What is psyllium

Psyllium or psyllium husk also called isphagula is a bulk-forming laxative that is used to treat constipation. Psyllium husk is rich in soluble fiber and has a cholesterol-lowering effect. Psyllium husk consists of the ground husk of the dried ripe seeds of the Plantago psyllium, Plantago Indica, Plantago Ovata, and Plantago Arenaria plants with laxative and cholesterol lowering activities. Psyllium husk is a soluble fiber, which absorbs water in the intestines, swells, and forms a bulky stool, which is easy to pass ¹. Psyllium husks contain mucilage that swells on exposure to water and provides an indigestible mucilaginous mass in the intestines, thereby causing lubrication, contraction of the smooth muscles of the intestinal walls, and thus stimulating bowel movement.

Psyllium husks are comprised of dietary fiber which, when mixed with water forms a gel-like mass that works as a mild laxative. This gel-like mass subsequently moves down a patient’s digestive system and makes stools softer by increasing their water contents. At the same time psyllium husk lubricates the intestine, which improves the transit of stools. Moreover, as the presence of the gel-like mass increases the stool bulk it also increases the tension and/or the stretch stimulus in the bowel wall which serves to trigger bowel movements. The dietary fiber of which psyllium husk is comprised is fermented to various degrees by bacteria in the colon, resulting in production of carbon dioxide, hydrogen, methane, water, and short chain fatty acids, which are absorbed and brought into the hepatic circulation. In humans, such fiber reaches the large bowel in a highly polymerized form that is fermented to a limited extent, resulting in increased fecal concentration and excretion of short chain fatty acids.

Psyllium and bran are the two best-studied dietary fibers. While bran was not shown to relieve IBS (irritable bowel syndrome) symptoms in studies, research suggests that psyllium can help ². Symptoms improved in 14 out of 100 people who had about 20 grams of psyllium in their diet per day.

Few data are available on psyllium use during breastfeeding; however, it is unabsorbed orally. The polysaccharide dietary fibres of which psyllium husk is comprised of need to be hydrolyzed to monosaccharides before intestinal absorption can occur. The sugar residues of the xylan backbone and side chains are joined by beta-linkages however, which cannot be broken by human digestive enzymes. Less than 10% of the mucilage gets hydrolyzed in the stomach, with formation of free arabinose. Intestinal absorption of the free arabinose is about 85% to 93%. As a consequence, psyllium remains predominantly in the gastrointestinal tract as a ‘bulk’ agent that passes largely unchanged throughout the gut. Psyllium has remarkable water holding capacity because of its high hemicellulose content. Psyllium husk when administered as indicated is usually excreted in the feces. As psyllium remains largely in the gut as a ‘bulk’ agent that passes predominantly unchanged throughout the gastrointestinal tract, there is little opportunity for marked absorption into or metabolism by the body. Most authorities consider psyllium acceptable to use during breastfeeding ³. Twenty postpartum mothers were given a laxative containing 2.7 grams of psyllium and senna equivalent to 15 mg of sennosides a and b daily on days 2 to 4 postpartum. Of the 11 infants who were breastfed (extent not stated), none had any loose stools ⁴.

Table 1. Psyllium husk nutrition

Nutrient	Unit	LEVEL TBSP 10 g	Value per 100 g
Approximates
Energy	kcal	35	350
Protein	g	0	0
Total lipid (fat)	g	0	0
Carbohydrate, by difference	g	8	80
Fiber, total dietary	g	7	70
Fiber, soluble	g	6	60
Fiber, insoluble	g	1	10
Sugars, total	g	0	0
Minerals
Calcium, Ca	mg	20	200
Iron, Fe	mg	1.8	18
Sodium, Na	mg	10	100
Vitamins
Vitamin C, total ascorbic acid	mg	0	0
Vitamin A, IU	IU	0	0
Lipids
Fatty acids, total saturated	g	0	0
Fatty acids, total trans	g	0	0
Cholesterol	mg	0	0

[Source ⁵]

Psyllium husk benefits

Psyllium husk for constipation

Physicians often define constipation as less than 3 stools/week ⁶. A more complete definition of constipation includes two or more of the following complaints (in the absence of laxatives) for at least 12 months: straining on >25% of bowel movements, feeling of incomplete evacuation after> 25% of bowel movements, hard or pellety stools on >25% of bowel movements, fewer than 3 stools/week, or stools less frequent than 2/week with or without other symptoms of constipation ⁶.

