Are They Safe? Do They Really Lower Cholesterol?
I originally posted on this topic in 2007 because I wanted to talk about the possible dangers associated with some “herbal” medicines, also know as nutraceuticals, and the research done on their possible cholesterol lowering effects. In the February 9th edition of the Journal of the American College of Cardiology, there is a paper about the hidden dangers of these “herbal” medicines. They reviewed nearly 90 papers that have addressed herbal and complementary therapies and cardiovascular effects. They listed 15 common herbal medicines that are known to adverse interact with conventional cardiovascular medicines. Many patients, however, think that since these medicines are “natural” their dangers should not be considered in the same way as medications. The author found data from the 1990s suggesting that more patients consult complementary and alternative medicine providers than regular physicians. I have included other medicines and functional foods that are thought to have a cholesterol lowering effect in this review.
Grapefruit juice, for example, has a negative effect on an enzyme called CYP3A4 in the intestine, which can cause substantial elevations of the statin drugs lovastatin, simvistatin, and atorvastatin when taken simultaneously. An 8 ounce glass of grapefruit juice in the morning followed by an evening dose of statin produces only a modest increase in the amount of the drug in the body while a larger glass does produce a substantially larger effect.
At least 3 well-designed studies failed to document any influence of garlic on serum lipoproteins (the particles that carry the cholesterol). Garlic is one of several herbal remedies with specific cardiovascular effects in it’s own right. Garlic inhibits platelet clumping in the blood and thus lead to increased bleeding risks when taken with clopidogrel (Plavix), warfarin (Coumadin), and aspirin.
Guggulipids are found in the arid regions of India and Pakistan, and believed to be the active ingredients in the resin of the Commiphora Mukul “Guggul” tree. This substance is marketed in the US under the name “Guggulipids” as a dietary supplement and is promoted to control cholesterol. The gum resin of the Guggul tree has been used in Ayurveda for more than 2,000 years and is believed to have many health benefits including treating obesity.
Though there have been numerous studies evaluating the impact of guggul on lipids, these studies have concentrated on the Eastern Indian population. Of the two placebo controlled trials, the study performed in the Indian population found that guggulipids lowered LDL cholesterol by 12%. On the strength of this study, guggul was approved for use in India. A single study reported in the US was a carefully designed 8-week, double blind randomized, placebo-controlled trial using a parallel design. During this carefully controlled clinical trial, the Guggulipids did not lower LDL cholesterol and in fact actually increased LDL cholesterol in the majority of treated patients. Of some concern was the high rate of hypersensitivity rashes (9% of the participants). Interestingly, in both Indian and Western studies, there does appear to be some patients who did respond to Guggulipids. The percentage of people responding favorably in the Indian trials suggests that perhaps the Indian population may differ in some basic ways (genetically or environmentally) from the primarily Caucasian population.
Policosanol is a mixture of long-chain primary aliphatic alcohols isolated from sugarcane wax. Policosanol products can also be derived from wheat germ, rice bran and beeswax. The most widely available policosanol product comes from Cuba and is sold as a lipid-lowering product in over 40 countries. Until recently, a single Cuban research group performed nearly all studies conducted on policosanol. These Cuban studies show promise. However, with the recent publication of a number of negative studies outside of Cuba, the beneficial effects of policosanol have been called into question. Overall, recent placebo-controlled trials examining the lipid altering effects of sugarcane-derived policosanol failed to find any significant lipid-altering effects. At the present time, policosanol cannot be recommended for the treatment of hyperlipidemia.
Is cinnamon safe? In 2003 an in-vivo study was concluded on 60 diabetic candidates in Pakistan. The results of this study were released to the Western media and a frenzy of cinnamon capsules were sold in the US and other countries promoting Cinnamon’s lipid lowering effects. Since that time, numerous studies in Germany and in the Netherlands have been published. The result of these studies differs significantly from the original Pakistani study. Based on the data from these studies, it would appear that the early enthusiasm for cinnamon supplementation might have been premature.
Last year I wrote a blog posting about the dangers of red yeast rice and I strongly encourage everyone to read it. I stated that there is a new compound from China that has been found called XYZ which has not been adequately studied and may pose a health risk. The official position of the National Lipid Association is to stay away from red yeast rice at the present time and I support their position. Red yeast rice is the fermented product of rice on which red yeast has been grown .The active ingredient in red yeast rice is believed to be Monacolin K, an agent reported to be identical to lovastatin (a commonly prescribed statin). Like statins, red yeast has been found to directly reduce lipids. There is little doubt that the proprietary preparation of red yeast rice, known as Cholestin favorably alters lipids.
However, due to legal issues, this preparation is no longer commercially available in the US. In 1998, the FDA determined that red yeast rice did not conform to the definition of a dietary supplement under the 1994 Diet Supplement and Health Education Act (DSHEA). This act states that marketed dietary supplements cannot contain a compound already approved as a drug (in this case, lovastatin) unless the substance was available commercially before the drug’s approval. At present, Cholestin is still available in Canada, Europe and Asia – however, great caution should be exercised because Cholestin has been reformulated and no longer contains the important red yeast rice extract, but rather polymethoxylated flavones extracted from citrus fruits, geraniol and marine fish oils. It is unclear if this or other proprietary preparations of” red yeast extract will provide the same lipid effects. The FDA has issued a warning to consumers regarding three brands of red yeast rice. For more information go to www.fda.gov and type “red yeast rice” in the s
The FDA recommends that consumption of 1.5 ounces of nuts per day MAY reduce cardiovascular risk. Aside from the fatty acid composition of nuts, other components such as arginine, plant sterols, and phenolic components may play a favorable role in the lowering of lipid levels for those who eat nuts as a regular part of their diet. Walnuts and almonds have been most comprehensively studied. Most clinical trials evaluating the impact of nuts on lipid profiles have been small scale (10-49 participants). LDL-C (the bad cholesterol) reduction has been consistently shown in these small scale studies, typically in the range of 12-13%. Though less consistent, triglyceride reduction was shown. However, HDL-C (the good cholesterol) generally remained unchanged. One must always remember that these studies are far too small to establish any guidelines and there certainly is not one ounce of outcome data regarding the effect on cardiovascular morbidity and mortality.
