42 resultados para Vitamins

em Deakin Research Online - Australia


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Background: Both folate and betaine are important predictors of total homocysteine (tHcy) during pregnancy. However, studies to date have only been undertaken in populations with Western dietary patterns.

Objective: We investigated the predictors of tHcy in pregnant women recruited in the Seychelles, a population where access to fortified foods is limited and where women habitually consume diets rich in fish, eggs, rice, and fruit.

Design: Pregnant women (n = 226) provided blood samples at enrollment, at week 28 of gestation, and at delivery. Cord blood was obtained from a subset of participants (n = 135).

Results:
As in other studies, maternal tHcy was lower during pregnancy than at delivery, whereas folate and vitamin B-12 status declined significantly to delivery. Despite low maternal folate status at delivery (median: 9.0 nmol/L), with 35% of women in the deficient range (serum folate: <6.8 nmol/L), cord blood folate status (median: 40.2 nmol/L) was similar to concentrations reported in Western populations. Folate was a significant predictor of tHcy at all time points (P < 0.001). In contrast with previous studies, betaine was only a significant predictor of maternal tHcy (P < 0.001) when the essential amino acid methionine was low.

Conclusions: The current study reports 2 important findings. First, fetal requirements for folate are paramount, such that cord blood folate status is maintained, even when maternal status is low. Second, betaine is a significant predictor of tHcy in pregnant women with low serum folate and low serum methionine concentrations.

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Background : Lower levels of B vitamins (particularly folate, vitamin B12 and vitamin B6) may be associated with psychological distress. Little is known about the impact of childhood nutrition on psychological distress in adult life.

Objective : We investigated whether prospectively measured childhood and adult dietary intakes of thiamin, riboflavin, niacin, folate, vitamin B6 and vitamin B12 were related to the psychological distress of women in mid-age, taking into account socio-economic, behavioural and lifestyle factors.

Design :
Prospective data were collected from a cohort of 636 British women followed up since their birth in 1946. Participants completed a 28-item, scaled version of the General Health Questionnaire (GHQ-28) to measure psychological distress at age 53 years. Dietary intakes in childhood (at age four) were determined by 24h recall and in adulthood (at age 36, 43 and 53 years) by a 5d food record.

Results : Low dietary vitamin B12 intake at age 53 was associated with higher psychological distress at that age. Women in the lowest third of vitamin B12 intake in adulthood had a higher GHQ-28 score compared with those in the highest third (percentage change, adjusted regression coefficient, 21 (95% CI 3, 39)). There were no other significant associations between dietary B vitamin intake in childhood or adulthood and psychological distress in the cohort.

Conclusions : Overall, there is evidence that intake of vitamin B12 at age 53 is related to adult psychological distress but there is no evidence for the effects of other adult B vitamin intakes or childhood intakes on psychological distress.

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Food allergy has a dramatic impact on a child's (and their family's) quality of life and places a major financial burden on the community. It has been hypothesized that the increase in food allergy may relate to the concordant rise in prevalence of vitamin D insufficiency. More recently a second hypothesis has implicated vitamin A sufficiency in the development of immune tolerance. Together, these hypotheses have prompted investigation into the circulating levels of vitamins A and D in relation to food allergy prevalence. This review aims to examine the relationship between vitamins A and D and food allergy. The first part of this review presents the available epidemiological data which proposes a dramatic increase of food allergy and related anaphylaxis during the last two decades. There is some indirect evidence that variation in food allergy prevalence within countries might be linked with ambient ultra violet radiation exposure and thus potentially with vitamin D levels. Only a few studies to date have directly examined the relationship between measured serum vitamin D levels and either food sensitization or allergy. The significance of vitamin A in food allergy prevalence is only provided through a hypothetical association due to its role in the immune system. The second part of this review discusses the relevant aspects of the analytical methods to assess vitamin A and D levels in children. The primary methods utilized relate to measuring the main circulating forms of vitamins A and D in blood i.e. retinol and 25-hydroxy-vitamin-D3 respectively. Chromatographic separation coupled with mass spectrometric detection is considered the gold standard method for both vitamins. These analytical methods should be fully validated for the use in pediatric populations to ensure they are fit for their clinical purpose.

