Herbal supplements and evidence-based recommendations

With so many dietary supplements on the market promising everything from enhanced cognitive function to improved immunity, it is crucial to discern which supplements are genuinely beneficial based on scientific evidence. Understanding when and why to recommend herbal supplements requires a keen eye on the latest research and a thorough evaluation of benefits versus risks. By focusing on evidence-based benefits and potential risks, we aim to provide a quick review of popular dietary supplements, making it easier to make informed recommendations.

Herbal supplements are highly accessible and come in various forms, including tablets, capsules, soft gels, powders, and liquids. However, regulation of this industry presents significant challenges. Understanding the benefits and safety concerns of these popular herbal supplements can guide better in making evidence-based recommendations.

Herbal supplements guide

With the rise of interest in natural remedies and health supplements, many individuals are turning to traditional and alternative medicine for support. This guide explores a variety of popular supplements, detailing their potential benefits, recommended dosages, and safety concerns.

Ashwagandha 

Ashwagandha, a small evergreen shrub found in dry areas of India, the Middle East, and parts of Africa, is deeply rooted in traditional Indian medicine. As an adaptogen, ashwagandha helps the body manage stress. Small clinical studies suggest it may reduce anxiety, improve sleep in patients with insomnia, and reduce stress levels.

• Dosage: Up to 1,000 mg daily for up to 12 weeks. A common dosing protocol is 500 mg daily, divided into two doses taken with breakfast and dinner.
• Safety concerns: Short-term use is likely safe for the general population. However, more research is needed to determine long-term safety. Ashwagandha is likely unsafe during pregnancy and lactation, and there is limited research on its use in children.

Berberine 

Berberine, a plant alkaloid found in various plants like barberry and goldenseal, can help regulate glucose and lipid metabolism. It may also lower C-reactive protein levels in people with metabolic conditions and improve hormonal outcomes in those with PCOS.

• Dosage: 500-1500 mg per day, divided into three to four doses. It should be taken with meals to maximize absorption.
• Safety concerns: Berberine is likely unsafe for pregnancy, children, and lactation. High doses (above 3000 mg/day) can cause gastrointestinal side effects like diarrhea and stomach pain.

Echinacea 

Echinacea is a perennial plant native to the Rocky Mountains in the USA. It is commonly used to prevent or treat the common cold. While it may help prevent colds when taken regularly, its effectiveness in treating an existing cold is limited.

• Dosage: Common dosages range from 300 mg to 500 mg taken three times a day.
• Safety concerns: Severe allergic reactions can occur, particularly in children. It is likely safe during pregnancy but not well-studied during lactation.

Elderberry 

Elderberry, a dark purple berry native to Europe, is known for its antiviral, antioxidant, and anti-inflammatory properties. It may help prevent and treat respiratory infections and strengthen the immune response under stress.

• Dosage: Doses may range from 175-900mg/day, with higher doses recommended for treatments from 48 hours-2 weeks and lower doses recommended for ongoing preventative measures up to 6 months.
• Safety concerns: Unripe elderberries can cause nausea, vomiting, and diarrhea. Consuming large quantities may lead to serious toxicity.

Ginkgo Biloba 

Ginkgo Biloba, a tree with leaves commonly used in dietary supplements, is known for its potential benefits in cognitive improvement and brain health. Ginkgo Biloba is believed to work through various mechanisms, including antioxidant properties, inhibition of the neurotoxic effects of amyloid beta, and improved blood circulation in the brain. Research suggests it may enhance aspects of cognitive function in individuals with dementia.

Additionally, preliminary evidence indicates that ginkgo can improve cognitive function in healthy middle-aged and older adults. Other potential benefits of ginkgo include reducing anxiety symptoms, alleviating symptoms of dementia, improving hearing loss when used with corticosteroids, mitigating symptoms of premenstrual syndrome, reducing both total and negative symptoms of schizophrenia, and aiding recovery from stroke. Oral ginkgo has not been shown to be effective in preventing or slowing the progression of dementia.

• Dosage: The standard dosage ranges from 60 to 240 mg daily for up to six months. It is best to take Ginkgo Biloba with meals.
• Safety concerns: While no significant safety concerns have been identified with Ginkgo Biloba leaf extract, some case studies suggest it may increase the risk of bleeding. Therefore, individuals, particularly those on blood thinners or with bleeding disorders, should consult a healthcare provider before starting ginkgo.

