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Natural Alternatives for Maintaining Healthy Cholesterol

By Yousry Naguib, Ph.D.

Vitamin Retailer magazine, October 2004

Cholesterol is a soft, waxy substance found among the fats in the bloodstream. It aids vital biological functions such as production of hormones, and it is an essential component of all cellular membranes.

Cholesterol is synthesized in our body by the liver, and found in animal foods – meats, dairy products. The risk of developing cardiovascular diseases depends not only on how much cholesterol but also on the kind of cholesterol. High levels of low-density lipoprotein (LDL), the “bad” cholesterol, are associated with increased risk of developing coronary heart disease; high levels of high-density lipoprotein (HDL), the “good” cholesterol, are associated with decreased risk.

Too much cholesterol in the bloodstream leads to narrowing and blockage of the arteries that greatly increase the risk of stroke, and heart diseases. Statistics show that one out of every two men and one out of three women will develop heart disease at some time in their life; heart disease is responsible for 50 percent of all deaths in Western countries.

Total cholesterol below 200, HDL above 40, LDL below 130, and triglycerides below 200 mg per deciliter of blood are considered desirable for lowering the risk of heart diseases.

Cholesterol problems can be managed by adopting a diet low in saturated fat and cholesterol, increasing fiber intake, losing weight, and regular exercise. If the total cholesterol is high, medications are prescribed to bring cholesterol to normal levels. The most prominent cholesterol drugs are the statin family that includes lovastatin, pravastatin (Pravachol), and simvastatin (Zocor). About 30 million Americans are currently using statin drugs. Niacin (vitamin B-3) is effective for some people but it must be taken in large doses, which often causes skin flushing and upset stomach.

In addition to prescription medications, there are natural alternatives for maintaining healthy cholesterol when combined with exercise and a diet low in saturated fats and cholesterol.

Red yeast rice

Red yeast rice is produced by fermentation of rice using the fungus Monascus purpureus. It has been used for a long time in Southeast Asia for the production of red dyes for coloring foods. Red yeast rice produces the active compounds that inhibit 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase; the enzyme that the liver uses to make cholesterol. The first of these HMG-CoA inhibitors was compactin (ML-236B), which was isolated from Penicillium citrinum.1 Later, a more potent HMG-CoA inhibitor designated Monacolin K (mevinolin, lovastatin) was isolated from Monascus rubber,2 and Aspergillus terreus.3

A study published in the American Journal of Clinical Nutrition found that healthy subjects (46 men and 37 women ages 34-78) with hyper-lipidemia who were not being treated with lipid-lowering drugs and received 2400 mg daily of red yeast rice containing, by weight, 0.4 percent HMG-CoA reductase inhibitor, had a significant reduction of total cholesterol (16 percent), and LDL cholesterol (22 percent) after 12 weeks of treatment, as compared to placebo.4 As a dietary supplement, red yeast rice may be suitable in lowering serum cholesterol in persons with moderately elevated serum cholesterol, and therefore prevent cardiovascular diseases.

Phytosterols

In recent years, phytosterols (plant sterols) have attracted a great deal of interests in the lay press for its effects on cardiovascular and menopausal health, and even cancer prevention.

Phytosterols are the counterparts of the animal product cholesterol. Phytosterols are structurally similar to cholesterol, which makes them compete with cholesterol during its absorption in the digestive tract, thereby lowering plasma cholesterol levels.5

The most common dietary phytosterols are beta-sitosterol, campesterol and stigmasterol. Plant sterols and stanols (hydrogenated form of sterols) are present in the average Western diet in small amounts, 250-500 mg per day (plant sterols) and 20-60 mg per day (plant stanols).6

The best dietary sources of phytosterols are vegetable oils (corn oil contains 0.77 percent phytosterols by weight), seeds, nuts and legumes, and wood pulp. Beta-sitosterol is present in many plants, such as wheat germ, and sweet corn. Beta-sitosterol is also a common active ingredient in the herbs (saw palmetto, pygeum africanum and pumpkin seed oil) recommended for enlarged prostate gland problems.