The American Dietetics Association evidence library concludes that “consumption of 50-113 grams (1/2 cup to 1 cup) of nuts daily with a diet low in saturated fat and cholesterol decreased total cholesterol by 4-21% and LDL-C by 6-29% when weight was not gained.” However, we have to remember that a diet rich in nuts is a heavy caloric load and may lead to weight gain. I recommend somewhat smaller portions of nuts as part of a healthful diet.
There are two kinds of fiber or nondigestible carbohydrates. The first, which is insoluble, aids in bowel function. An example is wheat bran. The second is soluble fiber, now referred to as viscous fiber, which has an additional cholesterol lowering effect. Examples include dried beans, grains, certain fruits and vegetables. Psyllium is a source of soluble fiber and has been shown to augment the lipid lowering response when combined with other lipid lowering medications. Oat products have the most soluble fiber of any grain. Several recent studies have looked specifically at the effects of oats or oat bran on LDL-C. Both oats and oat bran demonstrated favorable results in the lowering of LDL-C. Robitaille’s study on overweight pre-menopausal women provided 28 grams of oat bran daily over 4 weeks and not only obtained LDL-C reductions, but also demonstrated an 11.2% increase in HDL-C. In moderately hypercholesterolemic men and women, a study found significant positive results from the consumption of barley. A reduction of 20% in total cholesterol and 24% in LDL-C was obtained in 1 study.
The ATP III (Adult Treatment Panel) recommends a minimum of 5-10 grams a day of total dietary fiber for people with even mildly elevated LDL-C levels, but higher intakes of 10-12 grams of fiber per day can be more beneficial in those with more severe hyperlipidemia.
In large prospective epidemiological studies, total dietary fiber has been shown to protect against coronary heart disease. These studies examined the relationship between whole grain consumption and CHD. Researchers found 20-40% reduction in CHD risk for those who habitually consumed whole grains as compared to those who rarely ate whole grains. There are several mechanisms by which it is believed dietary fiber may protect against CHD. They include lowering serum cholesterol and LDL-C, attenuating blood triglyceride levels, and decreasing hypertension. Fiber consumption also predicts insulin levels and weight gain more strongly than a low total fat and saturated fat diet. High fiber diets may protect against obesity and cardiovascular disease (CVD) by lowering insulin levels. It has been shown that the intake of dietary fiber is inversely correlated with cardiovascular disease risk factors in both sexes.
However, most of the evidence shows that a mixture of both soluble and insoluble forms of fiber is an important part of a diet that promotes general good cardiovascular health. Based upon this conclusion, the National Academy of Science recommends 25 grams per day of fiber for women 19-50 years of age and 21 grams per day for women over 50. For men 19-50 years of age, 38 grams per day is recommended and 30 grams for men over 50. This is set from an established 14 grams of fiber per 1,000 calories.
In the last 12 years, soy has been believed to lower LDL-C. However, recent data has not shown soy to be a practical means to lower LDL-C. In order to achieve any meaningful LDL-C reduction, large amounts of soy are required. Even when individuals consume half their daily protein with soy protein only a very small reduction (3%) in LDL-C is achieved. Soy seems to be a more efficacious lipid-lowering agent in persons with marked hyperlipidemia. It should be noted that reduction in lipids may be due to replacing high-fat animal protein with soy rich foods that may indirectly result in lipid reduction via a reduction in saturated fat intake.
Lecithin is another widely promoted lipid-lowering functional food that is derived from soy beans and sold as a “fat emulsifier”. Many people believe that this “emulsifier” actually breaks down fat and cholesterol in the bloodstream. These claims are totally unsubstantiated by any medical literature.
Another promoted cholesterol lowering remedy is daily a dose of apple cider vinegar. To date, I have yet to see substantial evidence in the form of any clinical trial evidence that supports these claims.
I have tried to shed some light on the most common nutraceuticals that are promoted to lower lipid levels. I have used solid, evidence-based studies to provide the latest, most accurate information. Perhaps you have found studies on the Internet to support the claims that many of these functional foods will lower cholesterol levels. I would like to bring three important points to your attention.
- First, it is important to remember that most of consumer-based literature published has no or little scientific components and are purely retrospective data gathered via questionnaires. Remember, any one can write a paper on any topic and get in published in some type of journal but I can guarantee that none of these journals are “peer review” journals.
- Second, the nutraceutical industry is unregulated. Although Congress is once again calling on this industry to be regulated, nothing will probably be done. It is possible for companies promoting functional foods to fund a study that is designed to show the favorable results they had planned on prior to construction of the study.
- Finally, what is most important is outcome data. This simply means, as a result of the drug or supplement’s effect on lipid levels, did that substance affect change that resulted in fewer cardiovascular events and death?
As a cholesterol expert, I fully believe it is important to lower cholesterol by any means necessary. My greatest concern for patients and consumers regards the safety of many of the supplements we have discussed. Simply stated, they have not been well studied. Be an informed patient! When taking any substance, caution should always be exercised. There are many drug interactions with over-the-counter supplements, vitamins and other nutraceuticals and a medical professional well-versed in lipid
management should be consulted before considering any drug or non-drug protocol. A medical professional well-versed in lipid management should be consulted before considering using any type of medicine to lower cholesterol.
- Michael Richman, MD, FACS
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