Cholesterol & Steroids
click below for more on cholesterol and lipids
Dietary lipid metabolism of Triacylglycerols Dietary lipid metabolism of Phospholipids Dietary lipid metabolism of Glycolipids
Classes of lipids Plant sterols to lower cholesterol Red Yeast Rice
Introduction

Cholesterol is something of an "in vogue" taboo these days and a term we've made synonymous with "bad health." Although cholesterol can cause problems in excess, it is essential for our survival. In many ways you cannot exclude cholesterol from your metabolism. You cannot avoid it, considering it is manufactured in virtually every tissue in the human body. It is used as a precursor for hormone production (e.g. vitamin D). Cholesterol is also required in cell membranes (remember, you have around 170 trillion of these!). Cholesterol has other functions as well.

In regards to cardiovascular health, there are correlations between increases in dietary cholesterol intake and arterial disease. Keep in mind that we must use statistics cautiously as well. There are studies which demonstrate that groups with higher than average cholesterol live longer and suffer less with cardiovascular disease than those with lower cholesterol, when exercise is included in their lifestyle. Since cholesterol is a precursor to hormone production, this higher level may actually benefit those who exercise regularly. To attempt to lower cholesterol in these individuals may actually cause more harm than benefit.

However, for more sedentary lifestyles, keeping cholesterol to moderate levels is prudent. To achieve lower cholesterol levels, we first implement dietary strategies such as consuming a low cholesterol diet. If excluding cholesterol from the diet, we have to suspect that we are genetically producing abnormally high levels of cholesterol internally (within our body).

Therefore, even if we were to exclude large amounts of cholesterol from the diet of the population, a fair percentage would still develop hypercholesterolaemia (high plasma cholesterol). This suggests the genetic component, as increased levels of cholesterol and its inefficient metabolism run in certain families.

There are small percentages of individuals in the population who metabolize cholesterol far more efficiently than most. These individuals can eat several pure egg yolks (high in cholesterol) per day, and exhibit no detectable rise in cholesterol.

Still, others who make an effort of consuming a low cholesterol diet, exhibit higher than normal plasma cholesterol. our metabolism can be "unfair" at times. But every person has both metabolic advantages and disadvantages. It's finding out what they are and optimizing them that increases your quality of life and life-span.

That's why it's best to practice a bit of preventative medicine, and monitoring cholesterol intake certainly cannot be discouraged. We only wish to enlighten on the fact, that with cholesterol metabolism, like other substances, there is always more than meets the eye. Therefore, let's discuss cholesterol, it's uses, metabolism and other important facts about this molecuie.


Functions of cholesterol

Cholesterol is synthesized in most bodily tissues. The largest contributions to the overall cholesterol pool are made from the liver, adrenal cortices, intestines, and testes in the male, and the placenta and ovaries in the female. Cholesterol is a sterol (note the word "sterol" in cholesterol. A sterol is one of the classifications of steroids, which are a multi-ringed shaped molecules. Sterols have lipid-like solubility and can be used by the body to synthesize other molecules depending on need. For example, cholesterol can be modified to make vitamin D, bile acids (for emulsification and digestion of fats), and steroid hormones. Considering how important cholesterol is to survival, the body must maintain a constant supply. The liver plays a major role in the balance of cholesterol. The liver receives cholesterol from the diet, from manufacture in the small intestine, from very low density lipoproteins (VLDL) that carry cholesterol, and high density lipoproteins (HDL) that carry cholesterol from other manufacturing tissues.

Cholesterol exits the liver via HDL, VLDL, bile acids and bile salts. The bile is then stored in the gallbladder for secretion during digestion. Bile assists digestion by emulsifying fats and rendering them more soluble for eventual breakdown from the action of pancreatic enzymes.

click below for more on cholesterol and lipids
Dietary lipid metabolism of Triacylglycerols Dietary lipid metabolism of Phospholipids Dietary lipid metabolism of Glycolipids
Classes of lipids Plant sterols to lower cholesterol Red Yeast Rice

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