Diet and hypertension in the Asia-pacific region : a brief review

In this paper, the possible reasons for the prevalence of hypertension in the Asia–Pacific region are examined, along with its likely dietary, nutritional and sociocultural causes. This brief survey indicates the need for more comprehensive blood pressure monitoring and surveillance throughout the region. Findings from research conducted in the region and elsewhere suggest that a variety of aetiological factors predict the occurrence of hypertension, most of which are similar to those observed in western populations. However, several lines of research suggest that obesity, abdominal obesity and a number of dietary constituents, in addition to salt, may play relatively greater roles than in western populations. It is argued that hypertension may be prevented via a combination of individual, community and governmental approaches which promote social capital, environmentally sustainable food production and the public health.

The effect of insulin and exercise on c-Cbl protein abundance and phosphorylation in insulin-resistant skeletal muscle in lean and obese Zucker rats.

Aims/hypothesis: Recruitment of the protein c-Cbl to the insulin receptor (IR) and its tyrosine phosphorylation via a pathway that is independent from phosphatidylinositol 3prime-kinase is necessary for insulin-stimulated GLUT4 translocation in 3T3-L1 adipocytes. The activation of this pathway by insulin or exercise has yet to be reported in skeletal muscle. Methods: Lean and obese Zucker rats were randomly assigned to one of three treatment groups: (i) control, (ii) insulin-stimulated or (iii) acute, exhaustive exercise. Hind limb skeletal muscle was removed and the phosphorylation state of IR, Akt and c-Cbl measured.  Results:   Insulin receptor phosphorylation was increased 12-fold after insulin stimulation (p<0.0001) in lean rats and threefold in obese rats. Acute exercise had no effect on IR tyrosine phosphorylation. Similar results were found for serine phosphorylation of Akt. Exercise did not alter c-Cbl tyrosine phosphorylation in skeletal muscle of lean or obese rats. However, in contrast to previous studies in adipocytes, c-Cbl tyrosine phosphorylation was reduced after insulin treatment (p<0.001). Conclusions/interpretation: We also found that c-Cbl associating protein expression is relatively low in skeletal muscle of Zucker rats compared to 3T3-L1 adipocytes and this could account for the reduced c-Cbl tyrosine phosphorylation after insulin treatment. Interestingly, basal levels of c-Cbl tyrosine phosphorylation were higher in skeletal muscle from insulin-resistant Zucker rats (p<0.05), but the physiological relevance is not clear. We conclude that the regulation of c-Cbl phosphorylation in skeletal muscle differs from that previously reported in adipocytes.

Resistant starch in the Australian diet

We set out to estimate resistant starch (RS) intakes using the 24-hour food intake data from the 1995 National Nutrition Survey (NNS) database of 13 858 Australians. As there are often significant differences in the RS content of foods reported by various authors. we calculated intakes based on both published maximum and minimum value, for individual food,. RS intakes (mean and SEM) for all persons were in the range 3.4 ± 0.03 g/d (minimum estimate) to 9.4 ± 0.07 g/d (maximum estimate). Adult males (19+ years) consumed more RS (10.7 ± 0.11 g/day maximum estimale) than adult females (19+ years) (8.2 g ± 0.08 g/day maximum estimate). RS comprised a greater proportion of the total starch intake in the very young and in the older age groups. Across the population. foods contributing most to RS intake were potatoes, bananas and white bread.

Understanding the role of mediating risk factors and proxy effects in the association between socio-economic status and untreated hypertension

