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Start date: 2023Subject: search.filters.subject.321001 Clinical nutrition

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    Iron-containing supplement use from preconception to six weeks postpartum : a secondary data analysis from a cross-sectional survey among postpartum women in New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Nutrition and Dietetics, Massey University, Albany, New Zealand
    (Massey University, 2025) Dai, Yuan
    Background: The increased iron intake requirement during pregnancy makes it a more vulnerable time for women to become iron deficient, and oral iron supplement (FeS) is often needed to prevent iron deficiency (ID) and treat ID or iron deficiency anaemia. In New Zealand, the Ministry of Health does not routinely recommend taking oral iron-containing supplements during pregnancy and lactation unless clinically indicated. Limited studies have examined iron containing supplements use in New Zealand. This study aimed to investigate oral iron containing supplements usage before, during, and after pregnancy among a cohort of postpartum women in New Zealand. Methods: This secondary data analysis used data from an anonymous online questionnaire completed by women within six months postpartum, recruited between February and mid-August 2022. This study examined data from demographic and maternal information, and oral FeS and multivitamin supplement (MMNS) use. The formulation and number of women using the different brands of oral FeS and iron-containing MMNS were reported. The average daily elemental iron intake was calculated and categorised into five dose levels: low dose (200 mg/day). Descriptive statistics were reported, including frequencies, percentages, and median (25th, 75th). Results: Of the 863 women who completed the questionnaire, 600 were included in this analysis. Forty-seven oral iron-containing supplements, including 17 types of oral FeS and 30 types of iron-containing MMNS, were reported taken, with an elemental iron dosage between 5-105 mg per tablet/capsule. Six types of iron-containing MMNS were general MMNS, potentially unsuitable for preconception, pregnant and postpartum women to use. Seventy-five percent of women (n=600) took oral FeS, 43.8% (n=569) used iron-containing MMNS at some stage of preconception, during pregnancy and postpartum, with 30.1% using both and 12% using neither. More women used oral iron-containing supplements with higher dosages during pregnancy than postpartum and preconception. The median (25th, 75th) daily dosage was 21.4 (4.6, 60.4) mg in preconception, 39.5 (7.0, 60.4) mg in the first trimester, 60.4 (18.6, 60.4) mg in the second trimester, 60.4 (29.8, 65) mg in the third trimester, and 20.9 (6.3, 60.4) mg in postpartum. Around half of women during pregnancy (42.9% in the first, 48.5% in the second and 50.5% in the third trimester), 34% in postpartum, and 38% in preconception used preventative dosage. The treatment dosage was mainly taken in the second (10.1%) and the third trimester (12.4%), and less than 1% reported high dosage intake (>200 mg). Almost all (90%) oral FeS used were prescribed, while all MMNS were self-purchased, predominately (82%) based on women’s general knowledge either alone (49.5%) or in combination with other reasons such as information from the internet, books or newspapers; or it was recommended by family or friends or a nutritionist (32.5%). Conclusion: Oral iron-containing supplements were frequently used around pregnancy. Women took a wide range/array of brands of oral iron-containing supplements, which varied markedly in the amount of elemental iron they contained. The number of women who used oral iron-containing supplements and their dosage align with the increased iron requirement during pregnancy and decreased needs for postpartum. The Lead Maternity Carer (LMC) played an important role in influencing the decision to use and purchase oral FeS. However, most women who took an iron-containing MMNS did so independently of their LMC. This may have resulted in them selecting a supplement containing a level of elemental iron unsuitable for their requirements. Given that an increasing number of women are choosing to take an MMNS, more research is needed to explore what factors women consider when purchasing a supplement and if it even includes elemental iron content so that they can be better informed when it comes to selecting one that will help meet their iron needs and allow them to achieve optimal iron levels around pregnancy.