Clinical studies demonstrated that phytosterols have the ability to lower serum total cholesterol by 10-15 percent and LDL-cholesterol by up to 20 percent.7, 8 The National Cholesterol Educational Panel issued a recommendation in 2001 that phytosterols be added to cholesterol-lowering regimens, along with the more traditional cholesterol-fighting measures, such as regular exercise, weight loss, and a low-fat diet. The FDA has recently authorized a claim that would allow food manufacturers to label phytosterols-enriched foods with assertion that they may reduce the risk of coronary heart disease when combined with a diet low in cholesterol and saturated fats.9

In 16 recently published human studies that used phytosterols to reduce plasma cholesterol levels in a total of 590 subjects, phytosterols therapy was accompanied by an average 10% reduction in total cholesterol and 13 percent reduction in LDL cholesterol levels. The exact mechanism of action of phytosterols is not understood.10

Phytosterols can offer a safe and effective means of reducing cholesterol levels, and thereby improving cardiovascular health.

Policosanol

Policosanol is a cholesterol-lowering natural product derived from sugar-cane wax with a therapeutic range from 5 to 20 mg/day. Policosanol from honeybee’s wax, or rice bran, is also available on the market. Policosanol is a combination of long chain fatty alcohols, including octacosanol, triacontanol, dotriacontanol, tetratriacontanol, hexacosanol, heptacosanol, and nonacosanol.

Several research studies showed policosanol from sugar cane is effective at reducing cholesterol levels. A 2002 study published in the American Heart Journal reviewed the literature on placebo-controlled lipid-lowering studies using policosanol, and found that at doses of 10 to 20 mg per day, policosanol lowered cholesterol by 17-21 percent and LDL by 21-29 percent, and raised HDL by 8-15 percent. The study concluded that policosanol is “a very promising phytochemical alternative to classic lipid-lowering agents such as statins.” 11

In a recent clinical study, policosanol was compared to the statin drug, lovastatin, on 28 patients with intermittent claudication. Patients were randomly assigned to receive 10 mg policosanol or 20 mg lovastatin once daily for 20 weeks. Patients who took policosanol experienced a 17.5 percent drop in total cholesterol, a 31 percent drop in LDL cholesterol, and a 31.5 percent rise in HDL cholesterol. Lovastatin reduced total cholesterol (18 percent), LDL cholesterol (22.6 percent). Five lovastatin patients, but none from the policosanol group, experienced adverse events. These results suggest that policosanol is as effective as prescription drugs, without their side effects.12

Research also showed that policosanol reduces cardiac risk factors by inhibiting platelet aggregation, and inhibiting the development of atherosclerosis.13

Beta-Glucans

Beta-glucans are polysaccharides isolated from mushrooms, yeast, oats and barley. In 1997, the Food and Drug Administration allowed a health claim to be made for foods containing oat bran to be marketed as a cholesterol-reducing supplement at a dosage of 3 g beta-glucan.

In a controlled double-blind study, 66 men were randomly assigned to either oat milk (0.5 percent beta-glucan) or rice milk (control) for 5 weeks (0.75 liter/day). At the end of the study, the intake of oat milk significantly reduced serum total cholesterol (6 percent) and LDL-cholesterol (6 percent) levels, indicating that oat milk deprived of insoluble fiber has cholesterol-lowering properties.14

Beta-glucan derived from barley was also found to lower cholesterol in humans. Twenty-one mildly hyperchesterolemic men were randomly provided with either barley as a source of beta-glucan, or wheat, which contains largely cellulose insoluble fibers, for four weeks. Only the barley group showed a significant fall in plasma total cholesterol and in LDL-cholesterol.15

A study at the University of Massachusetts on 15 obese and hypercholesterolemic men found that supplementation with 15 grams beta-glucan fiber derived from yeast daily for eight weeks significantly reduced total cholesterol (by 6 percent) and LDL-cholesterol (by 8 percent).16

Tocotrienols

A recent research study (2002), involving ninety hypercholesterolemic human subjects, published in Atherosclerosis journal showed that a tocotrienol-rich fraction (TRF25) of rice bran is effective in lowering serum total cholesterol and LDL-cholesterol. Subjects were initially placed on the American Heart Association Step-1 diet, and then were administered 25, 50, 100, and 200 mg per day of TRF25 while on the restricted diet. The dosage 100 mg per day produced the maximum decreases in serum total cholesterol (20 percent), LDL-cholesterol (25 percent), and triglycerides (12 percent).17

