MSc in Public Health Nutrition

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The Acute Effect of Espresso Coffee and Caffeine on Measures of Cardiovascular and Cognitive Function, a Single Blinded Cross Over Study
(Queen Margaret University, 2015)
Coffee is one of the most popular beverages in the UK. This study investigated the acute effects of espresso coffee and caffeine on markers of cardiovascular health and cognitive performance. The study had two hypotheses: Caffeine and coffee would increase blood pressure and arterial stiffness; caffeine and coffee would improve cognitive function. Blood pressure (BP) and haemodynamic parameters of pulse wave velocity (PWV), heart rate (HR) and augmentation index (AIx) were measured. Cognitive function was analysed using four validated tests. There were three interventions: coffee, decaffeinated coffee and caffeine. Caffeine content corresponded to 1.5mg/kg bodyweight. Seven healthy female participants took part. Measurements were taken at baseline and 45 minutes post-intervention. Coffee and caffeine significantly raised PWV (P≤0.05), with values rising from 6.46±0.96m/s to 6.8±1.03m/s and 6.32±0.95m/s to 6.73±0.93m/s respectively. Caffeine significantly raised systolic BP (P≤0.05) from 108.67±7.92mmHg to 114.67±7.92mmHg. There was no significant effect on HR and augmentation index. All interventions significantly improved Stroop test performance (P≤0.05), coffee resulted in improvements from 26.55±7.39s to 23.5±7.98s, decaffeinated coffee from 25.7±5.44s to 21.80±4.69s and caffeine from 25.36±6.08s to 21.84±6s. Decaffeinated coffee significantly increased Corsi block tap test scores (P≤0.05), with mean scores improving from 42.86±16.23 to 61.87±19.05. An acute negative effect on central arterial stiffness following ingestion of both coffee and caffeine was observed in habitual consumers, with caffeine alone having a more detrimental effect on cardiovascular health. Only decaffeinated coffee induced positive results in every test and also had significant improvements in two out of four cognitive tests. This study shows the importance of considering both coffee and caffeine ingestion prior to analysing arterial stiffness. Neither hypothesis was fully proven: Caffeine alone has a more detrimental effect on cardiovascular health compared to coffee; coffee and caffeine did not increase overall cognitive performance in habitual consumers.
A Study To Determine The Impact Of Permaculture On Dietary Diversity And Nutritional Status In Children Below 5 Years In Malawi.
(Queen Margaret University, 2015)
Introduction: Every year, 3.1 million child deaths are associated with poor nutritional status, the majority occurring in the most socio-economically deprived areas (Black et al. 2013). Malawi is a Sub-Saharan African country where over 60% of people live below the international poverty line and 1 in 2 children are chronically malnourished (UNICEF 2013). Interventions in the agricultural sector have the potential to reduce the burden of malnutrition by increasing food production, diversity and consequently, dietary intake and nutritional status (Heywood 2013). Permaculture is an alternative agricultural design which mimics natural ecosystems to create a diverse productive system and has been reported to produce thrice as many crop varieties as the commonly practiced maize monocropping in Malawi (Conrad 2014). This study investigates the impact of permaculture farming on dietary diversity and nutritional status in children below the age of 5 years living in Malawi. Methods: A sample of 10 children was taken from permaculture-practicing families in Central Malawi and matched with 10 controls of similar ages. They were compared based on diversity of dietary intake and nutritional status. Dietary diversity was scored based on number of food groups consumed during the previous 24-hours, while nutritional status was defined by comparing anthropometric measurements against international growth standards (Kennedy et al. 2010; WHO 2006). Results: Mean dietary diversity scores were significantly higher in the intervention group than in controls (p=.003) and prevalence of consumption of 7 or more food groups was 40% higher in the intervention group. Anthropometric measurements revealed a 20% higher prevalence of underweight and wasting and a 30% higher prevalence of severe stunting among controls than intervention group (p>.05). Conclusion: Permaculture has a positive impact on dietary diversity in Malawian children; however the evidence for impact on nutritional status was not strong hence conclusions could not be drawn. Keywords: Permaculture, Malnutrition, Dietary Diversity, Malawi
An investigation into the effects of green tea consumption on body composition and cardiovascular health in a healthy population
(Queen Margaret University, 2015)
