What are natural treatments for high cholesterol?
One of the most significant discoveries in preventive medicine is that elevated levels of cholesterol in the blood accelerate atherosclerosis, a condition commonly known as hardening of the arteries. Like high blood pressure, inactivity, smoking, and diabetes, high cholesterol has proven to be one of the most important factors in the development 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.
When the consequences of elevated cholesterol were first being researched, total cholesterol was the only measurement considered. Today, the overall lipid profile is taken into account. LDL (bad) cholesterol, HDL (good) cholesterol, and triglycerides are the most common measurements related to cholesterol. Lipoprotein A and oxidized LDL cholesterol are also drawing increasing attention.
This change in emphasis has placed doubt on some long-standing recommendations. For example, reducing total fat intake generally decreases total cholesterol. On this basis, medical authorities long ago adopted a policy of recommending low-fat diets. However, when other lipid measurements are taken into account, it is clear that reducing fat intake is not the key. Low-fat diets improve total and LDL cholesterol levels, but they worsen HDL and triglyceride levels. Conversely, low-carbohydrate (carb), high-fat diets tend to raise levels of LDL and total cholesterol, but they reduce triglycerides and raise HDL. Some researchers use these effects as proof that the low-fat diet is healthier, but the current state of knowledge does not indicate whether the changes in lipids produced by low-fat diets are better or worse than the changes produced by low-carb diets. It is possible that a diet low in carbohydrates and high in monounsaturated fats (such as olive oil) offers the best of both worlds, but this has not been conclusively proven. What is clear is that losing weight is extremely important. If one is overweight and loses weight, one’s cholesterol profile is almost certain to improve.
Increasing exercise and losing weight may produce adequate improvements in the lipid profile. If such lifestyle changes are not effective, however, there are many highly effective drugs to choose from. Medications in the statin family are most effective, and they have been shown to prevent heart attacks and reduce mortality. Other useful conventional options include ezetimibe (Zetia), fibrate drugs, and various forms of the vitamin niacin.
Several herbs and supplements appear to help lower cholesterol levels. For some (such as stanols-sterols, vitamin B3, fiber, and soy), the evidence is sufficiently strong to have produced mainstream acceptance.
Stanols and sterols. 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 (usually modified into stanol esters) can help to lower cholesterol in persons with normal or mildly to moderately elevated cholesterol levels. Stanols are available in margarine spreads, salad dressings, and dietary supplement tablets. Related substances called plant sterols appear to have equivalent effects. In the following subsection, sterols and stanols and their esters will be referred to somewhat interchangeably.
Plant stanol esters reduce serum cholesterol levels by inhibiting cholesterol absorption. Because they are structurally similar to cholesterol, stanols (and sterols) can displace cholesterol from the “packages” that deliver cholesterol for absorption from the intestines to the bloodstream. The displaced cholesterol is then excreted from the body. This not only interferes with the absorption of cholesterol from food but has the additional (and probably more important) effect of removing cholesterol from substances made in the liver that are recycled through the digestive tract.
Numerous double-blind, placebo-controlled studies, ranging in length from thirty days to twelve months, have found stanol esters and their chemical relatives effective for improving cholesterol profile levels. The combined results suggest that these substances can reduce total cholesterol and LDL (bad) cholesterol by about 10 to 15 percent. However, stanols-sterols do not appear to have any significant effect on HDL (good) cholesterol or triglycerides.
Fish oil has also been shown to have a favorable effect on fats in the blood, in particular triglycerides. A study investigating the possible benefit of combining sterols with fish oil found that together they significantly lowered total cholesterol, LDL cholesterol, and triglycerides, and raised HDL cholesterol in persons with undesirable cholesterol profiles.
Persons taking statin drugs also may benefit from using stanols-sterols. According to one study, persons on statins and who start taking sterol ester margarine will see improvement in their cholesterol level to the same extent as if they had doubled the dose of statin. Stanols or sterols also appear to enhance the effects of cholesterol-lowering diets. Stanols or sterols also appear to be safe and effective in helping to improve cholesterol profile in people with type 2 (adult-onset) diabetes.
