A woman getting out of bed, clutching her stomach in pain.

The Hidden Truth: Does D mannose Lead to Digestive Distress?

Over the last few years, D-mannose has gained a reputation as an effective natural solution for dealing with urinary tract infections (UTIs). 

But you wonder if it’s safe? Does it cause digestive distress like irritable bowel syndrome, diarrhea, frequent stooling, and the like? 

Many research studies, albeit on a small scale, show that this sugar-like compound is effective and safe for preventing and treating UTIs with very few side effects, particularly digestive distress. Some of the potential side effects include minimal diarrhea and bloating. 

Like most dietary supplements, you’re more likely to experience side effects if you consume a high dosage of D-mannose. 

In this article, we dived deeper into the link between D-mannose consumption and digestive distress. 

We also discuss its health benefits, other adverse effects, natural sources of D-mannose, precautions to take when taking D-mannose supplements, and much more. 

Overview of D-mannose and digestive distress

A doctor holding a model of the human digestive system. D-mannose causes minimal digestive distress.

Our research shows that D-mannose leads to little to no digestive distress, and in cases where they exist, the experience is usually mild and doesn’t threaten the treatment regimen. 

Although most digestive disorders resolve by themselves after a few days or even hours, they can seriously affect your productivity for the few hours they persist. 

While supplements are great investments, knowing whether they present side effects helps you assess if the reward is worth the risk. 

And it’s with that same view in mind we explore if there’s a strong correlation between the use of D-mannose and digestive distress. 

As usual, we base our findings and conclusions primarily on articles published in research journals. So here’s what science says about this topic.

In recent years, scientists have explored nonantibiotic treatments for urinary tract infections (UTIs) and other day-to-day bacteria infections. 

This more recent focus is because the prolonged use of antibiotics often leads to the bacteria becoming antibiotic-resistant, which in the long run may lead to far-reaching complications when antibiotics cannot be used to treat more pressing issues. 

For this reason, most of the studies we’ll present in this section investigate D mannose as a potential treatment for UTIs. Our focus is on the safety and tolerability of D mannose, especially as it concerns digestive issues. 

Study 1

In our first study, the researchers provided 28 women with a D-mannose-containing study agent

The authors tested the participants at weeks 4 and 12 after treatment commenced and concluded that the “study blend showed a good safety profile and tolerability.” 

There were no reported side effects, and the study agents remained tolerable and safe up to 75 mL daily. However, it’s imperative to note here that the main ingredient in the study agent was a liquid blend of cranberry juice, D-mannose, and other compounds. 

Study 2

Researchers at the University Sapienza of Rome enrolled 43 participants with a history of UTIs in a study to examine if D-mannose alone was effective as a treatment for any acute urinary tract infection in women. 

The participants received Mannocist, a product containing 1.5 grams of D-mannose and other compounds like sodium bicarbonate, sorbito, and silicon dioxide. 

In the first three days, participants received Mannocist twice daily. Subsequently, the researchers reduced the dose to once daily for the next ten days. 

Per the research authors, no side effects, including digestive distress, were observed during the treatment. 

Study 3

Researchers in a study to examine the potency of D-mannose to prevent recurring UTIs divided 308 participants into three groups. Each study participant had a history of recurrent UTIs. 

The first group received 2 grams of D-mannose diluted with 200 ml water for six months. The second group received 50 mg of nitrofurantoin, another compound used to treat UTIs, daily for the same period. The last group did not receive any treatment, just a placebo. 

About 17.9% of the participants who received D-mannose and nitrofurantoin reported mild side effects, with mild diarrhea being the only oft-reported adverse reaction. 

However, the authors noted that the group who received D-mannose was significantly less likely to experience side effects than those who received nitrofurantoin. 

The result from the study cements how tolerable D-mannose is. 

Study 4

In our fourth study, 22 participants received 1.5 grams of D-mannose powder twice daily for four months. 

According to the researchers, the participants showed no adverse side effects and concluded that D-mannose is both safe and feasible as a treatment for recurrent UTIs.

Study 5

In this randomized trial, researchers divided the study participants into two. 

The first group received a gram of D-mannose three times daily for the first two weeks and then the same dose twice daily for 22 weeks afterward. The other group received antibiotic treatment. 

After analyzing the results, the authors concluded that “D-mannose appeared to be a safe and effective treatment for recurrent UTIs in adult women.” 

Study 6

This study examined the use of mannose as a treatment for “Carbohydrate-deficient glycoprotein syndrome type I (CDGS).” 

The researchers noted that taking doses of 0.1 grams of mannose per kg or 2.205 pounds body weight every three hours maintained the levels of mannose in the blood “at levels 3- to 5-fold higher than the basal level in both normal controls.”

