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Keto and Cholesterol

Let’s talk about cholesterol and the keto diet. Now, the Keto Diet isn’t for everyone, but I will attempt to give a general overview on cholesterol and explain why the lipid panels can look a little crazy, especially when you first start the keto diet.

First, why do we even need cholesterol?

1. Cholesterol is an essential component of cell membranes

  • Fluidity – letting things in and out of the cells

  • Rigidity – providing structure for the cell

2. Cholesterol is a building block for naturally occurring steroid hormones

  • Testosterone

  • Estrogens

  • Progestins

3. Cholesterol is a necessary component to make Vitamin D

4. Cholesterol is an important component of bile acids

  • Bile acids help our body digest fats

  • The keto diet includes high amounts of fat

5. Cholesterol is important for calcium homeostasis/regulation

  • Removes calcium from bones

  • Regulates calcium absorption in the intestines

  • Regulates reabsorption of calcium in the kidneys

6. Some lipoproteins (LDL & HDL) have been shown to inactivate endotoxins released by certain bacteria species

Since cholesterol is a lipid, it does not mix well with water (or blood, since it is mostly water) and must be packaged with water loving molecules to move through the blood stream. This packaging is called a lipoprotein. When your doctor measures your cholesterol on blood work, it is the lipoproteins that are being measured.

· LDL – Low-density lipoprotein – travels from the liver through the blood stream to the areas of the body that need cholesterol. LDL is not “bad” as conventional medicine would have you believe. It is a normal function of our body, a transport mechanism. It is the outbound train.

· HDL – High-density lipoprotein – transports cholesterol from the body back to the liver. This is the inbound train. It is called “good” cholesterol because it is bringing cholesterol back to the liver to be destroyed. Both LDL and HDL are necessary to transport cholesterol to where it needs to go. LDL and HDL need to be in balance with each other. When our lipoproteins are out of balance, this is called dyslipidemia.

· VLDL – Very low-density lipoprotein – this is the main transporter of triglycerides and is eventually converted to LDL.

· Triglycerides – Our dietary fats are converted to triglycerides for storage in our bodies. Insulin triggers this process. Insulin also signals the body to store excess carbohydrates as fat. In the absence of carbohydrates or sugar, our bodies can convert triglycerides to ketones to use as energy in the cells instead of glucose.

Our conventional healthcare system follows the Adult Treatment Panel III (ATP-III) recommendations to treat dyslipidemia and set goals for the amounts of lipoproteins that should be seen on the lipid panel. LDL is the primary target of ATP-III, with an optimal level <100. ATP-III also defines a total cholesterol <200 and an HDL of >60 (or at least not <40) as desirable. These values do not consider the genetic variations that people have or specific eating plans like the ketogenic diet. It also does not consider the size of the lipoprotein particles.

Yes, the size of the LDL particles matters! When we incorporate good fats into our diet, we get nice, big, fluffy LDL particles. These big LDL particles are easily recognized by the liver and cleared out within 24 hours of creation. However, in the 1980’s and ‘90’s, eating fat became stigmatized. Fat was bad, so fat-free and low-fat foods were created: skim milk, low-fat cheese, low-fat yogurt. These were the “healthy” foods. But we replaced fat with sugar to make food taste better and sugar and carbohydrates overtook the grocery store. We wanted convenience with pre-packaged, long-shelf life, processed foods. Obesity, metabolic disorder, heart disease all increased.

Hello, small LDL particles! These small, dense LDL particles are not as easily recognized by the liver due to an altered configuration, so they are not cleared as quickly. They can circulate for 5 days or more, wreaking havoc on our bodies. These particles are more easily oxidized (think about how an apple slice turns brown when exposed to air – that’s oxidation), have increased stickiness (so they stick to arterial walls forming plaques and blocking blood vessels), and are pro-inflammatory. Systemic inflammation is linked to many different disease states (like auto-immune disorders, diabetes, metabolic disorders, and heart disease).

But fat is making a comeback! The Keto Diet has been taking America by storm. The ketogenic diet is an eating plan of very low carbohydrates, moderate amounts of protein, and high fats. It can lead to rapid weight loss, but be careful, the weight can come back very quickly if you abruptly stop. Essentially, you are teaching your body to use ketones for energy instead of glucose. This is more efficient for our bodies because glucose needs a constant carbohydrate source. Most of us eat more carbohydrates than we need, but those extra carbohydrates are converted and stored as fat. Fat that remains stored unless we teach our bodies to use it. With a ketogenic eating plan, those fatty acids are converted to ketones for energy, the body secretes less insulin leading to less fat storage and more fat burning.

But what does the lipid panel look like? Remember, standard lipid panels look at LDL <100, Total Cholesterol <200 and HDL >60. Dramatic changes can happen to these levels on the Keto Diet. Here is an example from a study of a patient with ulcerative colitis that started a ketogenic eating plan: