27/11/2014
No Conflict
of Interest
Micronutrients in
Preconception
and Pregnancy
FULL DISCLOSURE
Personal Vested Interest
• 31.5 weeks gestation and
2 year old daughter
DR ALEXIS HURE
PhD, AdvAPD, BND (Hons I)
HMRI Public Health Postdoctoral Fellow
School of Medicine and Public Health, University of Newcastle
Professionally
• An unpaid consultant for
DANONE-Nutricia since 2009
Alexis.Hure@newcastle.edu.au
DOHaD for Doctors, 25th November 2014
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Philosophical Standpoint
Overview
1. Dietary intakes for pregnancy
Hippocrates
• “Let food be thy medicine and medicine be thy food”
• “First do no harm”
–
‘Nutritional Epi 101’
2. Public health guidelines
–
Critical appraisal
3. Mandatory fortification
–
Public health nutrition in action
4. Micronutrient supplements
–
–
Risks and benefits
Naming and shaming
5. Evidence into practice
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Nutritional Epidemiology
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Nutritional Requirements
• Under-reporting is very common
• Consumers, healthcare professionals are most familiar with
the term “RDI” - but what does this really mean?
– People change the foods they eat because they know they will be
asked about it
– Misrepresentation (deliberate, unconscious or accidental) to make
diets appear ‘healthier’ or quicker to report
– Recommended Daily Intake? XXX
– Recommended DIETARY Intake (with intakes averaged over 3-4 days)
• “RDIs exceed the actual nutrient requirements of practically all
healthy persons and are not synonymous with requirements."
• Quantitative bias analysis
– For groups: use energy cut-points (e.g. 4500-20,000 kJ/day)
– For individuals: Energy Intake to Basal Metabolic Rate (EI:BMR) ratio
• 1.55 is a normally active population (e.g. 1.27 - 2.1)
https://www.nrv.gov.au/home/introduction
• RDIs are mathematically derived: RDI = EAR +2SDEAR
– i.e. two standard deviations or twice the coefficient of variation above
the Estimated Average Requirement (EAR)
• Population-based surveys tend to under-estimate food and
nutrient intakes by around 20%
• EARs are what we should be using to:
– Australian Health Survey (2011-2012)
– examine the probability that an individual’s usual intake is inadequate
– or estimate the prevalence of inadequate intakes within a group
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Take Home Message
So are pregnant women in Australia
meeting their nutritional requirements
for pregnancy through diet?
• Don’t be fooled by:
1. Under-reported dietary data
2. Misusing RDIs
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Diet in Pregnancy
• Data from the ALSWH (2003) + AHS (2011-12) are consistent
– Almost 10 years between the two surveys
– Differences in populations (pregnant vs. all women)
– Dietary assessment methods (FFQ vs. 24 hr recall)
• Exceptions include:
– Low dietary fibre intake and low iron
– EAR for iron during pregnancy is very high:
22mg/day for pregnancy vs. 8mg/day for menstruating women
• Intakes of folic acid have increased with fortification to now
meet the EAR but this is separate to the recommendation for
preconception and first trimester supplementation
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Take Home Message
• Pregnant women in Australia are generally meeting their
nutritional requirements (as we currently understand them)
through diet alone
•
•
High fibre foods should be encouraged
– Wholegrain breads and cereals
– Vegetables and fruits
Good sources of iron include:
– Lean red meat, fish, poultry
– Eggs
– Legumes, including baked beans
– Fortified foods and beverages
• Breakfast cereals: Sultana bran, Weetbix, Special K etc.
