High Cholesterol
What is Cholesterol?
The common misconception about cholesterol is that it's something bad and needs to be avoided at all times. The truth is that cholesterol is an essential part of every cell structure and is needed for proper brain and nerve function. Without cholesterol we wouldn't be able to live.
It's so important that the body actually manufactures cholesterol in the liver and transports it through the bloodstream to sites where it's needed.
It's a fatty substance and as such doesn't mix very well with blood, because blood is mainly water. So in order to be carried around the blood it needs to latch on to molecules called lipoproteins.
Low-density lipoproteins (or LDLs) are the major transporters of cholesterol in the bloodstream and, because LDLs seem to encourage the deposit of cholesterol in the arteries, it's known as "bad cholesterol".
High density lipoproteins (or HDLs), on the other hand, are considered to be "good cholesterol" because they carry unneeded cholesterol away from the cells and back to the liver, where it's broken down for removal from the body.
If everything is functioning as it should, this system remains in balance.
However, if there is too much cholesterol for the HDLs to pick up promptly, or if there aren't enough HDLs to do the job, cholesterol can form plaque that stick to artery walls and may eventually cause heart disease. (Read more on heart disease by clicking here)
Healthy levels of total serum (or blood) cholesterol are between 190 and 210 mg/dl or 4.9 and 5.4 mmol/l. (Some countries, including the UK, measure cholesterol in mmol/l - millimoles per litre - while others, including the US, use mg/dl - milligrams per decilitre.) Variations either side correlate with increasing rates of disease.
Apart from the total level of cholesterol, it's also important the amount of HDL present in the blood. For men it should be 45 to 50 mg/dl and for women 50 to 60 mg/dl. Higher levels may be protective against heart disease, but levels under 35 are considered risky.
What Are Triglycerides?
Triglycerides are the most common dietary saturated fats. In fact, they make up approximately 95% of all ingested fats.
They too are transported by LDL and HDL molecules in the blood and if in excess can cause a lot of damage to the arteries. Levels should be less than 150 mg/dl.
Interestingly, apart from high intake of saturated fats in our diet, another cause of elevated triglycerides can be high intake of sugar and refined carbohydrates.
These, in fact, elevate insulin levels, which in turn, are associated with increased cholesterol, triglycerides, blood pressure and risk of death from cardiovascular disease.
What are the Causes of High Cholesterol?
As we've seen, cholesterol is so important to the body that the liver has the job to is synthesize it and only 20-25% comes from dietary sources.
Dietary sources of cholesterol are saturated fats from animal origin, such as lard, butter, cheese, beef, pork and poultry, dairy products, and margarine.
Under normal circumstances, if dietary intake is high, there is a corresponding reduction of cholesterol synthesis by the liver. So for most individuals, the amount of cholesterol consumed is unlikely to result in an elevated level of cholesterol in the blood. But that it's not always the case.
Unquestionably, eating animal fat boosts bad LDL cholesterol in most people to varying degrees and cutting out such fat usually lowers LDL cholesterol.
Other types of fat, such as monounsaturated - as in olive oil - and polyunsaturated - as in omega-3 fatty acids - don't have the same effect, in fact lower it.
Other factors such as your genetic makeup can affect your cholesterol levels, but in the main the consumption of foods high in cholesterol and/or saturated fat increases cholesterol levels, while a vegetarian diet, regular exercise and the nutrients niacin and vitamin C may lower cholesterol.
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