Chronic idiopathic constipation is common in the general population, especially in women and the elderly ⁷. Constipation is the most common gastrointestinal complaint in the US, resulting in 2.5 million physician visits every year, and hard stool is a complaint often associated with constipation ⁸. This suggests that a significant stool softening effect would provide a major benefit in the treatment of chronic idiopathic constipation. A study ⁹ was conducted to compare the stool softening (stool water content) and laxative efficacy of psyllium vs. docusate sodium in subjects with chronic idiopathic constipation using objective and subjective measures associated with constipation. The study showed that psyllium is superior at softening stool compared to docusate ⁹. In contrast to the widely held perception that stool softeners work faster than bulk laxatives, this study showed that psyllium treatment resulted in softer stools for the 3 days after initiation of treatment. Furthermore, the superior stool softening effect of psyllium increased over the 2‐week treatment period, suggesting that the effect may increase with continued use ⁹. There were no significant differences in subjective measures of constipation between treatment groups in the first week of treatment. Stool consistency, straining with bowel movement, pain with bowel movement and evacuation completeness showed directional improvement of symptoms for both treatment groups. That study also demonstrated that psyllium is superior to docusate for stool softening, as measured by percentage water content, as well as the other objective measures of constipation, suggesting that psyllium is a more comprehensive treatment for the objective measures in subjects with a history of chronic idiopathic constipation. The use of a non‐systemic bulk fiber may also be preferable from a safety perspective, particularly for women of childbearing potential.

Psyllium fiber improves glycemic control for type 2 diabetes mellitus

More than 3 decades ago, a study established that gel-forming fibers were therapeutically useful in reducing postprandial blood glucose, which is a phenomenon that was highly correlated with the viscosity of the gel-forming fiber ¹⁰. In this 1978 study, raw guar gum (highly viscous and gel forming) showed a marked reduction in peak postprandial glucose ¹⁰. When the guar gum was hydrolyzed (e.g., partially hydrolyzed guar gum), viscosity was attenuated and the viscosity and gel-dependent effects on postprandial glucose were lost. The introduction of a gel-forming fiber significantly increases the viscosity of chyme in the upper intestine, which reduces the contact with digestive enzymes and delays absorption, thereby causing an increased fraction of nutrients to be delivered to distal regions of the small bowel ¹¹. This effect is comparable to the effects of intestinal α-glucosidase inhibitors that reduce the digestion and absorption of carbohydrates and, thus, delay and blunt the delivery of glucose to the circulation. Moreover, the delivery of increased amounts of carbohydrate to the ileum has been associated with an increased release of the glucoregulatory factor glucagon-like peptide 1 (GLP-1), which may also contribute to better glycemic control in response to a gel-forming fiber ¹². Insoluble fibers (e.g., wheat bran) and soluble nonviscous fibers (e.g., inulin and wheat dextrin) do not exhibit these viscous and gel-dependent effects ¹³. It was hypothesized that psyllium would have little to no effect on fasting blood glucose in euglycemic subjects, that a beneficial effect existed in subjects with prediabetes, and that this effect would be amplified with a progressive loss of glycemic control.

This systematic study ¹⁴ strengthens the existing clinical evidence, which was previously shown in numerous disparate studies ¹⁵, ¹⁶, that psyllium dosed before meals as a dietary supplement provides an effective modality for lowering elevated fasting blood glucose concentrations. This effect is both significant and clinically meaningful, with an ~1% (10.6-mmol/mol) lowering of HbA1c, which is comparable to the effect of many drugs that are used to treat diabetes. Moreover, the effect seems to be dependent on blood glucose concentrations, which were minimal in persons with euglycemia and most pronounced in patients who were being treated for type 2 diabetes mellitus.

The benefits of increased dietary fiber intake to mitigate metabolic disease have been broadly shown over the past 40 years ¹⁷. Conclusions from a large body of evidence have shown that diets with a higher fiber content from whole foods are associated with reduced rates of cardiac disease and stroke as well as lower concentrations of plasma lipids and glucose ¹⁸. In contrast with studies of dietary fiber from whole foods, an examination of the effects of isolated fiber sources present in fiber supplements did not provide a mechanistic insight with viscous, gel-forming fibers such as psyllium, guar gum, and β-glucan having been shown to reduce the absorption of bile (cholesterol) and delay the absorption of glucose from the gut ¹¹. These effects are proportional to the degree of viscosity for gel-forming fibers ¹¹, suggesting a significant component of mechanical interference with normal absorptive function of the small intestine.

