Achievement of dietary fatty acid intakes in long-term controlled intervention studies: approach and methodology

Objective: To describe the calculations and approaches used to design experimental diets of differing saturated fatty acid (SFA) and monounsaturated fatty acid (MUFA) compositions for use in a long-term dietary intervention study, and to evaluate the degree to which the dietary targets were met. Design, setting and subjects: Fifty-one students living in a university hall of residence consumed a reference (SFA) diet for 8 weeks followed by either a moderate MUFA (MM) diet or a high MUFA (HM) diet for 16 weeks. The three diets were designed to differ only in their proportions of SFA and MUFA, while keeping total fat, polyunsaturated fatty acids (PUFA), trans-fatty acids, and the ratio of palmitic to stearic acid, and n-6 to n-3 PUFA, unchanged. Results: Using habitual diet records and a standardised database for food fatty acid compositions, a sequential process of theoretical fat substitutions enabled suitable fat sources for use in the three diets to be identified, and experimental margarines for baking, spreading and the manufacture of snack foods to be designed. The dietary intervention was largely successful in achieving the fatty acid targets of the three diets, although unintended differences between the original target and the analysed fatty acid composition of the experimental margarines resulted in a lower than anticipated MUFA intake on the HM diet, and a lower ratio of palmitic to stearic acid compared with the reference or MM diet. Conclusions: This study has revealed important theoretical considerations that should be taken into account when designing diets of specific fatty acid composition, as well as practical issues of implementation.

The effects of maternal postnatal depression and child sex on academic performance at age 16 years: a developmental approach

Background: Postnatal depression (PND) is associated with poor cognitive functioning in infancy and the early school years; long-term effects on academic outcome are not known. Method: Children of postnatally depressed (N = 50) and non-depressed mothers (N = 39), studied from infancy, were followed up at 16 years. We examined the effects on General Certificate of Secondary Education (GCSE) exam performance of maternal depression (postnatal and subsequent) and IQ, child sex and earlier cognitive development, and mother–child interactions, using structural equation modelling (SEM). Results: Boys, but not girls, of PND mothers had poorer GCSE results than control children. This was principally accounted for by effects on early child cognitive functioning, which showed strong continuity from infancy. PND had continuing negative effects on maternal interactions through childhood, and these also contributed to poorer GCSE performance. Neither chronic, nor recent, exposure to maternal depression had significant effects. Conclusions: The adverse effects of PND on male infants’ cognitive functioning may persist through development. Continuing difficulties in mother–child interactions are also important, suggesting that both early intervention and continuing monitoring of mothers with PND may be warranted.

Teaching assistants and pupils' academic and social engagement in mainstream schools: insights from systematic literature reviews

The last 20 years have seen a huge expansion in the additional adults working in classrooms in the UK, USA, and other countries. This paper presents the findings of a series of systematic literature reviews about teaching assistants. The first two reviews focused on stakeholder perceptions of teaching assistant contributions to academic and social engagement. Stakeholders were pupils, teachers, TAs, headteachers and parents. Perceptions focused on four principal contributions that teaching assistants contribute to: pupils’ academic and socio-academic engagement; inclusion; maintenance of stakeholder relations; and support for the teacher. The third review explored training. Against a background of patchy training provision both in the UK and the USA, strong claims are made for the benefits to TAs of training provided, particularly in building confidence and skills. The conclusions include implications for further training and the need for further research to gain an in-depth understanding as to precisely the manner in which TAs engage with children.