How Does Nitrogen Enter Our Body?

A couple walking together on a woodland trail.
••• Jupiterimages/Stockbyte/Getty Images

Atmospheric Nitrogen

The air you breathe is around 78 percent nitrogen, so nitrogen enters your body with every breath. Because nitrogen is an important part of human health, it is unfortunate that the nitrogen people inhale gets immediately exhaled. Animals, including humans, cannot absorb nitrogen in its gaseous form.

Plants and Soil

Plants also need nitrogen to survive. Many plants can absorb nitrogen from compounds in the soil like nitrates, nitrites and ammonia. Some plants -- mostly legumes and a few trees and shrubs like birch and alder trees -- have symbiotic relationships with bacteria; the microorganisms attach to the roots of the plants and make nitrogen compounds out of nitrogen gas in the soil. Plants use the nitrogen to produce proteins, enzymes, amino acids and nucleotides (components of DNA) -- all of which people absorb when they eat plants. This is the primary source of nitrogen in animals, but you also absorb nitrogen from meats you eat.

Other Sources

A small amount of nitrogen and other gases are absorbed into the outer layer of your skin, the epidermis. Nitrates and nitrites are added to meats to preserve the red color. Municipal water supplies are treated to remove nitrogen compounds that enter groundwater from agricultural fertilizer runoff, but small amounts still persist in most drinking water.

Waste Elimination

Most animals ingest more nitrogen than they can absorb, so much of it gets excreted. When cells use protein, the waste product is urea, which is almost half nitrogen. It travels through the bloodstream, and the urea gets filtered out in the kidneys and mixed with water to produce urine. The ammonia and urea in urine then become a valuable fertilizer for plants because of its high nitrogen compound content. Some nitrogen is lost in the shedding of hair, nails and skin as well.

Related Articles

Why Is Nitrogen Important for Living Things?
One Reason Why Nitrogen is Crucial for Sustaining Life...
How Do People Get Nitrogen Into Their Bodies?
Does Acid Rain Have an Effect on Agriculture?
Functions of Human Organs
Why is Breathing Important to Organisms?
Examples of Secondary Pollutants
How Do Phosphates Affect Water Quality?
How Do Plants Get Protein?
How Is Urea Made?
Does Rainwater Contain Nitrogen?
How Do Stomata Work in Photosynthesis?
What Role Do Decomposers Play in a Food Chain?
How Do Humans Get Oxygen in Their Bodies?
Does Rain Water Contain Nitrogen?
The Greenhouse Effect & Photosynthesis
Percentage of Nitrogen in the Air
How Does Hydrogen Enter Our Body?
What Are the 3 Most Common Elements in Human Bodies?
What Role Do Fungi Play in Food Chains?

Dont Go!

We Have More Great Sciencing Articles!