Psyllium: Health benefits and research gaps

Supplement may contribute to intestinal and cardiovascular health, but well-founded studies on efficacy and side effects are needed

Bruno de Pierro

The image shows the Plantago ovata planted in the soil

A soluble fiber derived from the husks of Plantago ovata seeds, psyllium has been used for medicinal purposes since antiquity, dating back to the origins of writing. With growing popularity in recent years, psyllium has been used as a functional ingredient and nutraceutical—in other words, a highly nutritious bioactive compound used as a dietary supplement.

A study published this year in Annual Review of Food Science and Technology conducted a bibliographic review of the health benefits, possible uses by industry, and the potential side effects of psyllium.

The authors observed that although widely used as a dietary supplement to benefit intestinal health, there is a shortage of scientific studies on the physical and chemical properties of psyllium and any possible harmful effects.

Knowledge gaps about psyllium

Few studies that go towards understanding the undesired secondary effects of psyllium were identified, warned the authors, who are associated to institutions in China and the US.

Some of these papers suggest that the consumption of fiber can hamper the absorption of calcium in the human organism. “More research is required to deepen understanding,” they write.

Drug interactions

The research indicates that, although able to reduce the absorption of certain medications (including lithium, carbamazepine, digoxin, and levothyroxine), psyllium was also found to boost therapeutic effects and mitigate the adverse effects of drugs such as orlistat, mesalamine, and hypolipidemics (used to reduce lipids).

“These discoveries suggest that psyllium may inhibit or act in synergy with the absorption of medications, depending on the specific context and drug involved,” the authors say.

Despite the knowledge gaps, they stress the importance of psyllium for health, particularly for its fibrous structure.

Psyllium fiber resists digestion in the upper gastrointestinal tract and is fermented by bacteria in the large intestine, producing beneficial components such as short chain fatty acids (SCFA), which act upon the metabolism and the immune response when the organism is attacked by infections.

What the regulators say

The Food and Drug Administration (FDA), which regulates food and medicines in the US, approved psyllium as a nutraceutical, noting that consuming 7 grams or more of the fiber daily, along with a diet low in saturated fat and cholesterol, can be effective in reducing the risk of heart disease.

The review also mentions studies that indicate the benefits of psyllium in controlling blood sugar levels (especially in people with type II diabetes), helping to prevent glycemic spikes.

The FDA, however, says that the scientific evidence is still limited, and does not recognize psyllium as sufficient for diabetes treatment.

In Brazil, the Brazilian Health Regulatory Agency (ANVISA) authorizes the registration of compound psyllium products, provided that the labels and publicity provide information on the proven properties, such as the fact that natural fibers assist intestinal function.

In recent years ANVISA suspended the registration of psyllium-based products whose publicity campaigns promised benefits such as fat elimination, appetite control, and weight loss.

As with psyllium, glucomannan became an internet hit with ads highlighting its supposed slimming properties.

This soluble fiber, obtained from the root of the tuber Amorphophallus konjac, which originated in Asia, was given the nickname “natural Ozempic,” an allusion to injectable medicine with the active ingredient semaglutide, a synthetic hormone that helps to control blood sugar levels and generates a feeling of satiety in the brain.

The sale of glucomannan as a food supplement is prohibited by ANVISA, who classifies the fiber as a food additive with no nutritional purpose.

Psyllium: proven benefits

The paper published in the Annual Review of Food Science and Technology presents multiple health benefits of psyllium, with evidence generated by clinical and preclinical trials.

• Cholesterol reduction: Psyllium can reduce total and LDL cholesterol (the so-called “bad” cholesterol), helping to prevent cardiac illnesses.

• Glucose control: Has the potential to reduce the risk of type II diabetes, improving fasting levels of plasma glucose and glycohemoglobin.

• Gastrointestinal health: Effective in relieving chronic constipation and reducing the gravity of irritable bowel syndrome, while also modulating the intestinal microbiota.

Other potential positive effects include increased satiety, colon anticancer action, and antioxidant properties.

In addition to its nutraceutical impacts, psyllium is a versatile functional additive in foods. According to the article, certain attributes allow it to act as follows:

• Gelling agent: Improves the texture and inhibits syneresis (separation of liquid) in gel products.

• Fat substitute: Reduces calorie content in foods such as yogurt and hazelnut spread.

• Emulsion stabilizer and gluten substitute: Provides structure to and improves the stability and viscoelastic properties of gluten-free breads and other bakery products.

The research also points to the use of psyllium in hydrogel delivery systems, namely materials with a high capacity for water absorption used to control drug release in the body.

Psyllium may be used, for example, to release bioactive compounds in a controlled and directed manner to the colon, helping with the treatment of intestinal illnesses and colorectal cancer.

The structural modification, whether chemical, enzymatic, or physical, may also optimize its properties for specific applications in the pharmaceutical industry.

The authors emphasize the need for more comprehensive studies into the physical-chemical characteristics and physiological responses of psyllium.

From the researchers’ point of view, psyllium offers a solid basis for the development of enhanced food products and industrial applications, with huge potential yet to be explored in the health and food quality areas.

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