Lion’s mane mushroom 

Lion’s mane (Hericium erinaceus) is a mushroom belonging to the Hericiaceae family that grows on the dead trunks of hardwood trees such as oak, beech, or Japanese walnut. Recently, it has gained popularity due to claims of its neuroprotective and antioxidant properties, which may improve cognitive function and symptoms associated with neurodegenerative conditions. However, the existing clinical trial evidence supporting these claims remains limited.

• Dosage: 1,050–3,000 mg, divided into three to four daily doses. However, the optimal dose remains uncertain.
• Safety concerns: There is insufficient reliable information available regarding the safety of this supplement. It should be avoided during pregnancy and lactation.

Milk thistle 

Milk thistle (Silybum marianum) is a medicinal plant native to Southern Europe, Central Asia, and Ethiopia. Research on milk thistle primarily focuses on its main bioactive extract, silymarin. This extract may improve glycemic control in diabetic patients. Some small clinical studies suggest that it may slightly improve markers of liver function in patients with non-alcoholic fatty liver disease (NAFLD), though the evidence remains insufficient and findings are conflicting.

• Dosage: The recommended dosage for silymarin is 420 mg per day, usually divided into three doses.
• Safety concerns: Milk thistle is generally considered a safe and well-tolerated supplement. However, there is insufficient reliable information available about its safety during pregnancy or lactation, and it is generally recommended that this supplement be avoided during those periods.

Panax ginseng 

A herb in traditional Chinese Medicine, known for its calming properties and classification as an “adaptogen.” Adaptogenic herbs are believed to help the body resist both physiological and psychological stress. However, research on its effects on mood and cognition has produced mixed results. Studies indicate oral Panax ginseng can enhance middle-aged individuals’ abstract thinking, attention, arithmetic skills, and reaction time.

However, these benefits have not been observed in younger adults. Panax ginseng extracts may modulate the immune system and reduce the incidence of flu when taken alongside flu vaccinations. However, it does not appear to reduce the severity or duration of flu symptoms.

• Dosage: 200 to 400 mg is recommended, with 400 mg showing the most notable cognitive improvements. For erectile health and libido, ginseng extract is commonly administered at a dosage of 3 grams daily, divided into three 1-gram doses.
• Safety concerns: High doses and prolonged use can lead to “ginseng abuse syndrome,” characterized by hypertension, nervousness, sleeplessness, diarrhea, and skin eruptions. Extremely high dosages (15 grams per day or more) have been associated with depersonalization, confusion, and depression. Limiting continuous use to less than six months is advisable to avoid adverse effects. This supplement is likely unsafe for use in children and during pregnancy, but there is still not enough reliable evidence for use during lactation.

Peppermint oil 

Peppermint oil, derived from the hybrid plant Mentha piperita (a cross between watermint and spearmint), is known for its high menthol content, which serves as the bioactive ingredient. Its antispasmodic properties in the stomach and intestinal tract aid digestion and reduce colonic motility. The American College of Gastroenterology (ACG) conditionally recommends oral enteric-coated peppermint oil to relieve IBS symptoms, such as abdominal pain.

• Dosage: 450-750 mg of peppermint oil daily, or 0.3-0.6 ml, divided into 2-3 doses.
• Safety concerns: Peppermint oil is generally recognized as safe. To avoid irritation, enteric-coated capsules are advisable for those with heartburn.

St. John’s Wort 

St. John’s Wort (Hypericum perforatum) is a plant native to Europe, typically blooming at the end of June. This plant has a long history in traditional Chinese medicine, where its extract has been used to treat depression. Modern research supports that St. John’s Wort can be effective for mild to moderate major depressive disorder, often causing fewer side effects than some conventional antidepressants.

• Dosage: The most common dosage of St. John’s Wort extract used in studies is 300 mg, taken up to three times daily, totaling 900 mg daily.
• Safety concerns: It has been associated with potentially severe interactions with certain medications. These interactions can alter the effects of the drugs, leading to reduced effectiveness or unexpected outcomes.

