| Concentrations of isoflavone phytoestrogens and their glucosides in Australian soya beans and soya foods
Roger A. King and Caroline M. Bignell
Abstract The possible role of the soya isoflavones in human health is of considerable interest. In this study the content of the isoflavones daidzein, genistein and glycitein in their aglycone forms and in their glucoside, malonyl glucoside and acetyl glucoside forms were measured in specific soya bean cultivars grown in Australia and in a range of soya foods. The concentrations of the isoflavones in soya bean cultivars ranged from approximately 0.5 to 1.7 mg/g, which probably reflects genetic and environmental influences. The concentration of total isoflavones in the foods ranged from just detectable to approximately 2.7 mg/g. Using our values we estimated that a serve of soya milk would provide about 20 mg isoflavones and a serve of either tofu or soya and linseed bread about 10 mg, which together would provide an amount that is similar to the estimated average daily Chinese and Japanese intake of 30 to 40 mg. In soya beans the isoflavones were present predominantly in their glucoside and malonyl glucoside forms. In soya foods the pattern of conjugates depended on the nature of the food. The acetyl conjugates were only just detectable in unprocessed soya beans, whereas canned beans and textured vegetable protein contained approximately 20% of the total in this form. In soya beans about 60% of the total was present in the malonyl form and 40% in the glucoside form, but in soya milk only about 5% was present in the malonyl form, whereas approximately 90% was in the simple glucoside form. The aglycone form was very low or undetectable in most soya foods, but it represented about one-half of the total in soya sauce. The present study provides reference values for isoflavone content of a range of Australian soya foods that should be of value to nutritionists and dietitians. (Aust J Nutr Diet 2000;57:70-78)
Vitamin E, peroxidative and non-peroxidative free radical damage markers, and sample collection timing in children and adolescents with cystic fibrosis
Neil R. Badcock, David Parsons, Rima E. Staugas, Jacqui J.E. Aldis and Richard T.L. Couper
Abstract Patients with cystic fibrosis are more susceptible than healthy children to oxidative cell injury due to both increased oxidative stress from chronic pulmonary infections and impaired absorption of anti-oxidant nutrients. Several methods of assessment of anti-oxidant status were evaluated in 31 children and adolescents with cystic fibrosis receiving regular vitamin E supplementation to determine whether one or more methods better reflect anti-oxidant status. Pre-dose ‘trough’ and three to four hours post-dose plasma vitamin E concentrations were measured with a view to determining the necessity of standardising blood collection times. Plasma vitamin E concentrations were then compared with red blood and buccal mucosal cell (BMC) vitamin E to decide which parameter is likely to reflect best vitamin E status in subjects at risk of vitamin E deficiency. Plasma and BMC vitamin E concentrations were compared with the peroxidative damage markers plasma and BMC malondialdehyde (MDA), and with plasma cis-9-trans-11-octadecadienoic acid (CTOA), an indicator of non-peroxidative damage. Mean and median concentrations of vitamin E were within the normal childhood ranges. Pre- and post-dose plasma concentrations of vitamin E, and of BMC vitamin E correlated closely, r = 0.924 and 0.895, P = 0.01 and 0.001 respectively. The coefficient of variation (%) of the patient results were within the analytical coefficient of variation. Significant correlations also were shown to exist between plasma vitamin E and red blood cell vitamin E (r = 0.859, P = 0.001) and between pre-dose plasma vitamin E and pre-dose BMC vitamin E (r = 0.547, P = 0.001). There was no correlation between plasma vitamin E and BMC MDA or between plasma vitamin E and CTOA. In contrast, BMC vitamin E inversely correlated with BMC MDA (r = –0.443, P = 0.02). These results indicate that in patients with cystic fibrosis receiving regular supplementary vitamin E, sampling either immediately pre-dose or three to four hours post-dose for plasma vitamin E determinations is acceptable. The study also demonstrated that BMC MDA may be a marker of cellular free radical damage as high concentrations correlate with reduced BMC vitamin E, a marker for the functional availability of the vitamin in respiratory tissue. Patients with cystic fibrosis may have increased free radical damage at the tissue level despite seemingly adequate concentrations of plasma vitamin E. (Aust J Nutr Diet 2000;57:79-83)
Providing breakfast at school: the NSW experience
Robyn E. Young and Peter J. Weston
Abstract This study aimed to provide insight into the proportion of schools providing breakfast, establish why breakfast was provided, describe the way breakfast was provided, and identify the factors that have led to successful and sustainable programs. This study also aimed to establish if there were differences in breakfast programs between disadvantaged and non-disadvantaged schools. A two-stage state-wide survey of New South Wales (NSW) schools was conducted in October and November 1996 by NSW Health. The first questionnaire was sent to 2616 schools (response 51.4%) and asked schools to indicate if they were currently or had previously provided breakfast. A more detailed questionnaire was sent to those schools that gave a positive response. Almost 29% of schools were providing, or had provided, breakfast at the time of survey. Approximately double the number of disadvantaged compared with non-disadvantaged schools provided breakfast. More secondary schools than primary schools provided breakfast. The provision of breakfast, but not necessarily a nutritionally-balanced breakfast, was the priority for schools surveyed. However, a nutritionally-balanced breakfast appeared to be a secondary outcome. Less than a quarter of schools conducted a planned needs assessment before commencing their breakfast program. This survey provided data for the development of guidelines entitled ‘Does your school need to provide breakfast?’ by NSW Health for NSW schools. (Aust J Nutr Diet 2000;57:84-89)
