Lipid profile of full-term infants on different regimens. The aim of the study is to compare infant's lipid profiles on different feeding regimen during the first 6 months of life and its correlation with their mothers' lipid profiles (exclusive breastfeeding and mixed feeding) and to compare infants' lipid profiles on different feeding regimen with each other (including those on exclusive formula feeding).

Infant and young child feeding is critical for their health and survival. Based on well-established evidence, the World Health Organization (WHO) and the United Nations Children's fund (UNICEF) recommend that mothers put newborns to the breast within one hour of birth, breastfeed infants exclusively for the first six months and continue to breastfeed for two years and beyond, together with nutritionally adequate, safe, age-appropriate, responsive feeding of solid, semi-solid and soft food starting in the sixth month.

For the first six months of life, breast milk alone is the ideal nourishment, providing all of the nutrients including minerals and fat soluble vitamins, an infant needs, meaning that no other liquid or food is needed.

In addition to providing a generally adequate nutrient supply that support normal growth and development , breastfeeding has been linked to multiple other advantages including a reduced risk of infection and long-term benefits for the risk of obesity, type II diabetes mellitus, blood pressure and better performance in intelligence tests.

The macro-nutrient composition of human milk varies within mothers according to nutritional status and across lactation. The mean macro-nutrient composition of mature, term milk is estimated to be approximately 0.9 to 1.2 gm/dl for proteins, 3.2 to 3.6 gm/dl for fats and 6.7 to 7.8 gm/dl for lactose.

There have been several systematic reviews supporting the positive effects of breastfeeding on cardiovascular risk factors, such as obesity and type 2 diabetes (DMII), hypertension. Breastfeeding also reduces plasma levels of total cholesterol (TC) and low density lipoprotein (LDL).

Breast milk is a protective factor against obesity. This effect could be explained by existing differences in macro-nutrients. Moreover, there are physiological differences between breast milk and artificial formulas in terms of their nutrients and hormone contents. For instance, protein content of baby formulas is higher than that of breast milk, and leptin exists in breast milk, but not in artificial formulas. Due to their high fat and protein contents, baby formulas would lead to increased secretion of Insulin Growth Factor-type 1 (IGF-1),and subsequently to stimulation of adipocytes, which eventually result in excess weight. Moreover, breastfeeding affects the intake of calorie and protein, insulin secretion, balancing fat reserves, and adipocyte size. The effect of breastfeeding is found to be independent from dietary patterns and physical activity in adulthood.

Many studies have confirmed the protective role of breastfeeding against type II diabetes mellitus. This effect is considered to be because of the difference in composition of breast milk and the difference in hormones of insulin, motilin, introglucagon, neurotencin, and pancreatic polypeptide in breast milk and artificial formulas, which in turn would lead to lower subcutaneous fat deposition in breastfed infants.

The effect of breastfeeding on hypertension has attracted much interest because of the differences between breast milk and artificial formulas, mainly in terms of their content of sodium and fatty acids. It is documented that breastfeeding can affect systolic and diastolic blood pressures in adulthood. The effect of breastfeeding on blood pressure in adulthood can be partly explained through the following mechanisms: (1) reduced sodium intake in infancy, (2) high content of long-chain unsaturated fatty acids in breast milk, which is an important component of the tissue membrane system, as coronary endothelial system, (3) protection against hyperinsulinemia in infancy, as well as prevention of insulin resistance in early life, adolescence, and adulthood.

There is a relationship between the molecular composition (especially lipids, glycerides and sterols) of the maternal plasma, milk and her infant.

There is paucity of studies comparing lipid profiles of exclusively breastfed and mixed fed infants and those correlating lipid profiles of breastfed infants and their mothers' lipid profiles.

Inclusion Criteria:

• Apparently healthy infants during the first 6 months of life on different feeding regimen

Exclusion Criteria:

1. Infants with perinatal problems .e.g.,

   • birth asphyxia
   • premature rupture of membranes
   • hypoglycemia
   • hypothermia
   • meconium stained amniotic fluid
   • pathological jaundice
   • congenital malformations
   • clinical evidence of chromosomal abnormalities

2. Infants born to mothers having any chronic disease e.g.,

   • diabetes mellitus
   • gestational diabetes
   • hypertension
   • pre-eclampsia
   • eclampsia
   • hypo/hyperthyroidism
   • on any long-term medication

Infants seeking medical advice in the outpatient clinics of Assiut University Children Hospital