Substances that May Lower Cholesterol
From AlaskaClinic
Substances That May Lower Cholesterol
When the recommended remedy for a medical condition or ailment involves substantial lifestyle changes, you can bet that people will be on the lookout for a quicker or simpler solution. That is certainly the case with high cholesterol. A number of specific foods or supplements have been touted as sure-fire ways to lower cholesterol. Some of these show promise; others don’t. But none take the place of an overall effort to lower fat and cholesterol in your diet.
Alcohol
Moderate alcohol consumption has emerged as a possible ally in preventing heart problems. Over the years, a large and consistent body of research has shown that people who drink in moderation (usually defined as one alcoholic drink a day for women, and one or two for men) have a lower rate of coronary artery disease than either teetotalers or heavy drinkers. In fact, a Harvard study on the benefits of modifying various risk factors found that, compared with abstaining, consuming one drink per day lowers heart attack risk by 25%–45%. Researchers also point to the French paradox — the puzzling fact that men in France and throughout the Mediterranean region, where wine consumption is high, have a heart attack death rate half that of American men, even though the Mediterranean diet contains more fat. The type of fat in the Mediterranean diet (primarily unsaturated fat such as olive oil) may also play a role in reducing cholesterol.
By decreasing the tendency of platelets to clump, much as aspirin does, alcohol suppresses the formation of blood clots that can cause heart attacks or strokes. So in theory, alcohol could reduce the rates of these events, although this has not been studied directly. It also seems to enhance the body’s ability to break apart small clots. Moderate drinking also raises the level of HDL about 10%. And resveratrol, a substance found in red wine, may prevent LDL molecules from being modified, which is a crucial step in plaque formation.
Such small potential benefits must be weighed against the known hazards of drinking alcohol. Alcohol can worsen various coronary risks, including high blood pressure and diabetes. Heavy use of alcohol can cause cirrhosis of the liver, is linked to several forms of cancer, and clearly plays a role in suicides and accidental deaths, especially automobile-related fatalities. It can also lead to alcoholism. And studies have shown that drinking heavily negates the heart-healthy benefits of moderate consumption. In a large Danish study, those who had 22–35 drinks a week had the same death rate as those who didn’t drink at all. And people who had more than 35 drinks a week had the highest death rate of all.
So, while a daily drink probably won’t hurt non-alcoholics who are already accustomed to it, experts do not recommend that anyone take up the habit in the name of raising HDL.
Plant Stanol Esters
Margarine is available containing beta-sitostanol, also known as plant stanol esters, a chemical cousin of cholesterol that is obtained from pine trees, soybeans, and other plants. In a study of the margarine Benecol, which contains beta-sitostanol, published in the New England Journal of Medicine, 153 people with borderline high cholesterol were given a year’s worth of margarine. Two-thirds received Benecol; the other third got plain old margarine. In the Benecol group, total and LDL cholesterol levels dropped 24 and 21 mg/dL (about 10%), respectively, compared with the control group.
It isn’t clear who might benefit from beta-sitostanol’s ability to lower cholesterol. The effect appears to be more pronounced when beta-sitostanol is used by people who consume an average (meaning relatively high-fat) diet. It may have little or no effect on people who have already switched to a lower-fat diet. However, plant stanols are included as a worthwhile option in the dietary component of the therapeutic lifestyle changes put forth in the NCEP’s cholesterol treatment guidelines.
One group of people should stay away from foods enriched with plant stanols — those with the rare genetic disorder known as phytosterolemia or sitosterolemia, who absorb these substances at abnormally high rates. Once inside the body, plant sterols and stanols accumulate and cause the same problems as too much cholesterol.
Another thing to think about is the impact on your wallet: Spreads enriched with stanols cost much more than you’d pay for regular margarine.
Fiber
Several sources of dietary fiber have an effect on cholesterol levels. The best way to get fiber is to eat a diet rich in whole grains, fresh fruits, and vegetables, which provides not only fiber, but other nutrients that may guard against heart disease, cancer, and other chronic diseases. In the Harvard-based Nurses’ Health Study, women who ate two to three servings of whole-grain products (mostly bread and breakfast cereals) each day were 30% less likely to have a heart attack or die from heart disease over a 10-year period than women who ate less than one serving per week.