Background: Obesity is a preventable condition which contributes to the development of many diseases leading to morbidity and early mortality in the Scottish population. Scottish diets are low in fruit and vegetables and consequently polyphenols. Polyphenols are a form of antioxidant which have been linked to longer life and a lower incidence of disease. Waist to height ratio is a measure of obesity used to discern a patient's chance of developing obesity related disease. It has been shown that green tea can decrease waist circumference, thus improving waist to height ratio. Methods to increase the consumption of polyphenols in the Scottish population would be beneficial to reduce obesity, specifically visceral obesity and lower the incidence of obesity related disease. Objective: To investigate the effects of short-term consumption of green tea on body composition and cardiovascular health in a healthy population. Methods: 10 healthy subjects were recruited. Participants consumed three cups of caffeinated green tea daily (600mls) for three weeks. Anthropometric measures, body composition and blood pressure, dietary intake, thirst perception, physical activity, urine and bowel frequency were assessed prior to the intervention and after. Compliance was assessed through the completion of an end of intervention questionnaire. Prior to this, the test beverage was analysed to determine total antioxidant and polyphenol capacity. Results: No significant changes observed in body composition, anthropometric measures, blood pressure, thirst perception or urination frequency after three weeks (p>0.05). A significant increase in the reported frequency of bowel movements observed, increasing from 1.49 ± 0.31 to 1.80 ± 0.28 over three weeks. No significant differences observed from the dietary analysis and physical activity questions. Conclusion: The results suggest that regular green tea consumption has little effect on the body composition of healthy adults. A significant increase was seen in the frequency of bowel movements, suggesting that green tea may have a potential laxative effect. Further investigation is needed as such therapeutic interventions which increase polyphenol intake across Scottish populations could be used to improve health.
Food Banks of the United Kingdom, how effective are they at providing services for people in need, and thus are they having a positive of negative effect on food insecurity in the UK.
(Queen Margaret University, 2016)
Objectives: This study aimed to interview customers of the Whitburn Trussel Trust Food Bank in West Lothian in order to determine how effective the food bank is at providing services for people in need. The interview will also include questions on what improvements could be made to the food bank inviting the customer's opinion. The information gathered from these questions will be given provided to the food bank and it is hoped that this research will provide the food bank with useful information that they can potentially put into practice. Design: Five people at the Whitburn Food Bank in West Lothian were interviewed about the services provided by the food bank and their own experiences there using a questionnaire complied by the interviewer. Results: The majority of findings were in keeping with the relevant literature. Referral methods, through local council aswell as reasons for referral, benefits delays and sanctions and low income were all given by interviewees, all of which is in keeping with the literature on this topic. Those who use the Whitburn food bank are most often single or in single parent families. The interviewees each had used the service a number of different times an felt that the limit on the use of The Trussell Trust food banks was too harsh and people should be allowed to use the service more frequently if require or on a case by case basis. Staff of the food bank however had a contrasting opinion believing this limit on usage to be adequate if benefit delay is involved but should be more flexible. Family is most often cited when clients of the food bank cannot avail of its services. All food stuffs from the food parcels are used by the clients or swapped if they will not use a certain item. Lack of food knowledge, dietary issues, lack of appliances and utensils are all cited as reasons for not being able to use all food provided by the food bank. Staff and clients would like to see a wider range of food available especially fresh and frozen aswell as recipes for food parcels. All clients felt financial services and cooking lessons if offered in the food bank would be a good idea and would take part if required. These services are offered in conjunction with the food bank but have had a poor uptake. Finally feelings on using the food banks services are unanimous with embarrassment and appreciation being cited. All clients felt the food bank offered an excellent and welcoming service. Conclusions: Further research is required in the field of food banks to further determine how to aid those affected by food poverty. The UK government urgently needs to assess the policies on benefits and sanctions aswell as the minimum wage in order to prevent those in need from using food banks and to reduce food insecurity in the UK.