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    Malnutrition risk, nutrition impact symptoms, and dietary intake in community-living head and neck cancer survivors six months to three years post-treatment : a case series : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Nutrition and Dietetics at Massey University, Albany, New Zealand
    (Massey University, 2024) Oakes, Danielle
    Background: Head and neck cancer (HNC), characterised by malignant neoplasms originating in the oral cavity, upper aerodigestive tract, the sinuses, salivary glands, bone, and soft tissues of the head and neck, is diagnosed in approximately 600 people annually in New Zealand. Although HNC is a less common cancer, it has a profound effect on almost all aspects of the lives of those affected, particularly the nutritional and social domains. This is due to the common treatment modality being surgery and/or radiotherapy, which can result in major structural and physiological changes in the affected areas, which in turn affects chewing, swallowing, and speaking (Nilsen et al., 2020). Specific nutrition impact symptoms (NIS) of HNC have been identified and are significant predictors of reduced dietary intake and malnutrition risk (Kubrak et al., 2010). Aim: We aimed to identify and describe the malnutrition risk, prevalence of NIS, and energy, macronutrient, and micronutrient intakes of community-living adult HNC survivors six months to three years post-treatment in New Zealand. Methods: Participants were recruited through virtual HNC support groups in New Zealand. A descriptive observational case series design was used. Malnutrition risk was determined using the Patient-Generated Subjective Global Assessment Short Form (PG-SGA SF). NIS were obtained via a validated symptom checklist, and dietary data was collected using a four-day food record. Results: Participants are referred to as PTP1-PTP7. PTP1 was well-nourished. PTP3 through PTP7 were categorised as mildly/suspected to moderately malnourished (PG-SGA SF scores of 2-7), and PTP2 was severely malnourished (score of 16). NIS were experienced by all seven participants, with “difficulty chewing,” “difficulty swallowing,” and “dry mouth” the most common. PTP2 scored loss of appetite, difficulty chewing, and difficulty swallowing as interfering “a lot.” Despite being well-nourished, PTP1 had inadequate energy intake (EI) (86% of their estimated energy requirement [EER]). PTP2, 3, 6, and 7 also had inadequate EI (79%, 79%, 73%, and 99%, respectively, of their EER). PTP1–PTP6 had adequate protein intake based on a range of 1.2-1.5 g/kg body weight per day, with PTP7 meeting 97% of their protein requirements. Deficiencies in dietary calcium and potassium were identified. PTP1, 2, 4, and 6 exhibited inadequate calcium intakes, corresponding to 74%, 73%, 72%, and 55% of their recommended dietary intake, respectively. PTP2, 3, and 6 demonstrated insufficient potassium intakes, reflecting 88%, 91%, and 91% of their adequate intake, respectively. Conclusion: The prevalence of malnutrition, NIS, and micronutrient deficiencies in this case series indicates an urgent need for greater long-term support for HNC survivors post-treatment and research to identify the true extent of malnutrition in this vulnerable cohort.
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    Bone density, biomarkers and nutrient intake of postmenopausal women : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Nutrition and Dietetics at Massey University, Albany, New Zealand
    (Massey University, 2024) Smith, Amanda
    Background: Osteoporosis is associated with an increased risk of bone fractures and carry a significant burden on the individual and the health care system. Of these individuals, postmenopausal women have a high risk for developing osteoporosis due to decreased oestrogen production. Objectives: This study explored the relationship between nutrient intake and bone health in postmenopausal women. Specifically, C-terminal of telopeptide of type 1 collagen (CTx-1), an indicator of bone turnover, and bone mineral density (BMD) were analysed in relation to the identified nutrient patterns. Correlations with additional markers associated with bone metabolism, parathyroid hormone (PTH), BMD, and vitamin D, were also examined. Method: The present study was an analysis using baseline data from the COPES 4 Bones project. Eighty seven postmenopausal women participated (aged 48-77). Questionnaires were used to obtain participant demographics and physical activity levels. A three-day food record was self-reported by the participants. BMD was measured using dual x-ray absorptiometry. Weight, height and BMI were measured using standard techniques. Fasted venous blood samples were collected to measure CTx-1, 25-hydroxyvitamin D3, and PTH. Nutrient patterns were derived from 3-day food records using principal component analysis. Linear regression was used to explore the association between BMD and the nutrient patterns. Age, weight, serum vitamin D, and physical activity were confounders in the model. Results: Four nutrient patterns were identified from the data. Nutrient pattern 1 (NP1) was characterised by high amounts of phosphorus, protein, zinc, and niacin equivalents. Nutrient pattern 2 (NP2) was characterised by high amounts of dietary fibre, magnesium, potassium and a low amount of saturated fat. Nutrient pattern 3 (NP3) was characterised by high amounts of monounsaturated fat, vitamin E, polyunsaturated fat and a low amount of carbohydrates. Nutrient pattern 4 (NP4) was characterised by high amounts of alpha carotene and beta carotene. One significant negative correlation was identified between NP2 and hip BMD without consideration of confounders. Conclusion: The current study identified NP2 as a potential factor contributing to bone health in a model exclusive of confounders such as weight and age. The research found weight to be positively associated with BMD. While dietary patterns were not explicitly studied, a diet consisting of high fruit and vegetable intake may be inferred from the characteristics of NP2. A negative relationship between a diet of this form and BMD challenges previously reported findings in postmenopausal women. Therefore, this work prompts future research to better characterise the role of nutrient intake in modulating bone health.
