What is it?
Black psyllium is found in some over-the-counter medicines and is effective for treating and preventing constipation. It is also used for diarrhea, obesity, diabetes, and for reducing the risk of heart disease, but there is less evidence that it is effective for these conditions.
How effective is it?
Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate.
The effectiveness ratings for BLACK PSYLLIUM are as follows:
- Constipation. Black psyllium is safe and effective for short-term, over-the-counter use for treating constipation.
Likely effective for...
- Heart disease. Black psyllium is a soluble fiber. Foods high in soluble fiber can be used as part of a low-fat, low-cholesterol diet to prevent heart disease. Research shows that a person must eat at least 7 grams of psyllium husk each day to reduce the risk for heart disease.
Insufficient evidence to rate effectiveness for...
- Diabetes. Early research suggests that taking black psyllium might help control blood sugar in people with diabetes by reducing how quickly sugars are absorbed from food.
- High blood pressure. Research suggests that taking psyllium can decrease blood pressure in some people, but the effect is very small.
- Build up of fat in the liver in people who drink little or no alcohol (nonalcoholic fatty liver disease or NAFLD). Early research shows that taking psyllium can lower body weight and body mass index (BMI) in people with NAFLD. But it doesn't work any better than standard care.
- Obesity. Research suggests that psyllium does not reduce weight, body mass index (BMI), or waist measurement in people who are overweight or obese.
- A long-term disorder of the large intestine that causes stomach pain (irritable bowel syndrome or IBS).
- High levels of cholesterol or other fats (lipids) in the blood (hyperlipidemia).
- Other conditions.
Are there safety concerns?
Black psyllium is LIKELY UNSAFE when taken by mouth without enough water. Be sure to take black psyllium with plenty of water. Otherwise, it might cause choking or block the gastrointestinal (GI) tract.
Special precautions & warnings:Pregnancy and breast-feeding: Taking black psyllium during pregnancy or breast-feeding seems to be LIKELY SAFE, as long as enough water is taken with the dose.
Intestinal problems: Don't use black psyllium if you have impacted stools, a complication of constipation in which the stool hardens in the rectum and can't be moved by usual movement of the bowel. Don't use black psyllium if you have any condition that increases your risk of getting blockages in your intestines. The concern is that when black psyllium absorbs water and swells up, it might block the GI tract in people with these types of conditions.
Allergies: Some people are severely allergic to black psyllium. This is more likely to happen to people who have been exposed to black psyllium on the job, such as nurses who prepare doses of powdered laxatives, or workers in factories that process psyllium. These people shouldn't use black psyllium.
Phenylketonuria: Some black psyllium products might be sweetened with aspartame (NutraSweet). If you have phenylketonuria, avoid these products.
Surgery: Because black psyllium might affect blood sugar levels, there is a concern that it might interfere with blood sugar control during and after surgery. Stop using black psyllium at least 2 weeks before a scheduled surgery.
Swallowing disorders: People who have trouble swallowing might be more likely to choke on black psyllium. If you have an esophageal problem or swallowing disorder, don't use black psyllium.
Are there interactions with medications?
- Carbamazepine (Tegretol)
- Black psyllium contains large amounts of fiber. Fiber can decrease how much carbamazepine (Tegretol) the body absorbs. By decreasing how much the body absorbs, black psyllium might decrease the effectiveness of carbamazepine.
- Black psyllium contains large amounts of fiber. Fiber can decrease how much lithium the body absorbs. Taking lithium along with black psyllium might decrease the effectiveness of lithium. To avoid this interaction, take black psyllium at least 1 hour after lithium.
- Metformin (Glucophage)
- Black psyllium contains large amounts of fiber. The fiber in psyllium might increase how much metformin the body absorbs. This might increase the effects of metformin. To avoid this interaction, take black psyllium 30-60 minutes after medications you take by mouth.
- Digoxin (Lanoxin)
- Black psyllium is high in fiber. Fiber can decrease how much digoxin (Lanoxin) the body absorbs. By decreasing how much the body absorbs, black psyllium might decrease the effectiveness of digoxin.
- Ethinyl estradiol
- Ethinyl estradiol is a form of estrogen that's in some estrogen products and birth control pills. Some people worry that psyllium can decrease how much ethinyl estradiol the body absorbs. But it is unlikely that psyllium will affect ethinyl estradiol absorption.
- Medications taken by mouth (Oral drugs)
- Black psyllium contains large amounts of fiber. Fiber can decrease, increase, or have no effect on how much medicine the body absorbs. Taking black psyllium along with medicine you take by mouth can impact the effects of your medicine. To prevent this interaction, take black psyllium 30-60 minutes after medications you take by mouth.
Are there interactions with herbs and supplements?
- Use of psyllium with iron supplements can reduce the amount of iron that the body absorbs. Take iron supplements one hour before or four hours after psyllium to avoid this interaction.
- Psyllium seems to slightly reduce the amount of riboflavin that the body absorbs, but it's probably not important.
Are there interactions with foods?
- Fats and fat-containing foods
- Psyllium can make it difficult to digest fat from the diet. This can increase the amount of fat lost in the stool.
- Taking black psyllium with meals over a long period of time might alter nutrient absorption. In some cases, taking vitamins or mineral supplements might be necessary.
What dose is used?
The following doses have been studied in scientific research:
- For constipation: The typical dose of black psyllium is 10-30 grams per day in divided amounts. Take each dose with plenty of water. Otherwise, black psyllium might cause choking. The FDA labeling recommends at least 8 ounces (a full glass) of water or other fluid with each dose.
- For heart disease: At least 7 grams of psyllium husk (soluble fiber) daily, as part of a low-fat, low-cholesterol diet.
To learn more about how this article was written, please see the Natural Medicines Comprehensive Database methodology.
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