A clinical study showed that the viscosity of a gel-forming fiber is actually a better predictor of cholesterol-lowering efficacy than is the quantity of fiber consumed ¹⁹. Focused studies of specific fibers with attributable actions on physiology have raised the potential for the use of these agents as nutriceuticals. Moreover, because the years of recommendations to increase the proportion of high fiber foods such as fruit, vegetables, and whole-grain cereals have had only a limited impact on the dietary practices of the American populace ²⁰, supplements would seem to provide the most-efficacious application of the health benefits of ingested fiber. However, not all fiber supplements provide these measurable health benefits. Gel-dependent effects in the small bowel (e.g., cholesterol lowering and improved glycemic control) and in the large bowel (e.g., relief from constipation and diarrhea) are not provided by nongelling, nonviscous, fermentable, soluble supplements (e.g., wheat dextrin and inulin) ¹¹.

On the basis of the experience in clinical trials ¹¹, there is no attributable risk of clinically significant hypoglycemia that is due to psyllium. However, there have not been formal studies of the use of psyllium with glucose lowering drugs to examine this possibility. A possible interaction should be evaluated and would need to be monitored in specific patients with the use of the combination of psyllium and drugs that can cause hypoglycemia. Although additional studies are needed to determine how best to incorporate psyllium into clinical practice, because of the broad use of psyllium for numerous health benefits (e.g., cholesterol lowering, satiety, and treatment of constipation, diarrhea, and irritable bowel syndrome) ¹³, the glycemic data presented in the current article show that psyllium would be an effective addition to a lifestyle-intervention program.

Psyllium fiber and cholesterol

Dietary fiber is a collective term for a variety of plant substances that are resistant to digestion by human gastrointestinal enzymes ²¹. Dietary fibers can be classified in 2 major groups depending on their solubility in water. In humans, the structural or matrix fibers (lignins, cellulose, and some hemicelluloses) are insoluble, whereas the natural gel-forming fibers (pectins, gums, mucilages, psyllium and the remainder of the hemicelluloses) are soluble. Studies have focused on soluble fibers such as oats, psyllium, pectin, and guar gum, and qualitative reviews suggested that these fibers lower total and LDL “bad” cholesterol ²². Water-insoluble wheat fiber and cellulose have no effect unless they displace foods supplying saturated fats and cholesterol ²³.

While a high saturated fat intake in the diet is believed to be a contributing factor towards elevated cholesterol levels, increased consumption of dietary fiber from cereals and fruits is inversely associated with the risk of coronary heart disease. In 1994, the Food and Drug Administration authorized a health claim that low-fat diets containing soluble gel-forming fibers such as psyllium and oat β-glucan lower plasma cholesterol and are thus associated with a lower risk of coronary heart disease. However, simply increasing the amount of gel-forming dietary fiber analogues in the diet results in a consistent but only modest effect on lowering lipids ²⁴. For example, 3 g soluble fiber from oats (3 servings of oatmeal, 28 g each) can decrease total and LDL cholesterol by <0.13 mmol/L. Increasing soluble fiber can make only a small contribution to dietary therapy to lower cholesterol ²⁵. Dietary fiber had a small HDL “good” cholesterol lowering effect at the borderline of statistical significance and did not affect triacylglycerol concentrations.

The mechanism by which fiber lowers blood cholesterol remains undefined ²⁵. Evidence suggests that some soluble fibers bind bile acids or cholesterol during the intraluminal formation of micelles ²⁶. The resulting reduction in the cholesterol content of liver cells leads to an up-regulation of the LDL receptors and thus increased clearance of LDL cholesterol. However, increased bile acid excretion may not be sufficient to account for the observed cholesterol reduction ²⁷. Other suggested mechanisms include inhibition of hepatic fatty acid synthesis by products of fermentation (production of short-chain fatty acids such as acetate, butyrate, propionate) ²⁸; changes in intestinal motility ²⁹; fibers with high viscosity causing slowed absorption of macronutrients, leading to increased insulin sensitivity ³⁰; and increased satiety, leading to lower overall energy intake ³¹.

Conflicting data do not support previous findings that patients with hypercholesterolemia are more responsive to dietary fiber than are healthy individuals ³². Subgroup analyses of initial cholesterol concentrations showed that persons with moderate or severe hypercholesterolemia (concentrations >6.20 mmol/L, or >240 mg/dL) showed only slightly larger decreases in total cholesterol than did those with lower cholesterol concentrations. Initial LDL cholesterol was a moderately significant predictor of LDL “bad” cholesterol changes, but the difference in responsiveness was small: 0.02 mmol/L (0.75 mg/dL) per gram of soluble fiber.

