Breast Milk, pros and cons
Breast Feeding
Feeding spurts

Breast milk composition:

• 70% whey (way better), 30% casein (reversed with cow milk)
• Whey (vs casein)
  • more easily digested
  • promotes more rapid gastric emptying.
  • contains enzymes that resist digestion and act as the first line of defense in the GI tract:
    • alpha-lactalbumin (the predominant whey protein, vs beta lactoglobulin in cow milk)
    • lactoferrin, lysozyme, secretory igA.
    • Also contains: bile-salt activated lipase which enables superior fat absorption. Don't heat breast milk, heat inactivates the lipase.
    • Other bioactive factors: cytokines, oligosacchararides (prevent bacterial attachment), nucelotides, vit A,C,E, amino acids, lipis. 
  • The various modified cow milk formulas have whey contents that vary from 18% to 100%. The whey proteins of human milk provide relatively greater amounts of lactoferrin, lysozyme, and secretory immunoglobulin A than are contained in cow milk formulas.

• Approx 20cal/oz: hindmilk has more calories. Volume of breast milk is higher in am, calories are higher in the afternoon. Fatty acid composition is variable - based on mom's diet

Decreased disease:

• decreased chronic d/o: chron's, lymphoma, some genotypes of DM1, decreased atopic conditions if family has atopy
• decreased GI disease: less often and less severe gastroenteritis
• decreased resp disease: decreased wheezing, decreased lower resp tract illness
• decreased OM: if br feed x 4 mos, rate of otitis decreases by half
• has strong protective effect against hemophilus influenza b
• decreased UTI
• decreased infant botulism (ie, br milk -> lower ph in GI tract, worse for clostridium botulinum)

Maternal:

• maternal=child bonding
• mom loses weight faster (initial milk stores pulled from mom's fat stores)
• decreased maternal premenopausal breast cancer, decreased ovarian ca
• contraception is 98.5-100% effective if all three criteria are met:  breast feeding ATC, no menses, infant < 6 m/o.
• faster uterine involution

Cheaper!

Cons:

• has low vitamin K, D, and Fe (although the Fe is very bioavailable)
• decreased ca/phos conent vs cow milk/infant formula, but it is more bioavailable. Net effect: bone mineralization content only slightly less.
• Fe, Zn, Copper decline as lactation continues, but levels are adequate until age 4-6 mos. Iron content is not enough if solely breast feeding after age 6 mos.
• To prevent rickets and vit D deficiency, give 200 IU vita A if:
• br fed and < 500 cc/day of vit-D enriched formula
• non br fed and < ""
• kids/teens with poor sun exp, < 500 cc/d of vit D enriched milk, and don't take MVI.

Random stuff: There is a little bit of unabsorbed lactose in stools, that helps soften stools, causes more nonpathogenic fecal flora, and aids absorption of minerals.

Storing Breast Milk:
3 hrs @ rm temp
3 days in fridge
3 mos in freezer
thaw in hot H2O not in fridge

Breast milk can be kept (a) at room temperature for 4 hours; (b) in the fridge for 3 days (ideal) to 8 days (acceptable); (c) in the freezer for 3 months (d) in deep freeze for 6 months (ideal) to 12 months (acceptable). If transporting breast milk in a ‘cooler’ with ice packs, use within 24 hours.

Infant formula can be kept at room temperature for 2 hours. If formula is partly used, finish the rest within one hour from the start of the feeding. Formula should not be refrozen. Prepare only as much as you will need. Formula prepared from powder can be stored in the fridge for up to 24 hours. Liquid formula (ready-to-feed or prepared from concentrate) can be stored in the fridge for up to 48 hours. Finish powdered formula within one month after opening the can; store the can of powder in a cool dry place, not in the refrigerator or freezer.

Breast milk vs Cow milk

There are differences in both the quantity and quality of protein
content in human and cow milk. The protein concentration of mature
human milk is 0.9 g/dL compared with 3.4 g/dL for cow milk and 1.5
g/dL for modified cow milk formulas that provide 20 kcal/oz. The
protein content of human milk is 70% whey and 30% casein; cow milk
contains 18% whey and 82% casein. The various modified cow milk
formulas have whey contents that vary from 18% to 100%. The
predominant whey protein of human milk is alpha lactalbumin and is
beta lactoglobulin in cow milk. The whey proteins of human milk
provide relatively greater amounts of lactoferrin, lysozyme, and
secretory immunoglobulin A than are contained in cow milk formulas.

The serum levels of methionine, phenylamine, threonine, and valine are
higher in infants fed whey-dominant modified cow milk formulas
compared with breastfed infants. There is no known adverse effect
associated with these differences.

The whey proteins, which are more plentiful in human milk, are
digested more easily and promote gastric emptying.

References:
Hall RT, Carroll RE. Infant feeding. Pediatr Rev. 2000;21:191-199
Slusser W, Powers NG. Breastfeeding update l: immunology, nutrition,
and advocacy. Pediatr Rev. 1997;18:111-119