They also concluded that no side effects were observed at the dosage above. However, they opined that taking 0.2 grams of mannose per kg of body weight may lead to adverse effects, especially diarrhea and bloating. 

Summary of scientific research linking D-mannose to digestive distress

The evidence in the above studies, and many more not cited here, show that D-mannose causes little to no digestive distress. 

In cases where study participants experienced adverse events, these side effects, mostly diarrhea and bloating, were often minimal. 

More importantly, most of these studies noted that the adverse effects did not necessitate treatment discontinuation. 

Additionally, we have highlighted multiple research studies to show D-mannose administered in different dosages and used for varying duration of treatment. 

Irrespective of the dose and duration of treatment, the findings remained consistent that D-mannose was safe with little to no reported adverse events. 

Notwithstanding, it’s important to note that most of the research studies have limitations. For example, the sample size in most of the available studies was small. 

This means there’s still more room for confirmation with studies that use larger sample sizes, higher-quality methodologies, and diverse populations.  

Health benefits of D-mannose

Woman experiencing UTI pain sits on couch, holding her stomach.

Some of the incredible health benefits of D-mannose include preventing and reducing the symptoms of UTIs, serving as a potential treatment for CDGS, aiding the metabolism of proteins, immune regulation, potentially stabilizing blood sugar, and preventing diabetes. 

We examine these benefits below. 

1. D-mannose helps maintain urinary tract health

Per the Centers for Disease Control and Prevention, UTIs rank number five among all healthcare-associated infections. So, it is a very big deal. 

One study puts the cost of recurrent UTIs between $390 and $730 per episode. 

Multiple research studies have demonstrated the possibilities of using D-mannose to maintain urinary tract health, both from a preventative and treatment point of view. 

One of the reasons why D-mannose is explored in these ways is because it prevents bacteria from bonding to the walls of your urinary tract. 

We’ll examine one such study for each use case below. 

Preventative benefits

One of the significant concerns about UTIs is their high risk of recurrence. Between 25-30% of women who’ve had UTIs before experience a recurrence within a span of six months. 

Studies have shown that taking D-mannose can significantly reduce this risk. 

One study divided 103 participants into three. The first group received D-mannose, the second an antibiotic called Nitrofurantoin, and the last received no treatment. 

The researchers found that the group that received treatments “had a significantly lower risk of recurrent UTI episodes.” Moreover, the data showed that the D-mannose group fared better than the Nitrofurantoin group. 

UTI treatment

Researchers administered D mannose twice daily for three days and subsequently once daily for ten days afterward. 

The researchers reported that the majority of the UTI symptoms were better after treatment per the validated questionnaire delivered to the study participants. 

Furthermore, they noted that "D-mannose seemed to have had a significant positive effect on UTIs' resolution and quality of life improvement." 

The D-mannose dietary supplement from Why Not Natural contains four additional components, making it a more potent option for keeping your urinary tract health in tip-top shape. 

These additional components include probiotics (lactobacillus rhamnosus and Lactobacillus reuteri), cranberry extract with 25% Proanthocyanidins (PAC), vitamin D3, potassium ascorbate, and organic bamboo silica. 

Are you wondering what probiotics are? Read: What are probiotics? Here's what you need to know.

2. Treatment option for Carbohydrate-deficient glycoprotein syndrome type I (CDGS)

CDGS is an inherited syndrome that distorts how the body processes certain compounds, particularly proteins and glycoproteins. 

While the prevalence of the condition is relatively low, it can lead to severe health issues like liver disease and terrible diarrhea. 

One study found that D-mannose supplementation led to the correction of protein glycosylation, typical of CDGS. 

This result led the authors to conclude that there’s a strong possibility of using D-mannose “as a potential therapeutic dietary supplement (nutraceutical) to treat CDGS patients.”

3. Essential for human metabolism

D-mannose plays an important role in how the human body processes food. Researchers found that D-mannose helps the body attach carbohydrates to certain proteins that aid immune regulation. 

Without the attached carbohydrates, these proteins would have been unable to perform their functions. 

4. Immune regulation participation

D-mannose also functions as a prebiotic. Prebiotics are compounds that facilitate the growth of healthy bacteria. 

Side note: there are good and bad bacteria, and the human body needs a healthy dose of the good ones to thrive. 

Healthy bacteria ensure the body’s immune response to infections is apt, prompt, and not overactive. 

5. D-mannose may potentially prevent diabetes and stabilize blood sugar

Per a study in animals, scientists found that giving rats D-mannose dietary supplements prevented diabetes. 

The researchers used a variant of mice known to develop diabetes at 12 weeks old for their trial. Half the mice population received normal water, and the other half consumed a water solution of D-mannose. 