CITRULLINE AND ITS EFFECTS ON MOOD AND COGNITVE FUNCTION
(Queen Margaret University, 2016)
Background: Oral citrulline supplementation is more effective at increasing circulating arginine levels than arginine itself. Upon stimulation, about 80% of citrulline is recycled to arginine by endothelial cells to produce nitric oxide. As little as 0.18 grams of L-citrulline has been reported to double plasma arginine levels. Arginine is a precursor for nitric oxide synthase (NOS) which is an enzyme that converts arginine into nitric oxide in the vascular endothelial cells with the presence of NADPH and oxygen as a co-substrate. Nitric oxide is produced through the conversion of arginine into citrulline and this is done with the presence of one of the three isoforms of NOS. Nitric oxide production is largely dependent on extracellular arginine availability. Nitric oxide is also known as an endothelial-derived relaxation factor that causes vasodilation. Arginine directly creates nitric oxide and citrulline inside the cell and citrulline is then recycled back into arginine, producing more nitric oxide. Citrulline supplementation should have a positive effect on both mood and cognitive function due to the enhanced production of nitric oxide from citrulline and due to this mechanism, an increase in vasodilation resulting from an increase in nitric oxide. Vasodilation is the increase of blood flow and an increased flow of blood to the brain, will reduce cognitive impairment and enhance cognitive function. Nitric oxide is also involved in the formation of several types of long-term memory and preferentially affects memory acquisition. Nitric oxide signalling is a candidate mechanism in the assembly of neocortial circuits underlying language and higher cognitive functions. Objective: The objective of the study was to examine the effect of citrulline supplementation on mood and cognitive function. Two intervention groups were selected, a younger group aged between 18 - 35 and an older group aged 50+. It was anticipated that a widened demographic scope would therefore, lead to different outcomes. Design: This was a single blinded, placebo-controlled parallel group study. A total number of 16 participants were recruited, 8 for the younger population group (18-35) and 8 for the older (50+) population. Participants were randomly allocated to either the intervention or placebo group. In each group, 4 participants were assigned to citrulline supplementation (1.5 grams daily for 4 weeks) and 4 participants to placebo (100mg vitamin C). Equal numbers were chosen to make the study an equal parallel group study. Tests were carried out at baseline and after completing the 4-week trial to obtain the final results. Results: Significant results were seen for pulse wave velocity in both groups; young (p-value = 0.032) and older (p-value = 0.030) before and after citrulline supplementation. This was the same for nitric oxide levels (p - value = 0.018) in the younger population after the 4 weeks of citrulline supplementation (p-value = 0.004). There was a significant reduction in the depressive mood state and in total mood disturbance in both younger and older groups taking citrulline supplementation. When the citrulline supplemented group was compared to the placebo group, no statistical significance was observed in any of the changes for the populations.
The effect of milk thistle complex herbal extract on blood glucose maintenance and the prevention of cardiovascular disease in healthy individuals.
(Queen Margaret University, 2016)
Milk thistle (MT/Silybum Marianum) has been used medicinally for over 2000 years for diseases of the hepatic and biliary system in both complimentary and western medicine. It is widely available in tablet, tincture and other formulations through consumer outlets. MTs effectiveness in glucose control in diabetics and in aiding cholesterol control in hypercholesterolemic patients is well evidenced proving its efficacy in glucose management and dyslipidemia treatment is significant in those diagnosed with diabetes and or cardiovascular disease (CVD). More robust and empirically sound studies are required to solidify the use of MT in the clinical setting and the wider consumer environment. A thorough literature review revealed no previously published studies looking at the effect of MT extract on healthy individuals. It may be useful to examine the effect of MT on blood glucose, hepatic function and CVD markers in healthy participants for possible use as preventative treatment to reduce the risk of progression of those diagnosed with metabolic syndrome to diabetes and CVD. The present paper examines the effect of a commercially available MT fruit complex extract containing additional botanical extracts from taraxacum officinalis (dandelion), cynara scolymus (artichoke leaves) and boldo leaves (from the Boldo bush) on glucose control and cardiovascular status in healthy individuals. Using a single blinded, two week trial of supplementation with MT Complex tablets at a dose of 3.2 mg S.marianum, 4.6mg C.scolymus, 1.2mg T.Officianalis, 0.7 mg P.boldus twice daily (provided by A Vogel UK). Participants had baseline measurements of fasting blood glucose (F.Gluc), oral glucose tolerance test (OGTT), cholesterol, pulse wave velocity (PWV), augmentation index (AI), height and weight taken at baseline and after two weeks. The participants were required to take the supplement twice daily during those two weeks and then returned to repeat the previously mentioned measurements. No significant change (P<0.005) was noted in any of the observed variables.
