Blood cholesterol is a term often used to describe circulating fat content in our blood. Fat molecules, combined with certain proteins, are arranged within human body in various formations which determines their size, weight, and role in overall metabolism. A simple blood test, called "Lipid Profile", typically lists all the major formations of fat molecules.
Aim of this write up is to familiarize the reader with the concept of circulating fat, it's effect on humans, develop basic understanding of Lipid profile, and modifications that can be done to prevent related related issues.
Fat, cholesterol, lipids are different terms used to describe various forms of fatty acids. Body fat comes from two sources: one that we consume in the form of oil, ghee etc. and other that body makes it due to abundance of energy. The second point is important to understand. If we consume too much energy, either in the form of carbohydrates or protein, body stores excess energy in the form of fat. Fat within the body can either be stored, or can be circulating in the blood. Circulating fat, aka total cholesterol, are composed in various formations to serve specific function. Needless to say, these fat molecules are vital for healthy living. It's only when they become too abundant or off balance is when they start causing problem than good.
A typical blood report for cholesterol (called 'Lipid Profile') mentions 'total cholesterol' and its components. Blood sample for lipid profile should be taken following 14 hours of fasting. Also, person should be on his/her routine diet at least 2-3 days prior. This is done to minimize erroneous blood report due to recent change in dietary pattern. There are 3 main components of a lipid profile that is extensively studied with reference to clinical outcomes. They are: Triglycerides (TG), Low Density Lipids (LDL), and High Density Lipids (HDL). There are many other components as well but they are beyond the scope of common discussion.
TG are basic fat configuration which is found in animal fat, vegetable oil, as well as in circulating blood. They are typically elevated in blood temporarily after food intake. Although high TG are implicated in blockages of blood vessels, its associated is not as strong as that of LDL or HDL. Nevertheless, attempts to should be made to reduce TG levels to below 150 mg/dl (<100 mg/dl in high risk subjects). Point to be noted that very high TG levels can cause issues other than heart as well and levels >500 mg/dl should be taken very seriously. Also, high TG can be a reflection of Diabetes, Thyroid diseases, kidney diseases etc. and these all should be checked. Best way to reduce TG levels include exercise, weight loss, dietary adjustments, avoid sugar/alcohol, control Diabetes and Thyroid if abnormal. There are medications, that added to lifestyle modifications, can further reduce TG levels if required.
LDL is the bad fat configuration. High LDL levels contribute to blockages in blood vessels. Such blockages if involve heart blood vessels can cause heart attack, brain blood vessels can cause stroke/paralysis, leg blood vessels can cause issues with leg pain and ulcer etc. Various LDL cutoffs are recommended for subjects with different risk profile for heart disease. While LDL level of below 70 mg/dl is recommended for highest risk patient, an LDL level of below 130 is acceptable for routine subjects. Lowering LDL has shown to reduce risk of heart disease significantly. Lifestyle modifications are an important aspect of LDL management. A class of drugs called 'statins' have been shown in multiple trials to decrease heart attack chances and improved survival. Based on a person's risk profile and lipid values, a physician decides whether he/she should be started on statins or not. If optimal control is not achieved by statins and lifestyle modifications, other drugs can be added to get LDL to the desired goal.
HDL is the good fat configuration. A level above 40 mg/dl for men and above 50 mg/dl for women is considered reasonable. For HDL, higher is better. Part of HDL level is genetically determined, part dependent on lifestyle, weight, diet etc. Low HDL increased risk of blood vessel blockages. Exercise and lifestyle modifications have shown to increase HDL levels and improve outcomes. Limited amount of alcohol intake has been associated with improved HDL levels although the causative effect still remains unproven. Certain medications had been tried in the past to increase HDL levels with varied
success.
As you can see, blood cholesterol levels have different components with each having their own role. A comprehensive review of lipid profile involves looking at all the parameters and evaluating other associated risk factors for heart disease. An informed physician takes everything into consideration before giving his/her judgement on further course of action. Equally important is how to prepare oneself for this blood test.
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