Assessing beans as a source of intrinsic fiber on satiety in men and women with metabolic syndrome.

Dietary fiber is well-known for its satiety inducing properties. Adding fibers to mixed dishes is one way to increase fiber intake. However, adding fibers to foods versus including foods inherently containing fiber may reveal differing effects on satiety. The present study aimed to explore the satiety effects of adding fiber to a mixed meal versus using beans (Phaseolus vulgaris) as a source of intrinsic fiber in the meal. In this pilot study, 12 men and women with metabolic syndrome were randomly assigned to eat three standard meals in a crossover design on three different occasions that contained either no added fiber (control (NF)), extrinsic or added fiber (AF), or whole black beans as the source of intrinsic fiber (BN). Meals were matched for energy and macronutrient composition. Five hour postprandial subjective satiety was measured along with blood glucose, insulin, and the GI hormones, cholecystokinin (CCK) and peptide tyrosine tyrosine (PYY3-36). All meals induced fullness to a similar degree; however, the AF meal suppressed prospective consumption (F2,187 = 9.05, P = 0.0002) compared to the BN or NF meals. The NF meal tended to result in more satisfaction than the BN meal (F2,187 = 5.91, P = 0.003). The BN meal produced significantly higher postprandial CCK concentrations compared to the AF (F2,187 = 6.82, P = 0.001) and NF meals (F2,187 = 6.82, P = 0.002). Similar findings were observed for PYY3-36 response for BN > AF meal (F2,170 = 9.11, P < 0.0001). Postprandial insulin was significantly reduced after the BN meal, compared to the NF (F2,187 = 22.36, P < 0.0001) meal. These findings suggest that incorporating whole black beans into a meal has acute beneficial metabolic and GI hormone responses in adults with metabolic syndrome and are preferred over adding equivalent amounts of fiber from a supplement.

Black Beans, Fiber, and Antioxidant Capacity Pilot Study: Examination of Whole Foods vs. Functional Components on Postprandial Metabolic, Oxidative Stress, and Inflammation in Adults with Metabolic Syndrome.

Beans (Phaseolus vulgaris) contain bioactive components with functional properties that may modify cardiovascular risk. The aims of this pilot study were to evaluate the ability of black beans to attenuate postprandial metabolic, oxidative stress, and inflammatory responses and determine relative contribution of dietary fiber and antioxidant capacity of beans to the overall effect. In this randomized, controlled, crossover trial, 12 adults with metabolic syndrome (MetS) consumed one of three meals (black bean (BB), fiber matched (FM), and antioxidant capacity matched (AM)) on three occasions that included blood collection before (fasting) and five hours postprandially. Insulin was lower after the BB meal, compared to the FM or AM meals (p < 0.0001). A significant meal × time interaction was observed for plasma antioxidant capacity (p = 0.002) revealing differences over time: AM > BB > FM. Oxidized LDL (oxLDL) was not different by meal, although a trend for declining oxLDL was observed after the BB and AM meals at five hours compared to the FM meal. Triglycerides and interleukin-6 (IL-6) increased in response to meals (p < 0.0001). Inclusion of black beans with a typical Western-style meal attenuates postprandial insulin and moderately enhances postprandial antioxidant endpoints in adults with MetS, which could only be partly explained by fiber content and properties of antioxidant capacity.

Another look at the results of the JUPITER trial.

Justification for the Use of Statins in Prevention: An Intervention Trial Evaluating Rosuvastatin (JUPITER) was a placebo-controlled trial undertaken on "apparently healthy" subjects selected primarily on the basis of high-sensitivity C-reactive protein concentrations >or=2.0 mg/L. JUPITER showed that rosuvastatin reduced the incidence of cardiac events compared to a control group. The study population (median age 66 years) included men and women with the metabolic syndrome (about 41%), median blood pressures in the prehypertensive range, current smoking (about 15%), median body mass indexes higher than normal, and Framingham 10-year risk >10% (about 50%). The presence of these risk factors indicates that a significant proportion of subjects were not "healthy" and warranted aggressive management under current guidelines, without the measurement of high-sensitivity C-reactive protein. Furthermore, <17% of the trial participants were taking guidelines-recommended aspirin, and 25% had systolic blood pressures >145 mm Hg and would have merited treatment for hypertension. It is likely that many of the participants did not receive care consistent with current standards. Thus, the benefit of statin therapy would have been more difficult to demonstrate if standard therapeutic recommendations had been followed. In conclusion, these considerations cast doubt on the contention that statin therapy should be initiated in apparently healthy individuals on the basis of elevated high-sensitivity C-reactive protein levels.

Assessment of risk for developing coronary heart disease in asymptomatic individuals.

