About ten percent of Americans get adequate fiber in their diet. Your body does not digest fiber. Bacteria ferment some fibers in your colon, while others pass through relatively unchanged. The more fermentable the fiber is in your colon, the more potential for bloating and discomfort.
If you have been on the standard American diet, you need fiber. If you introduce fermentable fiber too quickly, it can be like a champagne pop - without the cork, but lots of internal bubbles that can bloat and cause discomfort.
There is plenty of evidence that fiber is healthy for you, and promotes the kind of bacteria in your colon that you want.
The standard recommendation for fiber is about 25 grams daily for women and 38 grams for men through age 50, with lower age-adjusted targets of 21 and 30 grams after 50.
Fiber, Constipation, Diarrhea
One major role for fiber is to prevent constipation. Fiber can not only decrease constipation, but also firm up stools if your stools are a bit loose. On a GLP-1, one can get enough fiber, and last week we showed how to start fiber in the morning with some good breakfast.
What About Supplements
There are many fiber supplements out there. More and more are coming daily, but I want to talk about the more common ones. There is nothing wrong with taking a supplement, because we are not perfect, and sometimes taking a supplement is a good way to keep things moving along. Now my brain is thinking “old man River, it just keeps moving” - while a boat is quietly going down the Colonic River.
Metamucil (Psyllium)
This is probably one of the most commonly sold fibers in the US, and a favorite of many gastroenterologists. The fiber forms a gel, moves things along in the colon, and has a lot of good evidence for improving stool consistency, decreasing constipation, and even will lower your LDL cholesterol a bit.
When starting this supplement, bloating and discomfort can happen if you are starting from a regular diet. Introduction of any fiber can cause this. So start slow and work your way up.
Metamucil must be taken with 8 ounces of water. If you don’t take it with water or other liquid, the fiber can expand in the throat or stomach and cause a blockage, not to mention nausea, vomiting, and even a visit to the ER.
Metamucil is contraindicated for people with bowel obstructions, difficulty swallowing, undiagnosed rectal bleeding, or known psyllium allergies.
Citrucel (methylcellulose)
This was probably the most common supplement I have recommended to my patients, because it causes the least bloating. It is soluble, like Metamucil, but it is less fermentable, hence less discomfort. Kind of tastes like Tang, that breakfast drink for those of us who grew up in the 60’s and 70’s.
Benefiber (Wheat Dextrin)
Unlike psyllium husk, Benefiber does not thicken into a gel, or become gritty, making it able to mix into water, coffee, juice. Some even put it into foods like yogurt and oatmeal.
It ferments slowly, less bloating. Although any fiber can cause bloating.
Traditional vs New Types
Traditional fiber supplements are a single type of fiber molecule (e.g., 100% psyllium husk or 100% wheat dextrin). Effective for their specific tasks (like gelling or softening stool). Different fibers feed different populations of bacteria, and some bacteria benefit from the products made by others. This is another reason we like having various fibers in your diet. From a supplement standpoint, this is partially accomplished by combining different fibers. Early indications suggest this approach may support a broader range of bacteria than relying on a single fiber.
Loam, the new kid on the block
This was formulated by a friend of mine, Karan Rajan, a fellow surgeon from the UK. Like most of us surgeons, fiber intrigued him, but wanted something better than was on the market. I am on his scientific advisory board. I do not receive money for endorsing Loam.
Loam is a bland blend of six prebiotic fibers. It even has a small, placebo-controlled study showing changes in the microbiome, including increased microbial diversity.
This is a higher fiber per serving, about ten grams. When I heard that some people put it into coffee, I didn’t believe it. Okay, I partially believed it because most of the UK has awful coffee. So if Karan put it in his coffee, who could blame him? Then I put it in my coffee. No change in taste, didn’t form a gel, and made my morning coffee a healthier drink. Now I put it in my coffee.
If I were to make a daily drink with vitamins, electrolytes, and fiber for GLP-1 patients (okay, I am working on this), I would include this type of a multi dimensional fiber.
For the future of fiber therapy, these types of multi-fiber prebiotic blends will be the way to go. Although for treatment of constipation, bulk fibers like Metamucil are effective.
The Ileal Brake
The Ileal Brake isn’t a new electric bike addition, it describes how your small bowel and fiber help you feel full.
The ileum is the last part of your small intestine, just before the colon. When the partially digested food reach the ileum, it triggers a signal that slows the movement of food through the digestive tract. Partly mediated by GLP-1 but also fiber..
Protein is often described as the food that keeps you satisfied. And it does. But consider this: most protein is digested in the first foot of the small intestine. Fiber when it arrives in the distal small bowel produces an effect of satiety.
Isn’t it interesting that the hyper-processed food available contains little to no fiber and is so easy to consume without feeling full? Tell me you can’t just eat one.
Let’s Talk About Poop
Constipation is one of the more common side effects of GLP-1 medications. Most of the time, it is a nuisance. Sometimes, it becomes a serious problem.
