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.
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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