About 90% of the mice in the water-only group developed diabetes by the 12-week mark. However, “most of the animals” in the D-mannose group did not develop diabetes, even beyond the 23-week mark. 

Additionally, the researchers noted that D-mannose reduced the blood sugar levels in mice that had already developed diabetes. 

Despite these findings, clinical trials are needed to see if the same benefits are observable in humans. 

Other potential benefits

We've listed other potential benefits of D-mannose based on research in mice below. More research is necessary to confirm that these benefits are also applicable to humans. The benefits include:

  • Prevents diabetes before the onset of hyperglycemia, high blood sugar
  • Blocks the progress of diabetes
  • Suppresses inflammation
  • Induces the production of T-cells vital in fighting against autoimmune diseases
  • Prevents and treats allergies
  • Reduces the growth of cancer cells
  • Used as a biomarker for insulin resistance
  • Prevents weight gain

What foods naturally contain D-mannose?

Foods that are rich in D-mannose, such as cranberries, blueberries, apples, and peaches.

D-mannose is naturally occurring in many food sources, such as fruits and vegetables. Sources of D-mannose include:

  • Cranberries
  • Blueberries
  • Apples
  • Peaches
  • Mangoes
  • Green beans
  • Kidney beans
  • Aloe vera
  • Tomatoes 
  • Broccoli
  • Cabbage
  • Egg whites
  • Oranges

From the above list, cranberries, blueberries, and peaches are the richest sources. 

You can get 36 to 38 milligrams of D-mannose in every 100 grams of cranberry juice. For blueberries and peaches, this figure is 9 to 10 milligrams and 2 to 3 milligrams, respectively. 

What are the other sources of D-mannose?

The other sources of D-mannose you’ll find in the market are dietary supplements extracted from fruits and vegetables. D-mannose supplements occur in both tablet and powder forms, each equally potent. 

You may opt for the tablet form if you’re comfortable taking them. Conversely, the powdered form is best if you would like to use the supplement as a sweetener. Remember, it’s sugar similar to glucose. 

Other sources are vital because the D-mannose occurring in natural foods is not high enough for some of the benefits we highlighted earlier. 

For example, improving urinary tract health requires a dosage between 1.5 and 2 grams of D-mannose, according to the clinical trials we perused. 

The richest source of D-mannose, cranberry, only produces a small fraction per 100 grams, which means you’ll need to consume an unhealthy amount of the food to enjoy the intended benefits. 

Since this is not advisable, taking high-dose D-mannose supplements is the best available option

Recommended dosage of D-mannose

For many reasons, it’s always difficult to pinpoint the exact dosage required for supplements. These reasons include:

  • Your diet
  • Your present status—-individuals deficient in a vitamin will need more than those simply dealing with insufficiency
  • Certain medical conditions may demand a higher dosage to compensate for the limitations the ailment places on the body
  • The purpose of the supplementation

Suffice it to say that there’s no standard dosage for D-mannose. 

However, based on the clinical studies we assessed, the minimum dosage for the prevention and treatment of UTIs was at least 1 gram per day and at most 2 grams daily. 

For other use cases, the dose may be different. Researchers in one clinical study used a dose of 0.1 grams of mannose per kilogram body weight for CDGS treatment without any notable side effects. 

Each tablet in our 5-in-1 UTI supplement contains 1000 mg or 1 gram of D-mannose, probiotics, vitamin C and D3, cranberry extract, and other naturally occurring ingredients to help you defeat urinary tract infections for good. 

Does D-mannose have side effects?

Per the research studies we examined, the side effects of D-mannose are minimal, related to digestive issues, and often very mild. The oft-repeated symptoms in most of the trials we discussed were mild diarrhea and sparse cases of bloating. 

Moreover, the authors of these studies noted that these side effects did not require stopping the D-mannose treatments. Other potential side effects include nausea and increased gas. 

Additionally, research has shown that excess D-mannose, about 20-30% of the consumed dosage, finds its way into your urine barely within 60 minutes of consumption. 

This goes a long way to explain why there are barely any side effects from taking a moderate amount of D-mannose. 

How to reduce gas and bloating when taking D Mannose

Gas and bloating are some of the side effects of taking D-mannose. If you’re experiencing any of these symptoms, then you may need to assess your dosage or stop taking the supplement outrightly, depending on the severity of your symptoms. 

One particular study noted that doses of 0.1 grams of mannose per kilogram body weight administered every three hours did not induce any side effects. This means if you were 70 kg or 154 pounds, a likely dose of 7 grams may not lead to any side effects. 