The assessment of risk for developing coronary heart disease (CHD) in asymptomatic individuals continues to be an important challenge for clinicians. We suggest that the Framingham risk score provides a pragmatic basis for assessing global 10-year CHD risk in this population. The Framingham risk score should be supplemented with additional information pertaining to diabetes, metabolic syndrome, family history, and peripheral arterial disease before a final decision is made with respect to individual risk. In terms of additional investigations, it is suggested that measurement of the ankle brachial index and a stress test that focuses on functional capacity be incorporated into the evaluation of asymptomatic subjects for CHD. The role of emerging risk factors remains unresolved as is the value of attempting to routinely diagnose subclinical disease with measurements such as the coronary calcium score.

Left ventricular dysfunction and extravascular fluid in the lung: physiological basis for symptoms.

The essential feature of left ventricular dysfunction is an increase in left atrial pressure and pulmonary venous congestion leading to a fluid flux across the pulmonary microvasculature. Small acute increases (< 10 mmHg) in left atrial pressure enhance the extravascular fluid volume in the airways and activate the rapidly adapting receptors (RAR). With larger increases in left atrial pressure (approximately 25 mmHg) both the RAR and the C-fiber receptors in the airways and the alveoli are activated. Activation of RAR causes a reflex increase in respiratory rate, tracheal tone and mucus secretion from the airways. It appears that small increases in extravascular fluid volume of the airways also cause a reflex diuresis which is mediated by activation of neuronal nitric oxide synthase in the renal medulla. In contrast, when left atrial pressure is elevated chronically, further small increments in extravascular fluid volume of the airways no longer stimulate the RAR. The reflex diuresis is also not evident under these circumstances. However, the RAR continue to be activated by increments in left atrial pressure in excess of 25 mmHg. It is suggested that the RAR of the airways play a significant role in monitoring changes in the extravascular fluid volume of the airways and mediate the reflexes which are associated with the symptomatology of acute left ventricular dysfunction.

Cardiac event rate in a lifestyle modification program for patients with chronic coronary artery disease.

BACKGROUND: Several clinical trials have shown that intensive lifestyle modification programs have a significant impact on cardiovascular risk factors. HYPOTHESIS: This paper is a retrospective analysis to determine the effect of participation in a 2-year lifestyle management program on long-term clinical outcome in patients outside the setting of a clinical trial. METHODS: Patients with angiographically confirmed coronary artery disease (CAD) enrolled in a 2-year program of exercise training, dietary counseling, stress management, and therapeutic education. They were accepted into the program from 1991 through December 2002. Follow-up after completion of the program ranged from 10 to 2 years. RESULTS: In all, 134 patients enrolled in the program; of these, 77 completed the program and 57 failed to do so. Those who completed the program improved their effort tolerance and reached recommended goals for serum lipid and blood pressure levels. The cumulative event rate (cardiac death, myocardial infarction, and stroke) over 10 years in the patients who completed the program was 1.5%. The corresponding event rate in patients who dropped out was 18% (p < 0.02). CONCLUSIONS: It is suggested that patients who complete a 2-year lifestyle modification program appear to have a favorable prognosis over an extended period of time.

The rapidly adapting receptors in mammalian airways and their responses to changes in extravascular fluid volume.

In this short review, we shall focus on some recent findings on the physiological stimulus for the rapidly adapting receptors (RAR) of the airways. They are readily activated by a sustained inflation of the lungs and they are usually identified by their rapid adaptation to this stimulus. They are also activated by both tactile stimuli and irritant gases applied to the epithelium of the airways. The investigations reviewed here suggest that these receptors are activated by changes in extravascular fluid volume. The principal factors governing fluid flux from the microcirculation are identified in the Starling equation. These are the hydrostatic pressure, plasma oncotic pressure and capillary permeability. Findings from recent studies suggest that all these factors increase the activity of RAR. In addition, these receptors are also activated by obstruction of lymph drainage from the lung. Evidence is presented to show that manipulation of Starling forces also increases the extravascular fluid volume of the airways in areas where the RAR are located. On the basis of these findings, it is suggested that, along with mechanosensitivity to stimuli such as stretch, inflation and deflation, another physiological stimulus to the RAR is a change in extravascular fluid volume in the regions of the airways where these receptors are located.

Effect of fatty acids on endothelium-dependent relaxation in the rabbit aorta.