Most of the available epidemiologic studies suggest that dietary fiber is inversely related to coronary artery disease ³³, ³⁴, ³⁵. Earlier studies suggested that the effects of fiber may be larger than those shown in this meta-analysis ²⁵. However, methodologic problems including small sample sizes, incomplete dietary measures, and inadequate control of important confounders made it difficult to determine the effects of dietary fiber independently of other dietary components and, more specifically, the contribution of soluble compared with insoluble fiber. The modest reductions in cholesterol expected from intakes of soluble fiber within practical ranges may exert only a small effect on the risk of heart disease. For example, daily intake of 3 g soluble fiber from either 3 apples or 3 bowls (28-g servings) of oatmeal can decrease total cholesterol by ≈0.129 mmol/L (5 mg/dL), a ≈2% reduction. On the basis of estimates from clinical studies of cholesterol treatment ³⁶, this could lower the incidence of coronary artery disease by ≈4%. These findings are consistent with an earlier summary of the cholesterol-lowering effects of oat products ³⁷.

According to both the Food and Drug Administration and some fiber experts, viscosity is recognized as one of the major physico-chemical properties responsible for the physiological effects of consuming soluble fiber, including reduction in blood lipids ³⁸. Viscosity is a physicochemical property associated with dietary fibers, particularly soluble dietary fibers. Viscous dietary fibers thicken when mixed with fluids and include polysaccharides such as gums, pectins, psyllium, and β-glucans ³⁹. Although insoluble fiber particles may affect viscosity measurement, viscosity is not an issue regards insoluble dietary fibers. Viscous fibers have been credited for beneficial physiological responses in human, animal, and animal-alternative in vitro models.

A clinical study showed that the viscosity of a gel-forming fiber is actually a better predictor of cholesterol-lowering efficacy than is the quantity of fiber consumed ⁴⁰. Focused studies of specific fibers with attributable actions on physiology have raised the potential for the use of these agents as nutriceuticals. Moreover, because the years of recommendations to increase the proportion of high fiber foods such as fruit, vegetables, and whole-grain cereals have had only a limited impact on the dietary practices of the American populace ²⁰, supplements would seem to provide the most-efficacious application of the health benefits of ingested fiber. However, not all fiber supplements provide these measurable health benefits. Gel-dependent effects in the small bowel (e.g., cholesterol lowering and improved glycemic control) and in the large bowel (e.g., relief from constipation and diarrhea) are not provided by nongelling, nonviscous, fermentable, soluble supplements (e.g., wheat dextrin and inulin) ¹¹.

Psyllium husk how to use

Psyllium comes as a powder, granules, capsule, liquid, and wafer to take by mouth. It usually is taken one to three times daily. Follow the directions on the package or on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take psyllium exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

• Take psyllium with a full glass (at least 8 ounces) of water or other liquid. Psyllium can swell in your throat and cause choking if you don’t take it with enough liquid. Drink plenty of fluids each day to help improve bowel regularity.
• Swallow psyllium capsules one at a time. Do not take more than the recommended number of capsules per dose.
• Psyllium powder must be mixed with liquid before you take it. Do not swallow the dry powder. Mix the powder with at least 8 ounces of liquid such as water or fruit juice. Stir and drink this mixture right away. To get the entire dose, add a little more water to the same glass, swirl gently and drink right away.
• The psyllium wafer must be chewed before you swallow it.

Psyllium usually produces a bowel movement within 12 to 72 hours.

It may take up to 3 days before your symptoms improve. Do not take psyllium for longer than 7 days in a row without a doctor’s advice. Using a laxative too often or for too long may cause severe medical problems with your intestines.

Call your doctor if your symptoms do not improve, or if they get worse while using psyllium.

Psyllium may be only part of a complete program of treatment that also includes diet, exercise, and weight control. Follow your doctor’s instructions very closely.

Before taking psyllium:

• tell your doctor and pharmacist if you are allergic to psyllium or any other drugs.
• tell your doctor and pharmacist what prescription and nonprescription medications you are taking, including vitamins. Do not take digoxin (Lanoxin), salicylates (aspirin), or nitrofurantoin (Macrodantin, Furadantin, Macrobid) within 3 hours of taking psyllium.
• tell your doctor if you have or have ever had diabetes mellitus, heart disease, high blood pressure, kidney disease, rectal bleeding, intestinal blockage, or difficulty swallowing.
• tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking psyllium, call your doctor.
• tell your pharmacist or doctor if you are on a low-sugar or low-sodium diet.
• be careful not to breathe in psyllium powder when mixing a dose. It can cause allergic reactions when accidentally inhaled.

