Lecture 20: Lactation why should we do it? Flashcards
Describe Stage 1 of Lactogenesis
Lactogenesis Stage 1
- Mid gestation to day 2 postpartum : Preparation
- The human breast is capable of lactation from mid gestation but lactation does not usually occur until after parturition
- The withdrawal of the placental steroid is responsible for the onset of lactation
- E2 and particuarly P4 inhibit beast resposiveness to prolactin
- The suckling stimulus is transmitted to the hypothalamus reducing dopamine relase
- Dopamine is also called prolactin inhibiting substance
- Suckling also stimulates release of another hormone, vasoactive intestinal polypeptide (VIP) int ot he portal vessles
- VIP causes prolactin release
Describe stage 2 of Lactogenesis
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Postpartum days 3-8 : Start large-scale milk production
- Change in milk structure
- Increaseed a-lactalbumin and _decreased sodium and chloride i_n milk due to tightening of junctions in alveolar epithelium
- Change in milk structure
How does the make up of the milk change in stage 2 of lactogenesis?
Increaseed a-lactalbumin and d_ecreased sodium and chloride_ in milk due to tightening of junctions in alveolar epithelium
What are thes stages of lactation?
1) Lactogenesis stage 1
2) Lactogenesis stage 2
3) Glactopoiesis
4) Involution
Decribe Glactopoiesis
3rd stage of lactation
Maintenance of established milk secretion
Full on milk production- lasts until Involution
Describe Involution
Final stage of lactation (4th)
Post-lactational breast reduces in size
Approx 40 days after last feed
Return almost back to the original size
Due to build up of inhibting substances
The first milk we produce is called _____
Colostrum
Describe Colostrum
During the first days after delivery, the milk produced is a thick product called Colostrum
Colostrum contains less sugar and less fat than mature milk_- less about energy_
Colostrum contains more t_otal protein_ than mature milk and especially rich in antibodies (mainly IgA)
Colostrum contains less _____ and less _____ than mature milk.
Colostrum contains more ______ than mature milk.
Colostrum contains l_ess sugar_ and less fat than mature milk- less about energy
Colostrum contains more total protein than mature milk and especially rich in antibodies (mainly IgA- in the mucosal)
What are the major components of Human Milk (10)
What are their functions?
- WAIL LLL (111)
- Lactose – major energy chourse.
IgA – immunoprotection
Amylase/lipase – helps baby digest sugars and fats
Lysozyme – antibacterial
Water – hydration
Lipids – largest source of calories
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Phagocytes (90%) and lymphocytes (10%) and T cells (4%)
- Immunological protection
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Phagocytes (90%) and lymphocytes (10%) and T cells (4%)
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Small soluble signalling molecules (e.g. prostaglandins, cytokines, growth factors)
- Immunomodulators
- Promote leucocyte movement across gut etc. e.g. TGF in colostrum
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Enzymes e.g. amlyase, lipase
- Helps baby digest polysaccharrides
- Hydrolyses fat in babies in intestine
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Lipids, Long chain polyunsaturated fatty acids, Triglycerides
- DHA associated with increased visual acuity and cognitive ability
- Largest sources of calories for infants
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Lactose Major carbohydrate
- IMprotant energy source- break down to glucose and galactose (important for myelin synthesis)
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Proteins and Immunoglobulins esp IgA
- Immunoprotection
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Lactoferrin
- Antibacterial- soaks up iron
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Lysozyme
- Antibacterial
-
Vitamins
- Nutritional, antioxidant
-
Water
- Hydration
What are the differences between bovine and human milk?
- Humans take approx 4-6 months to double their birth weight
- Most other mammals do this more rapidly
- Therefore human milk must be specifically adapted for human requirements
- Sugar content is higher in human milk than bovine milk
- Protein composition (Casein: lactalbumin ratio) is very different
- Linoleic acid makes up almost 10% of fat in humans but only 16% in cows (different lipid composition)
Does the size of the breast matter?
Larger breast have a greater capacity for milk storage
But this d_oes not reflect milk production capacity._
The storage capacity may be different in the left and right breasts
Milk yield from right breasts is greater than left.
What are the benefits of breast feeding for the mother (5)
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Spacing of offspring
- Exclusive breastfeeding for 6 months prolongs the duration of the post-partum amenorrhea
- May also enhance weight loss after pregnancy
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Bonding to offspring
- Eye contact is important
- Enhances involution of the uterus
- Appears to protect against development of Type 2 diabetes
- May protect against postpartum depression
- Eveidence that breastfeeding protets against breast and ovarian cancer
Describe the benefits of breastfeeding (according to meta-analyses) to the mother (1) and the babe (8)
Mother
1) Protect from breast cancer
Babe
1) Breastfeed babies do not tend to be over-fed
2) At 12 months of age, breastfed babies are l_eaner than controls_
3) Breastfeeding may confer a slight protection against childhood obesity
4) Protect against GI tract infection_s and r_educes poorer outcomes (sterile source of nourishment)
5) Protection against Ottitis media (longer the duration of breast-feeding, greater the benefit)
6) Protected from developing atopy (during the first 6-9 months of life, the infant intestinal mucosa is permeable to proteins. Transfer of IgA (and other substances) prevents the access of allergens into the submucosal layers of the gut)
7) Protective against developing asthma
8) Decrease in sudden infant death syndrome
What is the proposed reasoning why breastfeeding protects babes from atopy
Protected from developing atopy
During the first 6-9 months of life, the infant intestinal mucosa is permeable to proteins.
Transfer of IgA (and other substances) prevents the access of allergens into the submucosal layers of the gut.
