High Cholesterol

One of the most significant discoveries in preventive medicine is that elevated levels of cholesterol in the blood accelerate atherosclerosis, or hardening of the arteries (see the discussion about cholesterol in the article on atherosclerosis). Along with high blood pressure, inactivity, smoking, and diabetes, high cholesterol has proven to be one of the most important promoters of heart disease, strokes, and peripheral vascular disease (blockage of circulation to the extremities, usually the legs).

Cholesterol does not directly clog arteries like grease clogs pipes. The current theory is that elevated levels of cholesterol irritate the walls of blood vessels and cause them to undergo harmful changes. Because most cholesterol is manufactured by the body itself, dietary sources of cholesterol (such as eggs) are not usually the most important problem. The relative proportion of unsaturated fats (from plants) and saturated fats (mainly from animal products) in the diet is more significant. The former lower cholesterol levels, whereas the latter raise them.

There is no question that increasing exercise and improving diet are the most important steps to take when cholesterol is high. These fundamental lifestyle changes are frequently effective and produce many benefits that go beyond simply lowering cholesterol levels.

However, if your cholesterol remains high despite your best efforts, you may need specific cholesterol-lowering treatments. There are a variety of effective drugs to choose from, and some, such as Pravachol (pravastatin), have been shown to prevent heart attacks and reduce mortality. While there are known and suspected risks associated with these medications, the benefits undoubtedly exceed the risks for those with significantly elevated cholesterol levels. In milder cases, however, some of the options described below might be better first choices.

Principal Proposed Treatments for High Cholesterol:

There are several herbs and supplements that appear to help lower cholesterol levels. However, before trying them, consult with your physician to find out whether you have time to experiment. If your cholesterol levels are very high and your arteries are already in bad condition, it might be wiser to turn to proven drug treatments. However, if your physician says that you can safely spend some time exploring your options, the treatments described in this section may be worth trying.

Stanols

Stanols are substances that occur naturally in various plants. Their cholesterol-lowering effects were first observed in animals in the 1950s. Since then, a substantial amount of research suggests that plant stanols (modified into stanol esters) and related substances called sterols can help to lower cholesterol in individuals with normal or mildly to moderately elevated cholesterol levels. Stanols are available in margarine spreads, salad dressings, and dietary supplement tablets.

What Is the Scientific Evidence for Stanols?

Plant stanol esters reduce serum cholesterol levels by inhibiting cholesterol absorption. Because they are structurally similar to cholesterol, stanols can displace cholesterol from the "packages" that deliver cholesterol for absorption from the intestines to the bloodstream. The displaced cholesterol is not absorbed and is excreted from the body; the stanols themselves are ultimately not absorbed either.

At least 13 double-blind placebo-controlled studies, ranging in length from 30 days to 12 months and involving a total of more than 1,000 individuals, have found stanols or sterols effective for improving cholesterol levels. The combined results suggest that stanols can reduce total cholesterol and LDL ("bad") cholesterol by about 10 to 15%. Stanols did not have any significant effect on HDL ("good") cholesterol or triglycerides in most of these studies. However, when combined with a standard cholesterol-lowering diet, use of a spread enhanced with plant sterols improved total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides as compared to a normal reduced-fat spread.

In one of the best of the double-blind placebo-controlled studies, 153 individuals with mildly elevated cholesterol were given sitostanol ester in margarine (at 1.8 or 2.6 g of sitostanol per day), or margarine without sitostanol ester, for a total of 1 year. The results in the treated group receiving 2.6 g per day showed improvements in total cholesterol by 10.2% and LDL cholesterol by 14.1%—significantly better than the results in the control group. Neither triglycerides nor HDL cholesterol levels were affected.

Two studies found stanols to be helpful for lowering cholesterol levels in individuals with type 2 (adult-onset) diabetes. One of these studies examined two treatments: pravastatin (a cholesterol-lowering drug) versus pravastatin along with sitostanol. The combination treatment was more effective at lowering total cholesterol and LDL cholesterol levels than the drug treatment alone. Additive benefits were also seen in a study of nondiabetics taking statin drugs who began taking stanols as well.

For more information, including dosage and safety issues, see the full stanols article.

Niacin (Vitamin B3): A Treatment Accepted by Conventional Medicine

The common vitamin niacin, also called vitamin B3, is an accepted medical treatment for elevated cholesterol with solid science behind it. Several well-designed, double-blind, placebo-controlled studies have found that niacin reduced LDL cholesterol by approximately 10%, triglycerides by 25%, and raised HDL cholesterol by 20 to 30%. Niacin also lowers levels of lipoprotein (a)—another risk factor for atherosclerosis—by about 35%. Furthermore, long-term use of niacin has been shown to significantly reduce death rates from cardiovascular disease.

