Why doesn’t corn get digested? And other digestion questions answered

The human digestive system is really quite incredible. It has the ability to extract the energy your body needs from the food you eat and then turn the rest into waste. 

While that sounds simple, your digestive system is extraordinarily complex. And you probably have lots of questions about it. Like, why doesn’t corn get digested or how long does gum take to digest?

Thankfully, Pharmacist and Nutritionist Sarah Gray has the answers to these and many more common digestion questions. 

Why doesn’t corn get digested?

When you see corn in your poo, don’t panic! Veggies are some of the best foods for gut health, so you want to keep eating them. What you’re seeing is actually the outer coating of the corn kernel that’s designed to protect it during harvesting.

“This coating is made of cellulose,” explains Sarah. “Your body doesn’t have the digestive enzymes or gut bacteria to break down cellulose. That’s why you see it in your poo.”

How long does it take food to be digested?

The process of digestion starts as soon as you put the food in your mouth. From there it moves through the stomach where your digestive enzymes do their thing to break the food down. It then moves through both the small and large intestines. 

“How long this takes varies from person to person, but it’s generally anywhere from 24 to 72 hours,” says Sarah.

Things like bowel problems or dysbiosis can also impact how long this takes. It also depends on the type of food you eat. If you consume fermented foods for gut health, you may digest them differently to more processed foods.

How long does it take to digest water?

This is an interesting one because the time it takes to digest water depends on how you drink it.

“It takes longer to digest water that you drink at mealtimes than water you drink on its own,” says Sarah. 

How long does gum take to digest?

Contrary to what you were told when you were a kid, it doesn’t take years for your body to digest gum. The process actually takes about seven days.

But Sarah says it’s not recommended that you swallow gum.

“Gum isn’t very nutritious, and there have been cases where swallowing gum has led to intestinal blockages.”

How long does it take for vitamins to digest?

It’s not actually digestion but metabolism that handles vitamins in the body.

“The intestine and liver are both associated with the metabolism of vitamins,” explains Sarah. “It varies from vitamin to vitamin, mineral to mineral, depending on their composition. For example, some vitamins are more water soluble and are absorb more quickly than others that are more fat soluble.”

Does coffee after a meal help with digestion?

Coffee can stimulate gastric acids, which may help with the digestive process. But Sarah warns that drinking coffee after a meal may have another unwanted effect.

“Coffee contains tannins, which can reduce your absorption of iron if you consume it at the same time as eating food,” says Sarah. “It’s not a hard and fast rule, but if you do have low iron, it’s definitely something to consider.”

Can you digest paper?

The question of digesting paper is similar to the question of why doesn’t corn get digested.

“Paper is mainly made from cellulose,” explains Sarah. “Humans don’t have the necessary enzymes to break down cellulose. It’s probably best to avoid eating paper!”

Are eggs difficult to digest?

The answer to this question depends on the person.

“If you enjoy eggs and your body digests them well without any gastric upset, that’s fine,” says Sarah. “But some people might not do that well with eggs. In these cases it is best to speak to an Accredited Practising Dietitian or Registered Nutritionist to find out why.”

Eating raw eggs can also cause unwanted gastrointestinal side effects, as well as increase your risk of food poisoning, so they’re best avoided. 

Is that enough to digest?

When it comes to your health, it’s a constant learning journey.  Whether you want to improve your gut health or understand the difference between prebiotics and probiotics, we’re here to help.

Related:

• Let's talk about bread and the immune system
• What is my gut microbiome (and why should I care about it?)
• How stress affects gut health

Sarah Gray is both a Registered Pharmacist and Registered Nutritionist with a particular interest in health education and helping people to take small steps to big change in their health journey. Sarah is a member of the healthylife Advisory Board.

Reviewed by the healthylife Advisory Board April 2022.