Lecture 6 Flashcards
Maternal nutrition during pregnancy: energy requirements
Pregnancy is an …. state for which …… changes alter nutrient metabolism
Pregnancy is an anabolic state for which hormonal changes alter nutrient metabolism.
Pregnancy is an anabolic state for which hormonal changes alter nutrient metabolism to support
1- Fetal growth and development
2-Reproductive tissue accretion
3-Maternal Homeostasis
Most nutrient requirements increase during
pregnancy and are typically estimated by adding an increment to the non-pregnant, non-lactating requirement.
Energy needed to balance
Basal energy expenditure
Thermic effect of food
Physical activity
Basal energy expenditure
Attributed to maintenance increase over the non-pregnant state due to added metabolism of uterus and fetus and increased work of the maternal heart and lungs = 450 to 750 KJ
Thermic effect of food
remains unchanged
Physical activity
energy cost remains the same
Recommended energy intakes in the different trimesters
Increases in total energy expenditure are minor with minimal weight gain expected during the 1st trimester, energy increases recommended only in the 2nd and 3rd trimesters
around about the number energy requirements for each trimester
1st trimester- Extra energy not required
2nd trimester - 1,400 kJ/d (or 340 kcal/d)
3rd trimester- 1,900 KJ/d (or 452 kcal/d)
Long-chain polyunsaturated fatty acids
Linoleic and a-linolenic acid are essential and used to make LCPUFAs
Chain elongation/saturation enzymes are shared by both
n-3 and n-6 fatty acids with competition between substrates for these enzymes
Endogenous synthesis of …. is far more effective than ….
AA
DHA
LCPUFAS background
LCPUFAs are essential for normal fetal development, particularly neural and visual function
DHA
Is a critical component of cell membranes especially in the brain and retina (50% of total rod and outer segments)
AA
Is both a membrane component and a precursor to potent signalling molecules, the prostaglandins and leukotrienes (mediate inflammatory responses)
Fetal LCPUFA accumulation:
n-3 fatty acid deposition
n-3 fatty acid deposition in the developing fetal brain and retina initially occurs fairly slowly and then rapidly accumulates during the last trimester
Fetal LCPUFA accumulation:
Fetus has active desaturates but limited
Fetus has active desaturates but limited ability to make LCPUFAs so it is dependent on placental supply for both LCPUFAs and essential fatty acids (linoleic and a-linolenic acid)
Fetal LCPUFA accumulation:
Cord blood concentrations influenced by ….
Maternal diet
Rich supply of n-3 fatty acids during pregnancy are associated with
Reduced incidence of low birth weight
????Higher DHA and/or EPA intake=
increase GA and heavier infants
???? Significant gene-diet interaction =
FADS (homozygous minor allele) had shorter pregnancies and lighter infants such that maternal and fetal fatty acid requirements during pregnancy depend on maternal genetic variation in LCPUFA synthesis
Results from a meta analyses about n-3 fatty acids during pregnancy
DHA and EPA supplementation during pregnancy does not significantly improve cognition or development in children
The meta analyses did however find that omega 3 reduces the risk of
egg and peanut allergy
Monomethylmercury occurs
naturally in the environment and in industrial pollution accumulating in streams and seas
Monomethylmercury taken uo by ………. and higher concentrations in
aquatic organism and concentrated in fish and higher concentrations in longer living fish such as shark, ray, swordfish
An estimated ……..% of the mercury finds its way into fish originates with……..
An estimated 40% of the mervury that eventually finds its way into fish originates with coal-burning power plants and chlorine production plants
Methylmercury concerns:
Maternal methylmercury exposure is directly
related to fish consumption
Methylmercury concern
Neurotoxin; Large amounts can damage the developing nervous system of the fetus and delay mental development
what are the guidelines / advice for pregnant women
Eat longer-lived and larger fish - Less than three to four times a week
Eat school shark, southern bluefin tuna, marlin and trout- only once a week or fortnight
Bluff and pacific oysters and queen scallops can have high cadmiun - should be eaten no more than once a month
what is the most common micronutrient deficiency in pregnant women
Iron
The total cost of iron during pregnancy and therefore the requirement may be as much as……. to meet the demands
1000mg
Requirements for absorbed iron increase slowly during pregnancy
First trimester
Third trimester
1.2mg/d first trimester
5.6mg/d Third trimester
What is the RDI for pregnant women aged 14-50 per day and what is the upper limit
27mg
45mg
Low Hb indicative of moderate or severe anemia has been associated with an increased risk of……… for the infant:
LBW, SGA, preterm birth, decreased infant iron stores, and consequent impaired cognition and growth of the child
Low Hb indicative of moderate or severe anemia has been associated with an increased risk of……… for the mother:
For the mother, severe anamia may increase the risks of cardiac failure or death from peripartum hemorrhage
peripartum (occurring during the last month of gestation or first few months after delivery)
what percentage of people globally have anaemia
40%
Iron supplementation recommended by WHO and folic acid - and for who
WHO recommends routine iron supplementation of 60mg daily (plus 400 mcg folic acid) for pregnant women living in areas where malnutiriton is prevalent
when should pregnant women start taking these supplements
Taken as early as possible and throughout pregnancy
Women that take supplements during pregnancy are less likely to have
LBW babies and mean BW was more controlled
Supplements during pregnancy dont have any affect on
Preterm birth or neonatal death
Screening iron status in NZ
Iron status booking <20wks and at 26-28wks gestation
At screening if your Hb is <100 at booking
urgent indication to start oral iron supplementation and consideration of parenteral (IV) iron
Side effects iron medication
Nausea, vomiting, constipation, diarrhea, dark colored stools, and/ or abdominal distress
how to take iron supplement
Start with half the dose and gradually increase to the full dose, taking the supplement divided doses with food
Supplemental iron is available in two forms:
Ferrous and ferric. Ferrous iron salts are the best absorbed forms
Prophylactic iron supplementation in pregnancy
refers to the routine provision of iron supplements to all pregnant women, regardless of whether they have been diagnosed with iron deficiency or anemia.