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    Dietary intake and food sources of omega-3 polyunsaturated fatty acids of vegans living in New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Human Nutrition, Massey University, Albany, New Zealand
    (Massey University, 2024) Li, Feiran (Fiona)
    Background: The vegan diet, which excludes all animal products, poses a high risk of inadequate intake of n-3 long-chain polyunsaturated fatty acids (n-3 LCPUFAs). N-3 LCPUFAs are essential for cardiovascular health, cognitive function, and inflammatory regulation. There is currently limited evidence on the dietary intakes and food sources of n-3 LCPUFAs in vegans. Objective: To investigate the intake, adequacy and main food sources of n-3 LCPUFAs in New Zealand vegans. Methods: This study used a four-day food record to assess the dietary intake of 212 (155 female) New Zealand vegans including energy, total fat, polyunsaturated fatty acids (PUFAs), and omega-3 and omega-6 fatty acid intake. The study determined the adequacy of linoleic acid (LA), alpha-linolenic acid (ALA), and n-3 LCPUFAs by comparing intakes with the New Zealand National Health and Medical Research Council (NHMRC) recommended intakes and calculated the proportion of each fatty acid in the total intake. The main food sources of n-3 LCPUFA were also determined. Results: Mean energy, total fat, polyunsaturated fatty acid, and LA intakes were significantly higher in males than in females, whereas there were no significant differences in intakes of n-3 LCPUFAs, ALA, EPA, DPA, and DHA. Most participants had adequate intakes of LA and ALA, but only a few women met the Adequate Intake (AI) for n-3 LCPUFA. The main food sources were nuts and seeds, mixed dishes and grains, while seaweed dominated EPA and DHA intake. Conclusion: The majority of the participants in this study had inadequate n-3 long-chain polyunsaturated fatty acid intakes. It may be necessary to optimise the dietary intake of n- 3 long chain fatty acids encouraging the consumption of foods rich in these nutrients.
