesterol receptors would not have their serum cholesterol level influenced by increased dietary-fat intake, particularly if that individual is following a lower-carbohydrate diet focused on using fats for energy.

It is also worth understanding that hyperlipidemia (an abnormally high concentration of fats or lipids in the blood) can be the result of other factors like steroids, exogenous hormones, other medications, low thyroid function and kidney disease. In fact, fructose is one of the worst offenders of fatty liver disease and high triglycerides.

Keto and Cholesterol

Numerous studies have researched the difference between the ketogenic diet compared to a low fat diet for weight loss and diabetic control.  In these studies, there was a consistent reduction of triglycerides in the ketogenic group, a result not witnessed in the low-fat group. There was also greater improvement of HDL (good cholesterol) in those following a ketogenic diet compared to the low-fat group.  Furthermore, when particle size was evaluated, the ketogenic group almost always had a greater reduction in small particle LDL, the one associated with increased risk for heart disease or stroke.

What You Need To Know

To summarize, which part of the lipid panel you choose to pay the most attention to is important. The focus should be on triglycerides and HDL and research is showing that a low-carb ketogenic diet usually results in improved cholesterol profile by lowering triglycerides and increasing HDL.  

Cholesterol is a complicated molecule in the body that comes in many different forms – each with different clinical significance. That said, an abundant amount of research suggests that low-carb, high-fat ketogenic diets have a clinically-positive impact on each form. More specifically:

·       Ketogenic diets increase the concentrations of heart-healthy HDL cholesterol more than low-fat, high-carb diets.

·       Lowering carbohydrate consumption in healthy individuals also leads to higher levels of HDL cholesterol.

·       Low-carb, high-fat diets decrease LDL particle concentration (LDL-P) and increase the size of LDL cholesterol.

·       Ketogenic diets decrease the amount of harmful VLDL cholesterol in the blood.

The ketogenic diet accomplishes this by replacing carbs with fats that reduce the total-to-HDL cholesterol ratio. This is strong information that shows the carbohydrate restriction as emphasized in the ketogenic diet can be a healthy choice for you.