The Facts About Cholesterol

The National Cholesterol Education Program (NCEP) encourages physicians to prescribe stringent dietary therapy of hyper cholesterolemia for at least 6 months before initiating drug therapy. Physicians should also be cautioned about premature use of hypercholesterolemic medications: no known study has demonstrated decreased mortality in recipients of such medications. Dietary therapy should strongly be encouraged, and physicians should adopt mandatory referral to a registered dietitian or other qualified nutrition professional before dietary therapy is declared a failure and drug therapy is started.

Lowering cholesterol levels decreases the incidence of heart disease. In fact, several studies have convincingly shown that adequate hypercholesterolemic treatment can not only prevent CHD, but can also reverse it. [Kuo, P.T., Hayase, K., Kostis, J.B., and Moreyra, A.E.: Use of combined diet and colestipol in longterm treatment of patients with type II hyperlipoproteinemia. Circ 59:199, 1979. ] Recently these topics have been comprehensively reviewed. Dietary therapy is the cornerstone of all hypercholesterolemic therapy, and it has been estimated that 60 million adult Americans may be candidates for dietary instruction.

Findings suggest that blood lipid cholesterol levels predict subsequent mortality in men, especially those with preexisting cardiovascular disease. Those with high blood cholesterol levels have a risk of death from cardiovascular disease, including coronary heart disease, that was 3? times higher than that for men with a "desirable" blood cholesterol level.

Familial hypercholesterolemia carries a marked increase in the risk of coronary heart disease (CHD), but there is considerable variation in susceptibility to CHD between individuals. Results indicate that an elevated level of lipoprotein is a strong risk factor for CHD in these individuals; the risk is independent of age, sex, smoking status, and serum levels of total cholesterol, triglyceride, or HDL-cholesterol. The higher level of lipoprotein observed in patients with CHD is the result of genetic influence. The New England Journal of Medicine: 322:1494, 1990.]

The efficacy of hypercholesterolemic diets lowering cholesterol and in some cases, in preventing CHD, has been convincingly demonstrated. Such efficacy does depend, however, on the vigour which the physician and dietitian support dietary therapy. Many physicians have declared dietary therapy a failure without providing their patients with real dietary advice and support.

Two factors that probably contribute to physicians disinterest in dietary therapy are extensive advertising of hypercholesterolemic drugs compared with the little advertisingof dietary therapy and patient reluctance to alter diet and life-style. Getting patients to alter their life-style is often a challenging task. A recent survey [Schucker, B., Bailey, K., Heimbach, J.T., Wittes, J.T., Cutler, J.A., Mackintosh, D.R., Gordon, D.J., Haines. C.M., Mattson, S.E., Goor, R.S., and Rifkind, B.M.: Change in public perspective on cholesterol & heart disease.JAMA 258:3527,1987] suggests, however, that the public is ready and able to embrace dietary therapy as the primary solution to hypercholesterolemia.

To further facilitate dietary therapy, recent research suggests that certain forms of fat (eg. fish and monounsaturated fatty acids) may be hypocholesterolemic, especially if they replace saturated fatty acids in the diet. Food technology is improving daily in palatably, removing fat from items like cheese, chips, and crackers. Frozen yogurt has become a popular replacement for ice cream. Fat substitutes, as they become available, may also facilitate compliance with a low-fat diet.

Psyllium is an especially attractive hybrid intervention in that it is well tolerated, lowers LDL-cholesterol by 10% to 20%, has no adverse effects on triglycerides, high-density-lipoprotein (HDL) cholesterol, or serum glucose, and is readily available and fairly inexpensive. It has a long history of use without any evidence of long-term adverse effects.

A recent article estimated that oat bran supplementation (90 gm per day) was a much more cost-effective method of lowering serum cholesterol than either cholestyramine or colestipol. [Kinosian, B.P., and Eisenberg, J.M.: Cutting into cholesterol: Cost-effective alternatives for treating hypercholesterolemia. JAMA 259:2249, 1988.] In addition, high-fibre diets may decrease risk of colon cancer, improve glucose tolerance, lower blood pressure, and assist in weight loss.

Many physicians think that they or their staff can tell the patient everything he or she needs to know about hypercholesterolemic diets by issuing the usual, though imprecise, dietary admonitions (eg. avoid red meat, whole fat dairy products, and egg yolks) and by photocopying a few sample menus. Without explanation and reinforcement, the patient is unlikely to achieve the dietary goals. Even if the patient does reduce intake of fat and cholesterol from the obvious dietary sources, he or she may continue to eat other notable, but perhaps somewhat hidden, sources of saturated fat (eg. baked goods, tropical oils, organ meats).

An additional advantage of dietary over drug therapy is that diet simultaneously ameliorates several cardiovascular risk factors (hyperlipidemia, hypertension, obesity, and diabetes) whereas drug therapy usually deals with only one. In fact, drug therapy for one risk factor often exacerbates another (eg. beta blockersfor hypertension may increase serum lipids, and niacin may accentuate glucose intolerance).

Dietitians are the best-qualified health professionals to help patients lower their cholesterol levels. With the impetus of the NCEP behind them, RDs should be aggressively promoting their services to physicians and the public, devising methods to obtain reimbursement, and making themselves visible as the best-qualified authorities on diet.

The public is increasingly interested in dietary control of hypercholesterolemia, as evidenced by the widespread media attention devoted to cholesterol. A major, but clearly surmountable, obstacle is inadequate referral to dietitians by physicians in their communities, about their knowledge, skills and availability to counsel clients on the dietary treatment of hypercholesterolemia. Via these mechanisms, dietitians will become increasingly recognized as the best sources of nutrition information, with ultimate benefit to the public. [Zeev Yetiv, MD, PhD. Jack, & Del Tredici, MS, RD. Ann M. Bringing the cholesterol message to the public: Dietitians must be proactive in nutrition counselling. JADA 90: 1383-1386]

Discuss It!