Normotensive adults on low-sodium, weight-loss, and control diets recorded preferences and perceived saltiness for sodium chloride (NaCl) added to cream soup at intervals over 1 yr. Reduction in sodium intake and excretion accompanied a shift in preference toward less salt: preferred concentrations by ad libitum salting declined from 0.72% at the onset to 0.33% NaCl at week 24; hedonic scores for high concentrations of NaCl decreased significantly while scores for low concentrations increased. After 3 mo of sodium restriction, NaCl preferences readjusted to a lower level: ad libitum additions of NaCl were similar after 13, 24, and 52 wk. Less hedonic variation was observed among controls than among Na-restricted groups. The weight-loss group showed increased liking for mid-range NaCl levels. Mechanisms underlying preference changes, including physiological, behavioral, and context effects, may provide insights into maintenance of low-sodium diets for treatment and prevention of hypertension.

The effects of acute caloric restriction on cholesterol balance and kinetics of plasma cholesterol specific activity were investigated in five hyperlipemic subjects with varying degrees of obesity. Caloric restriction decreased plasma triglycerides by 41 +/- 12%, plasma cholesterol by 11 +/- 9%, and the ratio of esterified to free cholesterol by 12 +/- 7+. Immediately on institution of caloric restriction there appeared to be an influx of tissue cholesterol into plasma and a reduction in endogenous synthesis of cholesterol. The cholesterol balance decreased from 1,469 +/- 441 to 1,212 +/- 349 mg/day and the rate of decay of plasma cholesterol specific activity decreased 62 +/- 3%. The effect of caloric restriction on hepatic synthesis of bile acids was also very prompt. The total fecal bile acids were reduced immediately by 36 +/- 7%. Because the effect on fecal excretion of deoxycholic acid was greater than that on fecal lithocholic acid, it was suggested that hepatic synthesis of cholic acid was reduced more than the synthesis of chenodeoxycholic acid. Caloric restriction did not cause any change in the percentage of absorption of dietary cholesterol (40 +/- 2% versus 42 +/- 3%). These observations are in accord with our model relating cholesterol metabolism with the metabolism of plasma lipoproteins in man.

The National Heart and Lung Institute Twin Study has examined 514 white adult male twin sets aged 42-56 with respect to blood pressure. The data were analyzed by a method of Christian et al. which eliminates possible biases in estimated genetic variances that could result from different total variances in MZ and DZ twins. Results of the test for the presence of genetic variance indicate that both systolic and diastolic blood pressure are to a considerable extent genetically controlled with an estimated heritability of 0.8 for systolic and 0.6 for diastolic pressure. Although these findings are at variance with some previous reports, it is thought that much of the discrepancy results from application of different analytic techniques, not in the data themselves. The application of these findings to our understanding of hypertension epidemiology and community hypertension control programs are discussed.

In the Hypertension Detection and Follow-up Program, 7825 (71.5 per cent) of the 10,940 participants had diastolic blood pressures averaging between 90 and 104 mm Hg on entry into the study and were designated Stratum 1. Half were referred to their usual source of care in the community (the referred-care group), and half were treated intensively in special clinics (the stepped-care group). Five-year mortality in the Stratum 1 patients given stepped care was 20.3 per cent lower than in those given referred care (P less than 0.01). Particularly noteworthy was the beneficial effect of stepped-care treatment on persons with diastolic pressures of 90 to 104 mm Hg who had no evidence of end-organ damage and were not receiving antihypertensive medication when they entered the study. This subgroup had 28.6 per cent fewer deaths at five years among those treated with stepped care than among those treated with referred care (P less than 0.01). These findings support a recommendation that in patients with mild hypertension, treatment should be considered early, before damage to end organs occurs.

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