Dietary intervention increases the size of the baby at birth

What you need to know:

There is evidence that dietary intervention during pregnancy can increase the size of the baby at birth. Interventions providing food and fortified food products or targeting pregnant women who are underweight, nutritionally at-risk or from a low income country are the most promising strategies to increase the size of the baby at birth. However, size is just a surrogate marker for other health and economic outcomes. Further large high-quality randomised controlled trials investigating combination dietary intervention and micronutrient provision from food are needed. Future trials spanning preconception, the duration of pregnancy and even between pregnancies are needed to advance our understanding of optimal maternal nutrition for maternal-child health.

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What this research is about:

Nutrition before conception and during pregnancy is important to ensure a healthy pregnancy outcome. Research has demonstrated the importance of diet as a prevention strategy for some adverse neonatal outcomes, particularly the role of folic acid for the prevention of neural tube defects. However, there is a clear need to identify the best dietary interventions for pregnant women aimed at preventing adverse neonatal and infant outcomes. The aim of this study was to synthesise the best of the available evidence by conducting a systematic review and meta-analysis to determine whether dietary interventions before or during pregnancy have any effect on neonatal or infant outcomes.

What did the researchers do:

A systematic review was conducted without date restrictions. Randomised controlled trials evaluating whole diet or dietary components and pregnancy outcomes were included. Two authors independently identified articles for inclusion and assessed methodological quality. Meta-analysis was conducted separately for each outcome using random effects models. Results were reported by type of dietary intervention: (i) counselling, (ii) food and fortified food products, or (iii) combination (counselling + food); and collectively for all dietary interventions. Results were further grouped by trimester when the intervention commenced, nutrient of interest, country income and body mass index.

What did the research find:

Of the 2326 abstracts screened, a total of 29 randomised controlled trials (31 publications) were included in this review, which included 10,026 participants. Results indicate that food or fortified food products increase birth weight (by approximately 125g) and reduce the incidence of low birth weight (by approximately 27% decrease in odds). Combining all dietary interventions, both increase birth weight and reduce the incidence of low birth weight (62g and 24% decreased odds respectively), and increase length (0.07cm). In sub-group analyses the largest gains in birth size are made in underweight and nutritionally at-risk populations, in both high and low income countries, and dietary interventions that focus on macronutrients.

How can you use this research:

This review advances our understanding of the role of nutrition for a healthy birth outcome. Providing nutrition education as well as food or fortified food products to pregnant women, particularly those who are underweight, at nutritional risk, or come from a low income country, is likely to increase the size of the baby at birth with important health and financial ramifications.

Contact person: Ellie Gresham ellie.gresham@uon.edu.au

Citation: Gresham, E., Byles, J.E., Bisquera, A., & Hure, A.J. The effects of dietary interventions on neonatal and infant outcomes: a systematic review and meta-analysis. American Journal of Clinical Nutrition. 2014.

Who is meeting fruit and vegetable intake targets?

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What you need to know: “2 fruits & 5 veg” dietary target for fruit and vegetables may be a dietary strategy to overcome overweight among men, but that overweight and obese women are already adhering to these targets.

What this research is about: This study is about the association between body mass index (BMI) and habitual fruit and vegetable consumption in a large sample of 246,995 Australian adults aged 45 + year.

What did the researchers do: We calculated fruit and vegetable intake from validated short questions in survey, and calculated Body Max Index (BMI) by self-reported weight and height by participants. The association between fruit and vegetable intake and BMI Data was analysed using multinomial logistic regression separately for men and women.

What did the research find: Compared to people with healthy BMI, underweight men and women were less likely to meet 2 fruit and 5 veg target, or at least 5 serves of fruit or veg a day target. Overweight or obese women were more likely to meet these targets while overweight or obese men were less likely to meet these targets.

How can you use this research: This research provides insight into potential relationship between fruit, vegetable intake and weight for people aged 45 or older.

Keywords: fruit; vegetables; BMI; dietary guidelines; obesity

Contact person: Karen Charlton

Citation: Charlton, K.; Kowal, P.; Soriano, M.M.; Williams, S.; Banks, E.; Vo, K.; Byles, J. Fruit and Vegetable Intake and Body Mass Index in a Large Sample of Middle-Aged Australian Men and Women. Nutrients 2014, 6, 2305-2319.  

Dietary intervention reduces maternal blood pressure and the incidence of preterm delivery

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What you need to know:

Dietary interventions showed some small but significant differences in pregnancy outcomes including a reduction in maternal blood pressure and the incidence of preterm birth. Further high quality randomised controlled trials, investigating micronutrient provision from food, combination dietary intervention, and spanning the duration of pregnancy (inclusive of preconception) are required to identify maternal diet intakes that optimise pregnancy outcomes.

