Dr. Paul D. Thompson, MD, explains how he traces extremely high cholesterol to its source, from family history and inherited genes to thyroid and kidney disease, and why some thin people on ketogenic diets develop remarkably high cholesterol levels.
Finding the Cause of Very High Cholesterol: Family History, Thyroid, Kidneys and Ketogenic Diets
Jump To Section
- How a doctor looks for the cause
- Inherited high cholesterol in certain groups
- Thyroid and LDL receptors
- Protein loss from the kidneys
- Weight loss, ketogenic diets and a strange exception
- A patient example and his advice
- Full Transcript
How a doctor looks for the cause
Finding the cause of very high cholesterol usually starts with the patient's history, according to cardiologist Dr. Paul D. Thompson, MD. Dr. Anton Titov, MD, asks him how doctors find the cause and how dangerous high cholesterol from a ketogenic diet can be.
Dr. Thompson says he can tell the problem is genetic if a patient's father had a heart attack at a young age. Belonging to certain ethnic groups is another clue, which is why taking a family history is one of the ways he identifies the cause.
Inherited high cholesterol in certain groups
Inherited high cholesterol is more frequent in some populations, and Dr. Thompson gives several examples. In Connecticut, one of the groups with high cholesterol levels is people of French Canadian descent. He explains that one of the first 8,000 settlers of Quebec brought in the gene for high cholesterol, which can be traced through Catholic Church records.
He says that one in 50 people of French Canadian origin has high cholesterol, compared with one in 500 Irish people like himself. He also names the Afrikaners in South Africa, Lebanese Christians in the Middle East and a northern Italian gene.
Thyroid and LDL receptors
Thyroid is the second of the four causes on his list, after genetics. Dr. Thompson explains that LDL receptors on the surface of the liver grab LDL cholesterol and pull it into the liver. Two good things follow: the blood level goes down, and the liver cell registers that it has enough cholesterol and does not need to make more.
Thyroid is necessary to make these receptors, he says. Without enough thyroid, the liver does not make enough LDL receptors, and the result can look like inherited high cholesterol.
Protein loss from the kidneys
Nephrotic syndrome can also cause high cholesterol levels. Dr. Thompson describes it as leakage of protein into the urine because something is wrong with the filtering part of the kidney. The liver then gets the message to make more protein.
One of the proteins the liver makes is apolipoprotein B (ApoB), which he calls the carrier for the bad and the ugly cholesterol. Patients with nephrotic syndrome are often sent to him with high cholesterol levels. A urine dipstick showing lots of protein, he says, is all he needs to know the cause.
Weight loss, ketogenic diets and a strange exception
Ketogenic diets are the surprising cause on the list. Dr. Thompson describes them as very low carbohydrate diets with a lot of protein and foods such as eggs, adding that it is not just the eggs. These diets can cause very high cholesterol levels, especially in skinny people.
He explains that LDL cholesterol usually comes down while a person is losing weight. When food intake is low, the liver behaves as if a famine may be coming and saves energy by not making cholesterol. Once the weight loss is over and the person is eating enough calories, LDL goes back close to where it started. Thin people on ketogenic diets are a strange exception, he says, because they can have remarkably high cholesterol levels.
A patient example and his advice
A patient whose chart was on his desk illustrates the point. The man was sent to Dr. Thompson with a cholesterol level of 800, with about 500 of that in the LDL. He was thin and 72 years old. Dr. Thompson reasoned that the cause could not be genetic, because with an inherited level that high he would have died from a heart attack by then.
When asked, the patient said he was following a ketogenic diet because he thought it helped his migraines, and he was eating a fair amount of eggs. Dr. Thompson told him to eat more carbohydrate and cut down on eggs, and he has not seen him back since. He says he is not against ketogenic diets, but people who follow them should have their cholesterol measured to make sure they are not among those whose levels rise sharply.
Full Transcript
Dr. Anton Titov, MD: Very high cholesterol, finding the cause of extremely high cholesterol. On your blog you listed the causes of extremely high LDL cholesterol. The causes include inherited disease, an underactive thyroid, kidney disease with heavy protein loss and ketogenic diets. Professor Thompson, how do doctors find the cause of very high cholesterol? How dangerous is high cholesterol from a ketogenic diet?
Dr. Paul D. Thompson, MD: Those are great questions. How does a doctor find the causes of the cholesterol? Usually by the history.
Dr. Paul D. Thompson, MD: For example, I can tell it is genetic if your dad had a heart attack at a young age. Also, there are certain ethnic groups that have very high cholesterol levels. Let us take an example.