• Milo
PUBLIC HEALTH GUIDELINES
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What you should know about this
recommendation
Folic Acid to Prevent NTD
• Supplementation with 500 mg per day for 12 weeks (or at least
1 month) pre-conception and throughout the first 12 weeks of
pregnancy
• Increase to 5 mg per day in women at high risk NTDs:
– Those with a family history or
who have had a previous pregnancy affected by NTD,
anti-epileptics,
diabetes, and
body mass index ≥30 kg/m2
• Grade A: can be trusted to guide clinical practice
– Based on a systematic review and meta-analysis of randomised
controlled trial data; the highest level evidence
• Clear clinical benefit: reduced incidence of NTD
• NT closes over ~ 6 wks gestation
– Guidelines include a buffer for potential dating inaccuracies
• Recommendations were always accompanied by a warning
that periconceptional supplementation with other vitamins
was not necessary and there was potential for harm
(for e.g. from excess vitamin A)
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What you should know about this
recommendation
Iodine for Child Cognition
From January 2010
• Pregnant and breastfeeding women are advised to take an
iodine supplement of 150 mg/day
• Women with pre-existing thyroid conditions should seek
advice from their medical practitioner before taking a
supplement
• NHMRC developed this recommendation via a review of the
literature and consultation with an expert group
– Consensus-based recommendation
– Formulated in the absence of quality evidence
• There are no 150mg iodine supplements available in
Australia to allow women to meet this recommendation
without taking a multi-nutrient preparation
• Main dietary sources:
– Fortified bread, dairy,
seafood and iodised salt
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MANDATORY FORTIFICATION
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Folic Acid Added to Foods
• 1998: Voluntary folic acid fortification of foods
• September 2009: mandatory fortification of wheat-flour used
for bread making (120-135mg FA / 100g bread)
• Expected to reduce the number of NTD-affected pregnancies
by 14 to 49 cases(or up to 14%) each year
Public Health Nutrition in Action
- A population-based safety net
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Diet and Pregnancy Outcomes
Added Iodine
• Dietary intervention during pregnancy increases birth weight
and length, and reduces the incidence of low birth weight and
preterm delivery
• Largest gains in birth size were in underweight and
nutritionally at-risk populations in both high- and low-income
countries and using dietary interventions that focused on
whole diet or macronutrients
• Salt used in bread-making (rolls, buns, etc. except organic
bread) is required to contain iodised salt
– 40-50mg iodine / 100g bread
• Under review: mandatory fortification with folic acid & iodine
http://www.foodstandards.gov.au/science/monitoringnutrients/monitoringfort/pages/default.aspx
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MICRONUTRIENT SUPPLEMENTS
Did you know…
Women taking any vitamin supplements prior to or early in
pregnancy are ~40% more likely to have a multiple pregnancy
- RR 1.38, 95% CI 1.12 to 1.70, 3 trials, n=20,986 women
Rumbold et al (2011). Vitamin supplementation for preventing miscarriage.
Cochrane Database of Systematic Reviews.
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Supplement When Needed
• When prescribing a nutritional supplement, what is the
outcome you are aiming for?
– Clinical benefit
• E.g. Reduced incidence of rickets
– Surrogate marker
• E.g. Increase in serum Vitamin D
– No evidence that routine vitamin D supplementation for healthy
women improves pregnancy outcomes but supplementation may be
beneficial in groups of women at risk of deficiency
Australian Health Ministers’ Advisory Council 2012, Clinical Practice Guidelines: Antenatal Care - Module 1.
Australian Government Department of Health and Ageing, Canberra. http://www.health.gov.au/antenatal
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Market Leaders
Evidence Into Practice
• Use supplements to correct nutritional deficiency or when
there are clinical benefits that outweigh the potential for
harm
– Not as a blanket recommendation or magic-bullet approach
• GPs can help to improve the micronutrient intakes of
pregnant women by promoting the importance of having a
good diet for pregnancy
• Food avoidance recommendations (listeria, mercury) may
cause harm by reducing micronutrient intakes from
consuming a wide variety of nutritious foods (Pezdirc, 2012, PHN)
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Refer to an Accredited Practising Dietitian for individual dietary
assessment if you or your patients are interested or concerned
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Having a baby born a good size and at the right
time is the strongest predictor of long term health
http://daa.asn.au/for-the-public/find-an-apd/
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Key Resources
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Use your BRAIN
• Australian Longitudinal Study on Women’s Health
• Australian Bureau of Statistics, Australian Health Survey Data
(2011-2012)
• Nutrient Reference Values for Australia and New Zealand
• Clinical Practice Guidelines: Antenatal Care – Module 1,
Australian Government, Department of Health and Ageing,
Canberra. http://www.health.gov.au/antenatal
• Food Standards Australia and New Zealand (FSANZ)
• National Health and Medical Research Council
• Cochrane Library of Systematic Reviews
• PubMed
B - Benefits
R - Risks
A - Alternatives
I - Intuition
N - do Nothing?
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