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    Gut health in New Zealand vegans : the relationship between dietary fibre and gastrointestinal symptoms : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Nutrition and Dietetics, Massey University, Albany, New Zealand
    (Massey University, 2024) Corkindale, Chelsea
    Background: Dietary guidelines recommend adequate dietary fibre intake to support normal laxation and gastrointestinal (GI) health. However, excess intake of some fibre types may lead to the onset of gaseous GI symptoms. Internationally, many vegans exceed the dietary fibre recommendations; however, no studies have investigated its link to reports of GI symptoms. Meanwhile, the gut health and dietary fibre intake of NZ vegans have not been investigated; thus, research is needed. Aim: To investigate the relationship between dietary fibre intake and gastrointestinal symptoms among NZ Vegans. Methods: As part of the Vegan Health Research Programme, this cross-sectional study recruited adults aged ≥18yrs who had followed a strict vegan diet for at least two years. Health and demographic data were obtained from questionnaires. Participants completed a 4-Day Food Record to investigate dietary fibre intake, which was compared to the NZ median intake and Nutrient Reference Values (NRVs) for the dietary fibre Adequate Intake (AI) and Suggested Dietary Target (SDT) recommendations. A Gastrointestinal Symptom Rating Scale (GSRS) questionnaire was completed by the participants to investigate the prevalence and severity of GI symptoms. A binary logistic regression analysis was conducted to determine whether there was a correlation between GSRS outcomes and dietary fibre intake. Results: Across the GSRS domains, no correlations were found between dietary fibre intake and reports of GI symptoms due to minimal variance in vegans' GSRS scores. Overall, participants (n= 212) reported minimal GI symptoms, ranging on average from ‘no discomfort – minor discomfort’ (GSRS scores 1-2) across the GSRS domains. Females reported worse symptoms of abdominal pain (p=0.02) and indigestion (p<0.001) than males, while younger participants experienced more abdominal pain than older participants (p=0.03), as examined through modelling a binary logistic regression analysis inclusive of dietary fibre intake (g/day), sex, age and BMI. Dietary fibre intake exceeded the NZ median intake (20g/day), averaging 45.91g/day (25th, 75th percentile, 36.33 to 54.75g/day); 97% of participants exceeded the NZ NRV Adequate Intake (AI) (25-30g/day), 90% exceeded the Suggested Dietary Target (SDT) (28-38g/day). While males consumed more dietary fibre than females (52.62g/day versus. 42.24g/day), females had greater energy-adjusted dietary fibre intakes than males (22.21g/1000kcal versus. 20.54g/1000kcal). Finally, the major sources of dietary fibre were legumes, bread, fruit, oats, and vegetables. Conclusion: NZ vegans experience minimal GI symptoms, while their dietary fibre intake exceeds the NZ NRV recommendations and population median intake. Overall, there were no associations between high dietary fibre intake and reports of GI symptoms among NZ vegans.
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    Dietary calcium intake and food sources in older adults living in Auckland, New Zealand : a thesis presented in partial fulfillment of the requirements for the degree of Master of Science in Human Nutrition at Massey University, Auckland, New Zealand
    (Massey University, 2023) Kotewodeyar, Chaitra Arya Gubbi
    BACKGROUND The New Zealand population is aging. Aging notably affects bone health, and maintaining healthy bones is essential for overall mobility and physical function. Maintaining bone health can help alleviate conditions such as osteoporosis and osteoarthritis. Calcium intake is crucial for preserving bone density, muscle function, nerve impulse transmission, and hormonal activities. For older adults, adequate calcium intake is particularly important to mitigate the risk of osteoporosis and fractures, which are common in this age group. Despite its importance, many older adults often fail to meet the recommended dietary intake of calcium, leading to significant health implications. Dietary calcium can be obtained from various food sources, including dairy products, leafy green vegetables, nuts, seeds, and fortified foods. Among these dairy products are the most significant contributors to calcium intake in Western diets. However, there is limited data regarding calcium intake and food sources of calcium in older New Zealand adults. AIM This research aims to investigate calcium intake and to identify the main food items contributing to calcium intake in community-dwelling older adults (65 to 74 years) living in Auckland, New Zealand. METHODS This sub-study was undertaken as part of the REACH (Researching Eating, Activity and Cognitive Health) study, a cross-sectional study investigating dietary patterns, cognitive health and metabolic syndrome in older adults aged 65-74 years living in Auckland, New Zealand. A 4-day food diary was used to assess dietary calcium intake, and food sources contributing to calcium intake. Socio-demographic details, such as age, gender, ethnicity, education, were comprehensively recorded. Anthropometric data was collected including height and weight. Body Mass Index (BMI) was subsequently calculated based on the formula weight (kg) / height (m²). RESULTS The REACH study encompassed 371 individuals, with food diaries available for 330 participants (114 males, and 216 females). The average energy intake for males was 9374 kj/day, whereas for females, it was 7450 kj/day. Calcium intake was 877mg/day for females and 997 mg/day for males, compared with the Estimated Average Requirement (EAR) of 1100mg/day. For females 65-69 years, 30% consumed less than the EAR. This percentage was 21% for females 70-74 years, and 10 % and 12% for males 65-69 and 70-74 years, respectively. The main food source of calcium was milk and milk products for the total population (providing 273mg/day in females and 342mg of calcium/day in males), followed by cheese (157mg/day in females and 173mg/day in males), and yogurt (93mg/day in females and 127mg/day males). CONCLUSION Findings from this study reflect a high prevalence of inadequate dietary calcium intakes, particularly in females aged 65 to 74 years living in Auckland, New Zealand. Dairy products provided the most calcium within these participants’ diets. Further research is needed to determine appropriate ways to optimize the calcium intake in older adults who have a low intake of calcium.