The association between socio-economic status (SES) and untreated hypertension varies according to a country's level of development and racial/ethnic group. We sought to confirm this variation in women from China and the United States (US) as well as to investigate the impact of SES on several mediating risk factors. We also investigate the extent to which SES explains racial/ethnic differences in untreated hypertension in the US. We used cross-sectional data from 1814 non-pregnant women in China (China Health and Nutrition Survey (CHNS), 1997) and 3266 non-pregnant women in the United States (National Health and Nutrition Examination Survey (NHANES III), 1988–1994) respectively. A variety of statistical modelling techniques was used to predict untreated hypertension as a function of several mediating factors and to simulate the impact of changes in SES. The age-adjusted prevalence of untreated hypertension was significantly higher (p<0.01) for low-income White and Black women compared to Mexican American or Chinese women. Untreated hypertension was not significantly associated with income or education in Mexican Americans or women in China. Obesity and light physical activity had the largest mediating effect on the association between SES and untreated hypertension for all racial/ethnic groups. However, this effect was not as strong as the proxy effect of income and education. SES did not completely explain racial/ethnic differences in hypertension in the US. While SES was more strongly associated with hypertension in Blacks than Whites, Blacks were still 1.97 (95% CI 1.47–2.64) times more likely to have untreated hypertension than Whites after adjusting for SES differences. The association between SES and untreated hypertension varied by country and racial/ethnic group. An important explanation for this variation was the differential effect of SES on mediating risk factors. SES disparities between Whites and Blacks in the US partly explain differences in the prevalence of untreated hypertension between these racial/ethnic groups.

An individualized psychosocial approach for "treatment resistant" behavioral symptoms of dementia among aged care residents

Background: Behavioral symptoms of dementia are common among residents in mainstream aged care settings, and have a substantial impact on residents and professional caregivers. This study evaluated the impact of individualized psychosocial interventions for behavioral symptoms through a small preliminary study.
Method: Interventions were delivered to a patient group of 31 psychogeriatric aged care residents who presented with behavioral symptoms of dementia that had failed to respond to pharmacological treatment approaches. Outcome data on severity of behaviors, health service utilization and staff burden of care were collected.
Results: A modest but significant reduction in staff ratings of the severity of aggressive and verbally agitated behavioral symptoms was found, with an associated reduction in their perceptions of the burden of caring for these patients. Reduced behavioral disturbance was associated with a reduction in the requirement for primary care consultations, and all participants were able to continue to reside in mainstream aged care facilities, despite an increase in the severity of dementia.
Conclusions: This study supported the use of individualized psychological strategies for behavioral symptoms at all stages of dementia. Methodological limitations of this preliminary study are discussed.

Dietary patterns of adolescents and risk of obesity and hypertension

Increasingly, measures of dietary patterns have been used to capture the complex nature of dietary intake and investigate its association with health. Certain dietary patterns may be important in the prevention of chronic disease; however, there are few investigations in adolescents. The aim of this study was to describe the dietary patterns of adolescents and their associations with sociodemographic factors, nutrient intakes, and behavioral and health outcomes. Analysis was conducted using data collected in the 1995 Australian National Nutrition Survey of participants aged 12–18 y who completed a 108-item FFQ (n = 764). Dietary patterns were identified using factor analysis and associations with sociodemographic factors and behavioral and health outcomes investigated. Factor analysis revealed 3 dietary patterns labeled a fruit, salad, cereals, and fish pattern; a high fat and sugar pattern; and a vegetables pattern, which explained 11.9, 5.9, and 3.9% of the variation in food intakes, respectively. The high fat and sugar pattern was positively associated with being male (P < 0.001), the vegetables pattern was positively associated with rural region of residence (P = 0.004), and the fruit, salad, cereals, and fish pattern was inversely associated with age (P = 0.03). Dietary patterns were not associated with socioeconomic indicators. The fruit, salad, cereals, and fish pattern was inversely associated with diastolic blood pressure (P = 0.0025) after adjustment for age, sex, and physical activity in adolescents ≥16 y. This study suggests that specific dietary patterns are already evident in adolescence and a dietary pattern rich in fruit, salad, cereals, and fish pattern may be associated with diastolic blood pressure in older adolescents.