That said, it’s critical to note clinical studies are often conducted in controlled environments with carefully selected participants. As such, you may react totally differently from the study population. 

That’s why we recommend moderate consumption of D-mannose. A maximum dose of two grams daily is adequate, especially for keeping your bladder and urinary tract healthy. Multiple research studies have shown D-mannose to be safe, with little to no side effects at this dosage. 

Not sure if you’re consuming excess dietary supplements? Read: 3 Ways To Tell That You Are Taking Too Many Supplements. 

Precautions to take when using D-Mannose

As with any dietary supplement, it's important to assess its safety as it affects your needs and peculiarities, especially if you're pregnant or have any serious medical condition like diabetes. 

There are three categories of people who should take great care when using D-mannose. In fact, these three categories of people should not take D-mannose without consulting their doctor. 

  • Pregnant women: No research has evaluated the safety and efficacy of D-mannose in pregnant women. It's better to avoid or speak to your doctor before consuming D-mannose or any other supplement at that. 
  • Breastfeeding mothers: The same reason above applies. 
  • People with diabetes: For anyone living with diabetes, it's essential to be wary of consuming any sugars.

Are you looking for dietary supplements that are safe and produced with the highest standard of quality in the industry? 

Dietary supplements from Why Not Natural contain no fillers, artificial sweeteners, preservatives, or artificial additives and have been tested and verified by independent agencies. 

Shop our wide range of vitamins and dietary supplements today for safe and effective products that complement your food intake. 

Can I take D-Mannose on an empty stomach?

There’s no scientific evidence to suggest it’s not safe to take D-mannose on an empty stomach. So, it’s not necessary to only take D-mannose with meals. 

We’d also like to add that since D-mannose is a sugar, we suggest avoiding taking the supplement with meals high in other types of sugars. This will ensure you’re maintaining healthy blood sugar levels. 

Is it safe to take D Mannose every day?

Many researchers who explored using D-mannose as a treatment option administered the sugar for multiple consecutive days, including up to 60 days, without any side effects. 

This suggests that it’s safe to take D-mannose daily. However, it’s imperative to stick to moderate dosage to minimize the risk of developing digestive issues like diarrhea or bloating. 

How many times a day should D-Mannose be taken?

Based on research studies, taking 1 to 2 grams of D-mannose supplement twice or thrice daily is safe. Michigan Medicine notes that the dose for D-mannose is 1 gram twice daily. 

It’s worth pointing out that your D-mannose dosage regimen will depend on multiple factors, including the purpose of consuming D-mannose and the potency of the supplement you’re taking. 

We’ve seen studies where the dosage started thrice daily and then reduced to twice daily. What’s notable about these studies is that they mostly used a moderate dose of D-mannose, often between 1 and 2 grams. 

What is the best time to take D-Mannose?

There isn’t a good time to take D-mannose. Since the recommended dose is twice daily, we suggest taking the first dose in the morning and the second dose at night before going to bed. 

So that you don’t miss a dose, we propose setting alarms on your phone and sticking to the same schedule. The schedule should match your daily routine so that it’s easier to comply with the plan. The more doses you miss, the longer it is before you see results.

Can I take D-Mannose with other medications?

Our literature review of academic journals and leading medical sources did not reveal any known interactions between D-mannose and other drugs. Thus, we recommend caution if you have to take D-mannose with other drugs. 

Consult your doctor if you’re taking any serious medications. However, D-mannose is safe to take with other dietary supplements without any mild or serious health concerns. 

Can D-mannose be taken with antibiotics?

You can take D-mannose with antibiotics. The authors of a research study noted this: “Our results indicate that high d-mannose concentrations have no effect on bacterial growth and do not interfere with the activity of different antibiotics.” 

Takeaway: Cleanse and defend your urinary tract with D-mannose

Premium urinary tract health supplement with Cranberry PAC, D-Mannose, Probiotics, Vitamin C & D.

We’ve been able to show how potent D-mannose can be in preventing and relieving the symptoms of UTIs. 

The six research studies we discussed established D-mannose as a safe, well-tolerated, and effective option for the above purpose. 

Furthermore, the research articles noted little to no side effects. The few studies that reported noticeable complications highlighted diarrhea as the leading side effect one may experience when taking D-mannose. 

Ultimately, the conclusion is that although D-mannose leads to digestive distress, the impact is negligible on treatment continuance. This means the potential digestive distress is not weighty enough to affect your quality of life. 

Are you shopping for a potent and high-quality D-mannose supplement? 

Our 5-in-1 UTI pill with D Mannose and other natural ingredients is the perfect supplement to protect you from UTIs, bacterial vaginosis, and yeast infections. 

Visit our shop today to take advantage of our ongoing sales and promotions.

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