Re-evaluating the Role of Saturated Fats for Health: A Closer Look
There is much controversy in nutrition science about what constitutes a healthy diet. One key controversy has to do with the effects of saturated fats on the human body. These macronutrients were thought to contribute to cardiovascular disease by raising blood cholesterol levels. But a new model proposed by researchers in Norway explains why the so-called “diet and heart hypothesis,” which has had much influence on dietary recommendations, may be wrong.
Recent research
In a new article published in the American Journal of Clinical Nutrition, the researchers raised the question: why do saturated fats raise blood cholesterol levels and why should that be dangerous? After all, saturated fats are naturally found in a wide variety of foods, including breast milk.
All cell membranes contain a certain amount of cholesterol molecules, which are necessary to regulate their stiffness. The new model proposed by the researchers is that when polyunsaturated fats are replaced with saturated fats in the diet, the cell membranes need less cholesterol. The reverse is also true, that is, increasing the intake of polyunsaturated fatty acids in the diet leads to less cholesterol in the membranes. They become more fluid.
Thus, cells regulate the fluidity of their membranes by incorporating cholesterol from the bloodstream. This may explain the decrease in its levels when more polyunsaturated fats are consumed. The authors called it The homeoviscous adaptation to dietary lipids (HADL) model.
- According to Dr. Simon N. Dunkel, one of the authors of the study, cells need to adjust the fluidity of their membranes in response to changes in their environment. This process, known as homeostatic adaptation, is believed to be a crucial aspect of human physiology. Our cells are able to maintain a balance of cholesterol in relation to the amount of fat in our diet through this mechanism.
Nutritional research often focuses on what changes occur in the body, but the question of why something, such as blood cholesterol, changes is just as important. This is where the new HADL model can help, which explains why cells need to change the cholesterol content of their membrane structures and, therefore, the blood.
The researchers note that the causes of atherosclerosis and cardiovascular disease are multifactorial. Using the HADL model, they propose to separate elevated blood cholesterol with increased fat intake from hypercholesterolemia as a cause of cardiovascular disease.
The article discusses other factors that contribute to increased cholesterol in people with cardiovascular disease, such as low-intensity chronic inflammation and insulin resistance. This suggests that metabolic abnormalities must be separated from elevated blood cholesterol caused by a significant change in saturated fatty acid intake with food.
The new model also questions the usefulness of lowering blood cholesterol by adding polyunsaturated fatty acids to the diet rather than addressing the underlying cause.
- According to Dr. Dunkel, the evidence supporting the claim that high saturated fat intake leads to heart disease is weak and contradictory. Additionally, there is a lack of a logical biological and evolutionary explanation for this alleged connection.
In addition, according to the researchers, people with metabolic disorders often do not show the expected changes in blood cholesterol with changes in fat intake, suggesting that the body is not adapting normally to them.
The HADL model indicates that the effect of dietary fat on blood cholesterol is not a pathogenic response, but rather a perfectly normal and even healthy adaptation to changes in diet.
Read more about total fats
Source of saturated fat
Saturated fats are found in a variety of animal-based products, including meat, dairy, and eggs. They can also be found in plant-based sources such as coconut and palm oil. Saturated fats are solid at room temperature and tend to be more stable than unsaturated fats, making them popular choices for cooking and food processing. However, they have long been considered detrimental to heart health due to their association with high cholesterol levels and an increased risk of heart disease. It is important to note that not all sources of saturated fats are equal, and the impact of these fats on heart health may depend on the specific type and amount consumed.
There are some sources of saturated fats that are considered healthier than others. These include:
- Coconut oil: This oil is high in medium-chain triglycerides (MCTs), which are absorbed and used by the body differently than long-chain fatty acids found in other types of saturated fats. Some research suggests that MCTs may have a positive effect on heart health and body weight.
- Grass-fed meat and dairy products: These products may contain higher levels of beneficial fatty acids and antioxidants compared to conventionally raised counterparts.
- Avocado and avocado oil: These sources of fat are high in monounsaturated fats, which have been shown to have a positive effect on heart health. They also contain antioxidants and other beneficial nutrients.
It is important to note that while these sources of saturated fats may have some potential health benefits, they should still be consumed in moderation as part of a well-balanced diet.