Human sympathetic nerve biology : parallel influences of stress and epigenetics in essential hypertension and panic disorder

Patients with panic disorder provide a clinical model of stress. On a "good day," free from a panic attack, they show persistent stress-related changes in sympathetic nerve biology, including abnormal sympathetic nerve single-fiber firing ("salvos" of multiple firing within a cardiac cycle) and release of epinephrine as a cotransmitter. The coreleased epinephrine perhaps originates from in situ synthesis by phenylethanolamine N-methyltransferase (PNMT). In searching for biological evidence that essential hypertension is caused by mental stress—a disputed proposition—we note parallels with panic disorder, which provides an explicit clinical model of stress: (1) There is clinical comorbidity; panic disorder prevalence is increased threefold in essential hypertension. (2) For both, epinephrine cotransmission is present in sympathetic nerves. (3) In panic disorder and essential hypertension, but not in health, single-fiber sympathetic nerve firing salvos occur. (4) Tissue nerve growth factor is increased in both conditions (nerve growth factor is a stress reactant). (5) There is induction of PNMT in sympathetic nerves. Essential hypertension exhibits a further manifestation of mental stress: there is activation of noradrenergic brain stem neurons projecting to the hypothalamus and amygdala. These pathophysiological findings strongly support the view that chronic mental stress is important in the pathogenesis of essential hypertension. A hypothesis now under test is whether in both disorders, under prevailing conditions of ongoing stress, PNMT induced in sympathetic nerves acts as a DNA methylase, causing the norepinephrine transporter (NET) gene silencing that is present in both conditions. PNMT can have an intranuclear distribution, binding to DNA. We have demonstrated that the reduced neuronal noradrenaline reuptake present in both disorders does have an epigenetic mechanism, with demonstrable reduction in the abundance of the transporter protein, the NET gene silencing being associated with DNA binding by the methylation-related inhibitory transcription factor MeCP2.

Chronic mental stress is a cause of essential hypertension : presence of biological markers of stress

1. In searching for biological evidence that essential hypertension is caused by chronic mental stress, a disputed proposition, parallels are noted with panic disorder, which provides an explicit clinical model of recurring stress responses.
2. There is clinical comorbidity; panic disorder prevalence is increased threefold in essential hypertension. Plasma cortisol is elevated in both.
3. In panic disorder and essential hypertension, but not in health, single sympathetic nerve fibres commonly fire repeatedly within an individual cardiac cycle; this appears to be a signature of stress exposure. For both conditions, adrenaline cotransmission is present in sympathetic nerves.
4. Tissue nerve growth factor is increased in both (nerve growth factor is a stress reactant). There is induction of the adrenaline synthesizing enzyme, phenylethanolamine-N-methyltransferase, in sympathetic nerves, an explicit indicator of mental stress exposure.
5. The question of whether chronic mental stress causes high blood pressure, still hotly debated, has been reviewed by an Australian Government body, the Specialist Medical Review Council. Despite the challenging medicolegal implications, the Council determined that stress is one proven cause of hypertension, this ruling being published in the 27 March 2002 Australian Government Gazette. This judgement was reached after consideration of the epidemiological evidence, but in particular after review of the specific elements of the neural pathophysiology of essential hypertension, described above.

Prevalence, detection and drug treatment of hypertension in a rural Australian population : the Greater Green Triangle Risk Factor Study 2004

Background: Hypertension is an important risk factor for cardiovascular disease; however, limited findings are available on its detection and management in rural Australia.

Aim: To assess the prevalence, awareness and treatment of hypertension in a rural South-East Australian population.

Methods: Three cross-sectional surveys in Limestone Coast, Corangamite Shire and Wimmera regions during 2004–2006 using a random population sample (n = 3320, participation rate 49%) aged 25–74 years. Blood pressure was measured by trained nurses. Information on history of hypertension and medication was obtained by questionnaires. Hypertension was defined as systolic blood pressure ≥140 mmHg and/or diastolic blood pressure ≥90 mmHg and/or on antihypertensive drug treatment.

Results: Overall, one-third of participants had hypertension; of these, two-thirds, 54% (95% confidence interval (CI) 47–60) of men and 71% (95% CI 65–77) of women, were aware of their condition. Half of the participants with hypertension were treated and nearly half of these were controlled. Both treatment and control were more common in women (60%, 95% CI 54–67 and 55%, 95% CI 47–64) compared with men (42%, 95% CI 36–49 and 35%, 95% CI 26–44). Monotherapy was used by 55% (95% CI 48–61) of treated hypertensives. Angiotensin-converting enzyme inhibitors were the most frequently used class of antihypertensive drugs in men, whereas angiotensin-converting enzyme inhibitors, angiotensin receptor antagonists and diuretics were all widely used among women.

