ATLANTA — People with metabolic syndrome have blood pressures that are more sensitive to salt than do people without the syndrome, according to a poster presentation by Dr. Luigi X. Cubeddu at a meeting sponsored by the International Society on Hypertension in Blacks.
His study, in 301 subjects with and without metabolic syndrome, showed that normal dietary salt intake induces large BP increases in people with the condition, making them “exquisitely sensitive to dietary salt.
“Salt restriction, in addition to exercise and caloric restriction, must be a fundamental part of the treatment plan for patients with the metabolic syndrome,” wrote Dr. Cubeddu of Nova Southeastern University, Fort Lauderdale, Fla.
The subjects' average age was 42 years; 109 of them were diagnosed with metabolic syndrome in accordance with guidelines from the National Cholesterol Education Program. As expected, subjects with metabolic syndrome had significantly higher baseline BP than those without: 127/83 mm Hg, compared with 114/75 mm Hg.
The investigators measured blood pressure and several other physiologic signs during a week-long baseline period in which salt intake was normal (8 g/day), and also during a week of high salt intake (about 18 g/day) and a week of low salt intake (2.3 g/day).
The high-salt condition resulted in increases in BP in both groups of subjects, but those with metabolic syndrome had significantly larger increases in both systolic and diastolic pressures. While the patients without metabolic syndrome increased their systolic BP an average of 5.0 mm Hg and their diastolic pressure an average of 3.0 mm Hg, those with metabolic syndrome experienced systolic and diastolic increases of 9.6 and 4.5 mm Hg, respectively.
The degree of salt sensitivity was also associated with the severity of metabolic syndrome. The more components of metabolic syndrome a subject had, the larger was his or her decrease in blood pressure associated with salt restriction.
Subjects with four or five components of metabolic syndrome saw decreases of 8.7 mm Hg systolic and 5.0 mm Hg diastolic in response to salt restriction, while those with just two of the traits saw decreases of 3.4 and 2.1.
The investigators noted that salt sensitivity is a gradual condition that worsens in parallel with metabolic syndrome, and that dietary salt is a major determinant of the increased prevalence of prehypertension and hypertension in such patients.
The meeting was cosponsored by the American Society of Hypertension.
ELSEVIER GLOBAL MEDICAL NEWS