most dramatic in colostrum and early milk and mostly resolve by 4 weeks after delivery (Figure 1B). Leptin is produced by mammary glands, secreted into human milk, and may be important in post-natal growth. Human milk leptin does not appear to differ between preterm and term milk. Bile salt-stimulated lipase activity is similar in term and preterm milk while lipoprotein lipase activity is higher in term milk.