First, what is constipation? Some people think that if they don’t have a bowel movement every morning, something is wrong. First, consider you are eating less so you will have less poop. You may go from having a regular bowel movement daily, every morning at 5 am before you wake up at 7 am. To having one every few days. The key is if you feel comfortable, your stools are easy to pass..
When stools become hard, dry, or difficult to pass, you are constipated. You can even have a bowel movement every day and still be constipated. See those little rabbit turds in the bowl, yup, you need more liquid in your diet.
Why GLP-1 Medications Can Cause Constipation
There are several reasons for constipation when taking a GLP-1 medication.
We went over eating less. It is the one most people tend to forget. But when eating less, you also get less water in your diet. If twenty percent of your water comes from food, and you are eating less food, you will slowly get less fluid. Your body may not need the calories from the food, but you always need the same amount of liquid to compensate for the liquids you lose daily, in sweat, tears, stool, urine, etc.
The chances are you are drinking less. Some people taking GLP-1 medications experience less thirst, we discussed this last week. I never had a water bottle as a kid, except when hiking or camping, then we had a canteen - one my dad had during World War 2, now I wish I still had that. Otherwise, there was a hose outside, fountains with free water in Rome, and a glass by the sink.
One of the “jobs” of your colon is to absorb water from stool. It does that no matter how long the stool remains in the colon. The longer it is there, the more water it absorbs.
When Fiber Helps
Since 90 percent of people are fiber deficient, the symptoms of constipation are likely to come forward as constipation when you take a GLP-1. Increasing fiber is a reasonable place to start. Mind you, if you have abdominal pain, bloating, then you need to chat with your doctor before trying fiber maxing (a new term I understand).
Psyllium, like Metamucil, is useful because it forms a gel and helps retain water in the stool. That gel is resistant to the colon sucking out water and works well to keep things moving along. It has good evidence for treating chronic constipation.
Remember, you need to drink 8 ounces of liquid with the Metamucil, and if you have mild constipation, increasing liquid in your diet is a first step. I don’t care what color your urine is, just drink more - slowly over time, not gulping huge amounts at once. There are some of you with fluid restrictions. Here is where you need to sit with a registered dietician, always a good option, and go through your diet.
When More Fiber Makes Things Worse
If stool is moving slowly through the bowel, adding more bulk may increase bloating, discomfort, and the feeling that something is stuck.
More fiber isn’t always better. If you are already constipated and becoming increasingly uncomfortable, repeatedly adding more fiber may worsen your situation. Think Grizzly bear (see the last article about fiber). You don’t want a butt plug of fiber.
I want to emphasize this again: if you have severe abdominal pain, vomiting, marked abdominal swelling, or difficulty passing gas, don’t take more fiber. Talk to your doctor.
When to Use Something Other Than Fiber
For uncomplicated constipation that isn’t improving with food, fluids, and fiber, there are medications that can help.
MiraLAX (polyethylene glycol or PEG) is often a good choice. It is an osmotic laxative, meaning it retains water in the stool, making it softer and easier to pass. Unlike fermentable fiber, it doesn’t work by feeding your intestinal bacteria.
It has better evidence for treating chronic constipation than fiber supplements alone. It won’t work overnight. It generally takes one to three days to work.
Senna and bisacodyl (Dulcolax) are stimulant laxatives. They increase intestinal activity. They are good for occasional constipation. They can cause cramping and diarrhea. Typically Dulcolax works in eight hours, so I recommend people take this at night.
Magnesium-based laxatives are another option, but they require caution in people with kidney disease, because magnesium can accumulate in the body. For some of you who have decided to take magnesium supplements, you may have already experienced your bowels working too well.
The evidence that stool softeners like Colace work are weak, and I do not recommend these.
You should not need laxatives just to have a bowel movement. If you do, it is time to discuss a longer-term plan with your doctor.
When to Call Your Doctor
Most episodes of constipation can be handled without a medical visit. But there are times when you should call.
If you have persistent constipation despite reasonable treatment, develop a significant change in your usual bowel habits, or repeatedly need laxatives, it is time to get some professional help. No, don’t go to the people offering colonic hydrotherapy - coffee is best given through the mouth.
Increasing the dose of a GLP-1 can lead to constipation, and then I’d go through the algorithm outlined above. Increase water or other fluids, consider a laxative, and slowly increase fiber.
Severe or persistent abdominal pain, repeated vomiting, a swollen abdomen, or an inability to pass gas requires urgent evaluation, particularly when they occur together. And please, if you have any blood in the stool, rectal bleeding, fever, or unexplained weight loss, please get prompt medical assessment.
The Goal Is to Have a Comfortable Bowel Movement
If you can doom-scroll while sitting on your toilet because you are waiting, you need more fiber and more water.
Sometimes, the most important thing you can do for your colon is stop adding fiber and call your doctor.
Let’s Have Lunch
Last week, we started with breakfast and overnight oats. I also mentioned lentil soup, and you can find my recipe at terrysimpson.com.
But lunch doesn’t have to involve cooking soup, or even cooking at all. For those of us taking GLP-1 medications, lunch is often smaller than it once was. Getting enough protein is important, but we also need to think about fiber.