The metabolic syndrome, Type II (non-insulin-dependent) diabetes and obesity are associated with endothelial dysfunction and increased plasma concentrations of NEFAs (non-esterified fatty acids; free fatty acids). The present study was undertaken to define the inhibitory effects of saturated NEFAs on EDR (endothelium-dependent relaxation). Experiments were performed in rings of rabbit aorta to establish (i) dose-response relationships, (ii) the effect of chain length, (iii) the effect of the presence of double bonds, (iv) reversibility and time course of inhibition, and (v) the effect on nitric oxide production. Aortic rings were incubated (1 h) with NEFA-albumin complexes derived from lauric (C(12:0)), myristic (C(14:0)), palmitic (C(16:0)), stearic (C(18:0)) and linolenic (C(18:3)) acids. EDR induced by acetylcholine (0.1-10 mumol/l) was measured after pre-contraction with noradrenaline. Inhibition of EDR was dose-dependent (0.5-2 mmol/l NEFA), and the greatest inhibition (51%) was observed with stearic acid (2 mmol/l). Lauric acid had the smallest inhibitory effect. The inhibitory effects were always reversible and were evident after 15 min of incubation. Linolenic acid caused a significantly lower inhibition of EDR than stearic acid. SOD (superoxide dismutase) restored the inhibitory effect caused by NEFAs, suggesting the involvement of ROS (reactive oxygen species) in removing nitric oxide. The nitric oxide concentration measured after exposure of the rings to acetylcholine was lower after incubation with NEFAs than with Krebs buffer alone. This finding is consistent with removal of nitric oxide by ROS. This claim was supported by the demonstration of increased concentrations of nitrated tyrosine in the rings incubated with NEFAs.

Counterpoint: carotid ultrasound-an essential investigation in the prevention of coronary artery disease?

The accompanying article asserts that measurement of carotid plaque area by ultrasonography adds a vital, new dimension to the investigation and management of patients at risk of developing coronary artery disease. The author contends also that traditional risk factors for coronary artery disease have failed to provide a basis for either predicting cardiovascular events or guiding effective therapy. Carefully acquired epidemiological data have established beyond reasonable doubt that traditional risk factors identify individuals who are likely to develop coronary artery disease. Further, effective management of these factors have been remarkably effective in preventing cardiovascular events. There is little prospective data in randomly selected populations to indicate that ultrasound examinations of the carotid arteries provides additional new information which would argue in favor of an alternative therapeutic approach for patients likely to develop coronary artery disease.

Low-carbohydrate-high-protein diets: is there a place for them in clinical cardiology?

Since the last meeting of the American Heart Association, a great deal of media attention has been focused on low-carbohydrate-high-protein diets (LC-HP) and their potential impact on the practice of cardiology. It has been suggested that these diets, which were introduced originally as weight-loss regimens, also have a significantly beneficial effect on a variety of cardiovascular risk factors. It is clear that people who consume such diets have a reduced intake of calories, resulting in a predictable degree of weight loss. These diets induce a moderate level of ketosis and, in some studies, have been shown to improve the lipid profile overall. There is also a reduction in the number of low-density lipoprotein particles. However, these trends also have been observed over periods of 24 weeks or less with low-calorie diets that already have an established record of safety and efficacy. Although there is a public perception that LC-HP diets have a near-perfect "success rate," the attrition rate on these diets varies from 20% to 43%, which is similar to other conventional weight-loss regimens. Additionally, from a nutritional standpoint, these diets are seriously deficient in several micronutrients and dietary fiber, thus creating a need for nutritional supplements. In contrast, the conventional weight-loss regimens have a favorable impact on serum lipids without the accompanying ketosis and have the potential to provide a nutritionally balanced diet without the need for supplements. Because of the nutritional deficiencies inherent in LC-HP diets and the absence of long-term data on their efficacy and safety, they cannot be recommended in place of currently advocated low-fat, low-calorie diets that have an established record of safety and efficacy.

Responses of bronchial C-fiber afferents of the rabbit to changes in lung compliance.

Rapidly adapting receptors (RAR) in the lung are stimulated when the lung compliance is reduced. The present investigation was undertaken to determine whether bronchial C-fibers are also activated when lung compliance is decreased since both RAR and bronchial C-fibers are influenced by extra-vascular fluid in the airways. Action potentials (AP) were recorded from bronchial C, pulmonary C, RAR and slowly adapting receptor (SAR) afferents in the cervical vagus in open chest New Zealand White rabbits ventilated at a constant rate and tidal volume. AP were recorded during (a) positive end-expiratory pressure (PEEP) of 2-3 cmH2O (control), (b) zero end-expiratory pressure (ZEEP), (c) negative end-expiratory pressure (NEEP) of -4 cmH2O, (d) restoration of PEEP and (e) final control after hyper-inflation. Both RAR and bronchial C-fiber activity increased significantly compared with control when lung compliance was decreased (bronchial C-fibers: 35 +/- 5 vs. 66 +/- 13 impulses per 30 sec and RAR: 3 +/- 1 vs. 94 +/- 14 impulses per 30 sec).