In the same year, another human study showed that daily supplementation with 200 mg tocotrienols from 3 commercially available sources for 28 days did not result in a significant change in blood lipid concentration in men and women with hypercholesterolemia.18

Citrus polymethoxylated flavones (PMF)

High dietary intake of citrus juice (orange or grapefruit) has been shown to reduce hypercholesterolemia, an effect attributed to the flavanone glycosides hesperetin from oranges and naringenin from grapefruit.19 In addition to these flavanones, citrus also contain PMF; the most common ones are tangeretin and nobiletin. PMF were also found to lower cholesterol and triglycerides in hamsters with diet-induced hypercholesterolemia.20

A novel patented formulation comprising both PMF and tocotrienols was shown in several clinical trials to lower total cholesterol by 20 percent, LDL cholesterol by 22 percent, and triglycerides by 28 percent. PMF modulate lipoprotein and lipid metabolism directly in the liver, by decreasing apoprotein B needed for endogenous synthesis of LD-cholesterol, and inducing the suppression of diacylglycerol acyltransferase, an enzyme required for triglycerides synthesis.

Guggul

Guggul is the resin of mukul myrrh tree (Commiphora mukul), native to Arabia and India. It has been used in Ayurvedic medicine for more than 2000 years to alleviate problems associated with viral infections, obesity and acne, and has recently been shown to improve cholesterol levels.

A 1994 study of 61 patients (31 in the guggulipid group and 30 in the placebo group) found that guggulipid, 50 mg twice daily for 24 weeks, decreased the total cholesterol level by 11.7%, the low density lipoprotein cholesterol by 12.5 percent, triglycerides by 12 percent, and the ratio of the total cholesterol to high density lipoprotein cholesterol by 11.1 percent, whereas the cholesterol levels were unchanged in the placebo group.21

Flaxseed

Flaxseed has recently gained attention in the area of cardiovascular disease primarily because it is one of the richest sources of alpha-linolenic acid and lignans, as well as being a good source of soluble fiber. Human studies have shown that flaxseed can modestly reduce serum total cholesterol and LDL-cholesterol.

In a double-blind randomized study, postmenopausal women who were not on hormone replacement therapy were instructed to consume 40 g of either ground flaxseed or wheat-based comparative control regimen daily for three months. Flaxseed supplementation lowered both serum total cholesterol and LDL cholesterol by 6 percent, whereas the comparative control regimen had no such effect.22

Garlic

Garlic has been widely recognized as a medicinal herb for prevention and treatment of cardiovascular and other diseases. While earlier trials suggest that garlic might mildly lower cholesterol and triglycerides levels in the blood,23 more recent trials found garlic to have minimal success in lowering cholesterol and triglycerides.24

In a four-year clinical trial on people ages 50-80, with atherosclerosis, consumption of 900 mg of a standardized garlic supplement was found to reduce arterial plaque formation by 5 to 18 percent.25

Coenzyme Q10

Coenzyme Q10 (coQ10) is found in virtually all cells of human body including the heart, liver, and skeletal muscles, CoQ10 functions as a carrier to transfer electrons across the membrane of mitochondria (the energy generator in the body’s cell) to drive the production of adenosine triphosphate (ATP), the fuel that energizes cells in our body. Heart muscle cells have the greatest concentration of mitochondria, 5,000 per cell.

Both cholesterol and coQ10 share a common biosynthetic pathway, which involves the formation of mevalonate compound with the aid of 3-hydroxy-methylglutaryl coenzyme A (HMG-CoA) reductase. Inhibition of HMG-CoA reductase by statin drugs at the mevalonate level will inevitably decrease the levels of both cholesterol and coQ10.

Human studies revealed a significant decrease in coQ10 serum levels as a result of HMG-CoA reductase inhibitor treatment. In a double blind, randomized clinical trial hypercholesterolemic patients received either Lovastatin or Pravastatin over a period of 18 weeks. At the end of the study period, the total serum level of coQ10 declined by about 25 percent in the Lovastatin and Pravastatin groups.26

References

1. Endo A, and coworkers. ML-236A, ML-236B, and ML-236C, new inhibitors of cholesterogenesis produced by Penicillium citrinium. J Antibiotics (Tokyo) 1976; 29:1346

