Monovalent and divalent cations in hypertension

Blood Pressure Regulation and Vegetarian Diets

Hypertension affects approximately 50 million individuals in the United States and approximately 1 billion worldwide. Although heredity plays a role in blood pressure variability, diet and lifestyle exert considerable influence in blood pressure regulation. This report reviews the evidence of the relationship between a vegetarian diet and blood pressure regulation and presents data as to the putative mechanisms of action.

Intracellular Mg2+, Ca2+, Na2+ and K+ in platelets and erythrocytes of essential hypertension patients: relation to blood pressure

Alterations in intracellular cation metabolism have been implicated in the pathophysiology of essential hypertension. Total magnesium, calcium, sodium and potassium levels were studied in serum erythrocytes and platelets, from 154 subjects (76 hypertensive and 78 normotensives; 104 blacks and 50 whites). In the combined black and white hypertensive group, platelet sodium and calcium and erythrocyte calcium were elevated and serum potassium, serum magnesium and platelet magnesium decreased. In the black hypertensive patients, platelet sodium and calcium and erythrocyte calcium were increased, whereas serum magnesium, serum potassium, platelet magnesium and erythrocyte magnesium were decreased. In the white hypertensive group, platelet sodium and erythrocyte calcium were raised and platelet magnesium was decreased. In the black hypertensive patients, serum and platelet magnesium and serum calcium were negatively and erythrocyte and platelet calcium positively correlated with mean arterial pressure. In the white hypertensive patients platelet sodium was directly related to mean arterial pressure. These results suggest that intracellular sodium and calcium overload and magnesium depletion may be important in the pathophysiology of hypertension. Magnesium disturbances are more consistent and widespread in black hypertensive patients than in white hypertensive patients.

University of California, Davis, conference: Mild hypertension

Prevalence of "higher than normal" blood pressures in a community is inversely related to the magnitude of the elevation; the milder grades of elevation are far more prevalent. A multifactorially inherited tendency to develop hypertension is modulated by multiple environmental influences. Autonomic nervous and behavioral factors plausibly appear to contribute to the initiating mechanisms of hypertension; the associated hemodynamic changes and the resulting cardiovascular structural changes interact to perpetuate the process. The complex interaction of hypertension and atherosclerosis is further complicated by direct as well as secondary effects of antihypertensive drugs on atherogenesis. Attributable cardiovascular risk is generally proportional to the degree of hypertension across the entire range of elevated blood pressure; this kind of relationship holds also for normal versus subnormal blood pressure values. Pharmacologic lowering of blood pressure, however, does not confer proportional benefit. Thus, such lowering of blood pressure to normotensive levels does not reduce the risk level to that in the normotensive population. Therapeutic outcome is influenced by the interaction of blood pressure lowering, type of antihypertensive agents used, existing risk factors, and target organ damage. Benefits of lowering blood pressure in established mild hypertension (diastolic blood pressure greater than 95 mm Hg) are confirmed. Drug treatment of patients with lower diastolic blood pressure or with isolated elevations of systolic blood pressures continues to be controversial as does the choice of initial therapeutic agent(s). The large-scale experience of clinical trials encompassing the long-term risks and benefits of the drug treatment of mild hypertension is limited to the use of diuretics and adrenergic beta blockers. A variety of new and promising therapeutic agents for use as alternate choices for initial therapy needs to undergo comparative evaluation.

Precursors of essential hypertension: body weight, alcohol and salt use, and parental history of hypertension

Body mass index, alcohol and salt consumption, and parental history of hypertension were examined as possible predictors of the development of essential hypertension in 1,031 persons, ages 30-49 years at entry, with documented normotension followed by documented hypertension after a mean interval of 6 years. In a comparison with 1,031 matched persistently normotensive persons initial body mass index and percentage increase in body mass index were each predictive of hypertension. Consumption of three or more alcoholic drinks a day at baseline was also predictive, more so if this level of intake persisted than if it diminished. Heavy salt intake as crudely estimated at baseline by one question was also associated with the development of hypertension. Parental history of hypertension was also predictive, more so for hypertension in the mother than for hypertension in the father, and the association was apparent only in female subjects. These characteristics at baseline showed independent associations with subsequent hypertension in multivariate analysis. When follow-up data were included in the multivariate analysis, alcohol consumption at the hypertensive examination was much more strongly related than at the baseline examination, suggesting a short-term effect, and heavy salt consumption was no longer predictive, possibly because of a marked loss of subjects due to missing follow-up data. This large study confirms longitudinally the importance of obesity, weight gain during adulthood, alcohol, family history, and, to some extent, salt as predictive and possibly causal factors for essential hypertension.

[Salt and blood pressure]

Current information on the relationship between sodium and blood-pressure regulation is reviewed from the point of view of epidemiological, clinical and experimental research, as well as evidence from intervention studies. Among other cations, calcium also has an influence on blood pressure. Epidemiological studies in particular are handicapped by the difficulties inherent in measuring salt intake in individuals with adequate accuracy. Despite remaining uncertainties and the need for further investigation, available data from different sources and a considerable number of studies justify the recommendation that the average daily salt intake of the population should not exceed 5 g (NaCl), corresponding to 85 meq or mmol of sodium (Na). This is a goal which should be approached gradually, paying simultaneous attention to other factors likely to be involved in the primary prevention of hypertension, especially overweight, and the maintenance of a sufficient supply of iodine and fluor for which salt is used as a vehicle in many countries.