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result(s) for
"Howe, Peter R. C."
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The benefits of regular aerobic exercise training on cerebrovascular function and cognition in older adults
2023
We compared the differences in cerebrovascular and cognitive function between 13 aerobic exercise trained, older adults and 13 age-, height- and sex-matched sedentary, untrained controls. We determined whether other measures accounted for differences in cerebrovascular and cognitive function between these groups and examined the associations between these functions. Participants undertook anthropometric, mood, cardiovascular, exercise performance, strength, cerebrovascular, and cognitive measurements, and a blood collection. Transcranial Doppler ultrasonography determined cerebrovascular responsiveness (CVR) to hypercapnia and cognitive stimuli. The trained group had a higher CVR to hypercapnia (80.3 ± 7.2 vs 35.1 ± 6.7%, P < 0.001), CVR to cognitive stimuli (30.1 ± 2.9 vs 17.8 ± 1.4%, P = 0.001) and total composite cognitive score (117 ± 2 vs 98 ± 4, P < 0.001) than the controls. These parameters no longer remained statistically different between the groups following adjustments for covariates. There were positive correlations between the total composite cognitive score and CVR to hypercapnia (r = 0.474, P = 0.014) and CVR to cognitive stimuli (r = 0.685, P < 0.001). We observed a relationship between cerebrovascular and cognitive function in older adults and an interaction between regular lifelong aerobic exercise training and cardiometabolic factors that may directly influence these functions.
Journal Article
Impact of cocoa flavanol consumption on blood pressure responsiveness to exercise
by
Coates, Alison M.
,
Howe, Peter R. C.
,
Buckley, Jonathan D.
in
Beverages
,
Biological and medical sciences
,
Blood pressure
2010
Impaired endothelial vasodilatation may contribute to the exaggerated blood pressure (BP) responses to exercise in individuals who are overweight/obese. The present study investigated whether consumption of cocoa flavanols, which improve endothelium-dependent flow-mediated dilatation (FMD), can modify BP responsiveness to exercise. Twenty-one volunteers (eight females and thirteen males, 54·9 (se 2·2) years, BMI 31·6 (se 0·8) kg/m2, systolic BP 134 (se 2) mmHg, diastolic BP (DBP) 87 (se 2) mmHg) were randomised to consume single servings of either a high-flavanol (HF, 701 mg) or a low-flavanol (LF, 22 mg) cocoa beverage in a double-blind, cross-over design with 3–7-d washout between treatments. Two hours after cocoa consumption, FMD was measured, followed by continuous beat-to-beat assessment (Finapres™) of BP before and during 10 min of cycling at 75 % of age-predicted maximum heart rate. Averaged data from two assessments on each type of beverage were compared by analysis of covariance using pre-exercise BP as the covariate. Pre-exercise BP was similar after taking LF and HF (153 (se 3)/88 (se 3) v. 153 (se 4)/87 (se 2) mmHg, respectively, P>0·05). However, the BP response to exercise (area under BP curve) was attenuated by HF compared with LF. BP increases were 68 % lower for DBP (P = 0·03) and 14 % lower for mean BP (P = 0·05). FMD measurements were higher after taking HF than after taking LF (6·1 (se 0·6) % v. 3·4 (se 0·5) %, P < 0·001). By facilitating vasodilation and attenuating exercise-induced increases in BP, cocoa flavanols may decrease cardiovascular risk and enhance the cardiovascular benefits of moderate intensity exercise in at-risk individuals.
Journal Article
Effects of n-3 fatty acids, EPA v. DHA, on depressive symptoms, quality of life, memory and executive function in older adults with mild cognitive impairment: a 6-month randomised controlled trial
by
Coates, Alison M.
,
Howe, Peter R. C.
