Bad cholesterol is a topic on which there are many misconceptions. All cells in the body need cholesterol to properly build and function. Most of the cholesterol in the body does not come directly from food, such as eggs and meat, but from the liver, which can produce cholesterol from everything we eat. In that case, what, if not food, raises cholesterol levels?
WHAT IS CHOLESTEROL?
Most people don't really know exactly what cholesterol is.
Without it, life is impossible. The cell membranes that envelop the cells and protect them must contain cholesterol in order to function properly. It makes the membranes firm enough and protects them from tearing. But that's not all!
All these vital components of the human body are made of cholesterol:
- Cortisol (a stress hormone with anti-inflammatory properties)
- Aldosterone (regulates salt balance)
- Vitamin D
- Bile (needed for absorption of fats and vitamins)
- Brain synapses (exchange of nerve impulses)
- Myelin sheath (wraps and isolates nerve cells)
WHAT IS THE DIFFERENCE BETWEEN FATS AND CHOLESTEROL?
Cholesterol is made up of carbon, hydrogen and oxygen. Its structure is similar to that of fat, but it is not so fatty but rather a solid, waxy substance that does not contain any fat. Here's what a fat molecule looks like:
And this is what a cholesterol molecule looks like:
At first glance it can be seen that they are radically different from each other.
Fat is a simple long chain, while cholesterol is a complex combination of rings - 3 hexagons plus one pentagon. He is affectionately called "three rooms with a bath" at the medical university. Fat building is relatively easy (involves 11 chemical steps from acetyl-coA to triacylglycerol), and cholesterol is difficult to build - the formation of one molecule requires over 30 chemical steps (from acetyl-coA to cholesterol). The body would not do this for no reason. Especially when it is built once, the body cannot destroy it - it cannot break its complex ring structure.
CHOLESTEROL IN FOOD
How much cholesterol should we consume?
Cholesterol is so important that the body can produce it from EVERYTHING - fats, carbohydrates or proteins. You do not need to consume cholesterol in order for the body to produce it. Even if your diet contains no cholesterol like vegetarians, the body will still build it. Write on the internet search engine "high cholesterol vegetarians" and you will find many cases of vegetarians suffering from high cholesterol even though they consume zero grams of it.
Which foods contain cholesterol?
Each animal cell contains cholesterol, therefore all foods of animal origin contain cholesterol.
Most people are unaware that all muscle meat (chicken, fish, beef, pork, etc.) contains almost the same amount of cholesterol per serving.
Certain animal foods - liver, yolks, dairy, glandular organs and the brain - are high in cholesterol. What caused this? The liver is where cholesterol builds up. The yolks have concentrated cholesterol because the developing chick needs it to build new cells. Cholesterol is present in milk because the little calf uses it to create new cells. Glandular organ meats (pancreas, kidney, etc.) contain more cholesterol because the glands synthesize hormones and hormones are made of cholesterol. There is a huge amount of cholesterol in the brain that is found in the myelin sheath. There he plays the role of a nerve cell insulator.
All plant foods contain no cholesterol. It is more accurate to say that plant foods do not contain animal cholesterol. Plants have their own kind of cholesterol, called phytosterols. They are toxic to the cells of the human body, so our intestines reasonably refuse to absorb them.
So, in most cases, foods of animal origin contain cholesterol that the body can absorb and use, and plant foods contain cholesterol that our body cannot absorb. The only known exception to this rule is crustaceans.
These animals are of two main types: crustaceans (lobster, shrimp, crab, etc.) and molluscs (mussels, oysters, etc.). Crustaceans - giant marine insects that hunt for their food - contain animal cholesterol that our body can absorb, but mollusks that collect nutrients by filtering seawater contain a different kind of cholesterol that we cannot absorb.
In fact, plant cholesterol and molluscan cholesterol not only repel our gut cells, but also interfere with the absorption of animal cholesterol. This is how some margarine brands are marketed. Manufacturers use chemically altered plant cholesterol to prevent the absorption of animal cholesterol.
Will cholesterol consumption increase the levels in my organism?
Yes, but only if your body needs more cholesterol.
The cells in the small intestine lining contain transport molecules (NPC1L1) that absorb cholesterol. [Cholesterol-lowering drugs block NPC1L1 but still do not reduce the risk of heart attack]. But if your body no longer needs cholesterol, there is another molecule (ABCG4a) that returns the cholesterol back to the intestines from where it is dumped. This is one reason why it is virtually impossible for cholesterol consumption to increase its levels in the body. The gut cells know exactly what amount is needed and will not allow the absorption of more cholesterol.
If we think about it, this mechanism is magnificent (the human body is so clever) - the body cannot break down the complex structure of cholesterol, so it doesn't make sense to absorb too much of it. Once inside the body, the only way for cholesterol to come out is through bile. Why should it be absorbed more than necessary if it is then necessary to remove it?