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Cognitive benefits of multivitamins have been observed in the elderly, but fewer trials have investigated younger, healthy cohorts. This randomised, double-blind, placebo-controlled study investigated the cognitive effects of 16-week multivitamin supplementation in adults aged 20-49 years.

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Complex coacervates of gelatin and sodium hexametaphosphate (SHMP) was used to microencapsulate tuna oil fortified with the multiple functional lipophilic ingredients, vitamin A, D3, E, K2, curcumin and coenzyme Q10. An emulsion homogenization speed of 15,000 rpm for 15 min resulted in low surface oil content (0.08%), high encapsulation efficacy (99.84%) and encapsulation yield (96.59%), with a significantly enhanced oxidative stability index (6.23 h). The Fourier transform infrared spectra showed that there was no observable oxidation of the oil during microencapsulation. This study shows that microencapsulation using complex coacervation is suitable for stabilizing multiple bioactive lipophilic ingredients.

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OBJECTIVES: In widely used protocols for the collection and isolation of cord blood mononuclear cells, investigators are left with substantial volumes of diluted plasma which could be used for other measurements. The aim of this study was to ascertain the validity of umbilical cord blood (UCB) diluted plasma samples for vitamin D, A and E analysis compared to UCB serum samples. DESIGN & METHODS: Twenty UCB matched samples of diluted plasma and serum were collected. The samples were analysed by two liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods on two separate occasions. RESULTS: The results of 25(OH)D3 obtained by the two laboratories demonstrated close agreement with a mean difference of 0.14nmol/L [95% confidence interval (95% CI), -6.8 to 7.1]. Both methods demonstrate close agreement for 25(OH)D3 in UCB serum versus diluted UCB plasma; mean difference 2.2nmol/L [95% CI, -9.5 to 13.9] and 4.1nmol/L [95% CI, -14.5 to 6.1] for the results from Lab A and Lab B, respectively. Vitamin A was quantified by Lab A in UCB serum and diluted UCB plasma; mean difference 0.07μmol/L [95% CI, -0.41 to 0.28]. Results of 25(OH)D3 epimer and vitamin E in the diluted UCB plasma were below the limit of quantification, and could not be compared with UCB serum. CONCLUSIONS: Diluted UCB plasma can be used for the quantification of retinol and 25(OH)D3 by LC-MS/MS. By contrast, quantification of 25(OH)D3 epimer and vitamin E in diluted UCB plasma is not supported by this study due to limitations in analytical sensitivity.

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The aim of the study was to assess whether omega-3 polyunsaturated fatty acid supplementation alone or in combination with folic acid and B-group vitamins is effective in lowering homocysteine. The Medline Ovid, Embase and Cochrane databases were searched for randomized-controlled trial studies that intervened with omega-3 supplementation (with or without folic acid) and measured changes in homocysteine concentration. Studies were pooled using a random effects model for meta-analysis. Three different models were analyzed: all trials combined, omega-3 polyunsaturated fatty acid trials, and omega-3 polyunsaturated fatty acids with folic acid and B-group vitamin trials. Nineteen studies were included, consisting of 3267 participants completing 21 trials. Studies were heterogeneous; varying by dose, duration and participant health conditions. Across all trials, omega-3 supplementation was effective in lowering homocysteine by an average of 1.18μmol/L (95%CI: (-1.89, -0.48), P=.001). The average homocysteine-lowering effect was greater when omega-3 supplementation was combined with folic acid and B-group vitamins (-1.37μmol/L, 95%CI: (-2.38, -0.36), P<.01) compared to omega-3 supplementation alone (-1.09μmol/L 95%CI: (-2.04, -0.13), P=.03). Omega-3 polyunsaturated fatty acid supplementation was associated with a modest reduction in homocysteine. For the purposes of reducing homocysteine, a combination of omega-3s (0.2-6g/day), folic acid (150 - 2500μg/day) and vitamins B6 and B12 may be more effective than omega-3 supplementation alone.