,
Buckley, Jonathan D.
in
Aged
,
Aged, 80 and over
,
Australia
2012
Depressive symptoms may increase the risk of progressing from mild cognitive impairment (MCI) to dementia. Consumption of n-3 PUFA may alleviate both cognitive decline and depression. The aim of the present study was to investigate the benefits of supplementing a diet with n-3 PUFA, DHA and EPA, for depressive symptoms, quality of life (QOL) and cognition in elderly people with MCI. We conducted a 6-month double-blind, randomised controlled trial. A total of fifty people aged >65 years with MCI were allocated to receive a supplement rich in EPA (1·67 g EPA+0·16 g DHA/d; n 17), DHA (1·55 g DHA+0·40 g EPA/d; n 18) or the n-6 PUFA linoleic acid (LA; 2·2 g/d; n 15). Treatment allocation was by minimisation based on age, sex and depressive symptoms (Geriatric Depression Scale, GDS). Physiological and cognitive assessments, questionnaires and fatty acid composition of erythrocytes were obtained at baseline and 6 months (completers: n 40; EPA n 13, DHA n 16, LA n 11). Compared with the LA group, GDS scores improved in the EPA (P = 0·04) and DHA (P = 0·01) groups and verbal fluency (Initial Letter Fluency) in the DHA group (P = 0·04). Improved GDS scores were correlated with increased DHA plus EPA (r 0·39, P = 0·02). Improved self-reported physical health was associated with increased DHA. There were no treatment effects on other cognitive or QOL parameters. Increased intakes of DHA and EPA benefited mental health in older people with MCI. Increasing n-3 PUFA intakes may reduce depressive symptoms and the risk of progressing to dementia. This needs to be investigated in larger, depressed samples with MCI.
Journal Article
Soya isoflavone supplementation enhances spatial working memory in men
2009
Females perform better in certain memory-related tasks than males. Sex differences in cognitive performance may be attributable to differences in circulating oestrogen acting on oestrogen β receptors (ERβ) which are prevalent in brain regions such as the hippocampus, frontal lobe and cortex that mediate cognitive functions. Since soya isoflavones are known to activate ERβ, chronic isoflavone supplementation in males may improve cognitive performance in memory-related tasks. A 12-week double-blind, placebo-controlled cross-over trial was conducted in thirty-four healthy men to investigate the effect of isoflavone supplementation on cognitive function. Volunteers were randomised to take four capsules/d containing soya isoflavones (116 mg isoflavone equivalents/d: 68 mg daidzein, 12 mg genistein, 36 mg glycitin) or placebo for 6 weeks, and the alternate treatment during the following 6 weeks. Assessments of memory (verbal episodic, auditory and working), executive function (planning, attention, mental flexibility) and visual-spatial processing were performed at baseline and after each treatment period. Isoflavone supplementation significantly improved spatial working memory (P = 0·01), a test in which females consistently perform better than males. Compared with placebo supplementation, there were 18 % fewer attempts (P = 0·01), 23 % fewer errors (P = 0·02) and 17 % less time (P = 0·03) required to correctly identify the requisite information. Isoflavones did not affect auditory and episodic memory (Paired Associate Learning, Rey's Auditory Verbal Learning Task, Backward Digit Span and Letter-Number Sequencing), executive function (Trail Making and Initial Letter Fluency Task) or visual-spatial processing (Mental Rotation Task). Isoflavone supplementation in healthy males may enhance cognitive processes which appear dependent on oestrogen activation.
Journal Article
Dietary intakes and food sources of omega‐6 and omega‐3 polyunsaturated fatty acids
by
Howe, Peter R. C.
,
Sinclair, Andrew J.
,
Meyer, Barbara J.
in
administration & dosage
,
Adolescent
,
Adult
2003
Both n−6 and n−3 polyunsaturated fatty acids (PUFA) are recognized as essential nutrients in the human diet, yet reliable data on population intakes are limited. The aim of the present study was to ascertain the dietary intakes and food sources of individual n−6 and n−3 PUFA in the Australian population. An existing database with fatty acid composition data on 1690 foods was updated with newly validated data on 150 foods to estimate the fatty acid content of foods recorded as eaten by 10,851 adults in the 1995 Australian National Nutrition Survey. Average daily intakes of linoleic (LA), arachidonic (AA), α‐linolenic (LNA), eicosapentaenoic (EPA), docosapentaenoic (DPA), and docosahexaenoic (DHA) acids were 10.8, 0.052, 1.17, 0.056, 0.026, and 0.106 g, respectively, with longchain (LC) n−3 PUFA (addition of FPA, DPA, and DHA) totaling 0.189 g; median intakes were considerably lower (9.0 g LA, 0.024 g AA, 0.95 g LNA, 0.008 g EPA, 0.006 g DPA, 0.015 g DHA, and 0.029 g LC n−3 PUFA). Fats and oils, meat and poultry, cereal‐based products and cereals, vegetables, and nuts and seeds were important sources of n−6 PUFA, while cereal‐based products, fats and oils, meat and poultry, cereals, milk products, and vegetable products were sources of LNA. As expected, seafood was the main source of LC n−3 PUFA, contributing 71%, while meat and eggs contributed 20 and 6%, respectively. The results indicate that the majority of Australians are failing to meet intake recommendations for LC n−3 PUFA (>0.2 g per day) and emphasize the need for strategies, to increase the availability and consumption of n−3‐containing foods.
