In my previous column, I talked about body parts that can be safely removed in adults without having a major impact on one's health or longevity. Examples included tonsils, the appendix and the gall bladder.
Many of our body parts come with more than is absolutely necessary. So if they have to be removed because of injury or disease, you can still be in good health.
Here are some examples of organs that have plenty of "reserves" or excess capacity:
Perhaps you've heard it said that you only use 10% of your brain or that half of the body's organs are not truly critical to life. While some body parts are clearly more vital than others, it's a myth that most of the brain goes unused. And no one would suggest parting with even the least useful organs unless there is a very good reason.
Still, it is true that we have many body parts that appear to have no role in maintaining health. What did your appendix ever do for you?
When it comes to giving up a non-vital body part the benefit may outweigh the risk. For example, there is some risk in having your appendix removed, but if it's inflamed, swollen and about to burst, there is a much bigger risk not having it removed.
Similarly, it's no small matter to donate a kidney to someone who desperately needs it. The surgery to remove your kidney has some risk and there is a small but real risk that you will develop problems in your one remaining kidney. But these risks may be worth accepting when a family member or friend is in serious need.
But that doesn't mean that your kidneys are unnecessary. If both kidneys were removed, only lifelong dialysis or a kidney transplant would keep you alive. Taken to an extreme, you could survive for quite a while without your spleen, most of your liver, your eyes, a lung, a kidney and an extremity or two. But that doesn't mean you don't need any of those things! In general, it's best to keep the parts you were born with if you can. Who knows? As our understanding changes over time, we may discover that the now "discredited" tonsil is vital after all!
While most people would not volunteer to have one of these parts removed, it's convenient that they're not vital. Millions of people worldwide owe their very survival to the ability to withstand removal of an organ, a limb or other body part due to disease or injury.
So, is it true that half of our organs are unnecessary? I suppose that depends on your definition of "necessary." You could probably live to a ripe old age missing half of your organs and all four limbs. But would you want to? There are factors to consider other than just survival. Quality of life matters! The next time someone tells you about all the unnecessary parts you possess, remind him or her of two important facts: It's generally best to keep the parts you were born with and, there may be reasons we are born with the full complement of body parts even if we aren't sure why.
Robert H. Shmerling, M.D. is associate physician at Beth Israel Deaconess Medical Center and associate professor at Harvard Medical School. He has been a practicing rheumatologist for over 20 years at Beth Israel Deaconess Medical Center. He is an active teacher in the Internal Medicine Residency Program, serving as the Robinson Firm Chief. He is also a teacher in the Rheumatology Fellowship Program.