INDIVIDUAL-RESPONSES TO A CHOLESTEROL-LOWERING DIET IN 50 MEN WITH MODERATE HYPERCHOLESTEROLEMIA

Background: Dietary modification is the recommended first step in the treatment of hypercholesterolemia. However, the efficacy of the National Cholesterol Education Program Step 1 Diet in outpatients with hypercholesterolemia has been debated. Methods: Fifty normotriglyceridemic men whose ad libitum low-density lipoprotein (LDL) cholesterol levels were 4.14 to 5.69 mmol/L (160 to 220 mg/dL) participated in a two-period outpatient diet counseling study that used a 1-month high-fat, high-saturated fatty acid period (Hi-Sat) and a 4-month low-fat, low-saturated fatty acid period (Step 1 Diet). Lipid, lipoprotein levels, and plasma triglyceride fatty acids were measured five times during the last 2 weeks of each dietary period and averaged for each patient. Dietary intake was assessed by 7-day food records. During the Hi-Sat period, an LDL turnover study was done to determine the fractional catabolic rate of LDL. Results: The mean reduction in total and LDL cholesterol levels achieved by diet was 0.54 mmol/L (21 mg/dL) and 0.39 mmol/L (15 mg/dL), respectively. These responses equaled those predicted from metabolic ward investigations. While dietary responsiveness was normally distributed, there was marked individual variation in response. The mean (+/- SD) for quartiles of LDL responsiveness were +0.41 +/- 0.21 mmol/L (+16 +/- 8 mg/dL), -0.16 +/- 0.13 mmol/L(-6 +/- 5 mg/dL), -0.57 +/- 0.16 mmol/L (-22 +/- 6 mg/dL),and -1.16 +/- 0.26 mmol/L (-45 +/- 10 mg/dL). These differences in response were partially explained by dietary adherence, baseline fractional catabolic rates of LDL, and the change in plasma triglyceride palmitate level. Conclusions: The Step 1 Diet is effective in lowering LDL cholesterol levels for many hypercholesterolemic men, and with appropriate counseling, outpatients can achieve results predicted by inpatient metabolic diet studies. Nonetheless, the responsiveness for individuals is highly variable, and this variability is influenced by both compliance and biologic factors. Since many men achieved LDL cholesterol levels low enough to remove the need for drug therapy in primary prevention for coronary heart disease, dietary therapy should remain the initial approach to the treatment of hypercholesterolemia.