High levels of HDL cholesterol, often called "good" cholesterol, are associated with a reduced risk of coronary artery disease (CAD). It appears that HDL particles "scour" the walls of blood vessels, cleaning out excess cholesterol that otherwise might have been used to make the plaques that cause CAD. The HDL cholesterol is then carried to the liver, where it is processed into bile, and secreted into the intestines and out of the body.
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HDL is more tightly controlled by genetic factors than are the other lipoproteins (ie, LDL, very–low-density lipoprotein (VLDL), intermediate-density lipoprotein [IDL], chylomicrons). For example, in certain families, especially some families with Japanese ancestry, a genetic deficiency of cholesteryl ester transfer protein (CETP) is associated with strikingly elevated HDL-C levels. 
Part of the “French paradox”-lower heart-disease rates in butter-and-cream-feasting France-may stem from the HDL benefits of wine consumption. For some people, however, alcohol causes more troubles than it cures. “Men should limit themselves to one or two drinks a day,” Willett says. “After that, you start worrying about adverse consequences.” While any alcoholic beverage will do, the antioxidants in red wine or dark beer may give you an added benefit.
Cholesterol is carried through the bloodstream attached to two different compounds called lipoproteins: low-density lipoproteins (LDL) and high-density lipoproteins (HDL). LDL is commonly known as the “bad” cholesterol because it transports cholesterol from the liver throughout the body, and potentially allows it to be deposited in artery walls. HDL, known as the “good cholesterol,” picks up cholesterol from the blood and delivers it to cells that use it, or takes it back to the liver to be recycled or eliminated from the body.
When it comes to cholesterol, not all types are created equal, and it is important to understand how lifestyle choices significantly impact cardiovascular health. High-density lipoprotein, or HDL, is known as the “healthy” or “good” type of cholesterol due to the fact that it scavenges and removes the “bad” type of cholesterol (low-density lipoprotein or LDL) known to clog arteries. A desirable HDL level is anything greater than 60 milligrams per deciliter (mg/dL).
According to a study published in November 2015 in the journal Nature, a diet high in carbohydrates — like added sugar, white bread, cookies, and cakes — reduces HDL cholesterol levels, increasing the risk for metabolic disorders. Refined carbohydrates found in foods labeled “low-fat” make these just as bad as full-fat foods because the fat is often replaced with carbohydrates from added sugar and other starches.
In randomly screened children aged 6-19 years who had age-, race-, and sex-specific total plasma cholesterol levels greater than or equal to 95th percentile levels, 7.8% of white males, 12.8% of white females, 25% of black males, and 17.2% of black females had hypercholesterolemia due to elevated high-density lipoprotein [HDL] cholesterol levels (but not due to elevated low-density lipoprotein [LDL] cholesterol levels) greater than age-, sex-, and race-specific 95th percentile levels. That is, they had HALP.
Paying close attention to what you eat can help you reduce your risk of developing atherosclerosis. Atherosclerosis is the narrowing of arteries caused by plaque build-up inside the arteries. As the arteries narrow, blood can't flow properly through the arteries. Theis can lead to a heart attack or stroke. If the artery-clogging process has already begun, you may be able to slow it down by making changes in your lifestyle, including your diet.
Weight Management. If you are overweight, losing weight can help lower your LDL (bad) cholesterol. This is especially important for people with metabolic syndrome. Metabolic syndrome is a group of risk factors that includes high triglyceride levels, low HDL (good) cholesterol levels, and being overweight with a large waist measurement (more than 40 inches for men and more than 35 inches for women).
Salmon is rich in omega-3 fatty acids, which are healthy fats that can help reduce blood pressure. Eating salmon can improve your "good" HDL cholesterol, but it won't lower your "bad" LDL cholesterol. HDL cholesterol helps sweep cholesterol off your artery walls, preventing dangerous plaque from forming. The American Heart Association recommends eating fatty fish like salmon at least twice per week for heart-healthy benefits. Other fish that contain omega-3s, such as mackerel, tuna and sardines, can also help.
Raise your glass for heart health! In moderation, alcohol is known to raise HDL, or "good," cholesterol. Drinking a daily glass of red wine increased "good" HDL cholesterol and also decreased "bad" LDL cholesterol after a few months, found one study. Red wine also contains antioxidants called polyphenols that help keep your blood vessels healthy and strong. Remember that moderation means one drink for women or two for men daily and, in this case, more is not better.
Fatty fish is not the only source of heart-healthy omega-3s! In fact, flaxseed is one of the richest sources of the anti-inflammatory fat. In animal models supplementation of flaxseed has shown to increase HDL levels which is why cardiologists and dietitians recommend it be incorporated into a balanced diet. Consumers beware though—in order for the gut to fully absorb the vitamins, minerals this seed provides, the ground version needs to be purchased.