2. Endo A. Monacolin K, a new hypocholesterolemic agent produced by a Monascus species J Antibiotics 1979; 32:852, and Endo A. Monacolin K, a new hypocholesterolemic agent that specifically inhibits 3-hydroxy-3-methylglutaryl coenzyme A reductase.J Antibiotics 1980; 33:334

3. Alberts AW, and coworkers. Mevinolin: a highly potent competitive inhibitor of hydroxymethylglutaryl-coenzyme A reductase and a cholesterol-lowering agent. Proc Natl Acad Sci. U.S.A. 1980; 77:3961

4. Heber D et al. Cholesterol-lowering effects of a proprietary Chinese red-yeast-rice dietary supplement American Journal of Clinical Nutrition 1999; 69:231

5. Heinemann T et al. Comparison of intestinal absorption of cholesterol with different plant sterols in man. Eur J Clin Invest 1993; 23:827.

6. Messina M, Barnes S. The role of soy products in reducing the risk of cancer. J Natl Cancer Inst. 1991; 83:541

7. Miettinen TA. Stanol esters in the treatment of hypercholesterolemia. Eur Heart J 1999; 1 (Suppl S):S50-S57

8. Gylling H. Studies of plant stanol esters in different patient populations. Eur Heart J 1999, 1 (Suppl S), S109

9. 65 Federal Register 54685 (2090) (codified at 21 CFR [ss] 101

10. Ling WH, Jones PJ. Dietary phytosterols: A review of metabolism, benefits and side effects. Life Science 1995; 57:195

11. Gouni-Berthold I, Berthold HK. Policosanol: clinical pharmacology and therapeutic significance of a new lipid-lowering agent. Am Heart J 2002; 143:356

12. Castano G et al. Effects of policosanol and Lovastatin with intermittent claudication: a double-blind comparative pilot study. Angiology 2003; 54:25

13. Arruzazabala, ML, et al. Antiplatelet effects of policosanol (20 and 40 mg/day) in healthy volunteers and dyslipidaemic patients. Clin Exp Pharmacol Physiol 2002; 29:891

14. Onning G et.al. Consumption of oat milk for 5 weeks lowers serum cholesterol and LDL cholesterol in free-living men with moderate hypercholesterolemia. Ann Nutr Metab 1999; 13:301

15. McIntosh GH et.al. Barley and wheat foods: influence on plasma cholesterol concentrations in hypercholesterolemic men. Am J Clin Nutr 1991; 53:1205

16. Nicolosi R et.al. Plasma lipid changes after supplementation with beta-glucan fiber from yeast Am J Clin Nutr 1999; 70:208

17. Qureshi AA et al. Dose-dependent suppression of serum cholesterol by tocotrienol-rich fraction (TRF25) of rice bran in hypercholesterolemic humans. Atherosclerosis 2002; 161:199

18. Mustad VA et al. Supplementation with 3 compositionally different tocotrienol supplements does not improve cardiovascular disease risk factors in men and women with hypercholesterolemia. Am J Clin Nutr 2002; 76:1237

19. Manthey JA et al. Biological properties of citrus favonoids pertaining to cancer and inflammation. Curr Med Chem. 2001; 8:135

20. Kurowska EM, Manthey JA. Hypolipidemic effects and absorption of citrus polymethoxylated flavones in Hamsters with diet-induced hypercholesterolemia. J Agric Food Chem 2004; 52:2879

21. Singh RB et al. Hypolipidemic and antioxidant effects of Commiphora mukul as an adjunct to dietary therapy in patients with hypercholesterolemia. Cardiovasc Drugs Ther 1994; 8:659

22. Lucas EA et al. Flaxseed improves lipid profile without altering biomarkers of bone metabolism in post-menopausal women. J Clin Endocrinol Metab 2002; 87:1527

23. Neil HA et al. Garlic powder in the treatment of moderate hyperlipidemia: A controlled trial and a meta-analysis. J R Coll Phys 1996; 30:329

24. Berthold HK et al. Effect of garlic oil preparation on serum lipoproteins and cholesterol metabolism. JAMA 1998; 279:1900

25. Koscielny J. The antiatherosclerosis effect of Allium sativum. Atherosclerosis 1999; 144:237

26. Mortensen SA et al. Dose-related decrease of serum coenzyme Q10 during treatment with HMG-CoA reductase inhibitors. Mol Aspects Med 1997; 18:S137

 

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