Lecture 6a: Maternal Nutrition Flashcards
What state is pregnancy?
an anabolic state - building
What alters nutrient metabolism in pregnant mothers?
Hormonal changes
What is a higher energy requirement in pregnant mothers needed to support?
- Fetal growth and development
- Reproductive tissue accretion
- Maternal homeostasis
What happens to basal energy expenditure during pregnancy?
Increases due to added metabolism of uterus and fetus and increased work of the maternal heart and lungs
What happens to thermic effect of food during pregnancy?
Remains unchanged
What happens to the cost of physical activity during pregnancy?
Energy cost remains the same
What is recommended energy intake during first trimester?
Extra energy not required
What is the recommended energy intake during second trimester?
1,400kJ/d (340kcal/day) added to EER of non-pregnant women
What is the recommended energy intake during third trimester?
1,900kJ/d (452kcal/d) added to EER of non-pregnant women
What are LCPUFA’s?
Long-chain polyunsaturated fatty acids
What are essential and used to make LCPUFA’s?
Linoleic (6) and a-linolenic acid (3)
What happens when we eat omega-6 and omega-3 fatty acids?
They go through cycles of desaturation and elongation
What is desaturation?
adding on double bonds
What is elongation?
adding 2 C atoms to carboxyl end of the chain
What do Omega-6 fatty acids (linoleic acid) end up as?
Arachidonic acid (AA) - one cycle
What do Omega-3 fatty acids (a-linolenic acid) end up as?
EPA and DHA
Why is more AA generated compared to EPA and DHA?
Omega 3 is more of a process, therefore less EPA and DHA are generated compared to AA
Why is there competition between substrates for n-3 and n-6 fatty acids?
Because chain elongation/saturation enzymes are shared between them
What is DHA a critical component of?
Cell membranes, especially in the brain and retina
What is AA a critical component of?
Both a membrane component and a precursor to potent signalling molecules, the prostaglandins and leukotrienes (mediate inflammatory responses)
What is fetal LCPUFA accumulation?
Fetus has active desaturases but limited ability to make LCPUFA’s so it is dependent on placental supply for both LCPUFAs and essential fatty acids - therefore accumulates over pregnancy
What is the cord blood concentration of LCPUFA’s influenced by?
Maternal diet
What happens to n-3 fatty acid deposition in brain and retina look like over pregnancy?
Occurs fairly slowly and then rapidly accumulates during the last trimester
What are sources of linoleic acid (n-6)?
Soybean, safflower, sunflower and corn oils; green leafy vegetables; nuts and seeds
What are sources of a-linolenic acid (n-3)?
Soybean, canola, flaxseed and walnut oils; nuts and seeds
What are sources of AA?
Egg yolk and meats (organ meats)
What are sources of EPA?
Fish oils, oily fish