by Paul E. Lemanski, MD, MS, FACP
Medicines are a mainstay of American life and the healthcare system not only because they are perceived to work by the individual taking them, but also because their benefit may be shown by the objective assessment of scientific study. Clinical research trials have shown that some of the medicines of Western science may reduce the risk of heart attacks, strokes and cardiovascular death while others may reduce certain types of cancer.
Editor’s Note: This is the 46th in a series on optimal diet and lifestyle to help prevent and treat disease. Any planned change in diet, exercise or treatment should be discussed with and approved by your personal physician before implementation. The help of a registered dietitian in the implementation of dietary changes is strongly recommended.
In the first 45 installments of The Non-Medicated Life, informed diet and lifestyle have been shown to accomplish naturally for the majority of individuals, many, if not most of the benefits of medications in the treatment of chronic medical conditions. Moreover, informed diet and lifestyle as a medical intervention may accomplish such benefits at lower risk for side effects and at a lower cost.
One way to measure the benefit of dietary and lifestyle changes on heart disease risk is through blood cholesterol testing. An understanding of such testing is essential for an individual to determine whether a change in diet and/or lifestyle is having the desired effect on risk and to serve as a focal point of discussion with their physician regarding their personal cardiovascular risk and the reduction of that risk. Part One will address the measurement of blood cholesterol and resulting cardiovascular risk. Part Two will address non-medicated ways to improve cholesterol measures and risk.
Cholesterol is a substance essential to human body structure and function. We may get cholesterol directly from a dietary source when we eat meat, fish or an animal derived product. Or we may synthesize cholesterol from saturated fat from an animal or non-animal source. Either excess dietary cholesterol or excess saturated fat may result in elevated blood cholesterol levels which may increase cardiovascular risk.
The measurement of the blood cholesterol generally requires a fasting lipid profile blood test which measures the total cholesterol in the blood, the triglycerides, the high density lipoprotein (HDL) or “good” cholesterol, and the low density lipoprotein (LDL) or “bad” cholesterol. The blood for the lipid profile needs to be drawn after a 12-hour fast, meaning no food for 12 hours and only water to drink.
LDL in the blood actually exists as spherical particles of varying size, some smaller, some larger. When LDL particles are in high concentration in the blood they may penetrate the wall of arteries and accumulate in the wall as a cholesterol plaque. The process of movement of LDL, from the blood into the artery wall may be accelerated when the LDL is packaged in smaller more numerous particles, rather than fewer larger particles. The formation of cholesterol plaques in artery walls is almost always a necessary prerequisite for heart attack and stroke.
HDL in the blood also exists as spherical particles of varying size. HDL is called the good cholesterol because it has the capacity to serve as a “vacuum cleaner” for LDL. In a process called reverse cholesterol transport, HDL may pick up LDL from the plaque in the artery wall and transport it back to the liver for reprocessing. In this way lowering LDL in the blood and raising HDL may reduce plaque and lower cardiovascular risk.
Within the last few years a measure called non-HDL cholesterol has been introduced. Non-HDL is a quantitative way to get a measure of the number of lipid particles in the blood that may cause plaque. Thus, non-HDL is elevated if the LDL particles are smaller and more numerous. Non-HDL is elevated also in circumstances when LDL may be normal, but other less common lipid particles that cause plaque are elevated. If one takes the total cholesterol number and subtracts from it the HDL number, the non-HDL is the result.
The use of the above described approach will identify the great majority of patients at risk and allow appropriate measures to be applied to mitigate that risk. Nevertheless, an additional proven measure which may be used to identify risk is high sensitivity C-reactive protein (hs-CRP). When LDL cholesterol gains access to the artery wall it becomes oxidized. Oxidized LDL is viewed by the immune system as non-self and is attacked by white blood cells. The infiltration of white blood cells into the artery wall for the purpose of attacking oxidized LDL is inflammation, which may be quantified by hs-CRP. Since inflamed plaque is more likely to become unstable and cause a heart attack, hs-CRP may help identify risk at another step in the atherosclerotic process independent of the risk identified by the standard lipid profile.
The National Cholesterol Program in its guidelines for physicians has established optimal levels or targets for triglycerides as less than 150 milligrams per deciliter (mg/dl), LDL as under 100 mg/dl, HDL as over 40 mg/dl for men and over 50 mg/dl for women, and non-HDL as under 130 mg/dl. For hs-CRP, the target is less than three milligrams per liter (mg/L) with an optimal level under 0.6 mg/L.
In the case of LDL and non-HDL, the targets may be adjusted to global cardiovascular risk. Thus, in those people with established heart disease – a history of heart attack, stent, bypass surgery, angina or any plaque visible on coronary catheterization – the LDL target is 70 mg/dl and the non-HDL target is 100. In those with no risk factors and no family history of coronary artery disease, an LDL of 160 and a non-HDL of 190 may be acceptable. A discussion with one’s personal physician is in order to establish the individual’s most appropriate targets.
In summary, blood cholesterol testing may help identify cardiovascular risk. Blood testing done after a 12-hour fast may determine the level of triglycerides, HDL and LDL as part of the standard lipid profile. Using the standard profile, the non-HDL cholesterol may be calculated which provides additional information on LDL particle number as well as other lipid particles, which cause plaque. Hs-CRP may help identify unstable plaque which increases the risk for heart attack and stroke.
In Part Two the cardiovascular risk which cholesterol testing identifies may be shown to serve as the basis of a non-medicated approach to reduce cardiovascular risk and avoid the proverbial bottle of pills to treat one of our most significant health problems.
Paul E. Lemanski, MD, MS, FACP (paul.lemanski@primecarepc.com) is a board certified internist with a master’s degree in human nutrition. He is director of the Center for Preventive Medicine, Albany Associates in Cardiology, Prime Care Physicians, P.C. Paul is an assistant clinical professor of medicine at Albany Medical College and a fellow of the American College of Physicians.
