We are what we eat. The lining of our gut is covered with millions of both good and bad bacteria which form a complex ecosystem called microbiome. The colony of bacteria is crucial for regulating our immune system and digestion of food. If our gut is healthy (more good bacteria), we are healthy.

Prebiotic is a naturally occurring non-digestible carbohydrate found in plant fiber while probiotics are naturally occurring bacteria in our body.
Prebiotics feed probiotics. Together prebiotic and probiotic can help make a strong gut flora of good bacteria to keep us healthy and disease free.

Carbohydrates; well, we need to understand a little bit about carbohydrates also before jumping on the pre and probiotic brigade. As carbohydrate plays a major role in explaining them.

Carbohydrate can be present in the food in the form of;
1. Sugar
2. Starch
3. fiber

Simple carbs are easy to digest such as sugar and the other forms what is called complex carb contain longer chains of sugar molecules and takes longer time to digest. Complex carb foods (wholegrain) normally have more fiber, vitamins and minerals.

Prebiotics are dietary ingredients with complex carbohydrates with high plant-fiber and something called ‘resistant starch’ that human can’t digest but our good bacteria can.
Yes, not all starches or carbohydrates are not equal. Simple carbohydrates (like sugar) get digested quickly causing a rapid spike in blood sugar level while some other starches (complex carbs) remain undigested in intestine thereby slowly releasing the sugar or energy levels.
Resistant starches are complex carbohydrates or fiber-rich carbs which resist digestion in the small intestine and passes to large intestine where they get fermented and become food for the friendly bacteria.
Wholegrain (rolled oats, millet), chia, green banana, soyabeans, raw garlic, flax seeds, apples, onion are a good source of prebiotic food.
Phew…wish I had focused on my science lessons during school days.