Lunch time food and drink purchasing habits in Scottish secondary school pupils: a pilot study.
(Queen Margaret University, 2017)
Background: Adolescence is a critical period for the formation of dietary behaviours and body weight patterns. In Scotland, school meal uptake is low and most secondary school pupils choose to leave the school at lunch time. Social and functional factors provide barriers to school meal uptake. Food and drink on sale in the vicinity of the school are not regulated and young people have increasingly easy access to foods high in saturated fatty acids, sugar and salt at lunch time. The food environment around and within schools is receiving increasing attention in policies and interventions aimed at reducing obesity in youth. Aim: The main aim of this study was to explore the nutrition of the food environment generally attended by pupils of secondary schools within the area, and compare with the food available within the schools. Barriers to school meal uptake were investigated. Methods: This study assessed the dietary intakes of pupils from two secondary schools over four lunch times. The food outlets within 1 kilometre (km) of each school were mapped and used to determine the association between overweight and obesity in the pupils with food outlet density and type. Quantitative data on barriers to school meal uptake was recorded using a questionnaire. Results: Street meals mean (+SD) energy, fat and sodium intakes 932.1g (+572.56), 46g, 1530.6mg (+1321.35) respectively were significantly different from the school meals and packed lunches, all p<0.05. Food outlet proximity to school or type and prevalence of overweight and obesity were not significantly associated, neither was type of lunch and pupil BMI. To be with friends was important in choosing where to purchase lunch. Improvements to food quality and variety and reducing queuing times would encourage pupils to purchase a school meal more often. Conclusion: Multiple components to the food environment in and around schools influence food and drink purchasing habits in youths. Collaborating with food vendors to improve the nutritionally quality of food and drink on sale within the vicinity of the school is one strategy that may be employed. School meals packed lunches offer a more nutritious meal than street meals at lunch time. Young people should be consulted on changes to the school canteen that would encourage school meal uptake. The importance of social factors to young people's food purchasing habits should not be underestimated and further research in this field will provide valuable advice to policies and initiatives aimed at reducing childhood obesity.
A pilot study showing the feasibility for investigating the effects of tart cherry juice on cognitive and cardiovascular health in older adults aged 50 to 70 years
(Queen Margaret University, 2017)
Aim - There have been studies in which the health effects of flavonoid rich food are investigated. Flavonoids and phytonutrient, found in various foods, are known to have multiple health benefits through their antioxidant activity. For example, tart cherries contain two sub-types of flavonoids; anthocyanins and flavonols. These fruits, especially rich in anthocyanins, have been found to enhance cognitive and cardiovascular functions during several studies. The aim of this pilot study is to analyse the common methodology for investigating the effects of tart cherry juice on cardiovascular and cognitive health in older adults from the results and suggest ideal research methods. Methodology - This pilot study is a randomised open-labelled study. Five healthy adults aged 50 to 70 years with a BMI of less than 30kg/m2 were recruited in Edinburgh. The study involved two drinks: commercially available tart cherry juice and cherry flavoured water. Ferric ion reducing antioxidant power (FRAP) and Folin-Ciocalteu assays revealed that tart cherry juice had significantly higher levels of both polyphenols and antioxidant activity than cherry flavoured water. Subjects were asked to consume 250ml of one of these treatments twice daily for fourteen days. Cardiovascular measurements included systolic blood pressure (SBP), diastolic blood pressure (DBP), and pulse wave velocity (PWV). Cognitive function was measured by two distinct tests; trail making test (TMT) and serial sevens test. Four measurements were taken: baseline characteristics before the consumption, acute effects two hours after drinking the first treatment, short-term effects taken after two weeks, the last measurement taken one day after halting the consumption. Results - Analysis of results from this study was not sufficient to confirm significant differences in both cardiovascular and cognitive functions. Nevertheless, it suggests the feasibility of undertaking a similar study in the future.
