From the Guidelines
Metamucil (psyllium husk) works primarily as a bulk-forming laxative by absorbing water in the intestines to form a gel-like substance that promotes regular bowel movements. When consumed, the soluble fiber in psyllium husk swells as it comes into contact with water in the digestive tract, increasing stool bulk and softening it, which helps ease passage through the colon 1. This mechanism makes it effective for treating both constipation and mild diarrhea. For constipation, it adds bulk and moisture to hard stools, while for diarrhea, it absorbs excess water to add form to loose stools. Metamucil also acts as a prebiotic, feeding beneficial gut bacteria and promoting intestinal health. Additionally, psyllium husk can help lower cholesterol levels by binding to bile acids in the digestive system, preventing their reabsorption and forcing the body to use cholesterol to produce more bile acids.
Some key points to consider when using Metamucil include:
- The typical adult dosage is 1 tablespoon (about 7 grams) mixed in 8 ounces of water, taken 1-3 times daily 1.
- It's essential to drink plenty of water when taking Metamucil to prevent the fiber from becoming too thick in the digestive tract, which could potentially cause blockages.
- Psyllium husk is considered safe to administer in pregnancy due to the lack of systemic absorption, and it can help promote regular bowel movements and prevent constipation 1.
- Soluble fiber, like psyllium husk, improves stool viscosity and transit time in addition to increasing bulk compared with insoluble fiber, which is exclusively bulk-forming 1.
Overall, Metamucil is a useful treatment option for constipation and mild diarrhea, and it can also provide additional health benefits by promoting intestinal health and lowering cholesterol levels. However, it's crucial to follow the recommended dosage and drink plenty of water to minimize the risk of adverse effects.
From the Research
Mechanism of Action of Metamucil (Psyllium Husk)
The mechanism of action of Metamucil, which is primarily composed of psyllium husk, can be understood through its effects on the digestive system and cholesterol levels.
- Psyllium has a considerable hygroscopic property, allowing it to retain water and expand rapidly, which helps in softening stool and promoting bowel movements 2.
- The expansion of psyllium in the presence of adequate fluids helps prevent constipation and can also help lower cholesterol levels by increasing the excretion of bile acids, which are made from cholesterol in the liver 3, 4, 5.
- Studies have shown that psyllium can lower LDL cholesterol by stimulating bile acid synthesis, which in turn increases the excretion of bile acids and total steroids 3, 4, 5.
- The hypocholesterolemic effect of psyllium is also attributed to its ability to increase the fractional turnover of bile acids, such as chenodeoxycholic acid and cholic acid 3.
- Additionally, psyllium has been found to increase the activity and mRNA levels of cholesterol 7alpha-hydroxylase, the rate-limiting enzyme in bile acid biosynthesis, which further contributes to its cholesterol-lowering effect 5.
Importance of Adequate Fluid Intake
It is essential to note that psyllium should be taken with an adequate amount of fluids to prevent intestinal obstruction, as the husk can expand and block the intestine if not enough fluid is present 2.
- Inadequate fluid intake can lead to intestinal obstruction, as seen in a case report where a patient developed an incomplete intestinal obstruction after ingesting psyllium husks without sufficient fluids 2.
- Therefore, it is crucial to instruct patients to drink a good amount of fluids when taking psyllium to avoid the development of bowel obstruction, especially with long-term use of such laxatives 2.
Overall Effects of Metamucil
The overall effects of Metamucil, which contains 100% natural psyllium, include promoting bowel regularity, lowering cholesterol levels, and providing multiple health benefits 6.
- A study found that pharmacists' counseling is associated with consumers' adherence and satisfaction to Metamucil, highlighting the importance of proper instruction and guidance when using this product 6.
- The majority of subjects in the study were satisfied with Metamucil and would continue taking it as a fiber supplement, indicating its effectiveness and acceptability as a dietary fiber supplement 6.