Journal Article
Dairy consumption and cardiometabolic health: outcomes of a 12-month crossover trial
by
Murphy, Karen J
,
Buckley, Jonathan D
,
Crichton, Georgina E
in
adults
,
blood lipids
,
blood pressure
2012
Background
A growing body of research suggests that regular consumption of dairy foods may counteract obesity and other components of the metabolic syndrome. However, human intervention trials are lacking. We aimed to determine the cardiometabolic health effects of increasing the consumption of reduced fat dairy foods in adults with habitually low dairy intakes in the absence of energy restriction.
Methods
An intervention trial was undertaken in 61 overweight or obese adults who were randomly assigned to a high dairy diet (HD, 4 serves of reduced fat dairy/day) or a low dairy control diet (LD, ≤1 serve/day) for 6 months then crossed over to the alternate diet for a further 6 months. A range of anthropometric and cardiometabolic parameters including body composition, metabolic rate, blood lipids, blood pressure and arterial compliance were assessed at the end of each diet phase.
Results
Total energy intake was 1120 kJ/day higher during the HD phase, resulting in slight weight gain during this period. However, there were no significant differences between HD and LD in absolute measures of waist circumference, body weight, fat mass or any other cardiometabolic parameter.
Conclusion
Recommended intakes of reduced fat dairy products may be incorporated into the diet of overweight adults without adversely affecting markers of cardiometabolic health.
Trial Registration
The trial was registered with the Australia and New Zealand Clinical Trials Registry (
ACTRN12608000538347
) on 24th October, 2008.
Journal Article
Combination chemotherapy with cyclophosphamide, epirubicin and 5-fluorouracil causes trabecular bone loss, bone marrow cell depletion and marrow adiposity in female rats
by
Xian, Cory J.
,
Howe, Peter R. C.
,
Georgiou, Kristen R.
in
Adiposity - drug effects
,
Animals
,
Antineoplastic Combined Chemotherapy Protocols - adverse effects
2016
The introduction of anthracyclines to adjuvant chemotherapy has increased survival rates among breast cancer patients. Cyclophosphamide, epirubicin and 5-fluorouracil (CEF) combination therapy is now one of the preferred regimens for treating node-positive breast cancer due to better survival with less toxicity involved. Despite the increasing use of CEF, its potential in causing adverse skeletal effects remains unclear. Using a mature female rat model mimicking the clinical setting, this study examined the effects of CEF treatment on bone and bone marrow in long bones. Following six cycles of CEF treatment (weekly intravenous injections of cyclophosphamide at 10 mg/kg, epirubicin at 2.5 mg/kg and 5-flurouracil at 10 mg/kg), a significant reduction in trabecular bone volume was observed at the metaphysis, which was associated with a reduced serum level of bone formation marker alkaline phosphatase (ALP), increased trends of osteoclast density and osteoclast area at the metaphysis, as well as an increased size of osteoclasts being formed from the bone marrow cells ex vivo. Moreover, a severe reduction of bone marrow cellularity was observed following CEF treatment, which was accompanied by an increase in marrow adipose tissue volume. This increase in marrow adiposity was associated with an expansion in adipocyte size but not in marrow adipocyte density. Overall, this study indicates that six cycles of CEF chemotherapy may induce some bone loss and severe bone marrow damage. Mechanisms for CEF-induced bone/bone marrow pathologies and potential preventive strategies warrant further investigation.
Journal Article
Food groups and fatty acids associated with self-reported depression: An analysis from the Australian National Nutrition and Health Surveys
by
Howe, Peter R.C.
,
Kreis, Irene A.
,
Kolanu, Nithin
in
acid value
,
administration & dosage
,
Adolescent
2013
The aim of this study was to explore the associations between incidence of depression and dietary intakes of foods and fatty acids in adult Australians.
