Thiamine is a vitamin that your body needs to turn food into energy. Scientists call it vitamin B1, and it's found in foods like whole grains, beans, nuts, and pork. Without enough thiamine, your muscles and brain can't work properly because they're not getting the fuel they need.

Your body can't make thiamine on its own, so you have to get it from what you eat. When you digest a slice of whole wheat bread or a handful of sunflower seeds, your body extracts the thiamine and uses it to help convert carbohydrates into energy your cells can use. Think of thiamine like a key that unlocks the energy stored in your food.

In the early 1900s, scientists discovered thiamine while investigating a disease called beriberi, which caused weakness, nerve damage, and heart problems in people whose diets lacked this vitamin. The discovery was revolutionary: it proved that certain diseases weren't caused by germs or bad air, but by missing nutrients in food. Today, many common foods like breakfast cereals and flour are fortified with thiamine to help ensure people get enough of it, making thiamine deficiency rare in places with varied diets.