What special dietary instructions should I follow?

To prevent constipation, drink plenty of fluids, exercise regularly, and eat a high-fiber diet, including whole-grain (e.g., bran) cereals, fruits, and vegetables.

Psyllium husk dosage

Usual Adult Dose for Constipation

Daily fiber:

• Adults 19 to 50 years: Male: 38 g/day; Female: 25 g/day
• Pregnancy: 28 g/day
• Lactation: 29 g/day

Dose:

• 1 to 2 rounded teaspoonfuls, 1 to 2 packets, 1 to 2 wafers, or 5 to 6 capsules orally with 8 ounces of fluid 1 to 3 times a day

Usual Adult Dose for Irritable Bowel Syndrome

Daily fiber:

• Adults 19 to 50 years: Male: 38 g/day; Female: 25 g/day
• Pregnancy: 28 g/day
• Lactation: 29 g/day

Dose:

• 1 to 2 rounded teaspoonfuls, 1 to 2 packets, 1 to 2 wafers, or 5 to 6 capsules orally with 8 ounces of fluid 1 to 3 times a day

Usual Pediatric Dose for Constipation

Daily fiber:

• Children 1 to 3 years: 19 g/day
• Children 4 to 8 years: 25 g/day
• Children 9 to 13 years: Male: 31 g/day; Female: 26 g/day
• Children 14 to 18 years: Male: 38 g/day; Female: 26 g/day

Constipation:

• Children 6 to 11 years: 1.25 to 15 g orally per day in divided doses
• Children greater than or equal to 12 years and Adults: 2.5 to 30 g per day in divided doses

Renal Dose Adjustments

No adjustments recommended

Liver Dose Adjustments

No adjustments recommended

Dialysis

No adjustments recommended

What should I avoid while taking psyllium?

Avoid taking other oral (by mouth) medicines within 2 hours before or 2 hours after you take psyllium. Bulk-forming laxatives can make it harder for your body to absorb other medications, possibly making them less effective.

Avoid breathing in the dust from psyllium powder when mixing. Inhaling psyllium dust may cause an allergic reaction.

If you take psyllium as part of a cholesterol-lowering treatment plan, avoid eating foods that are high in fat or cholesterol. Your treatment will not be as effective in lowering your cholesterol if you do not follow a cholesterol-lowering diet plan.

What should I do if I forget a dose?

If you are taking scheduled doses of psyllium, take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your dosing schedule. Do not take a double dose to make up for a missed one.

Psyllium side effects

Overdose with psyllium husk can cause abdominal discomfort, flatulence, and/or intestinal obstruction. The LD50 (lethal dose 50 where 50% of the test subjects die) of psyllium husk administered orally to mice has been observed in some studies to occur in doses up to 2940 mg/kg or 3360 mg/kg in rats.

Obstruction of the esophagus, stomach, small intestine, and colon has occurred when bulk-forming laxatives are administered without adequate fluids or in patients with intestinal stenosis.

Clinical studies have shown that 7 g per day of soluble fiber from psyllium husk may help reduce the risk of heart disease when used as part of a diet low in saturated fat and cholesterol.

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Stop using psyllium and call your doctor at once if you have:

• choking or trouble swallowing;
• severe stomach pain, cramping, nausea or vomiting;
• constipation that lasts longer than 7 days;
• rectal bleeding; or
• itchy skin rash.

Common side effects may include:

• bloating; or
• minor change in your bowel habits.

This is not a complete list of side effects and others may occur.

Hypersensitivity

Hypersensitivity side effects have been reported rarely. They have included sensitization from inhalation of fine dust particles dispersed into the air as the product is mixed or poured.

While hypersensitivity reactions may be severe, they are most frequently reported by workers in the pharmaceutical firms that manufacture the drug. This is because when it is mixed or poured, fine dust particles are readily dispersed into the air and can then be inhaled and cause sensitization. Orally ingested psyllium seems less likely to induce sensitization.

Gastrointestinal

Gastrointestinal side effects have included several cases of esophageal impaction and duodenal bezoars in patients receiving a bulk laxative product containing 82% psyllium and 18% senna (commercially available as Perdiem Overnight Relief). Other gastrointestinal side effects have included nausea, intestinal gas, cramps, mild diarrhea, rectal pain, constipation, and irritation.

Hematologic

The case report of eosinophilia was believed to be a sole manifestation of an allergic reaction to psyllium.

Hematologic side effects have included a case of eosinophilia.

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