functional nutrition

Sibo Doctor Approved
Alyssa Simpson RD, CDE, CLT
Alyssa Simpson

(602) 422-9800

Sibo Doctor Approved
certified gastrointestinal nutritionist
Sibo Doctor Approved
certified gastrointestinal nutritionist

Has Your Digestion Turned Against You? How to Improve Colon Health.

Share This Post!


Table of Contents

We’ve arrived. After our month-long journey through the digestive system, we’ve made it to the large intestine.

For many of my patients, this is the part of their digestion that gives them the most trouble. If you struggle with constipation, diarrhea, or a combination of both, you probably think about your large intestine more often than you’d like.

But before we dive into this last leg of the digestive system, it’s important to understand that issues in your large intestine don’t necessarily originate there. Digestion is a north to south process. That means that when things go wrong up top, they can cause problems all the way down.

Your diarrhea and/or constipation may be due directly to large intestine issues. But it could also be originating from other digestive dysfunction like:

? Eating while in a sympathetic (fight or flight state) that downgrades digestion.

? Inadequately chewing your food which makes it harder for your stomach to get the job done.

? Too little stomach acid which keeps your food from being able to move smoothly through your stomach and into the small intestine.

? An ineffective Migrating Motor Complex (MMC) that doesn’t adequately keep things cleaned up in the stomach and small intestine

As a functional nutritionist I look at the whole picture. It’s hard to properly diagnose and deal with symptoms when we only look at the symptom itself. Symptoms — any symptoms — are your body’s way of communicating with you. It’s telling you something is out of balance. And when we just put a band-aid on a symptom instead of figuring out why the symptoms are happening, we’re missing the body’s message.

That’s why it’s so important to look for the root cause. Our bodies are complex systems. And it’s important to zoom out and look at everything that’s going on. So if you’re struggling with typical IBS symptoms like diarrhea, constipation, bloating, gas, and abdominal pain, make sure you and your practitioner are looking beyond the actual symptom so you can address the underlying issue.

Back to our regularly scheduled programming…

What does the large intestine do?

The large intestine is a 5-foot long tube that extends from your small intestine to your anus. While most of the nutrients your body needs have already been absorbed before this stage of digestion, some important stuff happens here too.

The large intestine absorbs water and electrolytes from what’s left of your digested food and turns the rest into stool to be expelled from the body. But wait… there’s more.

The large intestine is also home to your microbiome. This is a colony of 10 trillion bacteria that affect all parts of your body.

The microbiome:

✔ Aids in the final stage of food digestion

✔ Contributes to immune health by stimulating the immune system

✔ Breaks down toxins

✔ Synthesizes vitamins (like B vitamins and vitamin K) + amino acids

✔ Produces and responds to neurochemicals like GABA, serotonin, dopamine, and melatonin.

A healthy microbiome is key. You want a microbiome that is plentiful (contains a lot of bacteria) and diverse (contains a variety of bacterial strains). Different strains of bacteria accomplish different tasks. And lower diversity is associated with stress and anxiety. So it’s important to have a wide variety of strains in your gut.

Better Digestion Tip #1: Take care of your gut microbiome

Improving your gut microbiome can make a difference in your digestion and overall health.

Avoid substances that damage your gut bacteria.

Antibacterial products

If you’re like most people these days, you use antibacterial products all the time. During the health crisis over the past three years, antibacterial products have become wildly popular. And while these products kill the bacteria that can make you sick. They don’t discriminate between the bad bacteria and the good bacteria in your microbiome.

I know you aren’t eating hand sanitizer (at least I hope not). But when you’re using hand sanitizer or antibacterial soap and cleaning products, the residue can make its way down into your gut and cause damage. I’m not saying you should stop using these products completely. But be aware. There is a downside.


Antibiotics are designed to kill bacteria. And when you take them, you’re sending them straight down into your digestive system. Antibiotics certainly have their place and can be lifesaving when they’re needed. But overuse of antibiotics has become commonplace.

Keep in mind that antibiotics aren’t a cure-all — they don’t do anything for you if your illness is caused by a virus or fungal infection. And even many bacterial infections will clear up on their own without the use of antibiotics.

Consider probiotic and prebiotic foods and supplements (if you tolerate them).

Probiotic foods and drinks like yogurt, sauerkraut, and kombucha introduce new gut bacteria to your system. Prebiotic foods like oats, bananas, garlic, and onions help feed the bacteria in your gut to keep them healthy. But watch out! If you have SIBO, IBS, or another digestive issue, probiotic and prebiotic foods might not work well for you and can actually make your symptoms worse. Make sure to work with your practitioner to heal the underlying issues so that you can tolerate these healthy foods and get their full benefit.

Byproducts of a Healthy Microbiome

It’s not just the bacteria itself that boosts your health. Your gut bacteria also produce byproducts called short chain fatty acids (SCFAs). These fats affect brain function and the communication between your gut and your brain. They also improve the integrity of your large intestine as a barrier, impact systemic inflammation, and improve insulin secretion.

One of these SCFAs is called butyrate. Butyrate helps you maintain digestive health by providing as much as 70% of the energy your colon cells need. It may also support immune function, reduce inflammation, and even prevent cancer.

Better Digestion Tip #2: Vary your diet.

Do you eat the same things every day? Increase diversity of plant fibers by choosing plant foods in a variety of different colors. These will feed bacteria and result in SCFA production, which keeps colon cells healthy. Consider adding probiotic foods or supplements if you tolerate them.

The Doorway to the Colon

The Ileocecal valve separates your small and large intestine. And ideally, it should be a one-way door. But sometimes the ileocecal valve can have issues closing properly. And when this happens, bacteria can move from your large intestine back up into your small intestine where they can grow and cause a condition called SIBO. SIBO is responsible for symptoms like gas, bloating, and belly pain.

If you have these symptoms, make sure to check with your practitioner about testing for SIBO.

Your Food’s Commute, or Transit Time

Transit time is how long food takes to move through your digestive system from chew to poo. Ideally, this should be between 12 and 24 hours. If the process goes too fast, you can end up with diarrhea. If it goes too slow, you can get constipated.

Better Digestion Tip #3: Calculate your transit time

Figuring out your transit time is easy enough. I recommend using either beets or corn. Beets turn your ? purple. So take note of the day and time when you eat beets, and keep an eye on your stools. The amount of time that passes (pun intended) between the time you eat the beets and the time you see purple poo is your transit time. If you want to use corn, swallow a few kernels of frozen corn unchewed and notice when they make their toilet debut. A word of caution: don’t use corn if you have diverticulosis.

If you’re working with a practitioner on your digestion, make sure and share your transit time with them. This information can provide insights into what’s happening in the dark, unseen parts of your digestive system.

If you need some help untangling your digestive issues, I’m here for you. Click the button below to schedule a consultation.

Free IBS Resource Guide
The Top 5 IBS Resources I Use Every Day
Get your Free Meal Picklist
Join My Free Facebook Group
Meet Alyssa
Alyssa Simpson RD, CDE, CLT
registered dietitian weight loss tips
Is IBS Slowing You Down?

Get Your Free IBS Resource Guide Now and start feeling better fast!