Different kinds of Hypothesis and reasons behind why some people may have High LDL yet healthy without any metabolic diseases. Many experts claim that a higher LDL may not be detrimental to health rather more useful, provided our “Triglycerides are low and HDL is High”.
Reputed International Medical Associations and many recent scientific studies determined that there is no clear link between Cardiovascular diseases and high Cholesterol levels.
LDL cholesterol is not bad. HDL is not cholesterol and neither is LDL. “High” and “low” refer to the relative proportion of protein to fat in the bundle. HDL stands for High Density Lipoprotein. LDL stands for Low Density Lipoprotein. (There are three other lipoproteins; chylomicrons, VLDL and IDL) Cholesterol and fat are not water-soluble so they need to be carried around the body in something to do their vital work. The carriers of such substances are called lipoproteins.
Lipoproteins:
Lipoproteins travel round the bloodstream and act as transporters. So LDL and HDL are carriers of cholesterol, as well as triglycerides and phospholipids and proteins. LDL is the carrier of fresh cholesterol and HDL is the carrier of recycled cholesterol.
Almost all the cholesterol in your body does not come from the food- it comes from your own body. Nearly all the cells make cholesterol and majority of it is manufactured in Liver. Your body makes 3000 mg of cholesterol every day. 50% of your cell membranes are made from cholesterol. When you eat more cholesterol, your body makes less, when you eat less, your body makes more.
- LDL is not cholesterol. Low density lipoprotein is a protein that shuttles cholesterol and triglycerides.
- LDL is the carrier that transports cholesterol from the liver to the vessels and cells.
- HDL (High Density Lipoprotein) transports the cholesterol from the arteries back to the liver.
Uses of Cholesterol are:
- Allows cell permeability – allowing electrolytes to travel in and out of the cell
- Protects the cell against microbes
- Needed to make bile
- Needed to make fat soluble vitamins – A, D, E, K1, K2
- Needed to make adrenal hormones like cortisol
- Needed to make sex hormones like estrogen and testosterone
- Your immune system needs cholesterol to function
- Needed to combat the negative effects of bacterial toxins
- Helps inhibit the damage from microbes
- Acts as a band-aid to help in the healing of the endothelium layer
There are 2 types of LDL
- Type A (large buoyant) – Normal, not involved in damage repair. Could last 2 days in the body.
- Type B (small dense) – These are small, they can enter the damaged wall of the artery and are involved in the clotting and plaquing. Could last 5 days in the body.
Look at your triglycerides – If they are high and your HDL is low, then you have more type B LDL which needs attention. But if your triglycerides are low and high HDL, then you have type A which is generally fine to have. Moreover, people who have a lot of small LDL particles tend to have low HDL cholesterol and elevated triglycerides – all of which are markers of insulin resistance and reflect increased cardiovascular disease risk.
One interesting note is that sometimes low triglyceride levels can occur with high LDL levels (which often indicate a higher heart disease risk). If low triglyceride levels lower heart disease risk, but high LDL levels increase it, what can cause this inconsistency?
There are two types of LDL particles that should be taken into account when calculating heart disease risk:
- LDL-A particles are larger, less dense, and lower your risk.
- LDL-B particles are smaller, denser, and increase your risk.
When you have low triglyceride levels but high LDL levels, it could indicate that you have a diet filled with healthy fats.
Healthy fats will not only cause an increase in good cholesterol (HDL) but can also change the type of the LDL particles in the blood. Therefore, those high LDL levels may not actually be a bad thing.
Instead, it is more likely that they are LDL particles that have become larger and less dense from the intake of healthy fat. Low triglycerides and high HDL levels in the blood will generally support this idea.
- Total cholesterol / HDL cholesterol ratio – Should be between 3 and 4 to ensure healthy cholesterol levels and a substantially reduced risk of heart disease. Total-to-HDL cholesterol ratio is the best predictor of cardiovascular disease risk on the basic blood lipid panel
- Triglyceride / HDL ratio – Another better way of calculating cholesterol link to cardiovascular disease.
- Less than 2 is good.
- Between 2 and 6 is bad and has to be lowered below 2.
- Greater than 6 is very bad.
Here are some of the problems with low cholesterol:
- Depression
- Cellular damage
- Low sexual hormones
- Strokes
- Aortic dissection
- Prone to suicide
- Short term memory loss in elderly
- Susceptibility to infection
- Increase risk for allergies and asthma
Main reasons why some healthy people may have higher LDL levels
- Ultra-endurance athletes habitually consuming a very low-carbohydrate/high-fat diet for over a year showed unique cholesterol profiles characterized by consistently higher plasma LDL-C and HDL-C, less small LDL particles, and lipoprotein profiles consistent with higher insulin sensitivity. There may be a functional purpose to the expansion of the circulating cholesterol pool to meet the heightened demand for lipid transport in highly trained, keto-adapted athletes.
- In most people who follow keto or low-carb diets, blood cholesterol goes up little, if at all. Some even experience a drop in LDL cholesterol after starting low carb. However, others experience an increase in both LDL and HDL cholesterol levels.
- A rise in cholesterol during keto or low-carb eating may be related to losing weight. It’s been known for decades that major weight loss can lead to a temporary rise in LDL cholesterol.
- Feldman’s theory about why this happens is based on research he’s conducted on himself and data he has gathered from hundreds of other low-carbers. He states that the higher energy demands, lower body fat stores, and lower glycogen stores in these LMHRs trigger the liver to increase production of lipoprotein particles so that triglycerides (fat) can be transported to cells for use as fuel. Since cholesterol travels along with the triglycerides, blood cholesterol levels might rise as the liver pumps out more lipoproteins to keep up with the body’s energy demands. (However, this theory is unproven and other potential explanations exists. For instance, the process of making ketones requires a compound called acetyl-CoA, which is a precursor to cholesterol. Having more acetyl-CoA in circulation could theoretically increase cholesterol synthesis)
- And a third theory is that higher saturated fat intake increases cholesterol absorption while a low insulin state decreases LDL receptor activity. When combined this can significantly increase circulating LDL concentration.
Generally what happens during Low Carb diet
- Decrease in body fat and abdominal fat
- Decrease in triglycerides
- Increase in HDL cholesterol
- Decrease in small LDL particles
- Lower blood glucose levels
- Lower insulin levels
- Increase in insulin sensitivity
The fact that so many risk factors remain stable or improve with carb restriction – even if LDL cholesterol levels increase – demonstrates the importance of not viewing any one value in isolation. Instead, it may be better to look at the body as a whole system.
The liver is central to the regulation of cholesterol levels in the body. Not only does it synthesize cholesterol for export to other cells, but it also removes cholesterol from the body by converting it to bile salts and putting it into the bile where it can be eliminated in the feces.
*Do read the Disclaimer
References:
https://www.dietdoctor.com/low-carb/cholesterol-basics
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC151113/
https://www.healthcentral.com/article/cholesterol-part-one-a-patient-guide