11 Lactation + Fat

Question 0

How is fat made soluble in milk?

Answer 0

TAGs are enclosed in membranes made of phospholipids, cholesterol, and proteins.

Question 1

What form is most milk fat in?

Answer 1

98% is in TAGs

Question 2

Why do infants need to out down a lot of body fat vs putting down muscle?

Answer 2

Need to buffer potentially risky transitional periods from utero to lactation (might be problems), and from exclusive breast feeding to mixed (could get infections).

Question 3

Why is fat such a high proportion of the calories in breast milk?

Answer 3

Efficient way to meet energy needs with small stomach capacity. Allows more efficient depositing of fat.

Question 4

Where are the lipids in milk from?

Answer 4

Less than or equal to 16 c are synthesized in alveolar cells. 18 C+ are from maternal adipose stores and diet

Question 5

What metabolic effect does prolactin have on lipoprotein lipase?

Answer 5

Changes maternal fat metabolism to decrease lipoprotein lipase activity in maternal adipose tissue, and increase lipoprotein lipase in mammary gland to preferentially channel free fatty acids to breast milk.

Question 6

What position is palmitate at in the highest proportion in breast milk? What are the advantages of this?

Answer 6

At 2 position, stay attached to glycerol which increases absorption into micelles.

Question 7

How does the palmitate in cows milk reduce the bioavailablity of certain minerals?

Answer 7

At 1 and 3 positions, more likely to form complexes with minerals, like calcium soaps, which will just be excreted at the feces so there will be decreased mineral and fat absorption.

Question 8

How does the absorption if oleic acid compare to saturated fat?

Answer 8

Much better absorbed

Question 9

How does the EFA content of breast milk, cows milk, and infant formula compare?

Answer 9

Breast milk has 5x more than cows milk, infant formula can be higher but uses parent molecules and it is unclear if infants can effectively elongate and desaturate these.

Question 10

What is an issue with too high DHA?

Answer 10

When supplementing in formula, DHA that is too high could inhibit arachnidonic acid, which would impede growth

Question 11

What are some important functions of lactose?

Answer 11

Exert osmotic pressure, increase bioavailability of minerals (chelates), possible prebiotic

Question 12

What three factors in breast milk improve fat absorption?

Answer 12

Lipoprotein lipase from maternal serum, bile salt stimulated lipases, pancreatic like lipases

Question 13

Why is the iron bioavailability of breast milk high?

Answer 13

Lactotransferrin and lactose aid in absorption

Question 14

How is the calcium to phosphorous ratio in breast compared to milk?

Answer 14

More calcium to phosphorous, good because excess Ph will inhibit calcium absorption

Question 15

Why is the solute load of breast milk important?

Answer 15

A lower solute load helps infants kidneys better handle the solutes that need to be excreted through urine. Too high a load can be especially difficult in state of dehydration.

Question 16

Preterm infants milk is:

Answer 16

Higher in energy, protein, Na and Cl, and lower in lactose. Still need to be fortified usually.

Question 17

How does the fatty acid composition change from colostrum to mature milk?

Answer 17

Higher in PUFA I colostrum, higher in saturated fat in mature. Laying down of nerve cells with colostrum, development of myelin sheath with mature milk.

Question 18

How are immune factors affected by malnutrition?

Answer 18

Only colostrum affected, decrease. Mature milk not affected.

Question 19

What is the major factor that determined the fat content of breast milk?

Answer 19

Maternal adipose stores laid down during pregnancy. If not enough, fat content decreases significantly.

Question 20

What vitamins are mostly affected by maternal malnutrition?

Answer 20

Water soluble vitamins and vitamin D

Question 21

What minerals in the breast milk will be affected by malnutrition?

Answer 21

Selenium and iodine

Question 22

Does a low dioxin diet make a difference in preventing breast milk contamination with dioxin?

Answer 22

No, mostly comes from maternal stores, not diet

Question 23

Describe late hemorrhagic disease of the newborn.

Answer 23

Neonate has low vit K and ability to synthesize, and breast milk is low in vit K. Ability to clot blood is decreased, so have spontaneous brain bleeds often when exposed to contaminants because cytochromes P-450 activity increases exertion of vit K.

Question 24

What issues can arise when using birth control and breast feeding?

Answer 24

Gynecomastia (enlarged breasts of infant) and suppression of lactation.

Question 25

What is required for newborns with PKU?

Answer 25

Low Phe infant formula

Question 26

What is galactosemia?

Answer 26

Autosomal recessive disorder. Reduced form of galactose severely toxic.

Question 27

What is breast milk jaundice?

Answer 27

5-beta-3-alpha-20-beta-idol is a metabolite of progesterone that inhibits bilirubin conjugation.