The main drawback to eating a high-fiber diet or taking a fiber-rich supplement is flatulence, especially if you go straight from low fiber consumption to high fiber consumption. The digestive system has trouble breaking down all the complex carbohydrates it receives and generates a higher-than-usual amount of gas. Slowly increasing the amount of dietary fiber can often prevent or at least minimize this problem. Constipation is another problem; it can be prevented by drinking extra water.
Fiber comes in two forms: water-soluble and insoluble. Soluble fiber in particular has been associated with improvements in lipid profiles. Oat bran, a good source of soluble fiber, was linked to a decline in cholesterol in the 1980s, prompting an unprecedented rush on the product, which quickly appeared in foods ranging from bread to beer. Studies of other foods high in soluble fiber, such as corn, beans, lentils, and peas, found much the same result. Soluble fiber helps reduce cholesterol levels in two ways: The high-bulk food crowds fat out of the diet, and — through a somewhat complicated chain of molecular events — it leaches LDL from the body, ultimately lowering the blood level of LDL. However, keep in mind that the impact of soluble fiber alone is relatively small. Researchers at the Harvard School of Public Health analyzed the results of 67 rigorous trials of soluble fiber and found that eating 3 grams of soluble fiber a day from oats (about three bowls of oatmeal) would decrease total and LDL cholesterol by about 5 mg/dL. A diet high in pectin, a soluble fiber found in such fruits as tart apples, citrus fruits, cranberries, and sour plums, can also reduce high cholesterol levels. Wheat bran, which is an insoluble fiber, has no direct effect on cholesterol.
Psyllium, a soluble fiber derived from the husk of a plant related to the common weed plantain (ribgrass), has earned a reputation for its cholesterol-lowering properties. According to the American Heart Association, in some studies, people eating a typical American diet who took fiber supplements with psyllium have had 15% drops in LDL levels, while people on a more restricted diet who took psyllium saw drops of 9%. Psyllium is safe and far less likely to cause bothersome side effects than some of the older cholesterol-lowering medications. You can buy psyllium in health food stores, groceries, and pharmacies. It is also the primary ingredient in fiber-based laxatives such as Metamucil and in breakfast cereals such as Kellogg’s All-Bran Bran Buds.
Flaxseed has also been touted for its ability to prevent heart disease. These tiny brown seeds are rich in soluble fiber and in omega-3 fatty acids similar to those found in fish. The data on the benefits of flaxseed are rather sketchy. A review paper that looked at numerous studies of flaxseed concluded that eating 1–5 tablespoons of flaxseed a day can modestly reduce total and LDL cholesterol levels, but doesn’t affect triglycerides or HDL. Ground flaxseeds seem to work best and are easier to digest. They can be added to baked goods or sprinkled on cereal or salads.
Fish Oil
Interest in the heart-health benefits of fish oil dates back about two decades, beginning with a 1980 study showing that Eskimos in Greenland — who eat nearly a pound of fish a day — have low rates of death from heart disease. In subsequent years, there has been substantial research on the effects of fish oil on the heart and arteries. Laboratory studies have shown that fish oil, which contains what are known as n-3 or omega-3 fatty acids, makes blood platelets less sticky, helps protect the linings of arteries, and may also lower blood pressure.
Population studies from several countries have shown lower rates of heart disease in people who eat fish regularly. In 1998, data from the Physicians’ Health Study showed that eating fish once a week versus less than once monthly halved the likelihood of dying suddenly from a heart attack. Total heart attack rates were not affected by fish consumption or the amount of omega-3 fatty acids ingested. One year later, a report in Lancet described a randomized trial in which men who’d had a heart attack received either a fish oil supplement, 300 mg of vitamin E, both, or neither. The groups who received the fish oil supplement had significantly lower rates of heart attack, stroke, and death during the next three and a half years. Rates of sudden death dropped by 45%.
Additional support for fish oils comes from a report on nearly 80,000 women in the Nurses’ Health Study. Published in 2001 in the Journal of the American Medical Association, this 14-year study found that eating fish at least twice a week versus less than once a month cut in half the risk of strokes caused by clots blocking an artery to the brain. The Nurses’ Health Study also found that eating one to three servings of fish per month cut the risk of heart disease by 20%, while eating at least five servings a week lowered risk by 40%.
