The Best Start
The story of infant nutrition begins with mom. The major nutrients that keep mothers healthy are broken down and then transformed into a liquid food that is delivered to their infants, who will, in turn, break down and re-assemble these nutrients in their own growing bodies. Breast milk must support the infant’s extraordinary growth and development as well as provide energy for cell division, tissue growth, and motor and neural activities. Milk builds babies.
But isn’t milk just milk? Sure, all mammals produce it and their babies drink it, but there’s a lot more to the story than that. First of all, each type of mammal, whether mouse or moose, makes their own version of milk, specially suited to the nutritional needs of their own offspring. These nutritional needs reflect how fast and big the offspring will grow, the environment in which the offspring grow, and even the size of the animal’s brains. All of these things are mirrored in the milk that nourishes mammal babies.
The basic components of milk are fats, proteins, carbohydrates, vitamins, minerals, and water. That goes for cow’s milk as well as human milk. But again, there are differences. Cow’s milk, for example, has approximately three times more protein than human milk. Both a baby and a calf need proteins as building blocks for growth and development. But while human babies can triple their birth weight in the first year, a calf’s birth weight can increase fivefold in just 6 months.
Analyzing Breast Milk
Researchers began to scientifically analyze the major components of milk (fats, proteins, and carbohydrates) more than a century ago. But determining precisely the complete list of all ingredients found in milk has been very difficult. Milk is an extraordinarily complex fluid, rich in vitamins, minerals, and other nutrients as well as a wide range of trace elements, antibodies, growth factors, and digestive enzymes. In a very real sense, milk is alive, because it also contains living immune cells.
The quest to unravel the mysteries of human breast milk has been an important challenge in public health. An international community of researchers has spent decades analyzing the components of milk, determining their function, and deconstructing and reconstructing the physiology of infant nutrition.
Although milk is a difficult substance to work with, some researchers note that, given our scientific sophistication, it’s surprising we know as little about breast milk as we do. Part of the problem is the limitations inherent in studying babies and nutrition. In the 1970s and 1980s, explains Sharon Donovan, professor of nutrition and pediatrics at the University of Illinois, “we developed better analytical chemistry and we started discovering lots of different growth factors in other secretions, like blood and tears and other biological fluids, and we also began to identify those in breast milk. So we started to compile lists and tables of different growth factors, hormones, cytokines, even live immune cells in human milk.”
That was certainly a critical first step, but the real challenge was to understand the function of breast milk within the context of infant physiology. You can only get so much information doing experiments in test tubes, says Donovan. What has changed dramatically in recent years, however, are the improved technological means scientists have to understand biochemical pathways and the genetic underpinnings of function.
“There have been a lot of changes,” says Bo Lönnerdal, professor of nutrition and internal medicine at the University of California, Davis, “and fortunately scientists have been following new developments and exploiting advances in other disciplines. Breast milk studies are by nature very interdisciplinary. It’s a fascinating time to be working in this area and I think most of the breakthroughs are still to come.”
One of the major challenges that remain, however, will be to design experimental approaches that will enable researchers to study not just the impact of a single ingredient in breast milk, but the combined interaction of breast milk components. How does a given nutrient act in the presence of other nutrients? When does it enhance, inhibit, or otherwise modify the action of nutrients? “As scientists,” says Donovan, “we often take a reductionist approach, so we’re just looking at one hormone or one growth factor. But it’s likely that all these things are working together in different ways because they are all present as a package and that’s how the infant experiences it.”
The complexity of breast milk has other important dimensions as well. “Typically, we think of breast milk as nutrition, fuel to be completely digested and absorbed,” explains Donovan. “But there are a number of components in breast milk that are not digested.” That doesn’t mean they aren’t important, however. Far from it. What researchers are finding is that many components in breast milk perform specialized “functional” roles that go well beyond providing the infant with a source of calories or building blocks. These functional components actively “do” something. For example, breast milk contains indigestible carbohydrates that encourage the growth of beneficial gut bacteria and stimulate the maturation of the infant’s intestinal lining. Other functional components include proteins that first battle pathogens in the baby’s body, and are then, in turn, digested as fuel and used as building blocks for the baby’s body.
Scientists are increasingly trying to decipher the functional roles played by various substances in breast milk. This knowledge will help researchers deepen their understanding of the mysteries of growth and development as well as improve nutrition for all infants. Meanwhile, the list of benefits of breastfeeding continues to grow longer as scientists unlock the secrets of just exactly why mother’s milk is the best way to support the health and well-being of babies.
Mother's Milk (VIDEO)
The Best Start
The Ultimate Homemade Meal
Baby's Nutrition Begins with You
Local & Imported Ingredients
Meals Made to Order
Ingredients May Vary
Designed for Growth
Recipe to Develop
The Closest Bond
Related Health Centers:
Infant Nutrition Health Center, Mother-Baby Bond Health Center, Mother’s Milk Health Center, Monthly Infant Development Calendar Health Center,Weekly Pregnancy Calendar Health Center