Are we what we eat?

Being an ecologist in training, I have learned a lot about cycles. I think i wrote about this earlier in the month. The most basic, or maybe the most complex, of these cycles is the physical cycling of matter on earth. I think many people don't think about this, but let me try to explain.
Take an infant. Let's imagine that this infant is breast-fed, and receives all of its nutrition through his mother. All of this nutrition consists of fats, proteins (which are broken down to amino acids), and carbohydrates, which are broken down into sugars for energy. Well, the fats are normally stored, and in infants I am sure they are a very important part of physical development. The proteins, which are broken down into amino acids, are re-organized again as proteins and become part of the child's frame, whether hair, muscles, skin, organs, etc. This process is fueled by the use of sugars. Along in this process is metabolism. This is how the child uses the energy in his food. The products of metabolism are, well, everything in his diaper, along with carbon dioxide and water. These leave through his lungs, and become part of the atmosphere. Now let's take a look at where these products go.
The stuff that goes into his diaper inevitably goes into a landfill, unless, of course, his parents use cloth diapers. In this case it will find its way to a treatment facility. The majority of this material is some form of carbon, nitrogen, and phosphorus, although there are also many many more things present. these three are the main ones. Whether they end up in a treatment facility or a landfill, their fate is the same. The carbon that is present is metabolized by microbes and turned into carbon dioxide or methane (natural gas). The phosphorus becomes, in most cases, phosphate, and the nitrogen becomes ammonia, nitrate, nitrite, or nitrogen gas. Let's recap what we have so far...
Carbon dioxide and water leave the baby's lungs and become part of our atmosphere (in the air). Carbon dioxide also comes from the baby's diaper and is part of our atmosphere, as well as nitrogen gas. ammonia, nitrate, nitrite, and phosphate, for the most part, stay on the land or find their way into surface waters.
Now, let's think about a thai chicken salad. The peanuts in the thai sauce, like all legumes, fix nitrogen gas from the atmosphere. Not all plants can do this, but some very important ones do, like peanuts. They also fix carbon dioxide from the atmosphere, and water from the soil. When I say "fix", I mean that the molecules become the actual plant or peanut. Carbon dioxide, through the energy of the sun, is turned into simple sugar, and that is turned into many many things inside the plant. Phosphate is also fixed in the peanut from the soil. We could say that, in a very simplified cycle, the carbon, nitrogen, and phosphorus from the baby's diaper, and the carbon dioxide and water from the baby's lungs, can become a peanut. The case is very similar for the rest of the thai chicken salad. The chicken more than likely is fed grain that is grown from carbon dioxide in the atmosphere, as well as water, nitrogen, and phosphorus that has gone through a cycle like this since the beginning of the world.
Now let's imagine that the mother eats this thai chicken salad. Part of the molecules become her, literally. She may turn them into muscle, bone, and other tissue. The rest has three places it can go...either out through her lungs (carbon dioxide and water), to the same place the baby's diaper stuff went to, or can be turned into breast-milk. In this case, quite a bit of it is turned into breast milk. Because baby's grow so quickly, they must turn a lot of this breast-milk into very important tissue (brain cells, muscles, his heart, bones, reproductive parts, etc.)
Why do I explain all of this? Well, whenever I think about cycles of material on earth, I can't help but be reminded of Ash Wednesday.
"Remember O man, that thou art dust, and to dust thou shall return."
The Ash Wednesday service is very penitent at our church, and I really appreciate being reminded that we are God's creation, and that we are made of the same matter as the rest of the earth. This is very humbling. It is also important to understand, though, that this makes our existence so much more incredible. Though we are made of the same material that cycles through the rest of the earth's atmosphere and organisms, God sets us apart. Although God formed man of the dust of the ground, he then "breathed into his nostrils the breath of life; and man became a living soul."
This is a miracle. Absolutely. We are of the same material as the things we are surrounded by, and eat, and breath, but we are also set apart. Although we are made of dust, and shall return to dust, there is another half of the story, which is very good and important.