Theodore A. Kotchen

Dietary guidelines for healthy American adults: A statement for health professionals from the Nutrition Committee, American Heart Association

In 1957 the American Heart Association proposed that modification of dietary fat intake would reduce the incidence of coronary heart disease (CHD), which had become the leading cause of disability and death in the United States and other industrialized countries.1 Since then the AHA has issued seven policy statements on diet and CHD as reliable new information has become available.2 3 4 5 6 7 8 In each of these statements emphasis was placed on consumption of total fat, saturated and certain unsaturated fatty acids, dietary cholesterol, and sodium because of their significant contribution to risk of CHD. Later, excessive alcohol intake was considered because of its association with hypertension, stroke, and other diseases. Such knowledge has encouraged other health organizations and the federal government to make similar recommendations. In May 1989 representatives of nine health organizations and governmental bodies met under the aegis of the AHA, reviewed the scientific evidence, and concluded that most Americans can improve their overall health and maintain it with a few specific but fundamental dietary changes.9 The following guidelines are consistent with those promoted by each organization: • Eat a nutritionally adequate diet consisting of a variety of foods. • Reduce consumption of fat, especially saturated fat, and cholesterol. • Achieve and maintain an appropriate body weight. • Increase consumption of complex carbohydrates and dietary fiber. • Reduce intake of sodium. • Consume alcohol in moderation, if at all. Children, adolescents, and pregnant women should abstain. Current AHA recommendations regarding diet and related lifestyle practices for the general population are based on evidence indicating that modification of specific risk factors will decrease incidence of CHD.8 These risk factors include cigarette smoking; elevated levels of plasma cholesterol, particularly low-density lipoprotein (LDL) cholesterol; low levels of high-density lipoprotein (HDL) cholesterol; increased blood …

AHA Dietary Guidelines Revision 2000: A Statement for Healthcare Professionals From the Nutrition Committee of the American Heart Association

This document presents guidelines for reducing the risk of cardiovascular disease by dietary and other lifestyle practices. Since the previous publication of these guidelines by the American Heart Association,1 the overall approach has been modified to emphasize their relation to specific goals that the AHA considers of greatest importance for lowering the risk of heart disease and stroke. The revised guidelines place increased emphasis on foods and an overall eating pattern and the need for all Americans to achieve and maintain a healthy body weight (Table⇓). View this table: Table 1. Summary of Dietary Guidelines The major guidelines are designed for the general population and collectively replace the “Step 1” designation used for earlier AHA population-wide dietary recommendations. More individualized approaches involving medical nutrition therapy for specific subgroups (for example, those with lipid disorders, diabetes, and preexisting cardiovascular disease) replace the previous “Step 2” diet for higher-risk individuals. The major emphasis for weight management should be on avoidance of excess total energy intake and a regular pattern of physical activity. Fat intake of ≤30% of total energy is recommended to assist in limiting consumption of total energy as well as saturated fat. The guidelines continue to advocate a population-wide limitation of dietary saturated fat to <10% of energy and cholesterol to <300 mg/d. Specific intakes for individuals should be based on cholesterol and lipoprotein levels and the presence of existing heart disease, diabetes, and other risk factors. Because of increased evidence for the cardiovascular benefits of fish (particularly fatty fish), consumption of at least 2 fish servings per week is now recommended. Finally, recent studies support a major benefit on blood pressure of consuming vegetables, fruits, and low-fat dairy products, as well as limiting salt intake (<6 grams per day) and alcohol (no more than 2 drinks per day for men and …

Rationale of the diet-heart statement of the American Heart Association. Report of the Nutrition Committee.

132. Cappuccio FP, MacGregor GA. Does potassium supplementation lower blood pressure? a meta-analysis of published trials. J Hypertens. 1991;9:465-473. 133. Witteman JC, Willett WC, Stampfer MJ, Colditz GA, Sacks FM, Speizer FE, Rosner B, Hennekens CH. A prospective study of nutritional factors and hypertension among US women. Circulation. 1989;80:1320-1327. 134. Joffres MR, Reed DM, Yano K. Relationship of magnesium intake and other dietary factors to blood pressure: the Honolulu heart study. Am J Clin Nutr. 1987;45:469-475. 135. Intersalt Cooperative Research Group. Intersalt: an international study of electrolyte excretion and blood pressure: results for 24-hour urinary sodium and potassium excretion. BrMed J. 1988; 297:319-328. 136. The effects of nonpharmacologic interventions on blood pressure of persons with high normal levels: results of the Trials of Hypertension Prevention, Phase I. JAMA. 1992;267:1213-1220. 137. Schotte DE, Stunkard AL. The effects of weight reduction on blood pressure in 301 obese patients. Arch Intern Med. 1990;150:

Effect of Calcium and Vitamin D Supplementation on Blood Pressure. The Women's Health Initiative Randomized Trial

Experimental and epidemiological studies suggest that calcium and vitamin D supplements may lower blood pressure. We examined the effect of calcium plus vitamin D supplementation on blood pressure and the incidence of hypertension in postmenopausal women. The Womens Health Initiative Calcium/Vitamin D Trial randomly assigned 36 282 postmenopausal women to receive 1000 mg of elemental calcium plus 400 IU of vitamin D3 daily or placebo in a double-blind fashion. Change in blood pressure and the incidence of hypertension were ascertained. Over a median follow-up time of 7 years, there was no significant difference in the mean change over time in systolic blood pressure (0.22 mm Hg; 95% CI: −0.05 to 0.49 mm Hg) and diastolic blood pressure (0.11 mm Hg; 95% CI: −0.04 to 0.27 mm Hg) between the active and placebo treatment groups. This null result was robust in analyses accounting for nonadherence to study pills and in baseline subgroups of interest, including black subjects and women with hypertension or high levels of blood pressure, with low intakes of calcium and vitamin D or low serum levels of vitamin D. In 17 122 nonhypertensive participants at baseline, the hazard ratio for incident hypertension associated with calcium/vitamin D treatment was 1.01 (95% CI: 0.96 to 1.06.) In postmenopausal women, calcium plus vitamin D3 supplementation did not reduce either blood pressure or the risk of developing hypertension over 7 years of follow-up.

Hypertension and Its Treatment in Postmenopausal Women: Baseline Data from the Women’s Health Initiative

Little is known about the patterns of treatment and adequacy of blood pressure control in older women. The Women’s Health Initiative, a 40-center national study of risk factors and prevention of heart disease, breast and colorectal cancer, and osteoporosis in postmenopausal women, provides a unique opportunity to examine these issues in the largest, multiethnic, best-characterized such cohort. Baseline data from the initial 98 705 women, aged 50 to 79 years, enrolled were analyzed to relate prevalence, treatment, and control of hypertension to demographic, clinical, and risk-factor covariates, and logistic regression analyses were performed to estimate odds ratios after adjusting for multiple potential confounders. Overall, 37.8% of the women had hypertension, which is defined as systolic blood pressure ≥140 mm Hg and/or diastolic blood pressure ≥90 mm Hg or being on medication for high blood pressure; 64.3% were treated with drugs, and blood pressure was controlled in only 36.1% of the hypertensive women, with lower rates of control in the oldest group. After adjustment for multiple covariates, current hormone users had higher prevalence than did nonusers (odds ratio 1.25). Hypertensive women had more comorbid conditions than did nonhypertensive women, and women with comorbidities were more likely to be treated pharmacologically. Diuretics were used by 44.3% of hypertensives either as monotherapy or in combination with other drug classes. As monotherapy, calcium channel blockers were used in 16%, angiotensin-converting enzyme inhibitors in 14%, &bgr;-blockers in 9%, and diuretics in 14% of the hypertensive women. Diuretics as monotherapy were associated with better blood pressure control than any of the other drug classes as monotherapy. In conclusion, hypertension in older women is not being treated aggressively enough because a large proportion, especially those most at risk for stroke and heart disease by virtue of age, does not have sufficient blood pressure control.