What this research is about:

The association between early life nutrition and long-term health has been of interest for decades. There is an abundance of evidence to suggest that when a woman has a good state of health and nutrition prior to and during pregnancy, there is a greater chance of a successful pregnancy and birth outcome. Inadequate nutrition during this time, particularly the first trimester, impairs fetal growth and has long-term negative consequences for the mother and developing fetus. The aim of this study was to determine the effect of dietary intervention before or during pregnancy on pregnancy outcomes.

What did the researchers do:

A systematic review was conducted without date restrictions. Randomised controlled trials evaluating whole diet or dietary components and pregnancy outcomes were included. Two authors independently identified articles for inclusion and assessed methodological quality. Meta-analysis was conducted separately for each outcome using random effects models. Results were reported by type of dietary intervention: (i) counselling, (ii) food and fortified food products, or (iii) combination (counselling + food); and collectively for all dietary interventions. Results were further grouped by trimester when the intervention commenced, nutrient of interest, country income and body mass index.

What did the research find:

Of 2326 screened abstracts, a total of 28 randomised controlled trials were included in this review, which included 8,322 participants. All studies were of positive or neutral quality according to the American Dietetic Association Quality Criteria Checklist, with 24 studies conducted in high income organisation for economic co-operation and development countries. Results indicate that dietary interventions during pregnancy, particularly dietary counselling, slightly reduce blood pressure (0.66 mmHg systolic and 2.76 mmHg diastolic) but not hypertensive disorders. Dietary interventions focusing on macronutrient intake reduce the incidence of preterm delivery (21% decrease in the odds). No other significant effects were observed for the other pregnancy outcomes.

 How can you use this research:

This review advances our understanding of the role of nutrition for a healthy pregnancy by observing small reductions in BP and slight increases in the length of gestation. Further large high-quality RCTs investigating combination dietary intervention and micronutrient provision from food are needed. Future trials beginning in preconception and spanning for the duration of pregnancy, as well as between pregnancies are needed to advance our understanding of optimal nutrition for maternal-child health.

 Keywords: diet, pregnancy, randomised controlled trial, systematic review, meta-analysis

Contact person: Ellie Gresham: ellie.gresham@uon.edu.au

Citation: Gresham, E., Bisquera, A., Byles, J.E., & Hure, A.J. The effects of dietary interventions on pregnancy outcomes: a systematic review and meta-analysis. Maternal and Child Nutrition. 2014.

Fruit a depression-buster for women

Eating two or more pieces of fruit a day can help women fight off depression

Women who eat fewer than two serves of fruit a day face a greater risk of developing depression, University of Queensland research shows.

UQ School of Population Health’s Professor Gita Mishra said the findings of a six-year study of more than 6000 Australian women revealed a clear link between fruit consumption and the development of depressive symptoms.

“We found that women who ate at least two servings of fruit a day were less likely to suffer from depression than women who ate fewer servings, even after taking into account other factors such as smoking, alcohol, body mass index, physical activity, marital status and education,” Professor Mishra said.

“We also found that eating two or more servings of fruit a day protected women from developing depression in the future.”

Professor Mishra said researchers had not found a link between vegetable intake and depression.

“More research is needed on the different effects of fruit and vegetables, but this may be because fruit has higher levels of anti-inflammatory compounds and antioxidants, such as resveratrol, which is not found in vegetables.”

She said the findings highlighted the importance of a diet high in fruit to avoid the development of depression in middle age.

“Women experience depression at about twice the rate of men, and the rate of depression is growing rapidly.

“By 2030 it is expected to be one of the world’s top three diseases, making it a priority area for public health interventions.”

Researchers surveyed participants in the Australian Longitudinal Study on Women’s Health, an Australian Government-funded project that is one of the world’s largest and longest-running studies of women’s health and wellbeing.

The research is published in the European Journal of Clinical Nutrition in a paper by Professor Mishra, UQ’s Professor Annette Dobson and the University of Sydney’s Dr Seema Mihrshahi.

Study reveals truth about diet in pregnancy

Researchers from the University of Newcastle have found there is no universal consensus on what constitutes an optimal diet for women before, during and after pregnancy, despite a glut of nutritional information being available.

Dietitian and PhD candidate, Ellie Gresham, led a team conducting the largest ever meta-analysis and systematic review of international research trials pertaining to dietary interventions for expectant mothers, dating from 1978 to 2011.

The initial search found more than 5,000 relevant articles, of which more than 2,300 were exhaustively screened. Included were studies that provided dietary counselling and/or food interventions. The collective results were then used to determine the overall effect of diet on neonatal and infant health.