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The adoption, in mid-1995, of the revised food Standard A9, which permits the more liberal addition of nutrients to a range of food products, highlighted the need to obtain information on nutrient intake from supplements to complement the i 995 National Nutrition Survey data on nutrient intake from food. This paper describes the method used to obtain quantitative information on nutrient supplement intake and reports on the prevalence of supplement use in different subgroups of the Australian population. Information on supplement intake was obtained in two Australian Bureau of Statistics Population Survey Monitor surveys in August 1995 and February 1996 using the Therapeutic Goods Administration (TGA) registration numbers to identify individual products. Approximately 18% of men and 29% of women aged 18 years and over reported consuming a nutrient supplement on the day before the survey and these proportions increased to 25% and 35% respectively for consumption during the two weeks before the survey. The prevalence of supplement intake increased with age, education level, socioeconomic status, employment status and with fruit and vegetable intake. The substantial proportion of Australian adults who consume nutrient supplements, and the rapidly changing composition of the Australian food supply in response to changes in food regulation, indicate that there is a need for regular monitoring of nutrient intake from supplements. The use of TGA registration numbers to identify supplements provides a practical way to address this need.

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Purpose – To examine consumers' beliefs about organic foods and their relationship with socio-demographics and self-transcendence (universal, benevolence) personal values.

Design/methodology/approach – A random questionnaire-based mail survey of 500 Australian (Victorian) adults (58 per cent response) was used. The questionnaire included items on organic food beliefs, the importance of self-transcendence values as guiding principles in life, and socio-demographics. Statistical analyses included cross-tabulations of organic food beliefs by socio-demographics and multiple regression analyses of positive organic food beliefs with personal value and socio-demographic items as the independent variables.

Findings – The majority of participants believed organic food to be healthier, tastier and better for the environment than conventional food. However, expense and lack of availability were strong barriers to the purchasing of organic foods. Generally, women were more positive about organic food than men (e.g. women were more likely to agree that organic food has more vitamins/minerals than conventional food). The personal value factor related to nature, environment and equality was the dominant predictor of positive organic food beliefs, followed by sex. These predictors accounted for 11 per cent of the variance.

Research limitations/implications – A survey response bias needs to be taken into account. However, the response rate was adequate for reporting and differences in age and education between participants and the Victorian population were taken into account in data presentation. Future understanding of consumers' use of organic foods will require the inclusion of a fairly extensive set of potential influences.

Practical implications – Communication appeals based on psychographics may be a more effective way to alter consumers' beliefs about organic foods than those based on demographic segmentation.

Originality/value – To the best of one's knowledge, this is the first study to examine the relationship between personal values, socio-demographics and organic food beliefs in a random population sample. This study is relevant to producers, processors and retailers of organic food and those involved with food and agricultural policy.

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This exploratory qualitative study examined consumers’ perceived barriers and benefits of plant food (fruits, vegetables, grains, legumes, nuts, seeds) consumption and views on the promotion of these foods. Ten focus groups were conducted in Melbourne, Australia. Groups consisted of employees of various workplaces, community group members, university students, and inner-city residents. Health-related benefits predominated, particularly relating to the properties of plant foods (e.g., vitamins). Taste, variety, versatility, and environmental benefits were also considered important. The main barriers to eating plant foods were lack of knowledge and skills and length of preparation time. The poor quality of plant foods was also an issue for consumers. Awareness of the promotion of plant foods was generally high. Participants noted that promotions require a stronger practical emphasis with a focus on quick, easy-to-prepare foods and meals. These findings provide insight into effective ways to promote a higher consumption of plant foods