Conclusion: This study emphasizes suboptimal detection and treatment of hypertension, especially in men, in rural Australia.

Increased probiotic yogurt or resistant starch intake does not affect isoflavone bioavailability in subjects consuming a high soy diet

Objective - Probiotics and prebiotics that affect gut microflora balance and its associated enzyme activity may contribute to interindividual variation in isoflavone absorption after soy intake, possibly enhancing isoflavone bioavailability. This study examined the effects of the consumption of bioactive yogurt (a probiotic) or resistant starch (a known prebiotic) in combination with high soy intake on soy isoflavone bioavailability.

Methods - Using a crossover design, chronic soy consumption was compared with soy plus probiotic yogurt or resistant starch in older male and postmenopausal females (n = 31). Isoflavone bioavailability was assessed at the beginning and end of each 5-wk dietary period by sampling plasma and urine after a standardized soy meal.

Results - Chronic soy intake did not significantly affect plasma or urinary isoflavones after the soy meal and there were no significant effects of probiotic or resistant starch treatment. However, there were trends for increased circulating plasma daidzein and genistein after the probiotic treatment and for increased plasma daidzein and genistein 24 h after soy intake with resistant starch treatment. Neither treatment induced or increased equol production, although there was a trend for increased plasma equol in “equol-positive” subjects (n = 12) after probiotic treatment.

Conclusion - The weak or absence of effects of probiotic yogurt or resistant starch supplement to a chronic soy diet suggests that gut microflora were not modified in a manner that significantly affected isoflavone bioavailability or metabolism.

Low-sodium dietary approaches to stop hypertension-type diet including lean red meat lowers blood pressure in postmenopausal women

Low-sodium Dietary Approaches to Stop Hypertension (DASH) diets are base producing but restrict red meat without clear justification. We hypothesized that a vitality diet (VD), a low-sodium DASH-type diet with a low dietary acid load containing 6 servings of 100 g cooked lean red meat per week, would be more effective in reducing blood pressure (BP) compared with a higher acid load reference healthy diet (RHD) based on general dietary guidelines to reduce fat intake and increase intake of breads and cereals. A randomized, parallel dietary intervention study was conducted to compare the BP-lowering effect of these 2 diets in postmenopausal women with high/normal BP. Women were randomly assigned to follow either VD or RHD for 14 weeks. Home BP was measured daily with an automated BP monitor under standard conditions. Of 111 women commencing the study, 95 completed (46 VD, 49 RHD). Systolic BP (SBP) throughout the intervention was lower in the VD group compared to the RHD group (repeated-measures analysis of variance time by diet, P = .04), such that at the end of the study, the VD had a fall of SBP by 5.6 ± 1.3 mm Hg (mean ± SEM) compared with a fall of 2.7 ± 1.0 mm Hg in the RHD (group difference, P = .08). When only those taking antihypertensive medications were assessed, the VD (n = 17) had a significant fall of 6.5 ± 2.5 mm Hg SBP (P = .02) and 4.6 ± 1.4 mm Hg diastolic BP (P = .005) after 14 weeks, and their BP was lower than that of the RHD group (n = 18) throughout the study (P < .05). We concluded that a low-sodium DASH diet with a low dietary acid load, which also included lean red meat on most days of the week, was effective in reducing BP in older women, particularly in those taking antihypertensive medications.

Fowl play and the price of petrel: long-living Procellariiformes have peroxidation-resistant membrane composition compared with short-living Galliformes

The membrane pacemaker hypothesis predicts that long-living species will have more peroxidation-resistant membrane lipids than shorter living species. We tested this hypothesis by comparing the fatty acid composition of heart phospholipids from long-living Procellariiformes (petrels and albatrosses) to those of shorter living Galliformes (fowl). The seabirds were obtained from by-catch of commercial fishing operations and the fowl values from published data. The 3.8-fold greater predicted longevity of the seabirds was associated with elevated content of peroxidation-resistant monounsaturates and reduced content of peroxidation-prone polyunsaturates and, consequently, a significantly reduced peroxidation index in heart membrane lipids, compared with fowl. Peroxidation-resistant membrane composition may be an important physiological trait for longevous species.