10: Lactation + Protein Flashcards
Oxytocin stimulates…
Milk let down (release)
Prolactin stimulates…
Milk production
How long should infants be exclusively breast fed?
6 mths
Are there benefits to breast feeding while HIV positive?
Transmission not especially high. Breast milk protective against infection. If using infant formula from powder, additional risk of water contamination to consider.
Why is there more weight gain in bottle fed infants over breast fed infants?
Tendency to get the baby to finish up the bottle, overriding the satiety signal. Can pose an increased risk of obesity later in life.
How are oligosaccharides different than your typical carb?
Usually linked sugars with some sort of nitrogen containing element. Indigestible, and instead bind to the gut wall to act as a decoy and bind up viruses and bacteria that could otherwise cause infection.
What are the three sources of milk components?
Maternal plasma (ex FAs), synthesized from maternal secretory cells (alveolar) from maternal plasma precursors, synthesized from other mammary cells in situ
What is the first stage of milk production? What gives it it’s characteristic colour? What are some properties?
Colostrum (first 3-7 days). Yellow because of beta carotene components. Higher protein and mineral content. Has a laxative effect which can help move the meconium plug if stuck.
“Passive immunity”
Antibodies transferred from mother to infant to make up for infants immature immune system.
What is necrotizing enterocolitis?
Overstimulation of colon destroys tissue, accounts for a high degree of mortality in preterm infants. Oligosaccharides will help protect against.
How is transitional milk different than mature milk?
In transitional milk, seeing protein drop relative to lactose and fat (which are increasing). When stabilize, that is mature milk.
How does breast milk promote growth and maturation of the GI tract?
Growth factors and hormones allow maturation and tightening of gap junctions so no longer leaky gut.
When are immunological factors of breast milk the highest?
In colostrum. Drop as infant begins to develop a more mature immune system and gain the ability to fight infections.
Are immune factors available in infant formula or cows milk?
Not in infant formula, at much lower levels and different proportions in cows milk.
Why are whey proteins resistant to digestion? Why is this an advantage?
Disulphide bonds. Can maintain immunomodulating factors in the gut.
What is the antibody found in the highest proportion in breast milk? How is it formed?
IgA. B cells travel to mammary gland to form plasma cells that produce IgA. Especially protective because B cells originate from maternal sites where pathogen exposure is high (gut and lungs).
Bifidus factor
Nitrogen containing oligosaccharide which promoted the growth of lactobacilli
Lysozymes
Break down proteoglycans, which are in high concentrations in gram neg bacteria which tend to be pathogenic.
Apart from out competing pathogenic bacteria, what additional benefit does healthy bacteria have in protecting against infection?
Production of short chain fatty acids combat infectious bacteria
Lactoferrin (2 functions)
Competes with siderophilic (iron absorbing) bacteria for iron, when iron is bound becomes similar to heme iron and can be absorbed (making iron in breast milk very bioavailable).
Lactoperoxidases
Kill streptococci and enteric bacteria
What immune components to macrophages synthesize?
Complement (combats viruses), lactoferrin, lysosyme. Also carries out phagocytosis.
Where are secretory IgA and other immunoglobulins produced?
Lymphocytes
Fibronectin protein
Enhances phagocytosis (tags). Similar to complement.
What hormones stimulate synthesis of intestinal enzymes and maturation of gut mucosa?
Cortisol, thyroxine, insulin.
Prostaglandins (2 functions)
Stimulates mucus secretion and cell division
Polyamines
Growth factors which increase cell replication
What important function do caseins play?
Form complexes in micelles with Ca, Mg, and phosphates. Can maintain higher concentrations of these important minerals to assist bone growth.
Is the whey: casein ratio the same in human and cows milk?
No. Human 60:40, cows 40:60
What negative effect is linked with cows serum albumin? Beta-lactoglobulin? IgG?
Serum albumen has a similar epitope to what is seen on the pancreas cells, so may be linked to type I diabetes. Beta-lactoglobulin suspect for creating milk allergy. IgG linked with colic.
What is the importance of taurine in breast milk?
Important for eye development, acts as a neurotransmitter, needed for bile acid conjugation.
When are elevated methionine levels seen in infants? Is this an issue?
Cystathionase enzyme (converts methionine to cysteine) can be late to develop, especially in premature infants. Methionine is the most toxic amino acid and can be neurotoxic.
How often do cows milk allergies occur in infants? How long does the allergy last?
2.7-5% of infants. usually grow out of it. Caused by leaky gut usually.
How does IgA aid in preventing development of allergies?
Blocks whole proteins from being absorbed by binding to them, causing a mucus release, and leading to the breakdown of the proteins.
When are lipopolysaccharides present and how do they relate to allergy development?
Present with higher concentrations of pathogenic gram neg bacteria. Causes greater leakiness of the gut and enhances the risk of allergies and infections.
What is Heiner’s syndrome?
Immune system reaction to unheated cows milk that leads to blood loss in the GI tract + iron deficiency anemia, and failure to thrive (downward deviation in linear growth and weight).
What effects does iron deficiency anemia have on an infant? What can be done to prevent it?
Because iron is critical for brain development, there will be a permanent reduction in brain function from anemia during the first year of life ( can not compensate for later). When introduce foods, now recommendations include introducing meat at 6 mths old specifically to meet iron requirements.
What is a possible explanation for poor suckling response in infants?
Neurologically impaired infants may have a poor suckling response.
How is ovulation suppressed during breast feeding?
Increased levels of estrogen and progesterone and increased levels of prolactin. Oxytocin contributes to this balance.
How does human breast milk protein content compare to other animals milk in terms of quantity?
One of the lowest protein concentrations, which corresponds to human slow growth rate.
How does a higher whey protein to casein ratio make human breast milk easier to digest?
Whey is softer and more digestible than curd. Acidity and pepsin secretion is immature in newborns, so have a harder time breaking down casein.
How are Ca and Zn made more bioavailable in breast milk?
Lactalbumin (metaloenzyme and whey protein).
How does mineral bioavailability in soy milk compare to breast milk?
Poorer for Zn, Ca, and Fe because of phytic acid protein complexes.