Niacin. 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 percent and triglycerides by 25 percent, and raised HDL cholesterol by 20 to 30 percent. Niacin also lowers levels of lipoprotein A (another risk factor for atherosclerosis) by about 35 percent. 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 too and (contrary to previous reports) does not seem to raise blood sugar levels. 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 lipid profile by raising HDL cholesterol. There are real concerns, however, 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 persons with healthy kidneys. Furthermore, even much lower doses of niacin than the usual dose given to improve cholesterol levels (100 milligrams [mg] versus 1,000 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 because rhabdomyolysis can be fatal.
Soluble fiber. Water-soluble fiber supplements (such as psyllium, hydroxymethylcellulose and its relatives, and beta glucan from oats) are thought to lower cholesterol, and the U.S. Food and Drug Administration (FDA) has permitted products containing this form of fiber to carry a “heart-healthy” label. The bulk of the supporting evidence for this theory comes from studies of oats conducted by manufacturers of oat products. A typical dose of oat bran is 5 to 10 grams (g) with each meal and at bedtime; psyllium is taken at 10 g with each meal.
Soy protein. Soy protein appears capable of modestly lowering total cholesterol, LDL cholesterol, and triglycerides by approximately 5 to 15 percent. 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. Higher doses appear to lead to increased benefit.
Although it was once thought that isoflavones are the active ingredients in soy responsible for improving cholesterol profile, evidence suggests otherwise. Other substances, such as certain soy proteins, may be more important. However, it also has been suggested that soy protein must be kept in its original state to be effective. Ordinary soy protein extracts are somewhat damaged (“denatured”). In a double-blind study of 120 people, a special “preserved” soy protein extract proved more effective for improving cholesterol profile than standard denatured soy protein extracts.
Artichoke leaf. Although primarily used to stimulate gallbladder function, artichoke leaf also may be helpful for high cholesterol. In a double-blind, placebo-controlled study of 143 persons with elevated cholesterol, artichoke leaf extract significantly improved cholesterol readings. Total cholesterol fell by 18.5 percent compared to 8.6 percent in the placebo group; LDL cholesterol fell by 23 percent versus 6 percent; and the LDL to HDL ratio decreased by 20 percent versus 7 percent. In a subsequent study of seventy-five otherwise healthy people with high cholesterol, artichoke leaf extract significantly reduced total cholesterol compared with placebo, but it did not affect LDL, HDL, or triglycerides levels.
Artichoke leaf may work by interfering with cholesterol synthesis. A compound in artichoke called luteolin may play a role in reducing cholesterol.
There are several other promising alternative treatments for high cholesterol. Numerous studies enrolling a total of many thousands of persons purported to show that the substance policosanol, made from sugarcane, can markedly improve cholesterol profile. However, the single Cuban research group behind these studies has a financial connection to the product. Not until 2006 did independent research groups begin to report their results on the use of policosanol for hyperlipidemia. Nine such independent studies have been reported, enrolling more than five hundred people, and in not one of these studies has policosanol proved to be more effective than placebo.
Red yeast rice is a traditional Chinese medicinal substance that is made by fermenting a type of yeast called Monascus purpureus over rice. It contains cholesterol-lowering chemicals in the statin family, including one identical to the drug lovastatin. Like statin drugs, red yeast rice appears to be effective for improving various aspects of lipid profile, including total cholesterol, LDL cholesterol, and the LDL/HDL ratio. Presumably it also presents the same safety risks as statins, compounded by the uncertainty regarding how much active drug any particular batch of red yeast rice contains.
In a twelve-month study of 223 postmenopausal women, calcium supplements (calcium citrate at a dose of 1 g daily) significantly improved the ratio of HDL cholesterol to LDL cholesterol. This appears to have been primarily caused by a meaningful rise in HDL levels.
Krill are tiny shrimplike crustaceans that flourish in the Antarctic Ocean and provide food for numerous aquatic animals. Krill oil, similar but not identical to fish oil, may improve cholesterol profile. Fish oil may enhance the effectiveness of drugs in the statin family. Eicosapentaenoic acid, another constituent of fish oil, may help prevent severe heart complications in people with high cholesterol who are already taking statins.
