Why, when we can live a full, rich, healthy life with only one kidney, are most of us born with two kidneys? It’s an enigma, but Christina Klein, MD, a transplant nephrologist at Piedmont Transplant Institute, is grateful that so many people are born with a kidney to spare.

How Is Only One Working Kidney Enough?

According to Klein, people born with two kidneys generally have 100 percent renal function, but people born with only one kidney aren’t left with only 50 percent; they typically enjoy 75 percent function. “Before they were born, [a person with only one kidney] developed more kidney tissue than you would have expected with just one kidney,” explained Dr. Klein.

People who have donated a kidney or had one removed for health reasons usually have 50 percent function in their remaining kidney immediately following surgery, but that often increases to 75 percent function over time due to tissue growth and a hyperfiltration process. 

Preparing for Living Kidney Donation

If you’re interested in donating a kidney, whether to a loved one or a stranger, you’ll have to undergo a thorough screening process to rule out both pre-existing kidney disease and the presence of risk factors for future kidney disease.

Your doctor will also likely provide recommendations for a long-term healthy lifestyle to optimally support your remaining kidney post-donation.

Dr. Klein recommends the following:

• Achieve and maintain a healthy weight (for your frame, muscle mass, etc.).
• Get regular, frequent exercise that is appropriate for your age and fitness level.
• Follow a nutritious diet low in salt, sugar, saturated fats, and trans fats.

“We know that someone who passes the donor screening and is able to donate a kidney to a loved one can live a nice, healthy, long life with just one remaining kidney,” she said, adding that she encourages anyone who can, to become a kidney donor. Most donors, Klein assured, do not have to be concerned about long-term health consequences.  

*Piedmont Healthcare. (2021). Life with Only One Kidney. https://www.piedmont.org/living-better/life-with-only-one-kidney