Find Out Which Organ Is Most Important

Some organs get plenty of press. News stories and resources about the heart, lungs and skin are commonplace. But according to Mehmet Oz, Oprah Winfrey's favorite go-to-doc, the liver is the body's most important organ and it gets little play.

The body's largest internal organ is its gateway, and the liver's detoxification system can be easily overloaded in this chemical age, where foods are treated.

Oz and Michael F. Roizen, co-founder and chairman of RealAge Inc. and a co-author with Oz, explain how the liver operates and how you can keep it working with the right foods and supplements in their book, "You: The Owner's Manual."


Read an excerpt below.

If your organs were celebrities, you'd immediately know how they stacked up in terms of status and fame. The heart and brain reign as biological kings. They're the A-listers, the ones that get all the attention, the glory, the magazine covers, the best tables, and the medical paparazzi detailing every minute of their existence.

Then there are the B-list organs, like the stomach, the lungs, the skin, and the sex organs.

Of course they're on our radar, we know what they do, and we'd surely recognize them if we saw them out and about combing the malls. Lastly, there are the C-listers—those organs that we might know by name but couldn't tell you much about. Yup, they're the organs with serious respectability problems; no matter how much good they do, they can't get a lick of press. Specifically, we're talking about the Rodney Dangerfield of internal organs: the liver. Sure, you know a little something about it (filters your tequila, right?), but that's about it.

The reality is that few of us know much about the liver and its digestive neighbor, the pancreas. If you were to play medical word association (you do, don't you?), most of you would probably answer the same way.

We say liver? You say booze. We say pancreas? You say diabetes. We say liver and pancreas? You say get to the point already.

And you're right: Those two organs are associated primarily with alcohol and obesity. But to stereotype the liver and pancreas in that way would be like saying that your brain's only function is memory or the only thing your private parts are good for is eliminating the morning's coffee.

And that's a shame, considering the biological miracles that the liver performs every day. Consider this: The liver is the only internal organ that can regenerate itself.

In fact, you can lose up to 75 percent of your liver, and the remaining parts can regenerate themselves into a whole liver again. Amazing stuff. ("If only hair workedthe same way," says the bald man ... )

As we continue our look at the digestive process, we need to examine these two organs. So let's peel back that fatty layer of digested mashed potatoes and take a look inside.

Your Liver: Break Down

If you allow us a quick diversion from medicine to mythology, we want to quickly tell the story of Prometheus. This poor fellow gave fire to the humans. His punishment from the Greek god Zeus for committing such a crime: He was chained to a rock, where a vulture would peck out his liver. Amazingly, the liver would regenerate overnight. How did the Greeks know of the liver's power? Maybe it was because they survived injuries to the organ in battle. While the Greeks were onto something, we're pretty certain that they didn't have as much insight into the liver as the scientific world does today.

Maroon and shaped like a boomerang, the liver is the second largest organ in the body (the skin always steals this glory). The reason why it's so vital is that it serves as your body's border inspection station. Virtually every nutrient we consume, whether it has a valid passport or not, must pass through the liver so it can be transformed into a different biochemical form. That transformation is what allows the nutrient to be used, transported to a different location in the body, or stored as an extra inch of blubbery goop on your thighs.

Structurally speaking, here's what you need to know about the liver. It's located just below the right rib cage in the upper right side of the abdomen, above the pancreas and the small intestine. Your liver does three main things: helps digest stuff, make proteins, and gets rid of bad stuff.

All of the blood that has visited your small intestines flows through your portal vein into your liver, so almost all of the nutrients you eat have to pass through the gauntlet of the liver before passing to the heart for generalized distribution. Why "almost"?

There's a little absorption in your mouth and under your tongue, but almost means 99 percent for the typical person. Your liver decides what gets kept out, what gets patted down and inspected, and what's allowed in to be distributed throughout your body.

Within the organ, there's a network of bile ducts; bile, if you remember from the last chapter, is the greenish liquid produced in the liver that helps break down fats. The liver also uses bile to clear bilirubin from the blood. Biliwhat, you say? Bilirubin?it's a substance that comes from the breakup of hemoglobin in dead redblood cells. An increased level of bilirubin results in jaundice (a yellowing of the skin and all mucous membranes?that includes the eyeballs, where the yellowing is usually detected earliest and most easily), a sign of many liver diseases.

The various functions of the liver are carried out by the liver cells, called hepatocytes.

They are responsible for the organ's ability to regenerate; hepatocytes act as stem cells that can re-form liver tissue. These cells work primarily to serve these functions:

NUTRIENT BREAKDOWN We all may know that skim milk is good for your bones, fish is good for your muscles, and olive oil is good for your heart. But only a weird cartoonist thinks that your bones actually bathe in milk or there's a blood vessel that transports fresh olive oil through a side door in the aortic chamber.

Everything we eat and drink has to be broken down into different chemicals before it can get to work on helping (or, in the case of some foods and drinks, harming) your body. And that's one of the primary jobs of the liver.

STORAGE AND CREATION The liver, which makes protein and stores glucose, vitamin B12, and iron, helps get nutrients to your body by processing all foods? carbohydrates, protein, and fat?into glucose that can be used throughout your body. Glucose is a fancy name for a specific and common sugar (yup, everything is turned to sugar). Iron stores in the liver are great enough for most people that iron supplements are not usually needed, except in people with iron deficiency anemia, which is the most common nutritional deficiency worldwide. The liver also serves as the initial source of glucose when you rush the hot dog stand at halftime (even be-fore you get there), since the sugar in your blood provides only ten minutes of energy.

It then does double duty to break down the nitrates from that hot dog in the detox function described below. This, by the way, is the reason why you don't burn fat immediately when you start exercising?it's because your body is using the fuel that's stored as glucose in the liver first.