But if your body's cholesterol levels are low, the cells in the gut will not remove it, but will enter it into the bloodstream because you need it.
What's more, our body recycles cholesterol extremely efficiently, because building it is very difficult. Why make unnecessary effort? Remember, the body cannot break down cholesterol, so the only way to get rid of it is to throw it away. The liver eliminates excess by releasing free cholesterol in the intestine along with the bile.
This free form is the only type of cholesterol that cells in the gut can absorb. Most of the cholesterol molecules in the food (85-90% of them) are not free but in the form of "cholesterol esters". [These are molecules to which fatty acids are attached]. The cells of the gut cannot absorb the cholesterol esters, which are the main form of cholesterol in food. Therefore, if the cells in the gut feel that the body needs more cholesterol, they will absorb it back from bile, not from food.
To summarize the relationship between cholesterol in food and blood cholesterol:
- Most of the cholesterol in the food is not absorbed unless its levels in the body are low.
- The amount of cholesterol consumed has almost no effect on its levels in the body.
- Much of the cholesterol in the body is produced by the cells of the body. Remember that ominous cue from the movie "When the Stranger Call"? "They call you from home." Excess cholesterol comes from your body, not from the food you consume.
How does the body generate cholesterol?
All cells can produce cholesterol, but those in the liver do particularly well. Only they can produce more than they need and spread cholesterol in other parts of the body.
Remember that over 30 chemical reactions are needed to create a single cholesterol molecule? The most important of these is step # 3, in which the important enzyme HMG-CoA (3-hydroxy-3-methylglutaryl-coenzyme A) reductase converts a molecule called HMG-CoA into another molecule known as mevalonate. Once this step begins, there is no going back. This reaction is determining whether or not cholesterol will be produced. Therefore, the enzyme responsible for the reaction, HMG-CoA reductase, is extremely important - it is the primary responsible for the cholesterol production line. This enzyme has to be controlled very carefully because I don't want it? cells in the body lose time and energy in indiscriminately producing expensive cholesterol cells.
The activity of the HMG-CoA reductase enzyme is mainly controlled by two factors:
- The levels of cholesterol in cells
- The levels of insulin in the blood
Things get very interesting here. It is logical for HMG-CoA reductase to respond to cholesterol levels in the cell. If they are low, it would be good to activate this enzyme to produce more cholesterol. If there is enough in the cell, it would be good to deactivate the enzyme and stop the production of cholesterol. But what is the role of insulin?
We usually assume that insulin regulates blood sugar, but its true role is to grow as a growth hormone. Insulin should be triggered as we grow. And what do we need to grow? More cells. What do we need for cell formation? Cholesterol. Therefore, at times when the body needs to grow (babies, teens, pregnant women), insulin triggers the HMG-CoA reductase enzyme, which in turn tells cells that more cholesterol is needed. Thus, the body can form new cells.
What causes high cholesterol?
Why the body produces more cholesterol than it needs?
Here's the problem: When people consume too much sugars and starches, especially refined foods and foods with a high glycemic index, insulin levels in the blood can increase significantly. The insulin then activates the HMG-CoA reductase, which tells the cells to produce cholesterol, even if they don't need it. This is the main reason some people have too high cholesterol in their blood. Sugars and starches can increase insulin levels, which confuses the body that it needs to grow, but in fact it is not necessary. This is how low-glycemic index diets and low-carbohydrate diets work - they reduce LDL (bad cholesterol) levels by limiting insulin, leading to reduced HMG-CoA reductase activity.
Statins, such as Lipidor, which are prescribed to reduce cholesterol levels, partly act by hindering the activity of HMG-CoA reductase. If in some circumstances their cells need more cholesterol but statins block the action of this enzyme, they may not be able to get it. Even worse, the synthesis of cholesterol produces not only cholesterol but many other important molecules, including vitamin A, vitamin E, vitamin K and coenzyme Q.
When you consume less carbohydrates, you do not artificially block synthesis, but simply allow the HMG-CoA reductase to respond to other, more important signals (such as cholesterol levels and growth requirements), and at the same time evaluate naturally when to activate and deactivate.
To summarize, refined carbohydrates accelerate cholesterol synthesis, while statins slow it down. Which approach should you use to deal with your "cholesterol problem - will you drink a drug that will artificially delay synthesis or change your diet and thus trigger cholesterol production when needed? [Tip: Eating changes do not require monthly payments and have no dangerous side effects.]
It is very likely that if you have "high cholesterol" you will not have a cholesterol problem but have a carbohydrate problem.
Good cholesterol and bad cholesterol
This brings us to the complex relationship between blood cholesterol tests and the risk of heart disease. This is an extremely broad topic, so we will only summarize some of the most important information.