Niacin appears to be a safe and effective treatment for high cholesterol in people with diabetes as well, and (contrary to previous reports) does not seem to raise blood sugar levels. Unfortunately, niacin, if taken in sufficient quantities to lower cholesterol, can cause an annoying flushing reaction and occasionally liver inflammation. Close medical supervision is essential when using niacin to lower cholesterol.

Combining high-dose niacin with statin drugs (the most effective medications for high cholesterol) further improves cholesterol profile by raising HDL (“good”) cholesterol Unfortunately, there are real concerns that this combination therapy could cause a potentially fatal condition called rhabdomyolysis.

A growing body of evidence, however, suggests that the risk is relatively slight in individuals with healthy kidneys. Furthermore, even much lower doses of niacin than the usual dose given to improve cholesterol levels (100 mg versus 1000 mg or more) may provide a similar benefit. At this dose, the risk of rhabdomyolysis should be decreased.

Nonetheless, it is not safe to try this combination except under close physician supervision. Rhabdomyolysis can be fatal.

For more information, including dosage and safety issues, see the full vitamin B3 article.

Fiber: Considered "Heart-Healthy" by the FDA

Water-soluble fiber supplements appear to lower cholesterol, and the FDA has permitted products containing this form of fiber to carry a "heart-healthy" label. Many forms are available, ranging from oat bran to expensive fiber products sold through multilevel marketing firms. A good dose of oat bran is 5 to 10 g with each meal and at bedtime, and psyllium is taken at 10 g with each meal. However, eating a diet high in fresh fruits and vegetables and whole grains may be even better because of the many healthful nutrients such a diet contains.

Soy Protein: Also Labeled "Heart-Healthy"

Soy protein appears to lower total cholesterol by about 9%, LDL ("bad") cholesterol by 13%, and triglycerides by 10%. The FDA has allowed foods containing soy protein to make the "heart-healthy" claim on the label. One study suggests that substituting as little as 20 g daily of soy protein for animal protein can significantly improve cholesterol levels.

Soy isoflavones are widely thought to be the active cholesterol-lowering ingredient in soy protein, but other studies suggest that this may not be true.

For more information, including dosage and safety issues, see the full soy article.

Policosanol

Policosanol is a mixture of waxy substances manufactured from sugarcane. It appears to slow down cholesterol synthesis in the liver and also to increase liver reabsorption of LDL ("bad") cholesterol. It is approved as a treatment for high cholesterol in about two dozen countries, mostly in Latin America.

Fifteen double-blind placebo-controlled studies, involving a total of about 1,100 individuals and ranging from 6 weeks to 12 months in length, have found policosanol manufactured from sugarcane effective for improving cholesterol levels.All but one of these trials was conducted in Cuba by a single research group. The cumulative results suggest that policosanol treatment can reduce LDL ("bad") cholesterol by 20% or more and total cholesterol by about 15%. Some studies found benefits regarding HDL ("good") cholesterol and triglycerides, but most did not. Interestingly, these trials enrolled only individuals whose cholesterol levels had not previously improved with diet alone.

In the most recent study, 244 postmenopausal women with high cholesterol received either placebo or policosanol at 5 mg per day for 12 weeks. Then, the dosage was doubled to 10 mg per day (in the treated group) and the study continued for an additional 12 weeks.

The results showed significant improvements, with greater improvements when the higher dose was used. At the end of the study, LDL cholesterol improved by 25.2%, total cholesterol by 16.7%, and HDL cholesterol by 27.2%; this was significantly more improvement than what was seen in the placebo group. Substantially identical results were seen in a study of similar design and length following 437 individuals with hyperlipidemia.

Seven double-blind studies enrolling a total of almost 400 individuals have compared policosanol against standard drugs, including pravastatin, simvastatin, fluvastatin, lovastatin, and acipimox, and found them equally effective.

Policosanol also appears to be safe and effective for reducing cholesterol levels in individuals with type 2 (adult-onset) diabetes. However, individuals with any form of diabetes should seek medical advice before taking policosanol.

For more information, including dosage and safety issues, see the full policosanol article.

Garlic: May Reduce Cholesterol Slightly

A number of studies published in the 1980s and 1990s found evidence that garlic preparations can lower cholesterol. However, several more recent and generally better-designed studies have found no benefit. The accumulating impact of these results has tended to reduce enthusiasm for using garlic as a cholesterol lowering agent.

Bucking this trend, one recent study suggests that garlic can work, providing its the right form of garlic. This 12-week, double-blind, placebo-controlled trial of 46 individuals with high cholesterol tested a special enteric-coated garlic product. (An enteric-coated product is one designed to bypass stomach acid and release its contents in the intestines.) The results showed significant improvement in levels of total cholesterol and LDL cholesterol.

Besides using an enteric coating, researchers in this trial used almost twice the dose of allicin generally administered in clinical trials. This may explain the positive results. An alternative explanation may lie in the fact that the improvements seen in this trial were on the low side, ranging from 5% to 8%. Recent studies that failed to find garlic effective were not designed to reliably identify benefits as modest as these.

