The human body contains 78 organs – at least, that’s the most widely accepted figure – but we know that not all of them are absolutely necessary. Take the appendix: many have asked what it’s even for, particularly when some studies have suggested you may be better off without it. So, we asked ourselves, what’s the absolute minimum number of organs the body needs? Which parts can you jettison without blinking an eye, and which can you afford to lose with a bit of clever medical intervention?
The organs you really don’t need
We’re starting with the most obvious example. In most people, the appendix is a little strip of tissue that sits happily in the gut minding its own business and not doing much of anything (although some research has found it might be a bit less useless than we thought).
If the appendix gets inflamed, however, it can progress pretty quickly to a medical emergency. Appendicitis is a common problem, particularly in kids and young adults. The causes are not well understood, so there’s no way to prevent it. Fortunately, the appendix definitely falls into the category of organs we can stand to lose, so the usual treatment for appendicitis is to simply whip it out.
Tonsils (and adenoids)
Anyone who has experienced the misery of a bout of tonsillitis will understand how unpleasant it would be to have repeated infections, and sometimes removing the tonsils altogether is considered the best way forward. The tonsils and adenoids – a related area of tissue at the back of the nose – can sometimes also cause issues with breathing during sleep, leading health professionals to recommend removal, often in children.
The tonsils do play a role in the immune system. This, added to the fact that removing the tonsils doesn’t always resolve chronic throat infections, means there’s been some debate as to whether this surgery is always a good option for kids. Generally, though, they are considered another tissue that we can cope quite well without.
Kidneys and liver
You might be surprised to find the liver in this part of the list, and you’d be right in thinking that you cannot survive complete removal of this organ. But part of the liver – the left lobe in children and the right lobe in adults – falls into the same category as a kidney in that you can donate these organs to someone else while you’re still alive.
Living kidney donation is the more common of the two. In the UK, almost 30 percent of kidney transplants are from living donors, compared with about 3 percent of liver transplants, most of which are in children where a smaller portion of the liver can be taken. While no surgery is without risk, many living donors experience no lasting ill-effects, with the added bonus of having saved someone else’s life.
Another resident of the abdomen that can cause you problems is the gallbladder. It does have a function – it’s a storage organ for the bile that your liver needs to work – but the digestive system can get along without it.
Gallstones and the issues they cause can be extremely painful, so removing the organ altogether is often recommended. Given that many people now have access to keyhole surgery, which is lower risk and has a shorter recovery time, and the fact that you most likely won’t notice it’s gone, the gallbladder is definitely an organ we can put in the “optional extras” category.
This is a bit of a tricky one. While it’s definitely possible to survive without either the male or female reproductive organs, the effects of removing them do vary.
For example, a woman who does not want to have any biological children, or any more than she already has, could have her uterus removed without any noticeable effects. Keeping at least one ovary means the normal hormonal cycling will continue, although menstruation will stop. But, removing both ovaries will put a woman into immediate menopause.
In men, the testicles can be surgically removed in a deceptively beautifully named procedure called an orchidectomy. If only one testicle needs to be removed, such as in the case of testicular cancer, sexual function and fertility should not be compromised. Prosthetic testicles can also be used to improve the physical appearance of the area after surgery.
So, this one really depends on the individual circumstances. You might be able to live without these organs, but for some people it will mean that further treatment, such as to combat the symptoms of early menopause or to facilitate having children, will be needed.
The organs you can afford to lose, but you'll know about it
You’d be forgiven for thinking that lungs might work like kidneys. You have two, so maybe losing one wouldn’t be so bad? It’s true that you can live without a lung, and there are lots of famous examples of people who have – perhaps most notably, in recent times, Pope Francis.
But while one kidney can really be said to do the job of two, people who have a whole lung removed might expect to regain 70 percent of their previous lung function. Not too bad, and sometimes there’s no other option available, but it still could mean that you’re not able to exercise as strenuously as you could before and that you generally need to take things a little slower.
We find ourselves back in the abdomen again, this time looking at the spleen. One of its major roles is in the immune system, so removing it does leave someone more susceptible to serious infections. For that reason, people are often recommended to take antibiotics for long periods of time, to ensure they’re up to date with vaccines, and to watch out for tick bites and other sources of disease.
A diseased or damaged spleen can cause a whole host of issues, which can lead doctors to recommend removal. While many of the functions of the spleen can be taken over by other neighboring organs, the effects on the immune system will be lifelong.
A very short hop away from the spleen is the pancreas. While you technically can survive without it, the consequences of removing the pancreas can be life-changing, and it’s only become an option comparatively recently.
A partial or total pancreatectomy can be performed, generally in an attempt to treat pancreatic cancer or other severe diseases of the pancreas. Because the pancreas is where insulin is produced, removing it immediately triggers diabetes. Patients need to inject insulin for the rest of their lives, as well as take replacement digestive enzymes that their bodies are no longer able to produce without a pancreas. Substantial lifestyle changes will be needed, but with these it is possible to survive removal of this organ.
Intestines and bladder
The colon, small intestine, or bladder can be completely or partially removed to treat conditions such as inflammatory bowel disease or cancer. The exact type of surgery depends on which parts of the organs are affected, and some of these surgeries may require the creation of a stoma. That’s an opening on the surface of the abdomen that lets waste from the digestive system pass through into a special bag that you wear over the opening. These can be either temporary or permanent, and allow people to live without large parts of their digestive organs.
This one might surprise you, but it is possible to live without your stomach. Generally, complete removal of the stomach is used to treat cancer.
People who’ve had their stomachs removed will need to make changes to their diet, such as eating different foods and eating smaller, more frequent meals. Vitamin supplements might be needed, particularly vitamin B12 as it’s difficult for the body to absorb without a stomach. But, with recovery over time, it is certainly possible to manage without this organ.
So, what’s the answer?
Answering our initial question is a little bit trickier than it might have seemed to start with. The first list of organs are really the ones you can not only live without but also not think about – you’re unlikely to have any lasting effects, and can go about your life as before. The next few are ones that you can survive without, but only thanks to modern medicine and significant lifestyle alterations.
This isn't an exhaustive list, either. You could live without your eyes, for example, and cope for at least a short while without both kidneys if you had access to dialysis.
And it probably goes without saying that some combinations of organs will be easier to live without than others. Plenty of people have neither an appendix nor tonsils; you might not cope quite so well if you had to lose both your spleen and your pancreas.
There will always be cases that defy the odds, though. You’d think that the brain would be pretty essential, but one woman baffled doctors when it emerged she was missing the part that normally processes language, and yet was herself bilingual.
And it can go both ways. It took a scan to investigate persistent back pain for one man to learn that he had an extra kidney.
It’s hard to put a number to the exact minimum number of organs a human body needs. But, it is kind of comforting to learn just how adaptable the body can be, and how medicine has made it possible to get by without a surprising number of its components.