There was a time when people did not care about their gut health. In fact, it was considered rude to talk about one’s gut. I am sure the etiquette experts of yesteryear would insist that polite conversation did not turn to topics like bacteria or ways to strengthen bacteria in your gut.

Sorry, Emily Post, but times they have a-changed and now, no matter what diet you may follow, guts have come to be seen as an important piece of health. Probiotics are starting to be seen as a piece of preventive medicine. Blame it on Jamie Lee Curtis and the Activia challenge. Blame it on Kombucha. But healthy guts are indeed here to stay.

The question is: is this a warranted, science-backed movement or is it just trendy? I’m as guilty as the next person when I fall for the nicely packaged, popular AF health elixirs. When it comes to probiotics, prebiotics and your gut, the answers may not be as simplistic as any of us desire.

Here are five key pieces of information if you are as curious as I am about gut health:

1) There are 40 trillion bacteria in your gut. It’s not like you are going to be quizzed on this fact but it is an astounding number. You are what you eat is mostly true because your health can be determined by which type of bacteria is in your gut. (1)
2) Variety is the spice of life (and the best kind of bacteria). In order to get diverse microbiota, you need a diverse diet. This is good for all of us to remember, whether your go-to happens to be a kale salad or mashed potatoes. (2) Foods that are especially good for gut bacteria are beans, legumes, cruciferous vegetables and raspberries.
3) Prebiotics and probiotics are not the same thing. Prebiotics are foods that promote the growth of beneficial microbes, while probiotics are foods or supplements that contain the live microflora. One is food for the microflora, one is microflora itself. We need both, especially as probiotics don’t normally permanently colonize the intestines. Look at them as a welcome visitor that has the potential to change the overall composition of your gut, but only if eaten regularly. (1)
4) Fermented food is not synonymous with probiotics. It is tempting to make this connection, but the microbes that may be essential to make the product may also be filtered out (think wine or sourdough bread). Treating a product with heat often inactivate the microorganisms. Kefir, yogurt, kombucha and kimchi are pretty solid bets, but don’t do a ton if they only make an occasional appearance in your diet. (3)
5) Careful and clever approaches to prebiotics may not be as simple as a tub of yogurt. A two-pronged cocktail of prebiotics and probiotics – in careful amounts – is known as a symbiotic and this may be the key to changing the balance of bacterial strain in your gut. In other words, like most health trends, the real story is more complex than learning the basics and winging it. Ed Yong wrote a book about the topic entitled, “I Contain Multiples” and it warns against haphazard probiotic treatments. “Taking probiotics,” he said, “is a little bit like raising a small number of captive, zoo-born animals and then releasing them into the jungle and hoping that they’ll do well.” (4)