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    Determinants of iron status in vegans living in Auckland, New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Nutrition and Dietetics, Massey University, Albany, New Zealand
    (Massey University, 2023) Dunnett, Amelia
    Background: A vegan diet has many health benefits; however, certain nutrients are not available in sufficient quantities or are less bioavailable in plant food. One example is iron, presenting a risk for iron deficiency (ID). Research on iron intake and status in vegans is limited and has not been explored in a NZ vegan sample population. Objectives: To investigate iron intake and status in a NZ vegan sample population. As well as exploring risk for ID and potential risk factors for iron depletion in this sample population. Methods: Vegans living in Auckland, NZ were recruited. Nutrient intake was gathered through participant-completed four-day food records (4D-FR). Biomarkers of iron status were measured including Serum ferritin (SF), haemoglobin (Hb), serum iron, iron-binding capacity (TIBC) and transferrin saturation (TSAT). Health, demographic and lifestyle factors were assessed through questionnaires. Participants were grouped as ID (SF <30µg/L) and iron sufficient (SF ≥30µg/L) and the differences between groups were assessed. Results: Vegan males and females (n=212) aged 19-75 years participated. Mean iron intake was above estimated average requirements (EAR) and recommended dietary intake (RDI) for males and above EAR for females. The prevalence of ID was 47.3% overall. Significantly higher rates of ID were found in females (F) (58.7%) compared to males (M) (15.4%) (p≤0.001). In all participants, being female (p≤0.001), younger age (p≤0.001), a previous diagnosis of iron deficiency (p≤0.001), and blood donation within the last six months (p=0.004) were potential risk factors of ID. In females, being younger (p≤0.001), blood donation within the last six months (p=0.025), and still menstruating (p=0.010) were significant potential risk factors of ID. In males, energy (p≤0.001), protein (p=0.004), dietary fibre (p≤0.001), iron (p=0.001), calcium (p=0.003) and vitamin C (p=0.006) intake was significantly higher in ID (n=6) compared with iron sufficient (n=41) males. No significant differences in dietary intake were observed between ID and iron sufficient females. Conclusion: Nearly half of the vegan sample was ID, with over half of vegan females ID. Iron deficiency was most prevalent in females, younger individuals, those previously diagnosed with ID and those that had donated blood within the last six months. Dietary intake was only found to be associated with ID in males and not females. This study has provided novel insights on the risk of ID for vegans living in New Zealand.