Effects of brewing temperature on release of caffeine and antioxidants in black tea and short-term effectiveness of black tea in improving cognition, mood, and alertness
(Queen Margaret University, 2017)
Background: Black tea is the second most consumed beverage globally and accounts for a significant proportion of caffeine and polyphenol intake in the UK and elsewhere (Yashin et al. 2015). Tea is historically associated with cognitive benefits such as mental clarity, alertness, positive impact on mood, and psychological well-being (Camfield et al. 2014). These distinct attributes are associated with two major constituents of tea: caffeine and antioxidants. Mostly, the research on tea has focussed on the impacts of infusion time and release of caffeine and antioxidants; while there is very limited research available that investigates the effects of infusion temperatures. Also, there is a lack of exploration in comparative human intervention studies on the short-term effects of teas with different antioxidant levels in improving cognition, mood, and alertness. Objective: To investigate the effects of infusion temperature on the release of caffeine and antioxidants in black tea. Further, to examine changes in antioxidant levels of tea after the addition of milk. Finally, the short-term comparative effectiveness of tea on cognitive ability, mood and alertness will be explored. Design: Four tea blends were tested in the laboratory for caffeine and antioxidant levels at a varying range of temperatures. Among the four blends, Tetley and Twinings were selected for a randomised controlled trial. Participants consumed tea-with-milk or tea-without-milk. The study was conducted at QMU. Twenty participants were recruited from the university and the public. Following 12 hour of fasting and abstinence from tea and caffeinated drinks, participants were tested for cognition and alertness by CAF-VAS and Stroop tests in the morning; afterward they were provided with a standard cup of tea with milk or without milk and the same tests were repeated after a gap of 60 minutes. The experiment was conducted on two non-consecutive days. On day 1, tea with the lowest antioxidant levels was tested and on day 2, tea with the highest released antioxidants was tested. Results: On HPLC analysis, all four blends exhibited the highest mean caffeine concentration at the brewing temperature of 100°C (127.3 ± 21.07 mg/235ml). Among the 4 blends, Yorkshire had the highest (134.2 ± 23.1 mg/235ml), while Twinings had the lowest mean values (99.09 ± 21.3 mg/235ml). On Folin assay, Tetley displayed the highest (206.3 ± 29.1 GAE/235ml), while Twinings had the lowest mean value (192.4 ± 39.2 GAE/235ml). Based on Folin assay, Tetley and Twinings were selected for the participant-based study. These two blends exhibited significantly higher antioxidants with milk (P ≤ 0.02) compared to the without-milk analysis. FRAP analysis showed the highest value for Tetley (14.02 ± 1.5 mMFeSO₄), while Yorkshire had the lowest FRAP value among the four blends (11.88 ± 1.9 mMFeSO₄). In FRAP analysis, tea-without-milk had significantly higher values (P ≤ 0.003) compared to tea-with-milk. On the Stroop test, participants showed significant improvement in response time after Twinings (P ≤ 0.03), while Tetley had no significant impact with or without-milk. On CAF-VAS, participants consuming Twinings showed improvement in relaxation (P≤0.005), alertness (P ≤ 0.01), and alleviating tiredness (P ≤ 0.002), Tetley exhibited improvement in the same parameters among the tea-without-milk group but the significant improvement was witnessed in the with-milk group (P ≤ 0.01). Conclusion: In-cup caffeine concentration increases with temperature and maximum concentration is attainable at 100°C; while for the release of antioxidants, the optimum temperature range is 80-100°C, which is a standard brewing temperature in most UK households. Among the four blends, Twinings, with the lowest caffeine and antioxidants, was the most effective in improving cognition, mood, and alertness. Key words: Caffeine, antioxidants, cognition, parameters.