Anyone hoping to benefit from fish oil would probably be better off sticking with dietary sources, primarily from cold-water fish such as salmon, trout, mackerel, sardines, and herring. Forgoing meat for cold-water fish, or any fish for that matter, may lower cholesterol and heart disease risk simply by reducing the amount of saturated fat in your diet.
Three groups of people may benefit from fish oil supplements. One group includes people with arrhythmias, or disordered heart rhythms. The omega-3 fatty acids in fish oil can stabilize wayward electrical activity in the heart and calm arrhythmias. The second group includes people with high levels of triglycerides, especially those who can’t control the problem through diet and exercise, because fish oil supplements have been shown to help lower triglycerides. The third group includes people with coronary heart disease. The American Heart Association recommends that these people eat one serving of fatty fish a day; recognizing that this may be more fish than most people will eat, the association notes that a supplement can be substituted.
Soy Protein
Soy protein has garnered interest from those who are looking for solutions for high cholesterol. There has been interest in soy protein for years, based largely on the low rates of heart disease in East Asia and other regions with high average consumption of soy protein. Then a large study in the New England Journal of Medicine in 1995 really turned the spotlight on soy. This study reexamined the results of 38 controlled trials of soy protein in humans and reported that 47 grams of soy protein daily (just under 2 ounces) lowered total cholesterol levels by 9%, LDL by 13%, and triglycerides by 11%.
In most of these studies, participants replaced animal protein with soy protein. Thus, some of the drop in cholesterol may reflect the lower intake of meat and meat products rather than the actual consumption of soy protein. Some researchers believe that the beneficial effects also involve some of soy’s other components, particularly substances known as isoflavones. Isoflavones are plant hormones that may prevent the oxidation of LDL and other processes that may lead to the buildup of cholesterol-rich plaque inside arteries. These hormones may also prevent blood-clot formation inside arteries by making platelets less likely to clump.
As part of a healthy diet, soy can be a great substitute for meats high in saturated fat or other unhealthy foods. What’s more controversial is whether soy should be taken as a supplement. Early studies suggested soy supplements might lower LDL cholesterol, but more recent studies have cast doubt on this. So, for now, it’s best to think of soy solely as a healthy protein source.
Antioxidants
While most cholesterol-fighting drugs are designed to lower cholesterol levels, another approach might be to limit the damage LDL can do once it is in the artery wall. Some researchers suggest preventing the conversion of circulating LDL to oxidized LDL. Drugs and vitamins called antioxidants have been able to do this — at least in test tubes — but whether they have a similar effect inside the body is still under investigation.
While some studies have shown that vitamins with antioxidant properties (such as beta carotene and vitamins C and E) can lower the risk for heart disease, the evidence is conflicting. One of the randomized studies found lower rates of heart attack and death from heart disease among people given 400 IU (the equivalent of 268 mg of vitamin E from food or 180 mg of synthetic E) or 800 IU of vitamin E rather than a placebo. However, in three other large-scale randomized studies, various doses of vitamin E didn't significantly reduce cardiovascular events. Because many of these studies involved high-risk populations or had other limitations, it's still possible that vitamin E could have protective effects, but hope has faded considerably in the past few years.
A large study known as the Heart Protection Study also dampened hope about vitamin C and beta carotene. This study involved more than 20,000 adults with diabetes, coronary artery disease, or other artery disease. Half the people were randomly assigned to receive high-dose supplements of vitamins E, C, and beta carotene, the other half a placebo. At the end of five years, a similar number of people in each group had had coronary events, stroke, or death.
Green tea has been shown to lower cholesterol in animals, and with its high level of antioxidants known as flavonoids, it would be logical to assume that green tea might help decrease LDL's damage. Human trials have had mixed results. However, a recent trial published in the Archives of Internal Medicine fueled hope for this traditional Asian drink. In this study, 114 Chinese adults who took a pill extract of green tea in addition to following a low-fat diet improved their cholesterol profile more than 106 adults who ate similarly but took a placebo.
