Home from the ICU? Do this first!

When you're in the intensive care unit, there's really just one thing on your mind: Survival.

It's a "big picture" kind of moment, with no time to sweat the small stuff -- and as a result, some of the smallest stuff of all can end up getting ignored.

And there's not much smaller than the essential microbes that live in your gut.

They're smaller than any of the cells in your body, yet they can play a huge role in your overall health.

The good ones will protect you... and the bad ones will make you sick.

But if you end up in the ICU for any reason, the balance will suddenly shift. According to the new study, there's a "massive depletion" in the levels of essential bacteria you need for good health.

Those are the germs that help digest food, pull out nutrients, and produce the serotonin used by the brain. They also help power your immune system, giving you a fighting chance against disease.

The same good bugs can also overwhelm the bad ones that want to make you sick, keeping them in check and preventing infection even when you've been exposed to those infection-causing bacteria.

But when you're in the ICU, those levels drop so rapidly you're practically running on empty.

In fact, the new study finds the shift happens so fast that illness-causing "bad" bugs can make up as much as 95 percent of your gut flora within days of your admission into the ICU.

That could lead to all kinds of problems from poor digestion to infection to another trip to the hospital down the road -- and maybe even a return to the ICU.

There are probably a number of factors in play here. Many patients in the ICU are put on antibiotics, which kill off all but some of the worst germs -- allowing them to take over, as we see in the new study.

Lousy low-nutrition hospital food can make the situation even worse.

Obviously, there's not much you can do about your gut bacteria when you're laid up in the ICU.

But once you're back home from a hospital stay -- especially if you've been in the ICU -- make sure you take a probiotic supplement. Take it for several weeks to a month at a minimum but honestly, at this point, you should probably consider taking a probiotic daily even if you haven't been in a hospital.

Studies show that even "healthy" Americans suffer from bacterial imbalances, increasing the risk of chronic disease later on.

Look for a formula with a blend of human-tested antibiotic strains, ideally with several billion colony-forming units (CFUs).