The effectiveness of cherry juice consumption on cognitive and cardiovascular function in healthy adults: a pilot study
(Queen Margaret University, 2017)
Background: Tart cherry juice contains high concentrations of flavonoids and anthocyanins, which have been linked to improved cognition, while several studies have shown a beneficial effect on blood pressure and arterial stiffness. Objective: The aim of this study was to examine the effect of tart-cherry juice on cognitive function and cardiovascular risk factors in healthy adults and to define an appropriate methodology design. Methods: An open-label randomised placebo-controlled pilot study was conducted on healthy adults. The participants consumed 250ml of either commercially available tart-cherry juice by Biona (intervention) or 250ml cherry-flavoured water by Volvic (placebo) twice daily for 14 days. Participants were asked to visit Queen Margaret University three times over the duration of the study (16 days), undertaking cognitive tests and BP measurements. Cognitive function was measured by the Trail-Making test and the Serial-Sevens test which evaluate executive function and short-term memory. The cardiovascular function was measured by blood pressure monitor and pulse wave velocity. FRAP and the Folin-Ciocaltreau method was used for the calculation of antioxidant level and total phenolics of the cherry juice. The participants' height, weight, and age were recorded at baseline. Measurements were taken at baseline, 2 hours after drinking the juice on the same day, on day 15 at the end of the intervention and one day follow-up to evaluate if the effects of the intervention persist. For the statistical analysis SPSS and Excel were used. Results: PWV (p=0.042) and Trail-Making test (p<0.001) were found significant for the treatment group, while comparison of treatment (n=3) and control group (n=2) showed that the SBP (p<0.001) and DBP (p<0.001) and PP (p=0.007) and the Trail-Making test (p=0.050) were significant. Conclusion: The results indicate that cherry juice can improve cognitive and cardiovascular function and the study suggests further work in this area may be of value.
Pilot Study: Assessment of the food environment attended by secondary school pupils in East Lothian and comparison with the food available at schools
(Queen Margaret University, 2017)
Objective: To explore and compare the nutrient intake of children who obtain lunch in school, outside of school, or having a packed lunch. In addition, to determine whether there is an association between food outlet density surrounding schools with overweight and obesity among East Lothian pupils. Methods: Secondary school pupils aged 12-14 years (n = 27) from two secondary schools in East Lothian, Scotland, were asked to complete a 10-minute self-administered questionnaire and complete food diaries for a period of four days (Monday to Thursday). Nutritional analysis of the diaries was carried out. Comparison of the lunch type groups (school v packed v out- with school) was performed. Food outlets were mapped around 1km of schools and analysed to conclude if food outlet density was associated with overweight and obesity amongst pupils. Results: The findings from this study found that school lunch meals were superior of nutritional quality compared to street lunch meals and packed lunch meals. Whereby, total energy intake, fat, monosaturated fat, polyunsaturated fat and sodium levels were significantly greater amongst street lunch meals (p < 0.05). Food outlet density within 1km of schools was not associated with overweight and obesity among pupils. Conclusion: Our results support the encouragement of eating school lunch meals during lunch time to improve pupil's nutrition quality of lunchtime meal. It also encourages initiatives to improve the nutrition value of food outlets within 1 km of school grounds.
The feasibility of reducing free sugar intake to 5% of daily total energy intake through provision of guidelines alone: An intervention study within a Scottish population.
(2018)
Consumption of free sugars is associated with excess energy intake, potentially leading to obesity, and the onset of dental caries. UK government recommendations state that the population should limit their intake of free sugars to 5% of daily total energy intake (TEI). This represents a reduction in the average adult and child consumptions, currently around 11% and 14% respectively. Variations in sugar terminology, food industry interests, food nutritional labelling clarity and habitual behaviour all represent barriers to achieving the recommended level. This pilot study presents an intervention of 13 adult subjects undertaking a two-week programme recording dietary intakes at baseline and then at two weeks, during an attempt to reduce free sugars to 5% TEI using advice available to the general public. Changes in free sugar intake as well as other macronutrients will be analysed to test the following hypotheses: 1. That reduction of free sugars intake to 5% TEI is possible using available guidelines and 2. Assuming a statistically significant change in free sugar intake, there will be no corresponding change in fat intake levels. The intervention resulted in significant reductions of total sugar (g), p= 0.002; free sugars (% TEI), p= 0.025; free sugars (g), p= 0.023. Fat intakes and TEI did not change significantly. The study concludes that individuals can target sugar specifically for reduction and that 5% TEI from free sugar may be possible for a UK free-living population via existing dietary advice. However, caution is required due to potential differences between the demographic properties of the study cohort and the UK population.