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    The nutritional status of long-term Home Enteral Nutrition (HEN) patients of Te Whatu Ora Counties Manukau : a focus on energy, macronutrients, vitamin D, and selenium : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Nutrition and Dietetics at Massey University, Albany, New Zealand
    (Massey University, 2024) Soljan, Emma
    Background: Good nutritional status is important for well-being and reduced morbidity and mortality risk and pressure on healthcare systems. Despite being under the care of dietitians, home enteral nutrition (HEN) patients may be at risk of malnutrition and macro- and micronutrient deficiencies. It is important to understand the nutritional status of these patients to recommend appropriate feeding and nutrient monitoring practices. Aim: To investigate the nutritional status (energy, macronutrients, vitamin D, selenium) of long-term home enteral nutrition (HEN) patients in Counties Manukau, New Zealand to determine the prevalence of malnutrition. Methods: Data were collected from 42 long-term (≥4 weeks) HEN patients (18+ years) under the care of Te Whatu Ora Counties Manukau. Enteral and oral intake were collected through 5 x 24-hour recalls and compared against patients’ prescriptions and estimated requirements (energy, macronutrients, vitamin D, selenium). Clinical signs of deficiency were assessed with a physical assessment (n=40), and nutritional biomarkers from a blood sample (n=22). Body composition was measured with bioelectrical impedance analysis (BIA) (n=29). Malnutrition prevalence was determined by the Global Initiative on Malnutrition (GLIM) criteria. Data were described by mean ± SD, geometric mean (95% confidence intervals), median (interquartile range), and frequencies. Independent t-tests, Mann-Whitney, and Chi-square tests were used to compare data by feeding route and prescription adherence. Results: Malnutrition prevalence was 62.5% (n=25). Prevalence of low BMI and fat free mass index (FFMI) was 47.5% and 44.8% respectively. Mean body mass index (BMI) (21.1 ± 3.6 kg/m²) was low but normal. Fat and/or muscle wasting occurred in at least 35%. Energy and/or protein intake was inadequate in 20% (n=8). Mean plasma vitamin D (143.55 ± 55.35 nmol/L) and selenium (1.37 ± 0.19 µmol/L) were within range with no evidence of deficiency, serum/plasma concentrations were high in 40% and 38.1% respectively. Mean vitamin D intake (13.2 ± 5.3 µg) was low in 26.2% (n=11) but met requirements for all age groups except ≥70 years. Mean selenium intake (95.0 ± 28.1 µg) was low in 7.1% (n=3) but met requirements for all. There were significant differences in nutritional status measures by feeding route and/or prescription adherence. Conclusions: Many HEN patients had poor energy and protein status but maintained good vitamin D and selenium status. Adjustments to feeding practices regarding energy and protein, and more frequent monitoring of malnutrition may be beneficial for prevention of morbidity and mortality.
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    Validation and reproducibility of an iodine and selenium specific food frequency questionnaire in breastfeeding women : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Nutrition and Dietetics at Massey University, Albany, New Zealand
    (Massey University, 2023) Bertasius, Charlotte
    Backgrounds: New Zealand has poor levels of iodine and selenium in its food sources. During lactation, women have increased selenium and iodine requirements, as their breastfeeding infant relies on their intake, putting them at increased risk of deficiency. Thyroid function is impacted by iodine and selenium status, and if these nutrients are low can cause consequences for the mother and breastfed infant. Dietary assessment methods, such as a Food Frequency Questionnaire (FFQ), can be utilised to assess nutrient intake, and validating an FFQ shows that the questionnaire can be used on the intended population to predict nutrient intake. To the best of our knowledge, New Zealand currently does not have a valid iodine and selenium specific FFQ for breastfeeding women. Due to this population risk with iodine and selenium, it is justified to test the validity and reproducibility of this FFQ on breastfeeding women in New Zealand. Aim: The aim of this study is to assess the validity and reproducibility of an iodine and selenium specific Food Frequency Questionnaire for breastfeeding women living in New Zealand. Methods: As part of the Mother and Infant Nutrition Investigation study (MINI), data was collected from breastfeeding mothers from three months to 12 months postpartum (PP). Participants (n = 87) were administered an iodine and selenium specific FFQ at three months and a four-day diet diary (4DDD). To assess reproducibility the FFQ was readministered at 12 months PP (FFQ2). FFQ1 was validated via 4DDD and selected biomarkers (urinary and breastmilk iodine concentrations and plasma selenium); statistical analysis was used, including Wilcoxon signed ranked test, Spearman’s correlation, cross-classifications, weighted kappa statistics, Bland Altman plots, the same statistical analysis carried out to assess reproducibility between FFQ1 and FFQ2. Results: For the validation, the correlation observed ranged from 0.317 (selenium) to 0.532 (total iodine) between the FFQ and 4DDD and for FFQ to EIB, 0.146 (selenium) and 0.155 (total iodine). Cross-classifications majority of the nutrient groups were >50% correctly classified (32.9% (selenium) to 71.6% (iodine food only)) when comparing the FFQ to 4DDD. Most of the groups were <10% misclassified (1.37% (iodine and salt) to 11.0% (selenium)). For the FFQ to EIB, the correctly classified participants were 50% (iodine) and 73.1% (selenium), and the grossly misclassified participants were 16.35% (iodine) and 3.4% (selenium). For FFQ to 4DDD, the weighted kappa values showed poor agreement (k<0.21) for two groups and fair agreement (k 0.21-0.41) for three groups. For EIB, the weighted kappa showed poor agreement (k<0.21) for four groups and fair agreement (k 0.21-0.41) for one. The Bland-Altman plots showed fair agreement for the difference between FFQ1 to 4DDD or EIB. For reproducibility, the correlation between FFQ1 and FFQ2 was 0.625 (iodine) and 0.429 (selenium). Cross-classification for correctly classified participants was >50% for iodine; for selenium and iodine, <10% were grossly misclassified. The weight kappa value showed poor agreement (k0.21) for both iodine and selenium. Conclusion: The FFQ showed reasonable validity when assessing iodine and selenium intake using the FFQ for breastfeeding women in New Zealand and showed good reproducibility for iodine and selenium. This FFQ could be used in future research on this population and could be used in primary care as a convenient way to assess iodine and selenium intake for breastfeeding women in New Zealand.