Dr. Paul D. Thompson, MD: In Connecticut, in the United States, one of the groups that has high cholesterol levels are French Canadians, people of French Canadian descent. Why?
Dr. Paul D. Thompson, MD: Because one of the first 8,000 settlers of Quebec (believe it or not, you can trace this back by the Catholic Church records), one of the first 8,000 settlers of Quebec brought in the gene for high cholesterol levels. So, those French Canadians, right? They are Catholics, so we are not having any birth control.
Dr. Paul D. Thompson, MD: They are up there in the cold. One in 50 people of French Canadian origin has a high cholesterol. One in 500 Irish dudes like me has high cholesterol.
Dr. Paul D. Thompson, MD: There are other groups. In South Africa, the Afrikaners brought in the gene for very high cholesterol levels. In the Middle East, Lebanese Christians have the gene.
Dr. Paul D. Thompson, MD: There is also a northern Italian gene. There are certain ethnic groups. So one of the ways we know what the cause of the cholesterol level is: we take a family history.
Dr. Paul D. Thompson, MD: Now, I did list four causes of very high cholesterol levels. One was picking the wrong parents, genetics. The second one was thyroid.
Dr. Paul D. Thompson, MD: I think I talked about the fact that you have these LDL receptors on the surface of the liver. They grab LDL cholesterol, they pull it into the liver, and two good things happen. The blood level goes down, and the liver cell says, oh, I have got enough cholesterol.
Dr. Paul D. Thompson, MD: I do not need to make any more. Thyroid is necessary to make these LDL receptors. So if you do not have enough thyroid, you do not make enough LDL receptors, and it can look like you picked the wrong parents.
Dr. Paul D. Thompson, MD: Now, something called nephrotic syndrome can also cause high cholesterol levels. What is that? Nephrotic syndrome is when people have a leakage of protein from the kidneys.
Dr. Paul D. Thompson, MD: Something is the matter with the filtering part of the kidney. So they have leakage of protein into the urine. So the liver gets the message: I need more protein, make me more protein.
Dr. Paul D. Thompson, MD: One of the proteins that the liver makes is ApoB, apolipoprotein B, and apolipoprotein B is the carrier for the bad and the ugly cholesterol levels. Okay? So if you have nephrotic syndrome, patients will often be sent to me with high cholesterol levels.
Dr. Paul D. Thompson, MD: All I do is a dipstick of their urine, see that there is lots of protein, and know what the cause is. Now here is a very surprising thing: ketogenic diets, very low carbohydrate diets with a lot of protein and a lot of things like egg.
Dr. Paul D. Thompson, MD: It is not just the egg. It can cause very high cholesterol levels, especially in skinny people. Now, what is going on there?
Dr. Paul D. Thompson, MD: Usually when you lose weight, your cholesterol level comes down. Your LDL cholesterol level comes down when you are losing weight, and when you reach a new low weight, it goes back to where you were. The LDL goes back to where you were, pretty close to where you started.
Dr. Paul D. Thompson, MD: Now, why does that happen? When you are losing weight and you are not eating enough, your liver thinks this may be the great famine, right? Oh, I better not waste any energy making cholesterol.
Dr. Paul D. Thompson, MD: This guy is not eating much. We could be in a famine mode here. Let us save some energy.
Dr. Paul D. Thompson, MD: So generally, when you are losing weight, your LDL cholesterol comes down. It goes back to where it was when the weight loss is over and you are eating enough calories. There is a strange exception.
Dr. Paul D. Thompson, MD: Skinny people, thin people doing ketogenic diets can have remarkably high cholesterol levels. Right over here, on the other side of my desk, I have the chart of one of my patients, sent to me with a cholesterol level of 800. Like 500 of that was in the LDL.
Dr. Paul D. Thompson, MD: He was thin, he was 72 years old. Now, why does 72 years old matter? Because I know it could not have been genetic, because if it was genetic and it was that high, he would have died from a heart attack by now.
Dr. Paul D. Thompson, MD: So I asked him, and indeed he was following a ketogenic diet for migraines. He thought it helped his migraines. He was not heavy; he was not fat.
Dr. Paul D. Thompson, MD: He was following a ketogenic diet, and he was eating a fair amount of eggs. I have not seen him back since I told him he needed to eat more carbohydrate and he needed to cut down on the egg input. If you are one of those folks out on the ketogenic diets, and I am not against them, you have got to get your cholesterol level measured to make sure you are not one of those dudes and dudettes who really raises your cholesterol levels on a ketogenic diet.