Data from the 1995 Australian National Nutrition Survey (NNS), the 1995 Australian National Health Survey (NHS) and an updated fatty acid database were merged and the 24-h fatty acid intakes were calculated for the 10 986 adult participants ages 18 to 79 y in the 1995 NNS. The merged data set was used to run a logistic regression with depression as the response variable and the food groups and calculated fatty acid values, age, and sex as predictors.
The regression model indicated that increased intakes per kilojoule of meat, poultry, and game; vegetables; and eicosapentaenoic acid (EPA) are associated with lower odds of having depression, whereas increased intakes of non-alcoholic beverages, milk products and dishes, and docosapentaenoic acid (DPA) are associated with an increase in the odds of having depression. The results confirm a collective effect of diet on mood. Although other studies have shown that fish consumption is associated with lower odds of depression, this study showed lower odds of depression with high meat consumption, possibly reflecting the fact that Australians consume six times more meat than fish.
Significant associations between food and mood identified in this study warrant further research to determine causality.
Journal Article
Knee extensor strength differences in obese and healthy-weight 10-to 13-year-olds
by
Sarah P. Shultz
,
R. Mallows
,
Masaharu Kagawa
in
adiposity
,
Adolescent
,
Biomedical and Life Sciences
2013
The purpose of this study was to investigate if obese children have reduced knee extensor (KE) strength and to explore the relationship between adiposity and KE strength. An observational case–control study was conducted in three Australian states, recruiting obese [
N
= 107 (51 female, 56 male)] and healthy-weight [
N
= 132 (56 female, 76 male)] 10- to 13-year-old children. Body mass index, body composition (dual energy X-ray absorptiometry), isokinetic/isometric peak KE torques (dynamometry) and physical activity (accelerometry) were assessed. Results revealed that compared with their healthy-weight peers, obese children had higher absolute KE torques (
P
≤ 0.005), equivocal KE torques when allometrically normalized for fat-free mass (FFM) (
P
≥ 0.448) but lower relative KE torques when allometrically normalized for body mass (
P
≤ 0.008). Adjustments for maternal education, income and accelerometry had little impact on group differences, except for isometric KE torques relative to body mass which were no longer significantly lower in obese children (
P
≥ 0.013, not significant after controlling for multiple comparisons). Percent body fat was inversely related to KE torques relative to body mass (
r
= −0.22 to −0.35,
P
≤ 0.002), irrespective of maternal education, income or accelerometry. In conclusion, while obese children have higher absolute KE strength and FFM, they have less functional KE strength (relative to mass) available for weight-bearing activities than healthy-weight children. The finding that FFM-normalized KE torques did not differ suggests that the intrinsic contractile properties of the KE muscles are unaffected by obesity. Future research is needed to see if deficits in KE strength relative to mass translate into functional limitations in weight-bearing activities.
Journal Article
Improvement of Major Depression is Associated with Increased Erythrocyte DHA
2013
The aim of this study was to determine if changes in omega-3 polyunsaturated fatty acid status following tuna oil supplementation correlated with changes in scores of depression. A total of 95 volunteers receiving treatment for major depression were randomised to consume 8 × 1 g capsules per day of HiDHA (2 g DHA, 0.6 g EPA and 10 mg Vitamin E) or olive oil (placebo) for 16 weeks, whilst undergoing weekly counseling sessions by trained clinical psychologists using a standard empirically validated psychotherapy. Depression status was assessed using the 17 item Hamilton rating scale for depression and the Beck Depression Inventory by a psychodiagnostician who was blind to the treatment. Blood was taken at baseline and 16 weeks (
n
= 48) for measurement of erythrocyte fatty acids. With HiDHA supplementation, erythrocyte DHA content rose from 4.1 ± 0.2 to 7.9 ± 0.4 % (mean ± SEM,
p
< 0.001) of total fatty acids but did not change (4.0 ± 0.2 to 4.1 ± 0.2 %) in the olive oil group. The mean changes in scores of depression did not differ significantly between the two groups (−12.2 ± 2.1 for tuna oil and −14.4 ± 2.3 for olive oil). However, analysis of covariance showed that in the fish oil group there was a significant correlation (
r
= −0.51) between the change in erythrocyte DHA and the change in scores of depression (
p
< 0.05). Further study of the relationship between DHA and depression is warranted.
Journal Article