Cholesterol and fructose The Hidden Danger of Fructose
How VLDL and sdLDL Increase the Risk of Cardiovascular Disease
Fat Formation and the Role of VLDL, LDL, and sdLDL
Excessive fructose consumption can trigger an unhealthy cycle in our bodies, particularly through the conversion of fructose into triglycerides —a type of fat that is stored in our cells. Once fructose reaches the liver, the metabolic process begins, during which a large portion of the fructose is converted into fat. This fat is either stored directly in the liver, leading to non-alcoholic fatty liver disease , or it is released into the bloodstream in the form of VLDL (very-low-density lipoprotein) particles.
VLDL: Fat-Carrying Buoys
VLDL particles are fat-laden transport vehicles responsible for carrying triglycerides from the liver to other parts of the body, where they are either used for energy or stored in fat cells. You can think of these VLDL particles as “fat-carrying buoys” that float through the bloodstream, dropping off their cargo and gradually becoming smaller. However, when the liver becomes heavily fatty—often due to high fructose consumption—it produces especially large VLDL particles that carry a lot of fat. These "especially large buoys" shrink after delivering their fat load into extremely small and dense sdLDL (small dense LDL) particles, which are known as particularly dangerous "bad cholesterol." These small, dense LDL particles can more easily lodge in artery walls and cause inflammation.
Fructose: The Hidden Sugar
Fructose is found in many processed foods, often in the form of corn syrup or added sugar, and is one of the main sources of hidden sugars in our diet.
Visceral Fat: The Invisible Danger
The fat produced by fructose is often stored as visceral fat, which surrounds the organs and increases the risk of metabolic diseases.
The liver and fructose
Fructose is converted into fat in the liver. High fructose consumption leads to fatty liver and increases the risk of insulin resistance.
Fructose and cholesterol
The breakdown of fructose creates VLDL particles, which become LDL (bad cholesterol) in the body. This increases the risk of arteriosclerosis and heart disease.
LDL and sdLDL: The dangerous cholesterol particles
LDL particles, especially the so-called sdLDL (small dense LDL), pose a particular danger. These small, dense LDL particles are much more harmful than normal LDL particles because they have a greater tendency to penetrate artery walls. There, they cause inflammation and promote the formation of plaque—deposits that narrow the arteries and dramatically increase the risk of Cardiovascular diseases, such as heart attacks and strokes. The buoy analogy illustrates this process: Imagine VLDL particles as large, fat-laden buoys that are loaded with fat molecules. As they unload their cargo, they shrink into LDL particles that continue their journey through the bloodstream. sdLDL particles, which are small and dense, resemble "fine sand" that settles into the smallest crevices of the artery walls. They can penetrate deep into the endothelium (the innermost layer of blood vessels), causing inflammation that plays a critical role in the development of atherosclerosis What makes this particularly problematic is that, due to fat overload in the liver, these VLDL particles become extremely large. After delivering their fat load, they shrink into particularly small, dense sdLDL particles, which are especially dangerous. These small particles are the ones that lodge in the artery walls, promoting plaque formation, which narrows the arteries and significantly increases the risk of cardiovascular diseases.
LDL: The bad cholesterol
LDL builds up in the arteries and increases the risk of cardiovascular disease. High LDL levels are often caused by too much fructose and saturated fatty acids.
HDL: The good cholesterol
HDL helps transport excess cholesterol back to the liver where it is broken down. A healthy HDL level can reduce the risk of cardiovascular disease.
sdLDL: The Real Enemy
Small, dense sdLDLparticles are particularly dangerous because they easily penetrate the artery walls and cause inflammation, leading to plaque formation.
The balance between LDL and HDL
A healthy ratio of HDL to LDL is crucial. High fructose consumption can disrupt this balance and weaken HDL effectiveness.
How fructose is metabolized in the liver
fructose is Processed Differently While glucose can be directly used by nearly all body cells, fructose must first be metabolized in the liver. This is because the body lacks specific transporters for fructose to enter cells directly, as is the case with glucose.
When we consume fructose—whether from fruit or added sugar in processed foods—it is transported to the liver, where it can follow two primary pathways:
- Converted into fat: When there is an excess of fructose, it is converted into fatty acids and stored in fat cells. This process contributes to non-alcoholic fatty liver disease (NAFLD) , a condition that is common in individuals with high fructose consumption.
- Converted into glucose: A small portion of fructose can be converted into glucose, which can then be used in the body's energy cycle. However, this occurs to a much lesser extent than its conversion into fat.
