Scientists are changing their views on cholesterol

Science by HLTH Code Team


Cholesterol has long been a heated topic of dietary debate, with its association with heart disease casting a shadow over its role in nutrition. However, recent research has reshaped our understanding of dietary cholesterol and saturated fats, highlighting their essential roles in the body.

The Importance of Cholesterol

Cholesterol is a lipid molecule that is crucial for various bodily functions. It is a structural component of cell membranes, contributing to their fluidity and integrity. Cholesterol is also a precursor for the synthesis of steroid hormones, such as estrogen, testosterone, and cortisol, which regulate numerous physiological processes including metabolism, immune response, and reproductive health1. Furthermore, cholesterol is necessary for the production of bile acids, which aid in the digestion and absorption of dietary fats2.

Where Cholesterol Comes From

The liver plays a central role in cholesterol metabolism. Cholesterol is synthesized through a complex process involving more than 20 enzymatic reactions. The key rate-limiting enzyme in this pathway is HMG-CoA reductase, which catalyzes the conversion of HMG-CoA to mevalonate, a critical step in the biosynthesis of cholesterol3. The liver regulates cholesterol levels by balancing its synthesis, dietary intake, and excretion.

When dietary cholesterol intake is low, the liver compensates by increasing its own production. Conversely, when dietary cholesterol intake is high, the liver reduces its synthesis to maintain homeostasis. This feedback mechanism highlights the liver’s adaptability in managing cholesterol levels4.

Misconceptions about Dietary Cholesterol

For decades, dietary cholesterol has been vilified for its perceived role in increasing blood cholesterol levels and promoting heart disease. This belief stemmed from early studies that linked high cholesterol levels to cardiovascular disease. However, contemporary research has shown that the relationship between dietary cholesterol and blood cholesterol levels is more nuanced.

  1. Dietary Cholesterol and Blood Cholesterol: Studies have demonstrated that dietary cholesterol has a relatively small impact on blood cholesterol levels for most people. The body compensates for dietary intake by adjusting its own production, resulting in minimal changes in overall cholesterol levels5.
  2. Cholesterol and Heart Disease: Large-scale studies and meta-analyses have found no significant link between dietary cholesterol and an increased risk of heart disease in healthy individuals6. The focus has shifted towards understanding the role of specific types of cholesterol, such as low-density lipoprotein (LDL) and high-density lipoprotein (HDL), and their impact on cardiovascular health.
  3. Saturated Fats: Saturated fats have also been implicated in heart disease. However, recent evidence suggests that not all saturated fats are created equal. Of note, the American College of Cardiology published a meta-analysis on saturated fats7. The key point from the first sentence is enlightening, “The recommendation to limit dietary saturated fatty acid (SFA) intake has persisted despite mounting evidence to the contrary.”The impact of saturated fats on health depends on the specific fatty acids involved and their food sources8. For example, saturated fats from whole foods like dairy and coconut oil may have different effects compared to those from processed foods that contain seed oils.

Why You Need Cholesterol

Despite its controversial reputation, cholesterol is vital for a healthy body:

  1. Hormone Production: Cholesterol is a precursor for the synthesis of vital hormones. Adequate intake supports hormonal balance, which is crucial for overall health9.
  2. Brain Health: Cholesterol is essential for brain function. It is a key component of myelin, the protective sheath around nerve fibers, and is involved in the formation of synapses, which are critical for learning and memory10.
  3. Cell Membrane Integrity: Cholesterol maintains the structure and fluidity of cell membranes, ensuring proper cell function and communication11.
  4. Nutrient Absorption: Cholesterol aids in the absorption of fat-soluble vitamins (A, D, E, and K), which are important for various bodily functions including vision, immune function, and blood clotting12.

Ideal Sources of Dietary Cholesterol

Incorporating dietary cholesterol and saturated fats from whole, nutrient-dense foods can contribute to a balanced diet. Here are some of the best sources:

  1. Eggs: Eggs are an excellent source of dietary cholesterol and provide high-quality protein, vitamins, and minerals. They are particularly rich in choline, a nutrient important for brain health13.
  2. Shellfish: Shellfish such as shrimp, crab, and lobster are rich in cholesterol and provide essential nutrients like iodine and selenium14.
  3. Organ Meats: Organ meats, including liver and kidney, are nutrient powerhouses, offering high levels of vitamins A and B12, iron, and zinc15.
  4. Dairy Products: Full-fat dairy products like cheese, yogurt, heavy cream and butter contain saturated fats and are good sources of calcium and vitamin D16.
  5. Meat: Beef and other meats provide essential amino acids, vitamins, and minerals along with beneficial saturated fats.
  6. Coconut Oil: Coconut oil is rich in medium-chain triglycerides (MCTs), a type of saturated fat that is metabolized differently and may offer various health benefits17.


Dietary cholesterol and saturated fats have been extraordinarily misunderstood for decades. Emerging research has clarified that dietary cholesterol has a limited to negligible effect on blood cholesterol levels for most people. Cholesterol is essential for various bodily functions, including hormone production, brain health, and nutrient absorption. Incorporating cholesterol and saturated fats from whole, nutrient-dense foods can support overall health and well-being. As our understanding of nutrition evolves, it is important to re-evaluate dietary guidelines and focus on balanced, wholesome diets.


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  3. Goldstein, J. L., & Brown, M. S. (1990). Regulation of the mevalonate pathway. Nature, 343(6257), 425-430.
  4. Dietschy, J. M., & Turley, S. D. (2001). Cholesterol metabolism in the brain. Current Opinion in Lipidology, 12(2), 105-112.
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  16. Thorning, T. K., Bertram, H. C., Bonjour, J. P., de Groot, L., Dupont, D., Feeney, E., … & Givens, I. (2017). Whole dairy matrix or single nutrients in assessment of health effects: current evidence and knowledge gaps. The American Journal of Clinical Nutrition, 105(5), 1033-1045.
  17. Nagao, K., & Yanagita, T. (2010). Medium-chain fatty acids: functional lipids for the prevention and treatment of the metabolic syndrome. Pharmacological Research, 61(3), 208-212.

This article is for informational and educational purposes only. It is not, nor is it intended to be substitute for professional medical advice, diagnosis, or treatment and should never be relied upon for specific medical advice.