“Our aim was to analyse whether dietary interventions had an effect on pregnancy, neonatal and infant outcomes,” Ms Gresham said.

“We found there was a positive effect on birth weight and a reduced incidence of low birth weight using whole foods and fortified foods as dietary interventions. Fortified foods included foods and drinks with higher levels of nutrients.”

Results of the review have now been published in the prestigious American Journal of Clinical Nutrition, accompanied by an editorial from researchers at the UK’s University of Southampton Medical Research Council Lifecourse Epidemiology Unit.

Evidence shows small babies are more likely to start life in neonatal intensive care, and maternal nutritional status can have lasting effects on offspring health and wellbeing.

“It’s an important time for both mother and child but we still can’t pinpoint what is optimal,” Ms Gresham said.

“While there are national dietary guidelines we can’t say to expectant mums that if you follow this particular diet you will have a healthy baby.

“From here, more high-quality research is needed for pre-conception diets, through pregnancy and lactation phases and finally subsequent pregnancies. This will help determine the most crucial times to pay attention to diet.”

Low birth weight affects approximately 8-10 per cent of Australia’s newborns. The research found no significant effects on other outcomes such as placental weight, head circumference and infant deaths.
Editorial author, Professor Keith Godfrey, said the review was the largest of its kind to date.

“The review provides some clues to help improve the health of the next generation, and also highlights the challenges in providing sound advice for pregnant mothers, Professor Godfrey said.

“While it is clear that diet in pregnancy can affect immediate outcomes, far less is known about diet around the time of conception or the consequences for the child’s health in later life.”

Ellie Gresham is a member of the University of Newcastle’s Priority Research Centre for Gender, Health and Ageing. The centre works in conjunction with HMRI’s Public Health Program. HMRI is a partnership between the University of Newcastle, Hunter New England Health and the community.

For more information on this publication, visit: http://ajcn.nutrition.org/content/100/5/1298.abstract

Young women becoming more active, and more stressed

Young Australian women are fatter, fitter and more fraught today than they were in the mid-’90s, according to the Australian Longitudinal Study on Women’s Health researchers.

The 17-year study, led by the University of Newcastle’s Professor Julie Byles and University of Queensland’s Professor Gita Mishra, found that 70 per cent of women aged between 18 and 23 in 2010 met Australian guidelines for physical activity, compared with 59 per cent in 1996.

Professor Mishra said that while this finding was encouraging, the percentage of overweight and obese young women was increasing.

“In 2013, 33 per cent of the young women surveyed were overweight or obese, compared with 20 per cent in 1996,” she said.

Professor Julie Byles said researchers also found that the prevalence of stress in this age group was higher than in the previous generation of young women surveyed in 1996. She said about half the young women surveyed said they had experienced high or very high psychological stress in the past year.

“The rate was even higher, 55 per cent, for women aged between 18 and 20 years, which probably reflects the stressful transition period between adolescence and young adulthood,” Professor Byles said. “Worryingly, we also found that 59 per cent of these young women had experienced suicidal thoughts in the past year, while 45 per cent had engaged in self-harming behaviour.”

Other notable findings in the report titled Health and wellbeing of women aged 18 to 23 in 2013 and 1996:Findings from the Australian Longitudinal Study on Women’s Health include:

Physical health: More than one in five young women reported frequent severe tiredness, back pain, headache or period pain, while one in four reported trouble sleeping – double the incidence reported in 1996. About one in three young women had low iron levels, and one in 25 young women had asthma.

Smoking: From 1996 to 2013, the percentage of women aged 18 to 23 who had never smoked increased from 53 per cent to 63 per cent, while there was also a substantial decline in the percentage of current smokers from one in three (32 per cent) to less than one in five (19 per cent).

Drinking: In 2013, one in four young women (26 per cent) drank alcohol weekly or more frequently (compared with 29 per cent in 1996). There was little change in drinking patterns since the 1996 survey.

Violence: One in five young women had experienced physical or sexual violence in the past 12 months while 56 per cent had experienced either form of violence at some point in their lives.

Bullying: One in five young women said they were bullied in the past 12 months while 70 per cent had been bullied at some point in their lives.

Intimate partner violence: The percentage of women who had been in a violent relationship had increased to 13 per cent in 2013, up from 11 per cent in 1996.

Impact of education: Women with less than a year 12 education fared worse in almost all categories surveyed – reporting poorer mental health; higher incidence of being bullied; more likely to have experienced intimate partner violence; more likely to have not used contraception and been pregnant at some stage; less likely to have received the Human Papillomavirus (HPV) vaccination.