The main difference compared to glucose is that fructose does not directly influence the insulin mechanism . This means that fructose does not raise blood sugar levels and, therefore, does not trigger the immediate release of insulin. However, the buildup of fat in the liver caused by fructose consumption eventually leads to insulin resistance and a range of metabolic disorders, including type 2 diabetes.
Plant-based foods to lower cholesterol
Legumes, whole grains, fruits and vegetables contain no cholesterol and are rich in fiber, which helps lower cholesterol levels.
Nuts and seeds for better cholesterol
Almonds, walnuts and chia seeds contain healthy fats and omega-3 fatty acids that help increase HDL levels and protect the heart.
Avoid saturated fatty acids
Saturated fats from animal products increase LDL levels. Vegetable fats such as olive oil and avocados, on the other hand, promote good HDL.
Avoiding sugar and refined carbohydrates
Processed sugars and refined carbohydrates raise insulin levels and promote fat storage. A low-sugar diet helps regulate cholesterol.
The Vicious Cycle of Fat Formation and Deposition
When the body is regularly overloaded with high amounts of fructose, the VLDL metabolism becomes dominant. A vicious cycle develops: The liver produces more triglycerides and VLDL particles to get rid of the excess fat. However, these VLDL particles are converted into LDL and sdLDL, which in turn increase the risk of artery blockages. The formation of plaque in the arteries, triggered by sdLDL particles, narrows the blood vessels and reduces blood flow to vital organs such as the heart and brain. Over time, this increases the risk of heart attacks, strokes, and other serious cardiovascular diseases. Studies have shown that people with high levels of sdLDL are at a much higher risk for these diseases compared to those with normal LDL levels.
The Role of Insulin and Fructose
An important aspect of fructose’s metabolic effects is that, unlike glucose it does not trigger a direct rise in insulin levels . This means that the pancreas does not immediately respond to remove sugar from the bloodstream. Instead, fructose goes directly to the liver, where it is processed and converted into fat These fats are mostly released into the bloodstream as triglycerides and stored as visceral fat in the body.
Visceral Fat and Uncontrolled Fat Storage
Visceral fat is particularly dangerous because it accumulates deep in the abdominal cavity and surrounds the organs. It is not just subcutaneous fat but fat that can impair the function of important organs like the liver, heart, and pancreas. Increased visceral fat mass, in turn, raises the risk of Cardiovascular diseases, insulin resistance and type 2 diabetes..
In addition to visceral fat, the body also deposits excess fats uncontrollably in various organs, such as the liver and pancreas. This leads to non-alcoholic fatty liver disease and promotes inflammatory processes that further contribute to organ dysfunction. Fatty liver is often the first step towards insulin resistance, as the liver can no longer efficiently process sugar.
Omega-3 fatty acids for the heart
Omega-3 fatty acids from flaxseeds, chia seeds and walnuts support heart health and help lower LDL and triglycerides.
Antioxidants for healthy arteries
Antioxidants from plant foods such as berries, green vegetables and nuts fight inflammation and protect the arteries from plaque formation.
Dietary Fiber: The Cholesterol Brake
Fiber, especially soluble fiber from oats, beans and fruit, binds cholesterol in the intestines and helps remove it from the body.
Plant-based nutrition as prevention
A vegan, plant-based diet is low in saturated fats and rich in nutrients that minimize the risk of cholesterol deposits and heart disease.
The Role of HDL and Cholesterol
While LDL and sdLDL are considered "bad cholesterol," there is a type of cholesterol known as "good cholesterol": HDL (High-Density Lipoprotein). HDL particles play a protective role in the body by transporting excess cholesterol from the arteries back to the liver, where it is broken down and excreted from the body. You can think of HDL as small "cleaning buoys" that float through the bloodstream, cleaning up harmful cholesterol particles before they can cause damage in the arteries.
However, with high fructose consumption, the liver increases the production of VLDL particles , which are the precursors to LDL and sdLDL . This disrupts the balance between HDL and LDL: so many LDL particles are produced that the protective effect of HDL becomes relatively insufficient to remove the excess cholesterol from the arteries. This leads to an increased buildup of cholesterol in the arteries and raises the risk of atherosclerosis and other cardiovascular diseases.
Video and image source: Adobe Stock
Important NOTE:
The information provided in our articles was created with the greatest care and to the best of our knowledge and belief. They serve exclusively for informational purposes and do not constitute medical advice. No liability is assumed for the accuracy, completeness or topicality of the content. We assume no responsibility for the application or implementation of the information. If you have any health questions or complaints, it is always advisable to consult a qualified doctor or other specialist.
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