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    Investigating the eating behaviours of free-living low-carbohydrate diets users in New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Nutrition and Dietetics, Massey University, Albany, New Zealand
    (Massey University, 2024) Nunn, Chloe
    Background: Many individuals adopt a low-carbohydrate (low-CHO) diet as a weight management approach. Eating behaviours are a crucial determinant of dietary intake and health, however, their relation to low-CHO diet users has scarcely been assessed. Aim: This study aimed to investigate the body compositions, dietary intakes, and eating behaviours of free-living, self-reported low-CHO diet users in NZ and how they differed between CHO intake groups. Methods: This cross-sectional study recruited men and women aged 20-45 years following a low-CHO diet for at least four months. Participants completed a health and demographics questionnaire, the Three-Factor Eating Questionnaire (TFEQ), a 4-day weighed dietary record, and provided anthropometric measurements. Participants were grouped into three CHO intake ranges defined as moderately low (ML) (>100 and <150 g/day) (n=10), low (L) (≥50 and <100 g/day) (n=20), and very-low (VL) (<50 g/day of CHO) (n=39). Results: Sixty-nine individuals with a mean age of 35 years participated in this study. Their mean macronutrient intakes as a contribution to total energy were 12.5 ± 8.28% for CHO, 58 ± 11.3% for total fat, 22.6 ± 6.98% for saturated fatty acids (SFA), and 24.5 (23.3-25.9) % for protein. Total fat and SFA (%EI) increased as CHO intake decreased, while protein intake was similar in each CHO group. They had a mean body fat percentage (BF%) of 27.9 ± 9.9% and a median muscle mass of 28.0 [25.2-33.2] kg. Body composition was similar in each CHO group. Overall, participants showed high restraint, low rigid and flexible restraint, low disinhibition, low habitual, situational, and emotional disinhibition, low hunger, and low internal and external hunger. TFEQ scores did not differ significantly between CHO groups. Restraint was positively associated with CHO (%EI) (r = 0.34, p = <0.01) and inversely associated with total fat (r = -0.35, p = <0.01) and SFA (%EI) (r = -0.31, p = 0.01). CHO intake (%EI) was positively correlated with rigid restraint (r = 0.27, p = <0.01) and flexible restraint (r = 0.34, p = <0.01). Restraint correlated with BF% (r = 0.28, p = 0.02), and each increasing restraint score predicted a 0.6% increase in BF%. As diet duration increased, BMI (r = -0.27, p = 0.03), WC (r = -0.28, p = 0.03), and habitual disinhibition (r = - 0.27, p = 0.03) decreased. Conclusions: Our findings suggest that low-CHO diet users exhibit high dietary restraint, low disinhibition, and low hunger. Restraint may increase as CHO intake increases and fat intake decreases. BF% was accompanied by high restraint. It is important to consider the associations eating behaviours can have with dietary intake and body composition in low-CHO diets in determining the suitability of such a diet.