"Good" cholesterol = HDL
HDL particles collect cholesterol from the body and transport it back to the liver where it can be excreted by the body if it is not needed.
"Bad" cholesterol = LDL
LDL particles carry cholesterol-produced cholesterol to the rest of the body's cells.
Cholesterol in the HDL and LDL particles is exactly the same, but HDL carries it in one direction and LDL in the opposite direction. The reason LDL is considered "bad" and HDL is "good" is because numerous epidemiological studies (the most famous of which were conducted in Framingham, USA) show that high LDL levels are associated with higher myocardial infarction and high HDL levels are associated with a lower myocardial infarction risk.
In the past, we thought HDL was good because it acts as a garbage truck that clears the bad cholesterol from our bodies, and LDL is bad because it makes its way into the coronary arteries and clogs them with bad cholesterol, which causes plaque formation and causes heart attacks.
Cholesterol, carbohydrates and heart disease
Today, however, this simplistic thinking about cholesterol and heart disease is undergoing serious development. It turns out that things are more complicated. LDL exists in several forms. It can be large and fluffy or it may be small and dense. Under the new concept, small, dense and oxidized LDL may be the only type of LDL associated with heart disease. Therefore, rather than assuming that all LDLs are "bad", it would be more accurate to say that not all LDLs are the same - the large, fluffy LDL is "good" and the small, dense, oxidized LDL is "bad".
Unfortunately, standard blood tests cannot determine which type of LDL you have, because they count all at once. Standard tests can only calculate how much of your cholesterol is moving in the LDL particles. They cannot determine how many LDL particles are in your body, how large they are, how dense they are, and how much they are oxidized.
What we know from studies is that people who consume a lot of refined carbohydrates typically have more "bad" (smaller, denser, more oxidized) LDL particles. This sounds logical, especially since we know that carbohydrates are "pro-oxidants", ie. they cause oxidation.
Many data also indicate that refined carbohydrates can cause inflammation. The fact that doctors find cholesterol in the plaque that clogs the arteries does not mean that it causes plaque buildup. We already know that heart disease is inflammatory. The innocent, smooth, floating spheres of fat and cholesterol do not just decide to enter the bloodstream and somehow make their way to a healthy coronary artery. The first step in the formation of a plaque obstructing the blood vessels is inflammation in the lining of the artery itself. When doctors cut the plaques, they don't just find cholesterol. They detect traces of inflammation (such as macrophages, calcium and T-cells). In an inflammatory process in the body, cholesterol arrives to repair the damage because it is needed to build new cells. The conclusion that coronary artery plaques are caused by cholesterol in them is comparable to the assumption that crashes are caused by ambulances that arrive at the scene of the accident.
Recent studies have shown that a diet rich in refined carbohydrates and foods with a high glycemic index increases the risk of inflammation in the body and especially in the blood vessels. Diabetes - a disease that is closely linked to high blood sugar levels - damages the blood vessels in the retina, kidneys and small blood vessels that nourish the nerve endings in the feet. People with diabetes have been shown to be more at risk of heart disease. Therefore, we can assume that all people with high blood sugar and / or high insulin levels caused by a refined carbohydrate diet are also likely to be at greater risk of cardiovascular disease.
Today, a number of researchers in the field of cardiology are rejecting the idea that saturated fat and cholesterol cause heart disease. After all, how can saturated fat and cholesterol we consume for hundreds of thousands of years be the cause of a relatively new phenomenon such as heart disease? Modern cardiologists find something completely different - that refined carbohydrates (such as sugar and flour), which have only been consumed in significant quantities over the last 100 years, are the most important nutritional risk factor for heart attacks:
"The evidence strongly supports ... the linkage of these diseases to harmful factors, including the intake of trans fatty acids and foods with high glycemic index or load."
'There is insufficient evidence to link the intake of… saturated or polyunsaturated fatty acids; fats,… meat; eggs; and milk. ” [Mente et al 2009].
What does that mean?
There are several plausible explanations for the mechanism by which refined carbohydrates can increase the risk of heart disease and alter the cholesterol profile:
- Refined carbohydrate-rich foods reduce HDL levels and help increase insulin levels, oxidation and the development of inflammatory processes in the body, including in the coronary arteries.
- High blood sugar and insulin levels turn large, safe LDL particles into small, dense, oxidized LDL particles that are proven to increase the risk of heart disease.
- High levels of insulin trigger the HMG-CoA reductase enzyme involved in the synthesis of cholesterol, which forces the body to produce more cholesterol than necessary.
It is becoming increasingly clear that cholesterol is safe until it is "damaged" by refined carbohydrates.
Dr. Georgia Ed's original article can be found on her website Diagnosis: Diet.
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