Why Parasites Thrive: What in the Body Allows Overgrowth?

When most people hear the word parasite, they imagine something rare and exotic. But the truth is, many of us are exposed to parasites regularly—through food, water, travel, pets, and even our environment. In small amounts, the body can usually keep them in check. The problem arises when the internal balance shifts and our defenses weaken. That’s when parasites can take hold, multiply, and create symptoms ranging from digestive upset to fatigue, skin issues, and brain fog.

So, what is it about the body’s internal terrain that allows parasites to overgrow? Let’s look at the main factors.