In iron replete women may increase the risk of gestationsla diabetes and increased oxidative stress
Interventions aimed at preventing iron deficiency
- Food based strategies
-Iron supplementation
-Fortification of staple foods with iron
Delayed ‘optimal’ cord clamping
changing the timing from immediately after delivery to 1-3 minutes after delivery IMPROVES iron status of infant
why does the delay improve iron status
Transfer from the placenta of about 80ml of blood at 1 minute after birth, reaching about 100ml at 3 minutes
these additional volumes can supply extra iron amounting to 40-50mg/kg of body weight
Iodine
Essential for the production of thyroid hormones required for regulating the body’s metabolism and for normal growth and neurocognitive development of the fetus, infant and child.
severe iodine deficiencies cause …….
are they common or rare in NZ
Severe iodine deficiency cuases intellectual disability
rare - Due to WHO universal salt iodisation
Iodine and pregnancy
Despite mandatory bread fortification, pregnant women are still susceptible to iodine deficiency due to higher requirement
Iodine supplementation
150mcg tablet taken once a day when pregnant and breastfeeding
Vitamin A
Key nutrient in pregnancy as it plays important roles in reactions involved in cell differentiation
Is vitamin A deficiency rare or common
Deficiency is rare in industrialised countries but a major problem in developing nations and can produce malformations in fetal lungs, urinary tract and heart
Excessive intakes of vitamin A
Increase risk of fetal abnormalities
Craniofacial, cardiovascular, thymus dysfunction and microcephaly : Small ears or no ears, abnormal or missing ear canal
Vitamin D: Increased risk for pregnant people with /who
- Naturally dark skin tone
-Live south of nelson/marlborough during winter or spring
-spend limited time outdoors and/or have minimal sun exposure due to cultural or personal reasons
Vitamin D insufficiency linked to: maternal health outcomes
-Gestational health outcomes
-Pre-eclampsia
Vitamin D insufficiency linked to: Infant health outcomes
-Low birth weight
-Dental Decay
-Acute Respiratory infections
Listeria Monocytogenes
Foodborne bacteria: widely distributed yet does not cause symptoms in healthy individuals but can cause listeriosis in pregnant women and newborn infants
how does listeriosis develop
As a result of infection with listeria monocytogenes, usually from a food
what does Listeriosis cause
Causes influennza type symptoms and can result in premature labour and reduced fetal movements.
If listeriosis is not treated
it can be life threatening to fetus via infection of placenta, membranes and amniotic fluid, causing intrauterine sepsis and fetal death
Precuations
Listeria can multiply over a wide range of temperatures from 1.5 degrees to 50 degrees
Foods should be heated thoroughly to steaming hot (over 70degrees)
grows happily in refrigerated conditions at 4 degrees
pregnant women should avoid unsafe foods
Foods that are unsafe -listeria
such as:
uncooked seafood
hummus based dips and spreads
cold pre cooked chicken
raw unpasteurised milk
soft serve ice cream
soft cheese
how many infection in pregnant women are reported each year
what was the percent of mother to mother transmission
what percent did this cause fetal complications
19-30 infections
96%
83%
Toxoplasmosis
Parasitic disease cuased by toxoplasma gondii
- can cause eye or brain damage in unborn babies
Toxoplasmosis can come from
eating unwashed vegetables, undercooked meat or ready to eat meats such as salami or ham
drinking raw unpasteurised milk
cross contamination from cats
Alcohol and pregnancy
Alcohol readily passes the placenta such that fetal blood alcohol levels will be similar to maternal blood alcohol levels
Fetal alcohol syndrome (FAS)
Is most recognisable outcome of maternal alcohol drinking, first characterised in 1973
Features of FAS
Growth deficiency pf prenatal onset
Central nervous system dysfunction
A specific pattern of facial characteristics
Fetal alcohol spectrum Disorder
1- Full FAS is generally only present with exposure of fetus to regular heavy alcohol intake
2-Alcohol related neurodevelopment disorder (ARND)
3- Alcohol related birth defects (ARBD)
Alcohol recommendations: New Zealand
-Stop drinking alcohol if coud be or are pregnant
-Packaged alcohol containing more than 1.15% alcohol will be required to have a “pregnancy warning label”
-Fermented food and drinks, such as kombucha, may contain low levels of alcohol from the brewing process and should be avoided