Guggul: Traditional Indian Herb

Guggul, the sticky gum resin from the mukul myrrh tree, may be an effective treatment for high cholesterol. According to preliminary studies, it appears that guggul can lower cholesterol by about 11 to 12% and triglycerides by 12.5 to 17%. The full benefits may take several months to develop.

For more information, including dosage and safety issues, see the full guggul article.

Artichoke (Cynarascolymus): A New Treatment

Although primarily used to stimulate gallbladder function, artichoke leaf may be helpful for high cholesterol as well.

According to a double-blind placebo-controlled study of 143 individuals with elevated cholesterol, artichoke leaf extract significantly improved cholesterol readings. Total cholesterol fell by 18.5% as compared to 8.6% in the placebo group; LDL cholesterol fell by 23% versus 6%; and the LDL to HDL ratio decreased by 20% versus 7%.

Artichoke leaf may work by interfering with cholesterol synthesis. A compound in artichoke called luteolin may play a role in reducing cholesterol.

For more information, including dosage and safety issues, see the full artichoke article.

Other Proposed Treatments for High Cholesterol:

There are several other promising alternative treatments for high cholesterol.

In a 12-month study of 223 postmenopausal women, calcium supplements (calcium citrate at a dose of 1 gram daily) significantly improved the ratio of HDL ("good") cholesterol to LDL ("bad") cholesterol. This appears to have been primarily due to a meaningful rise in HDL levels.

A special form of the vitamin pantothenic acid, known as pantethine, might significantly lower total blood triglycerides as well as cholesterol, but not all studies agree. Further research is necessary to evaluate the safety and effectiveness of this expensive supplement.

Most but not all studies suggest that chitosan, a type of fiber derived from crustacean shells, may lower cholesterol levels.

L-carnitine is another expensive supplement that might be able to improve cholesterol levels.

The Iranian herb Achillea wilhelmsii was tested in a double-blind trial of 60 men and women with moderately elevated cholesterol. The results showed that treatment with an A. wilhelmsii extract significantly reduced LDL and total cholesterol after 4 months, and increased HDL cholesterol after 6 months.

A 2-month double-blind study of 40 individuals with elevated cholesterol compared placebo, grape seed extract, chromium (in the form of polynicotinate), and the combination of chromium and grape seed. While neither chromium nor grape seed was effective alone, the combination produced statistically significant reductions in total and LDL cholesterol.

Caigua (Cyclanterha pedata) is an edible plant used traditionally in Peru to treat diabetes and other diseases. A pilot trial found some evidence that caigua might reduce total and LDL cholesterol, as well as raise HDL cholesterol.

The supplement fish oil also appears to lower total blood triglycerides and might raise HDL cholesterol as well, although study results arent entirely consistent. Fish oil has particularly been studied for reducing triglyceride levels in people with diabetes, and it appears to do so safely and effectively. However, the drug gemfibrozil appears to be more effective than fish oil.

Although fish oil is much better studied, there is some evidence that flaxseed oil or whole flaxseed may reduce LDL cholesterol, perhaps slightly reduce hypertension, and, overall, slow down atherosclerosis.

A growing body of evidence suggests that increased consumption of nuts such as almonds, walnuts, pecans, and macadamia nuts may help lower cholesterol and prevent heart disease.

Preliminary evidence suggests that creatine supplements may also be able to reduce triglycerides.

Preliminary studies suggest that an extract from the intestines of pigs known as mesoglycan can improve cholesterol levels.

Studies on whether chromium can improve cholesterol levels have returned mixed results. In people taking beta-blockers, it may raise levels of HDL cholesterol.

A combination of vitamins C and E may be helpful for those who are taking the drug tamoxifen. Tamoxifen has a tendency to raise triglyceride levels. In one study, simultaneous use of vitamin C (500 mg daily) and vitamin E (400 mg daily) counteracted this side effect.

Some but not all studies suggest that "friendly" bacteria (probiotics) might be able to reduce cholesterol levels.

Weak evidence suggests genistein may be helpful for reducing cholesterol and keeping it from depositing on cell walls.

Evidence from animal studies and one small controlled (but not blinded) study in humans suggests that spirulina might help lower cholesterol.

Animal and preliminary human trials suggest that the herb alfalfa may be helpful for high cholesterol as well.

One study provides preliminary evidence that black cohosh may improve cholesterol profiles in post-menopausal women. The extent of this effect was not stated in the currently available abstract.

Other herbs and supplements commonly recommended for high cholesterol include ashwagandha, bilberry leaf, chondroitin, copper, fenugreek, gamma oryzanol, grass pollen, He shou wu, lecithin, and maitake, but there is as yet no real evidence that they really work.