'Filling the Gap’ – children aged between six and eight years: sources of nutrition information used by families, school nurses and teachers
Veronica Graham, Kay Gibbons, Catherine Marraffa and Jane Sultana
Abstract This study aimed to identify sources of, and gaps in, nutrition information and services used by parents of children aged between six and eight years, their primary teachers and school nurses. This is the fourth part of a larger study of children from birth to eight years of age. Parents of 96 children aged between six and eight years completed a questionnaire. The children were randomly selected from 12 primary schools in Melbourne’s western metropolitan region. The grade one primary teachers and the school nurses working in the area also completed a questionnaire and participated in in-depth follow-up interviews. The results indicated that school nurses generally viewed nutrition education as an integral part of their role and were interested in ongoing professional development on paediatric nutrition. Teachers saw themselves as having a role with the children through teaching nutrition as part of the standard curriculum, but most had not received any formal training in nutrition. Sources of nutrition information used by these nurses and teachers included brochures by food companies, newspapers and magazines, and television. Both teachers and nurses requested current, culturally specific nutrition information suitable for use with parents and children. Parents of the children identified family (67%) and own knowledge (65%) as main sources of nutrition information, followed by friends (44%), doctors (40%), television and radio (39%), books (35%) and magazines (31%). Some parents (34%) requested nutrition education to occur through the school system. Dietitians potentially have a role in resourcing the food industry, the popular media as well as health professionals. (Aust J Nutr Diet 2000;57:90-94)
The potential of foods containing inulin as laxatives for older Australians – a pilot study
Wendy Hunter, Gwyn P. Jones, Helen Devereux and Alison Stewart
Abstract Inulin and oligofructose are polysaccharide food ingredients thought to have beneficial effects on human gastro-intestinal health. Benefits include the promotion of laxation but inulin and oligofructose have not been used as food ingredients specifically for this purpose. We conducted a pilot study with a small taste panel (n = 10) recruited from a Melbourne residential hostel for older people to find out if they could discriminate between control foods and foods containing between 2.5% and 10% by weight of inulin or oligofructose. Eight different foods were tested and, although subjects were able to detect a difference on more than two-thirds (44 out of a total of 64) of tastings, foods containing inulin or oligofructose were found to be acceptable (55 out of a total of 65). Meals provided by the hostel provided an average of only 17.4 g of fibre per person per day, which is less than optimal. Inulin or oligofructose could be employed as food ingredients with the potential to improve large bowel function in older Australians particularly in institutional settings. (Aust J Nutr Diet 2000;57:95-97)
Increasing n-3 PUFA intakes by dietetic means: a case study involving normal, healthy adults in the Illawarra region of NSW
Shamala C. Ratnesar, Linda C. Tapsell, Barbara J. Meyer, G. Dennis Calvert and Len H. Storlien
Abstract The omega-3 (n-3) and omega-6 (n-6) group of essential polyunsaturated fatty acids (PUFAs) has been a part of the human diet throughout the ages. However, changes in the composition of the food supply and the types of foods eaten in contemporary Western cultures have led to low intakes of n-3 PUFA and an imbalance in the ratio of n-6:n-3 PUFA. While fish and seafood are the richest source of very long chain (VLC) n-3 PUFA (eicosapentaenoic acid 20:5 n-3, docosapentaenoic acid 22:5 n-3 and docohexaenoic acid 22:6 n-3) some people do not eat fish. Other sources of VLC n-3 PUFA such as n-3 enriched eggs as well as plant sources of a-linolenic acid (18:3 n-3) such as linseeds, canola, mustard seed, walnut and soya bean oils, soya beans, baked beans, walnuts and soya and linseed bread are becoming increasingly important in the Australian diet. In this study we examined the food choices of a sample of volunteers for a dietary study in the Illawarra region of New South Wales. From this information we identified food sources of n-3 PUFA which would be suitable to recommend to this group, devised a set of practical guidelines for them to use and developed sample menu plans based on the eating patterns of the subjects. These approaches display the ways and means by which dietitians may advise individuals on how to make changes to their diets to improve n-3 PUFA intakes. (Aust J Nutr Diet 2000;57:98-103) |
Australian Journal of Nutrition and Dietetics, Volume 57, Number 2, June 2000