According to the Mayo Clinic, ideal HDL levels for both men and women are 60 milligrams of cholesterol per deciliter of blood. If a man’s HDL level is below 40 milligrams of cholesterol per deciliter of blood or a woman’s HDL level is below 50 milligrams of cholesterol per deciliter of blood, then disease risk, specifically heart disease, is considered to be heightened. Even if your HDL level is above the at-risk number (but below the desirable number), you still want to work on increasing your HDL level so you can decrease your heart disease risk. (9)
George T Griffing, MD is a member of the following medical societies: American Association for the Advancement of Science, International Society for Clinical Densitometry, Southern Society for Clinical Investigation, American College of Medical Practice Executives, American Association for Physician Leadership, American College of Physicians, American Diabetes Association, American Federation for Medical Research, American Heart Association, Central Society for Clinical and Translational Research, Endocrine Society
HDL serves as a chemical shuttle that transports excess cholesterol from peripheral tissues to the liver. This pathway is called the RCT system. In this system, plasma HDL takes up cholesterol from the peripheral tissues, such as fibroblasts and macrophages. (A study by El Khoury et al indicated that in persons with HALP, macrophages have an increased plasma cholesterol efflux capacity.  ) This may occur by passive diffusion or may be mediated by the adenosine triphosphate (ATP)–binding cassette transporter 1. The latter interacts directly with free apo A-I, generating nascent, or so-called discoidal, HDL. Cholesterol undergoes esterification by lecithin-cholesterol acyltransferase (LCAT) to produce cholesteryl ester, which results in the production of the mature spherical HDL. Cholesterol is also taken up from triglyceride-rich lipoproteins in a process mediated by a phospholipid transfer protein (ie, CETP). [19, 20, 21, 22]
Hyperalphalipoproteinemia (HALP) may be familial, including primary (without CETP deficiency) and otherwise (with CETP deficiency), or secondary.  Familial HALP (aside from the primary form) is a well-documented genetic form of hypercholesterolemia characterized by a deficiency of CETP, a key protein in the reverse cholesterol transport (RCT) system that facilitates the transfer of cholesteryl esters from high-density lipoprotein (HDL) to beta lipoproteins. Primary HALP is a term used for familial elevated HDL cholesterol levels that are not due to CETP deficiency and for which the cause is unknown. Secondary HALP is due to environmental factors or medications.
HDL particles are heterogeneous. They can be classified as a larger, less dense HDL2 or a smaller, denser HDL3.  Normally, most of the plasma HDL is found in HDL3.  To add to the complexity of HDL classification, HDL is composed of 4 apolipoproteins per particle. HDL may be composed of apo A-I and apo A-II or of apo A-I alone. HDL2 is usually made up only of apo A-I, while HDL3 contains a combination of apo A-I and apo A-II. HDL particles that are less dense than HDL2 are rich in apo E.
What causes high cholesterol? High cholesterol is a risk factor for heart attacks and coronary heart disease, because it builds up in the arteries, narrowing them. It does not usually have any symptoms, and many people do not know they have it. We look at healthy levels and ranges of cholesterol, at ways to prevent it, and medications to treat it. Read now
A largely vegetarian "dietary portfolio of cholesterol-lowering foods" substantially lowers LDL, triglycerides, and blood pressure. The key dietary components are plenty of fruits and vegetables, whole grains instead of highly refined ones, and protein mostly from plants. Add margarine enriched with plant sterols; oats, barley, psyllium, okra, and eggplant, all rich in soluble fiber; soy protein; and whole almonds.
But keep in mind that not all cholesterol is created equally. LDL cholesterol, also known as “bad cholesterol,” is the form that can build up on the artery walls and increase your risk of heart disease. HDL cholesterol, on the other hand, is often dubbed “good cholesterol” because it travels through the bloodstream, removing harmful cholesterol from the arteries to help enhance heart health.
Hayek T, Chajek-Shaul T, Walsh A, Agellon LB, Moulin P, Tall AR, Breslow JL. An interaction between the human cholesteryl ester transfer protein (CETP) and apolipoprotein A-I genes in transgenic mice results in a profound CETP-mediated depression of high density lipoprotein cholesterol levels. J Clin Invest. 1992 Aug;90(2):505–510. [PMC free article] [PubMed]
Foods high in monounsaturated fats (such as olive oil, nuts, and the oils in many salad dressings) seem to boost HDL best; it’s likely that foods high in omega-3 fatty acids (such as cold-water fish) do so as well. Saturated fats, the kind in meat and dairy foods, are likely to drive up harmful LDL, so take this opportunity to cut way back. Worst of all are trans-fatty acids, the hardened oils often found in margarine, crackers and other snack foods-a substance Harvard Medical School nutrition expert Walter C. Willett, M.D., author of Eat, Drink, and Be Healthy, calls “uniquely bad.” These foods can do exactly the opposite of what you want, lowering HDL while raising LDL.
Could one of your current prescriptions be a cause of your low HDL levels? Possibly! Medications such as anabolic steroids, beta blockers, benzodiazepines and progestins can depress HDL levels. If you take any of these medications, I suggest talking to your doctor and considering if there is anything you can do that could take the place of your current prescription.