10: Lactation + Protein

Question 0

Oxytocin stimulates…

Answer 0

Milk let down (release)

Question 1

Prolactin stimulates…

Answer 1

Milk production

Question 2

How long should infants be exclusively breast fed?

Answer 2

6 mths

Question 3

Are there benefits to breast feeding while HIV positive?

Answer 3

Transmission not especially high. Breast milk protective against infection. If using infant formula from powder, additional risk of water contamination to consider.

Question 4

Why is there more weight gain in bottle fed infants over breast fed infants?

Answer 4

Tendency to get the baby to finish up the bottle, overriding the satiety signal. Can pose an increased risk of obesity later in life.

Question 5

How are oligosaccharides different than your typical carb?

Answer 5

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.

Question 6

What are the three sources of milk components?

Answer 6

Maternal plasma (ex FAs), synthesized from maternal secretory cells (alveolar) from maternal plasma precursors, synthesized from other mammary cells in situ

Question 7

What is the first stage of milk production? What gives it it’s characteristic colour? What are some properties?

Answer 7

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.

Question 8

“Passive immunity”

Answer 8

Antibodies transferred from mother to infant to make up for infants immature immune system.

Question 9

What is necrotizing enterocolitis?

Answer 9

Overstimulation of colon destroys tissue, accounts for a high degree of mortality in preterm infants. Oligosaccharides will help protect against.

Question 10

How is transitional milk different than mature milk?

Answer 10

In transitional milk, seeing protein drop relative to lactose and fat (which are increasing). When stabilize, that is mature milk.

Question 11

How does breast milk promote growth and maturation of the GI tract?

Answer 11

Growth factors and hormones allow maturation and tightening of gap junctions so no longer leaky gut.

Question 12

When are immunological factors of breast milk the highest?

Answer 12

In colostrum. Drop as infant begins to develop a more mature immune system and gain the ability to fight infections.

Question 13

Are immune factors available in infant formula or cows milk?

Answer 13

Not in infant formula, at much lower levels and different proportions in cows milk.

Question 14

Why are whey proteins resistant to digestion? Why is this an advantage?

Answer 14

Disulphide bonds. Can maintain immunomodulating factors in the gut.

Question 15

What is the antibody found in the highest proportion in breast milk? How is it formed?

Answer 15

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).

Question 16

Bifidus factor

Answer 16

Nitrogen containing oligosaccharide which promoted the growth of lactobacilli

Question 17

Lysozymes

Answer 17

Break down proteoglycans, which are in high concentrations in gram neg bacteria which tend to be pathogenic.

Question 18

Apart from out competing pathogenic bacteria, what additional benefit does healthy bacteria have in protecting against infection?

Answer 18

Production of short chain fatty acids combat infectious bacteria

Question 19

Lactoferrin (2 functions)

Answer 19

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).

Question 20

Lactoperoxidases

Answer 20

Kill streptococci and enteric bacteria

Question 21

What immune components to macrophages synthesize?

Answer 21

Complement (combats viruses), lactoferrin, lysosyme. Also carries out phagocytosis.

Question 22

Where are secretory IgA and other immunoglobulins produced?

Answer 22

Lymphocytes

Question 23

Fibronectin protein

Answer 23

Enhances phagocytosis (tags). Similar to complement.

Question 24

What hormones stimulate synthesis of intestinal enzymes and maturation of gut mucosa?

Answer 24

Cortisol, thyroxine, insulin.

Question 25

Prostaglandins (2 functions)

Answer 25

Stimulates mucus secretion and cell division

Question 26

Polyamines

Answer 26

Growth factors which increase cell replication

Question 27

What important function do caseins play?

Answer 27

Form complexes in micelles with Ca, Mg, and phosphates. Can maintain higher concentrations of these important minerals to assist bone growth.

Question 28

Is the whey: casein ratio the same in human and cows milk?

Answer 28

No. Human 60:40, cows 40:60

Question 29

What negative effect is linked with cows serum albumin? Beta-lactoglobulin? IgG?

Answer 29

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.

Question 30

What is the importance of taurine in breast milk?

Answer 30

Important for eye development, acts as a neurotransmitter, needed for bile acid conjugation.

Question 31

When are elevated methionine levels seen in infants? Is this an issue?

Answer 31

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.

Question 32

How often do cows milk allergies occur in infants? How long does the allergy last?

Answer 32

2.7-5% of infants. usually grow out of it. Caused by leaky gut usually.

Question 33

How does IgA aid in preventing development of allergies?

Answer 33

Blocks whole proteins from being absorbed by binding to them, causing a mucus release, and leading to the breakdown of the proteins.

Question 34

When are lipopolysaccharides present and how do they relate to allergy development?

Answer 34

Present with higher concentrations of pathogenic gram neg bacteria. Causes greater leakiness of the gut and enhances the risk of allergies and infections.

Question 35

What is Heiner’s syndrome?

Answer 35

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).

Question 36

What effects does iron deficiency anemia have on an infant? What can be done to prevent it?

Answer 36

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.

Question 37

What is a possible explanation for poor suckling response in infants?

Answer 37

Neurologically impaired infants may have a poor suckling response.

Question 38

How is ovulation suppressed during breast feeding?

Answer 38

Increased levels of estrogen and progesterone and increased levels of prolactin. Oxytocin contributes to this balance.

Question 39

How does human breast milk protein content compare to other animals milk in terms of quantity?

Answer 39

One of the lowest protein concentrations, which corresponds to human slow growth rate.

Question 40

How does a higher whey protein to casein ratio make human breast milk easier to digest?

Answer 40

Whey is softer and more digestible than curd. Acidity and pepsin secretion is immature in newborns, so have a harder time breaking down casein.

Question 41

How are Ca and Zn made more bioavailable in breast milk?

Answer 41

Lactalbumin (metaloenzyme and whey protein).

Question 42

How does mineral bioavailability in soy milk compare to breast milk?

Answer 42

Poorer for Zn, Ca, and Fe because of phytic acid protein complexes.