Phytosterols
Simply stated, phytosterols are the “fat” of plants. The proprietary phytosterol blend found in Cholesterol Shield^™ occurs naturally and is structurally similar to cholesterol, though its activity is very different.† The major phytosterols found in nature are β-sitosterol, campesterol, and stigmasterol. The typical daily diet contains 100-300 mg phytosterols.²

At usual levels of consumption, phytosterols have little effect on blood cholesterol concentration. However, because phytosterols share structural similarities with cholesterol, they bind to sites in the intestines that would be used for cholesterol binding were they not blocked. Dietary consumption of phytosterols in the 1200 mg per dose range reduces intestinal and biliary cholesterol absorption and helps to retain healthy cholesterol levels that are already within normal limits.†²

Phytosterols appear to decrease the solubility of cholesterol in the intestines, thus interfering with its absorption. Phytosterols also increase bile salt excretion in the intestines.†^2-7 In humans, administration of phytosterols significantly decreased cholesterol absorption from food by 38%.†³

Pantethine
Cholesterol Shield also contains pantethine, a precursor of coenzyme A (CoA). CoA is involved in 70 enzymatic pathways, including cholesterol synthesis.8 Pantethine modulates the action of several enzymes, including 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) reductase.†^9,10 Pantethine inhibits the activity of HMG-CoA reductase; this enzyme plays an important part in the pathway of cholesterol synthesis.†^9,11,12

Human studies have demonstrated that pantethine is beneficial for retaining healthy cholesterol levels that are already within normal limits.†^13-17 Additionally, studies have shown that 600 mg of pantethine per day is required to achieve this beneficial support.† No studies have found beneficial effects at lower dosages.

A year-long trial with pantethine was conducted in 24 individuals. The treatment was well tolerated with no subjective complaints or detectable side effects. Blood lipid assays repeated after 1, 3, 6, 9, and 12 months of treatment revealed consistent benefit for retaining healthy cholesterol levels that are already within normal limits.†¹⁵

In another study, the effect of pantethine (various mg doses daily for 3 to 6 months) was evaluated in 72 individuals. The results demonstrated that pantethine was tolerated well and retained healthy cholesterol levels that were already within normal limits.†¹⁶

Combination of Phytosterols and Pantethine
Since pantethine and phytosterols exert their beneficial effects in different ways, it is theorized that a product combining both complimentary ingredients may synergistically provide even greater levels of significant support.†

Mechanisms of Action on Cholesterol Metabolism

High serum cholesterol levels are associated with coronary artery disease. Specifically, cholesterol deposits in the arteries develop into plaques that reduce or block blood flow. In addition, dense connective tissue deposits lead to arteries that become stiff and unyielding (sclerosis). Eventually, hard calcifications form. This is known as “hardening of the arteries.” Arteries that have lost flexibility are easily ruptured, and in the areas where plaques protrude into flowing blood, blood clots may develop. Heart attacks or stroke may then result.¹

Estimates are that 100.9 million American adults have total blood cholesterol values of 200 mg/dL and higher, and about 40.6 million American adults have levels of 240 or above. In adults, total cholesterol levels of 240 mg/dL or higher are considered high risk, and levels from 200 to 239 mg/dL are considered borderline-high risk.¹⁹ The National Cholesterol Education Program has developed the following guidelines for serum cholesterol levels.

NCEP's ATP-III guideline²⁰

A small number of transient mild gastrointestinal problems have been associated with ingestion of pantethine. Usually, they are reversed quickly when pantethine is taken with food.⁸

