Nutritional Aspects Of Lactation Flashcards
What is the purpose of prolactin?
Prolactin leads to mammary gland development and to milk production.
Prolactin stimulates the synthesis of milk proteins and lactogenic enzymes.
The high prolactin level during pregnancy is not maintained after delivery.
During nursing, however, prolactin release surges after suckling
Prolactin and oxytocin are…
Essential for lactation
What is the use of oxytocin?
Oxytocin causes the release of milk into the lactiferous ducts and sinuses so that it can be removed by suckling.
This is known as milk ejection or let-down reflex.
Release of oxytocin happens after suckling but can become a conditioned response by visual stimulation or conscious thought.
Describe milk
Milk is a dispersion of
1. milk fat globules with TAGs
2. casein micelles with protein,
calcium and phosphorus
all in a phase of milk serum with lactose,whey protein, vitamins and minerals
Water: 87%
Fat: 4%, large variability
Protein:1%
Lactose: 7%
How does human milk change from colostrum, transition milk to mature milk?
- Colostrum (first milk is the best for the newborn)
- Produced during pregnancy and up to 4-5 days postpartum
- Primary functions are supporting the immune system and cellular growth • Viscous fluid with yellow color due to high vitamin A content
- Highest protein content mainly from secretory IgA and lactoferrin.
- Lower in lactose than mature milk
Human milk…
A dynamic body fluid which changes in composition
What is transition milk?
Transition milk
- Produced after first week of lactation (5-14 days postpartum)
- Protein content and secretory IgA is less than in colostrum, whereas the content of lactose, lipid, water-soluble vitamins, and calories is greater.
- The volume increases by the end of the second week postpartum
What fats are in human milk?
TAGs and cholesterol
Fatty acid composition in TAGs includes medium- and long chain fatty acids synthesized in the lactating mammary gland. TAGs are rich in oleic acid (36%) and contain PUFA (w6 > w3) from maternal diet including arachidonic acid (ARA) and DHA
W(at carbs are in human milk?
Lactose and prebiotic HMO
What proteins are in human milk?
High whey to casein ratio in comparison to cow’s milk Nutrients rich in essential and conditional essential amino acids Proteins with non-nutritive functions
What are the vitamins in human milk?
Rich in vitamin A, B-vitamins and vitamin C
Low in vitamin K and vitamin D, sunlight exposure of infant
recommended
Whaat enzymes are found in human milk?
Enzymes
- Lysozyme
- Bile-dependent lipase
- Many different enzymes, some with unknown functions
What bioactive functions are in human milk?
- Leukocytes protect the infant against infections
- Immunoglobulin secretory IgA protects mucosal surface of the intestine of the infant
- Lactoferrin, cytokines, growth factors and hormones
- Many more
Describe whey protein
• Mostlya-lactalbumin
• Easier to digest than casein. It
does not precipitate at acid pH.
• Especially rich in leucine for stimulation of protein synthesis.
Describe Casein
- Caseinmicellescontainwater, calcium and phosphorus
- Slow digestion of the protein, precipitates at acid pH (curd)
- Especially rich in proline for collagen synthesis
What milk has highest whey:casein ratio?
Highest in colostrum
What are the advantages of whey in human milk?
a. a-lactalbumin: is the predominant protein in whey and is often referred to
as the whey protein. It is rich in cysteine and tryptophan.
b. Lactoferrin: binds iron and inhibits growth of iron-dependent bacteria in the
GI tract of neonates and infants.
c. Lysozyme: is an enzyme that protects the infant against E. coli and Salmonella. It promotes the growth of healthy intestinal flora and has anti-inflammatory functions.
d. Immunoglobulins: mostly IgA which inhibits binding of pathogens, and protects the intestin
Whaat are 3 main types of infant formulas?
- Cow milk-based formula (often whey added)
- Soy-based formula (not for premature infants)
- Specialized formula (hypoallergenic or lactose-free)
Additives may include:
Lactoferrin, HMO, ARA, DHA, lutein, taurine, choline, vitamins,
and many other components dependent on the chosen formula
What is the correlation of HIV and breastfeeding?
- “The CDC and American Academy of Pediatrics recommend that in the US, where mothers have access to clean water and affordable infant formula, HIV-infected mothers completely avoid breastfeeding their infants, regardless of anti-retroviral therapy (ART) and maternal viral load.”
- “In resource-limited settings like in some parts of Afrika, the WHO recommends that HIV- infected mothers breastfeed exclusively for the first 6 months of life, and continue breast- feeding for at least 12 months, with addition of supplementation of complementary foods. These mothers should be given ART to reduce the risk of transmission through breastfeeding.”
• WHO: “Breastfeeding is one of the foundations of child health, development and survival, especially when diarrhea, pneumonia and undernutrition are common causes of mortality
among children younger than five years.