One double-blind study found evidence that cinnamon, taken at a dose of 1 to 6 grams daily, improved triglyceride, LDL cholesterol, and total cholesterol, without worsening HDL cholesterol. Inconsistent evidence hints that flaxseed might reduce LDL cholesterol and, overall, slow down atherosclerosis. Flaxseed oil may be helpful too, although evidence is again inconsistent. It may be the generic fiber and not the other specific ingredients in flaxseed that benefit cholesterol levels. Studies of purified lignans (found in flaxseed) have yielded mixed results. Also, a growing body of evidence suggests that increased consumption of nuts such as almonds, walnuts, pecans, and macadamia nuts may improve lipid profile and reduce heart disease risk, presumably because of their high monounsaturated fat content.
Olive oil is known to improve cholesterol profile. Until recently, it had been thought that the monounsaturated fats in olive oil are its primary active ingredients. However, some evidence hints that polyphenols in olive oil (particularly, virgin olive oil) also may play a positive role.
Some studies suggest that friendly bacteria (probiotics) might improve cholesterol profile. Prebiotics, substances that enhance the growth of friendly bacteria, have shown inconsistent benefit in studies. One study found that any improvement, if it does occur, is short-lived.
Both black and green teas enriched with either theaflavin or catechins have shown promise for lowering cholesterol. Without such enhancement, both green tea and black tea may be ineffective. Dark chocolate contains substances related to those in black and green tea, and it too has shown some promise for improving cholesterol profile.
Other preliminary double-blind trials suggest potential benefit with the Iranian herb Achillea wilhelmsii, the Peruvian herb caigua (Cyclanterha pedata), carob fiber, caterpillar fungus (Cordyceps sinensis), Ipomoea batatus (sweet potato), and a drink containing broccoli and cabbage. Chitosan, a type of insoluble fiber derived from crustacean shells, has been proposed for reducing cholesterol levels. Evidence suggests that if it does offer any benefits, they are minimal at best.
A comprehensive review combining the results of fourteen studies found that glucomannan, a dietary fiber derived from the tubers of Amorphophallus konjac, significantly reduced total and LDL cholesterol levels. Weaker, and in some cases inconsistent, evidence suggests potential benefit with alfalfa; berberine (found in goldenseal, honey, Oregon grape, and barberry); beta-hydroxy-beta-methylbutyrate; blue-green algae; conjugated linoleic acid; L-carnitine; the Ayurvedic herb Eclipta alba (also known as Bhringraja or Keshraja); grape polyphenols; mesoglycan; and nopal cactus.
Studies on whether the mineral chromium can improve cholesterol levels have returned mixed results. However, this mineral may offer benefit for people taking drugs in the beta-blocker family. These medications, used for high blood pressure and other conditions, sometimes reduce HDL cholesterol levels. Chromium supplements may offset this side effect.
One study provides preliminary evidence that the herb black cohosh may improve lipid profiles in postmenopausal women. Rice bran oil, like other vegetables oils, appears to favorably change lipid profile and to reduce heart disease risk in other ways. Weaker evidence suggests that gamma oryzanol, a substance found in rice bran oil, can also improve lipid profiles.
Substances related to vitamin E called tocotrienols are sometimes promoted as improving cholesterol levels. However, while benefit has been reported in test-tube studies, animal studies, and nonblinded human trials, properly designed studies have failed to find it effective. Other herbs and supplements sometimes recommended for high cholesterol include ashwagandha, fenugreek, He shou wu, maitake, and royal jelly, but there is no evidence that they work.
A number of studies published in the 1980s and 1990s reported that various garlic preparations, including raw garlic, stabilized garlic powder, and aged garlic, can lower cholesterol. However, several more recent and generally better-designed studies have found that if any benefits exist, they are so small as to be of little help in real life.
Although lecithin is commonly believed to reduce cholesterol levels, evidence indicates that it does not work. Similarly, guggul, the sticky gum resin from the mukul myrrh tree, has been widely marketed as a cholesterol-reducing herb. However, while preliminary studies found evidence of benefit, the studies all had significant design flaws; a well-designed study did not find guggul effective.
Vitamin C, cranberry, curcumin (turmeric), and elderberry have failed to prove effective in studies thus far. Also, one study failed to find special fats called medium-chain triacylglycerols more effective for reducing cholesterol than ordinary unsaturated fats.
One study, in which participants took more than 50 mg of zinc daily, showed that zinc might reduce levels of HDL, or good, cholesterol. Unexpected results in a single trial hint that the sports supplement pyruvate might negate some of the beneficial effects of exercise on HDL levels. In addition, various herbs and supplements may interact adversely with drugs used to treat high cholesterol.
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