Obesity-Related Hypertension: Epidemiology, Pathophysiology, and Clinical Management

The prevalence of obesity, including childhood obesity, is increasing worldwide. Weight gain is associated with increases in arterial pressure, and it has been estimated that 60-70% of hypertension in adults is attributable to adiposity. Centrally located body fat, associated with insulin resistance and dyslipidemia, is a more potent determinant of blood pressure elevation than peripheral body fat. Obesity-related hypertension may be a distinct hypertensive phenotype with distinct genetic determinants. Mechanisms of obesity-related hypertension include insulin resistance, sodium retention, increased sympathetic nervous system activity, activation of renin-angiotensin-aldosterone, and altered vascular function. In overweight individuals, weight loss results in a reduction of blood pressure, however, this effect may be attenuated in the long term. An increasing number of community-based programs (including school programs and worksite programs) are being developed for the prevention and treatment of obesity. Assessment and treatment of the obese hypertensive patient should address overall cardiovascular disease (CVD) risk. There are no compelling clinical trial data to indicate that any one class of antihypertensive agents is superior to others, and in general the principles of pharmacotherapy for obese hypertensive patients are not different from nonobese patients. Future research directions might include: (i) development of effective, culturally sensitive strategies for the prevention and treatment of obesity; (ii) clinical trials to identify the most effective drug therapies for reducing CVD in obese, hypertensive patients; (iii) continued search for the genetic determinants of the obese, hypertensive phenotype.

Salt in Health and Disease — A Delicate Balance

This review provides an overview of our current understanding of the relation of salt consumption to hypertension and cardiovascular disease.

Association of Adrenal Steroids With Hypertension and the Metabolic Syndrome in Blacks

Blacks have a high prevalence of hypertension and adrenal cortical adenomas/hyperplasia. We evaluated the hypothesis that adrenal steroids are associated with hypertension and the metabolic syndrome in blacks. Ambulatory blood pressures, anthropometric measurements, and measurements of plasma renin activity (PRA), aldosterone, fasting lipids, glucose, and insulin were obtained in 397 subjects (46% hypertensive and 50% female) after discontinuing antihypertensive and lipid-lowering medications. Hypertension was defined as average ambulatory blood pressure >130/85 mm Hg. Late-night and early morning salivary cortisol, 24-hour urine-free cortisol, and cortisone excretion were measured in a consecutive subsample of 97 subjects (40% hypertensive and 52% female). Compared with normotensive subjects, hypertensive subjects had greater waist circumference and unfavorable lipid profiles, were more insulin resistant, and had lower PRA and higher plasma aldosterone and both late-night and early morning salivary cortisol concentrations. Twenty-four-hour urine-free cortisol and cortisone did not differ. Overall, ambulatory blood pressure was positively correlated with plasma aldosterone (r=0.22; P<0.0001) and late-night salivary cortisol (r=0.23; P=0.03) and inversely correlated with PRA (r=−0.21; P<0.001). Plasma aldosterone correlated significantly with waist circumference, total cholesterol, triglycerides, insulin, and the insulin-resistance index. Based on Adult Treatment Panel III criteria, 17% of all of the subjects were classified as having the metabolic syndrome. Plasma aldosterone levels, but not PRA, were elevated in subjects with the metabolic syndrome (P=0.0002). The association of aldosterone with blood pressure, waist circumference, and insulin resistance suggests that aldosterone may contribute to obesity-related hypertension in blacks. In addition, we speculate that relatively high aldosterone and low PRA in these hypertensive individuals may reflect a mild variant of primary aldosteronism.

Surgical therapy for persistent hypertension after renal transplantation.

SUMMARY The presence of the original diseased native kidneys in renal allograft recipients is associated with an increased prevalence of persisting post-transplant hypertension. In 9 of 10 such transplant patients bilateral nephrectomy of these native kidneys, performed at least 1 year after successful transplantation of a renal allograft, resulted in improved blood pressure control. Although these 10 patients had higher peripheral plasma renin activity (PRA) than normotensive patients (5.9 ± 1.3 ng/ml/hr versus 1.5 ± 0.3 mg/ml/hr), selective renal vein renin measurements did not consistently demonstrate higher renin concentrations from the native kidneys. Removal of the original kidneys was beneficial even in some patients who had stenosis of the allograft artery demonstrated by arteriography.

A study of the renin-angiotensin system in newborn infants

The renin-angiotensin system was studied in newborn infants. Bioassayable andimmunoassayable renin activities were elevated during the first six days after delivery. At 3 to 6 weeks of age, although elevated above that in adult control subjects, renin activity was lower than in the first postnatal week. Cord blood renin values were greater than those for maternal renin during labor. Renin substrate concentration was elevated in infants less than six days of age and also in 3- to 6-week-old infants. The enhanced activity of the renin-angiotensin system may contribute to the increased renal vascular resistance and the altered renal hemodynamics that occur in the newborn infant.