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Cholesterol--Part-I: Setting the record Straight.

Posted Apr 06 2010 12:00am
                Cholesterol has the misfortune of being branded as a dietary villain though it has done nothing to deserve this unsavoury reputation.Before you start getting apoplectic about clogging arteries and deadly plaques,let me remind you that sometimes innocence is put in a deceitful garb(to paraphrase the Bard).And some witless innocents like the dashing Cassio are condemned and victimized though they are entirely well-meaning.
So what is cholesterol?
Cholesterol is a chemical compound of the steroid group-it is a solid wax like substance of the lipid family produced by all animals in their liver.Around 85% of the cholesterol is manufactured in the body.Because it is so crucial,the body does not depend on dietary sources alone but has an in-house manufacturing unit in the liver.Cholesterol gives structure to cell membranes,enables neuron functioning,aids brain function,maintains bone density,facilitates vitamin D synthesis from sunlight,is a precursor for the synthesis of steroid hormones(adrenal and reprodutive),produces bile for fat digestion,repairs tissue lesions. Dietary sources (meat,dairy,eggs and saturated fats derived therefrom) form only a small percentage of total cholesterol in your body.

How did it become so bad?
In the seventies a series of studies found that the victims of Coronary Heart Disease had higher serum cholesterol levels and the arterial plaques of these people had cholesterol deposits.So avoiding dietary sources of cholesterol,principally saturated fats,meats,eggs and full fat dairy became the centerpiece of dietary advice for a healthy heart.
Now,this is a classic case of a symptom(red flag) being mistaken as the cause of the disease.If firemen are always found at site of a fire,does it mean that they cause the fire?
What is the truth?
Of late scientists have become unanimous that systemic,low grade inflammation is the cause of a whole bunch of degenerative diseases including CHD.This is indicated by high c-reactive protein(CRP) levels.
CRP is a liver derived molecule secreted after tissue injury.Elevated serum CRP levels indicate chronic vascular inflammation.As cholesterol is the natural repair material of the body,it is immediately dispatched to heal the inflamed lesions.One major cause of inflammation is ingestion of processed foods and damaged oils and trans-fats and when inflammation remains unabated;the cholesterol band-aids keep on accumulating over the arterial lesions,hardening over time.
Eating Saturated Fat does not cause CHD.
A latest NCBI meta-analysis admits that there is no strong evidence of dietary saturated fat causing Heart Disease:
A meta-analysis of prospective epidemiologic studies showed that there is no significant evidence for concluding that dietary saturated fat is associated with an increased risk of CHD or CVD
Another study(2009) says the same thing about dairy:
There is no clear evidence that dairy food consumption is consistently associated with a higher risk of CVD.
And the famous Harvard Egg study failed to implicate the dreaded egg yolks as guilty of raising Cholesterol levels.
In summary, the earlier purported adverse relationship between dietary cholesterol and heart disease risk was likely largely over-exaggerated. 
Infact the researchers further accept that the earlier studies linking dietary cholesterol with CHD were essentially flawed.
It is now acknowledged that the original studies purporting to show a linear relation between cholesterol intake and coronary heart disease (CHD) may have contained fundamental study design flaws, including conflated cholesterol and saturated fat consumption rates and inaccurately assessed actual dietary intake of fats by study subjects.
Thus,the real message here is that eating cholesterol will not cause CHD. In absence of inflammation,cholesterol is not a problem it was thought to be.This also explains why some populations with high serum cholesterol levels have low rates of CHD and why certain populations (like vegetarian Indians) who consume little dietary cholesterol,end up having high rates of CHD.
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