Lipemia to Ketosis: A Historical Journey Through Fats in the Blood Let’s take a deep dive into the world of fats in the blood, starting with the classic historical experiments on lipemia and ending with how ketosis and exogenous ketones fit into the picture of modern metabolic health. .
Lipemia: The First Observations of Fat in the Blood The story of lipemia—the condition where blood becomes milky or cloudy due to high levels of fat—begins in the early days of lipid metabolism research. Scientists noticed that after a fatty meal, blood drawn from patients sometimes had a creamy layer floating on top. This layer turned out to be chylomicrons, large fat particles that carry triglycerides (Fat molecules) from the intestines into the bloodstream after eating.
In other cases, blood became uniformly turbid or milky—this was due to smaller fat particles (like VLDL and triglycerides) staying suspended in the liquid portion of the blood. These early observations of lipemia led to breakthroughs in understanding how fats travel through the body, why some people have abnormal lipid levels, and the role of these fats in metabolic disorders.
Lipemia and Cardiovascular Risk: The Link to Atherosclerosis From these early experiments, researchers learned that high triglycerides, the primary cause of lipemia, were linked to a higher risk of cardiovascular disease (CVD). When blood contains high levels of triglycerides, it also tends to carry more VLDL particles, which are rich in fats and cholesterol. Over time, this can contribute to plaque formation in the arteries.
LDL Oxidation and Foam Cells: As LDL (“bad cholesterol”) circulates through the blood, it can become oxidized, especially in people with elevated triglycerides or metabolic disorders. Oxidized LDL is engulfed by macrophages (immune cells) that turn into foam cells, which form the basis of atherosclerotic plaques.
Inflammation and Endothelial Dysfunction: The accumulation of foam cells and fatty plaques in the arteries triggers inflammation, which further damages the arterial walls, eventually leading to the narrowing of blood vessels. This is the foundation of atherosclerosis, a key driver of heart attacks and strokes.
Ketosis: The Body’s Natural Fat-Burning Mode While lipemia deals with fats after digestion, ketosis is the body’s way of shifting to fat burning as a primary energy source. When carbohydrates are restricted, as in a keto diet or during fasting, the liver breaks down stored fat into fatty acids, which are converted into ketones. These ketone bodies (like beta-hydroxybutyrate) are then used as fuel in place of glucose.
The metabolic benefits of ketosis include:
Fat loss: By burning stored fat for energy, ketosis can lead to significant weight loss.
Lower triglycerides: Over time, ketosis can reduce the amount of triglycerides in the blood, which helps improve cardiovascular health. (Caveat here is that post meal, which generally have a higher fat content for keto practitioners, levels will be transiently higher. Fasted blood monitoring is very important as will be discussed later.)
Improved insulin sensitivity: Ketosis reduces the body’s reliance on glucose, which can enhance insulin sensitivity and help manage conditions like type 2 diabetes.
Exogenous Ketones: The Shortcut, or Snake Oil? Exogenous ketones are supplements that raise blood ketone levels without needing to follow a strict ketogenic diet. While they may temporarily increase ketones in the blood and provide a quick source of energy, the true metabolic benefits of ketosis—like fat loss and improved metabolism—come from the body producing its own ketones by breaking down stored fat.
Here’s the difference:
What Exogenous Ketones Do:
They raise blood ketone levels quickly and may provide mental clarity or boost athletic performance–in someone that needs an energy source! As in calories!! If you are experiencing the “Keto crash,” exogenous ketones are useful in short bursts for quick energy while allowing you to remain compliant with your macros.
What They Don’t Do:
They don’t trigger the body to burn fat for fuel, so they don’t promote fat loss on their own.
They don’t replicate the long-term benefits of being in natural ketosis, which is driven by metabolic changes like improved fat metabolism and lower insulin levels.
While exogenous ketones can be useful for athletes or those in the keto trenches seeking a temporary cognitive respite from the keto fog, they’re often overmarketed as a way to achieve the benefits of ketosis without diet changes.
I’m exercising a lot of restraint here cuz ya boi wants to go off! Can’t believe I managed to only imply that it is snake oil once in the title and then again here. That’s it. Good job me!
Connecting Lipemia, Ketosis, and Cardiovascular Health At the intersection of lipemia and ketosis lies a key question: How do these metabolic processes influence cardiovascular risk?
Lipemia and CV Risk: Elevated triglycerides, as seen in lipemia, are linked to a higher risk of atherosclerosis and cardiovascular events. When the blood is overloaded with fat, it contributes to plaque formation and arterial damage.
Ketosis and Lipid Profiles: Natural ketosis, achieved through diet or fasting, can reduce triglycerides and potentially improve LDL/HDL ratios. However, some people may experience a rise in LDL cholesterol on a ketogenic diet, so it’s important to monitor lipid levels carefully.
In Summary: Be safe out there y’all. I’m shouting these truths cuz I luv ya.
No need to break your wallet with exogenous ketone products. Keto can be great for the right people but please be careful. Don’t get too comfortable out there with elevated lipids even if your doctor is ‘hip’ and says “we don’t really know long term effects of keto…” BAH! There is strong evidence for lipemia and cardiovascular risk, you know, heart attacks and strokes… Take a statin or something.
With love,
InvolutedThymus ~XOXO
Thank you for this!
Question about the foam cell formation, is this a given event across the board? Or is there some specific mechanism driving the oxidation?
There’s a term for individuals, typical of lean mass and lower BMI, that have an alternate response to a ketogenic diet. As I’m aware, people that are overweight and have some undesirable lipid levels can see improvements after taking on a ketogenic diet, but for some reason other people with more “healthy” phenotype have a worsening of biomarkers.
What are your thoughts on this?
Thank you for the insightful question! It allows me to emphasize the important distinction between ketosis and atherosclerosis. Foam cell formation, which is a key event in the development of atherosclerotic plaques, is not limited to individuals with risk factors for heart disease. There’s evidence showing that plaque precursors, including foam cells, can be found even in healthy adolescents. This suggests that the initial stages of atherosclerosis might occur as part of natural biological processes, but the progression to harmful plaque formation depends on various factors, including lifestyle, genetics, and environmental triggers.
As for ketosis, the metabolic state is designed to utilize fat as a primary energy source. In individuals with excess body fat or those who have unfavorable lipid profiles, entering ketosis allows them to metabolize their more abundant fat stores, often resulting in improved lipid biomarkers and overall metabolic health. However, in individuals with a leaner, “healthy” phenotype and lower fat reserves, the situation is different.
When these individuals enter ketosis, if their body fat is below a certain threshold, their body may need to either mobilize fat from existing stores or synthesize new fats to provide substrates for ketone production. This process can lead to a temporary or sustained worsening of lipid biomarkers as the body shifts its fat metabolism pathways. This difference in how ketosis is utilized likely explains the variation in biomarkers you mentioned between individuals with different body compositions.