Even though moderate amounts of vitamin supplements seem reasonably safe for most people, the data don't support a blanket recommendation that everyone take antioxidants to prevent heart disease. The best advice is simply to eat a diet rich in the fruits and vegetables that provide these vitamins, such as citrus fruits, broccoli, and tomatoes.
Policosanol Alcohol
This dietary supplement made from alcohols extracted from sugar cane shows promise as a cholesterol-lowering agent. Although we’re not sure exactly how it works, policosanol alcohol seems to block the production of cholesterol. Trials have shown it to lower LDL cholesterol levels moderately in people with diabetes, postmenopausal women, the elderly, and those with familial hypercholesterolemia, a genetic disorder that causes high cholesterol. That said, most of the trials have been done by one group of scientists, and there haven’t been enough long-term, independent clinical trials on policosanol alcohol to recommend it. And more importantly, no one knows if policosanol’s beneficial effects actually translate to lower rates of heart attacks and strokes.
The substance does appear to be safe and not to interact with most medications used to treat heart disease, although a trial focused on this question needs to be done, particularly on how it interacts with aspirin. One noteworthy side effect is that it increases the effects of medications that decrease clotting (aspirin, warfarin). Policosanol alcohol can make platelets less sticky, making you prone to bleed more than usual. It should not be used with statins until the mechanism of action is better understood. Pregnant and breast-feeding women should also avoid it.
Garlic
Garlic is a popular folk remedy for many diseases, and some studies have shown that it can lower cholesterol slightly. In 2000, researchers did an analysis of the studies published on garlic and cholesterol. They found that garlic slightly reduces cholesterol compared with placebo. This lowering isn’t much compared with other interventions, like a healthy diet’s impact of a 5%–10% decrease. Also, not all of the trials showed that garlic improved cholesterol, and the study authors did not endorse garlic as a means of controlling cholesterol. If you like garlic, there’s no reason not to add it to your favorite dishes. No one knows what component of garlic might affect cholesterol metabolism, so it’s difficult to design rigorous empirical tests. It’s also unclear whether cooking garlic, or processing it into tablets or extracts, inactivates any potential cholesterol-lowering activity.
Guggul
This extract from a tree native to Asia was used medicinally as early as 600 B.C. to fight obesity and muscle stiffness among other things. More recently, it’s been used in Asia to lower cholesterol, and it’s now making its way into the medicine cabinets of Westerners as well. There are few randomized, controlled trials of this substance, and a recent one shows that guggul doesn’t live up to its hype. In this 2003 study, 103 American adults with high cholesterol were assigned to take either a placebo, 1,000 mg of guggul extract, or 2,000 mg of the extract, three times a day. Surprisingly, researchers found that the extract actually increased LDL and decreased HDL. Researchers noted that the higher-fat American diet may have made a difference in how guggul worked, since other trials that focused on Asians — who typically eat a diet lower in fat — had encouraging results.
Co-enzyme Q10
It seems logical that the antioxidant marketed as co-enzyme Q10 (known medically as ubiquinone) would help prevent the muscle problems that statins can cause. It’s been shown that when statins block the production of cholesterol, they also decrease the amount of ubiquinone the body creates. So wouldn’t raising ubiquinone levels through supplements decrease statins’ effects on muscles? While the logic is there, the proof isn’t. Very few studies have looked at ubiquinone in this light, and those that did were small and not entirely conclusive. One small study indicated that co-enzyme Q10 might decrease the severity, if not the frequency, of muscle problems.
What does this mean to you? If you’re experiencing side effects from a statin, immediately bring it to your doctor’s attention. Your doctor can help you decide if the side effects are serious enough to warrant stopping or changing your statin treatment. Or you and your doctor could decide to try co-enzyme Q10 to alleviate muscle pains, even though there’s no guarantee it will help.
From the Harvard Health Publications Special Health Report, What to Do About High Cholesterol. Copyright 2005 by the President and Fellows of Harvard College. Illustrations by Susan Avishai, Harriet Greenfield, M.A., Michael Linkinhoker, Morgan Schweitzer, and Ed Wiederer. All rights reserved. Written permission is required to reproduce, in any manner, in whole or in part, the material contained herein. To make a reprint request, contact Harvard Health Publications. Used with permission of StayWell.
