The effects of dietary docosahexaenoic acid (DHA), an ω‐3 polyunsaturated fatty acid, on blood pressure and some pressure‐regulating systems were measured in young spontaneously hypertensive rats (SHR). Plasma aldosterone and corticosterone levels, adrenal aldosterone production in vitro , and characteristics of adrenal angiotensin receptors were measured after 6 weeks of diet. Renal cytochrome P450 (CYP) 4A gene expression and arachidonic acid metabolism by renal microsomes were also investigated. Plasma cholesterol, triglycerides, and high‐density lipoprotein cholesterol were measured. Diets contained either corn/soybean oil alone (CSO), or oil enriched with DHA. After 6 weeks, rats fed DHA had systolic blood pressures averaging 34 mmHg less than controls ( P < 0.001). Plasma aldosterone levels were 33% lower in the DHA‐fed animals than in controls (22 ± 3 vs. 33 ± 3.7 ng/dl, P < 0.05). Plasma levels of corticosterone were 18% lower in animals fed DHA than in controls, but this difference was not statistically significant. Adrenal glomerulosa cells from DHA‐fed rats produced less aldosterone in vitro in response to angiotensin II, ACTH, or potassium. The difference was less marked when aldosterone production was stimulated by supplying exogenous corticosterone, suggesting an effect of DHA on postreceptor steps in signal transduction or the early pathway of aldosteronogenesis. We found no significant differences in angiotensin receptor subtype, number, or affinity. Production of arachidonic epoxides by renal microsomes was 17% lower in DHA‐fed animals than in controls ( P < 0.05). Renal cortical mRNA levels of CYP4A genes and formation of 19‐ and 20‐hydroxyeicosatetraenoic acid (HETE) did not differ between dietary groups. Plasma total cholesterol and high‐density‐lipoprotein (HDL) levels were significantly reduced in SHR fed the DHA supplement, but triglyceride levels were not significantly different. The effects of DHA on steroid and eicosanoid metabolism may be part of the mechanism by which this fatty acid prevents some of the hypertension in growing SHR.
Cardiovascular Health-Dietary Recommendations for Fatty Acids: Is There Ample Evidence?" held on June 5-6, 2000, in Reston, Va.The conference was held to summarize the current understanding of the effects of fatty acids on risk of cardiovascular disease (CVD) and cancer, as well as to identify gaps in our knowledge base that need to be addressed.There is great interest in learning more about the biological effects of the individual fatty acids, their role in chronic disease risk, and their underlying mechanisms of action.As research advances are made, there is always the need to question how new findings may be translated into practice.There is a long history of research providing the basis for the modification of existing dietary guidelines.Research findings have been used to verify intake criteria and are considered along with practical issues of implementation to establish new guidelines.A substantive body of consistent evidence sufficient to defend a dietary recommendation or a change in existing dietary guidance is essential.The conference highlighted the progress that has been made in understanding the biological effects of fatty acids and also addressed the need to learn more about how different fatty acids affect the risk of chronic disease, within the context of refining dietary guidance to further enhance health.
The stress response increases sympathetic nervous activity, which can adversely affect the cardiovascular system. Cardiovascular disease is due in part to stress-induced mechanisms mediated primarily through increased adrenergic stimulation. These stress-induced mechanisms include elevations in serum lipid levels, alterations in blood coagulation, atherogenesis, vascular changes in hypertension, and myocardial ischemia. Stress management interventions for hypertension are controversial; however, interventions for coronary heart disease-prone behavior patterns have proven successful. Stress management interventions have also reduced cardiovascular events, mortality, and coronary atherosclerosis. Assessment of stress includes individual interviews, which can be complemented by information derived from questionnaires and mental stress testing. Educational and relaxation strategies can prepare patients to understand and cope with stress. These approaches will hopefully decrease the occurrence of stress and, ultimately, the risk for cardiovascular disease.
Graduate nursing students were surveyed to determine the knowledge and attitudes of cardiovascular disease prevention. Questionnaires were self-administered to first-year graduate nursing students (n = 50) in a school of nursing prior to and following a physiology course with cardiovascular disease prevention content. In general, the results demonstrated that the respondents were least knowledgeable regarding the prevalence of smoking, the gender differences in high-density lipoprotein (HDL)-cholesterol levels, the influence of body weight on lipids and the recommended percentages of calories from dietary fat. A significant improvement in knowledge was noted after the course. Positive attitudes regarding the importance of cardiovascular disease prevention and the partnership between patients and clinicians necessary to manage risk were identified. These attitudes did not change significantly following the course. These results indicate that graduate education which emphasizes cardiovascular disease prevention increases knowledge. Coupled with positive attitudes and healthy personal lifestyle behaviours, knowledge of cardiovascular disease prevention may enhance the ability of nurses to integrate preventive standards into clinical practice and ultimately decrease the risk of cardiovascular disease.
This article summarizes the highlights of the 1993 Report of the Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure. These guidelines provide nurses and patients with important information about therapies for hypertension (e.g. lifestyle modification and pharmacologic therapy); treatment for specific populations (e.g. black, young, pregnant, and elderly patients); and, factors which cause hypertension (e.g. cocaine, lithotripsy, cyclosporine, and erythropoietin). This article addresses antihypertensive drugs and provides an algorithm for the treatment of hypertension. The implications for nurses in view of these new guidelines are also presented.
Background Hyperlipidemic children are at high risk for early coronary heart disease (CHD). Low tissue levels of ω-3 fatty acids are inversely associated with CHD. Previous studies show that high levels of plasma ω-3 fatty acids, eicosapentaenoic acid (EPA) and docosapentaenoic acid (DPA) from a seafood diet, are associated with an increased likelihood of healthy aging. The Mediterranean diet rich in EPA and docosahexaenoic (DHA) acids is also associated with decreased risk of CHD. These long chain fatty acids positively influence vascular function and reduce CHD by altering membrane fluidity, receptor activity, gene expression and eicosanoid synthesis. The purpose of this study was to determine the effect of the Mediterranean diet alone or combined with EPA on the plasma fatty acid profile of hyperlipidemic children. Methods A randomized, double-blind, placebo-controlled trial was conducted in 6 children (9-16 yrs) with hyperlipidemia. The Mediterranean diet was consumed for 6 wks, followed by the diet combined with EPA supplements (1.2 gms/day) for 6 wks. A Mediterranean diet score was obtained at baseline and after the diet. Plasma phospholipid fatty acid composition was also determined. Plasma was extracted in chloroform:methanol and thin-layer chromatography was used to separate phospholipid fractions. Fatty acid methyl esters were quantified using gas chromatography and identified with standards and expressed as % of total fatty acids. Results Mean Mediterranean diet scores were significantly increased (Baseline: 5.5 ± 0.5 vs Diet: 8.0 ± 1.3; P <.002) verifying dietary compliance. A significant increase in plasma EPA and DPA and a significant decrease in total ω-6 fatty acids and the Arachidonic Acid/EPA Ratio were observed in hyperlipidemic children following EPA supplementation. Conclusion This is the first study to show that EPA supplementation favorably alters the plasma fatty acid composition in hyperlipidemic children by increasing circulating ω-3 fatty acids, EPA, DPA, but not DHA. Studies suggest that increased plasma EPA and DPA are associated with decreased risk of CHD events and greater likelihood of healthy aging. Therefore, these changes may favorably alter pathophysiological vascular processes in hyperlipidemic children and prevent the development of early CHD.