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1. Guyton AC, Hall JE. Lipid Metabolism. In: Textbook of Medical Physiology. Philadelphia, Penn: W.B. Saunders; 1996:872-873.
2. Executive Summary of The Third Report of The National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, And Treatment of High Blood Cholesterol In Adults (Adult Treatment Panel III). JAMA. 2001;285:2486-2497.
3. Maki KC, Davidson MH, Umporowicz DM, et al. Lipid responses to plant-sterol-enriched reduced-fat spreads incorporated into a National Cholesterol Education Program Step I diet. Am J Clin Nutr. 2001;74:33-43.
4. Jones P, Ntanios FY, Raeini-Sarjaz M, Vanstone CA. Cholesterol-lowering efficacy of a sitostanol-containing phytosterol mixture with a prudent diet in hyperlipidemic men. Am J Clin Nutr. 1999;69:1144-1150.
5. Normen L, Dutta P, Lia A, Andersson H. Soy sterol esters and -sitostanol ester as inhibitors of cholesterol absorption in human small bowel. Am J Clin Nutr. 2000;71:908-913.
6. Pelletier X, Belbraouet S, Mirabel D, et al. A diet moderately enriched in phytosterols lowers plasma cholesterol concentrations in normocholesterolemic humans. Ann Nutr Metab. 1995;39:291-295.
7. Hendriks HF, Weststrate JA, van Vilet T, Meijer GW. Spreads enriched with three different levels of vegetable oil sterols and the degree of cholesterol lowering in normocholesterolaemic and mildly hypercholesterolaemic subjects. Eur J Clin Nutr. 1999;53:319-327.
8. Hallikainen MA, Sarkkinen ES, Gylling H, Erkkila AT, Uusitupa MI. Comparison of the effects of plant sterol and plant stanol ester-enriched margarines in lowering serum cholesterol concentrations in hypercholesterolaemic subjects on a low-fat diet. Eur J Clin Nutr. 2000;54:715-725.
9. Pantethine. Monograph. Altern Med Rev. 1998;379-381.
10. Cighetti G, Del Puppo M, Paroni R, Galli G, Kienle MG. Effects of pantethine on cholesterol synthesis from mevalonate in isolated rat hepatocytes. Atherosclerosis. 1986;60:67-77.
11. Cighetti G, Del Puppo M, Paroni R, Fiorica E, Galli Kienle M. Pantethine inhibits cholesterol and fatty acid synthesis and stimulate carbon dioxide formation in isolated rat hepatocytes. J Lipid Res. 1987;28:152-161.
12. Hsu JC, Tanaka K, Inayama I, Ohtani S. Effects of pantethine on lipogenesis and CO2 production in the isolated hepatocytes of the chick. Comp Biochem Physiol. 1992;569-572.
13. McCarty. Inhibition of acetyl-CoA carboxylase by cystamine may mediate the hypotriglyceridemic activity of pantethine. Med Hypotheses. 2001;56:314-317.
14. Gaddi A, Descovich GC, Noseda G, et al. Controlled evaluation of pantethine, a natural hypolipidemic compound, in patients with different forms of hyperlipoproteinemia. Atherosclerosis. 1984;50:73-83.
15. Arsenio L, Bodria P, Magnati G, Strata A, Trovato R. Effectiveness of long-term treatment with pantethine in patients with dyslipidemia. Clin Ther. 1986;8:537-544.
16. Bertolini S, Donati C, Elicio, et al. Lipoprotein changes induced by pantethine in hyperlipoproteinemic patients: adults and children. Int J Clin Pharmacol Ther Toxcol. 1986;24:630-637.
17. Eto M, Watanabe K, Chonan N, Ishii K. Lowering effect of pantethine on plasma beta-thromboglobulin and lipids in diabetic mellitus. Artery. 1987;15:1-12.
18. Coronel F, Tornero F, Tornero T, et al. Treatment of hyperlipemia in diabetic patients on dialysis with a physiological substance. Am J Nephrol. 1991;11:32-36.
19. American Heart Association. Cholesterol. http://www.americanheart.org/Heart_and_Stroke_A_Z_Guide/chol.html.
20. Stamler J, Daviglus ML, Garside DB, Dyer AR, Greenland P, Neaton JD. Relationship of baseline serum cholesterol levels in 3 large cohorts of younger men to long-term coronary, cardiovascular, and all-cause mortality and to longevity. JAMA. 2000;284:311-318.