Cholesterol

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Function

  • Membrane structure and function
  • Hormone production
  • lipid digestion and transport
  • precursor to vitamin D
  • development of the brain and nervous system in babies and children throughout their growing years

Sources

  • Mother's milk
  • Meat, eggs, fish
  • Milk, and milk products

Regulation

Cholesterol is formed primarily in the liver (about 66-75%). In most cases, the human body will produce enough cholesterol to maintain normal body needs. The liver is the major production factory for cholesterol. Cholesterol is also recycled when the liver excretes bile into the digestive track. Typically about half of the excreted cholesterol from the bile is reabsorbed by the small intestines back into the bloodstream.

Most ingested cholesterol is poorly absorbed due to the esterification of dietary cholesterol (the alcohol portion of cholesterol reacts with fatty acids). However, when the dietary intake is high, liver synthesis is low; when intake is low, synthesis increase (Lecerf JM & de Lorgeril M, 2011). For these reasons, dietary intake of cholesterol has little if any effect on serum (blood) cholesterol. Major studies (eg: Tucumseh Study, Framingham Study, etc) have found virtually no relationship between diet and serum cholesterol levels (Kannel 1971, Nichols 1976).

However, eating smaller meals more frequently throughout the day has shown to significantly reduce organ cholesterol biosynthesis and fasting cholesterol levels (See Meal Frequency Rationale).

Cardiovascular Disease

Earlier purported adverse relationship between dietary cholesterol and heart disease risk appear to be largely over-exaggerated. Original studies suggesting a linear relation between cholesterol intake and coronary heart disease may have contained fundamental study design flaws (Jones PJ, 2009). Interestingly, regular or high egg consumption does not appear to increase the risk of stroke and cardiovascular diseases (Kern 1991, Qureshi 2007, Zazpe 2011, Scrafford 2011).

Also see Blood Cholesterol Screening and Tests for Chronic Low Level Inflammation.

References

Jones PJ (2009). Dietary cholesterol and the risk of cardiovascular disease in patients: a review of the Harvard Egg Study and other data. Int J Clin Pract Suppl. 163; 1-8, 28-36.

Kern FJ Jr (1991). Nornial plasma cholesterol in an 88-year-old man who eats 25 eggs a day. Mechanisms of adaptation. N EngI J Med. 324,896-9.

Qureshi AI, Suri FK, Ahmed S, Nasar A, Divani AA, Kirmani JF (2007). Regular egg consumption does not increase the risk of stroke and cardiovascular diseases. Med Sci Monit. 13(1).

Zazpe I, et al (2011). Egg consumption and risk of cardiovascular disease in the SUN Project. Eur J Clin Nutr. 65(6):676-82.

Scrafford CG, Tran NL, Barraj LM, Mink PJ. (2011). Egg consumption and CHD and stroke mortality: a prospective study of US adults. Public Health Nutr. 14(2):261-70.


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