Turmeric (Curcuma longa) 

Curcuma longa, commonly known as turmeric is a a flowering plant of the ginger family. The primary bioactive substance in turmeric is curcumin, a polyphenol with potent anti-inflammatory properties and the ability to enhance the body’s production of antioxidants. Curcumin supplements reliably lower certain markers of inflammation and boost endogenous antioxidant levels. However, in the presence of chronic inflammatory diseases, curcumin supplements tend to have minimal effect.

Curcumin has been shown to be moderately effective in improving symptoms of depression and provides moderate to significant improvement for osteoarthritis. Research is promising for inflammatory bowel disease, particularly ulcerative colitis, but further studies are needed to determine optimal dosing.

• Dosage: 300 mg to 4,000 mg per day. When taken orally, curcumin is poorly absorbed. To improve absorption, it is often paired with piperine (a compound found in black pepper) or combined with lipids.
• Safety concerns: Curcumin is likely safe when used short-term.

Efficacy and safety

Unlike pharmaceuticals, herbal supplement sellers are not required to prove that their products contain what their labels claim, nor must they test their products for efficacy. This practice can be misleading and often sells false hope to consumers. In the USA, the FDA oversees the industry under the Dietary Supplement Health and Education Act (DSHEA) of 1994. This act mandates product safety and labeling but does not require proof of effectiveness before market release.

The FDA’s primary responsibility is to ensure the safety and purity of dietary supplements after they enter the market and remove any potentially dangerous products from consumer shelves. Typically, the FDA only acts in response to numerous complaints about a supplement. Since the FDA does not verify herbal supplements, there is a concern regarding contamination with heavy metals, pesticides, and bacteria. Many studies have also found that herbal supplements contain fillers or substitutes that might reduce effectiveness.

The herbal supplement industry is highly lucrative, valued at an estimated $177.50 billion in 2023. The global dietary supplements market is projected to reach $300 billion by 2028, with herbal supplements playing a significant role. The most serious safety issue posed by dietary supplements is the sale or marketing by other health professionals or influencers of adulterated products containing illegal and unsafe ingredients whose effectiveness has not been demonstrated.

Ethical considerations

The involvement of dietitians in selling herbal supplements raises critical ethical considerations. As trusted healthcare professionals, dietitians are expected to provide evidence-based advice that prioritizes the well-being of their patients and clients. However, when dietitians endorse or sell herbal supplements, potential conflicts of interest can arise. Financial incentives may influence their recommendations, leading to the promotion of products that may not be rigorously tested or proven effective. This can undermine the trust between dietitians and their clients, as the integrity of their professional advice may be questioned.

Furthermore, dietitians should ensure transparency by fully disclosing any financial relationships with supplement companies and providing unbiased information about the benefits and risks associated with herbal supplements.

How to spot quality supplements 

Identifying high-quality products can be challenging given the lack of stringent regulation in the herbal supplement industry. Thankfully, several certifications are available that offer third-party testing by independent laboratories. These certifications help ensure that the products meet high standards for quality and safety, thereby building trust with consumers.

Key certifications to look for: 

• National Sanitation Foundation (NSF): The NSF certifies dietary supplements and ingredients, verifying that they meet strict standards for public health protection. It confirms that the product contains the ingredients listed on the label and that there are no harmful levels of contaminants.
• United States Pharmacopeia (USP): The USP verification mark signifies that the product has been tested for quality, purity, and potency. It confirms that the product is made according to the FDA’s Good Manufacturing Practices (GMP) and contains the ingredients in the declared strength and amounts.
• Natural Products Association (NPA): The NPA offers a GMP certification program for dietary supplements, ensuring compliance with GMPs. It confirms that the product is manufactured in a quality manner, ensuring the identity, purity, strength, and composition of the supplement.

In conclusion, it is crucial to understand both the benefits and risks associated with herbal supplements. While these products can offer health benefits, the lack of regulation means consumers must be cautious and well-informed. As dietitians, staying informed and prioritizing evidence-based practice when advising clients on herbal supplements is crucial.

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References

Examine.com. Berberine. Retrieved June 18, 2024, from https://examine.com/supplements/berberine/

Therapeutic Research Center. Berberine. Natural Medicines. Retrieved June 18, 2024, from https://naturalmedicines.therapeuticresearch.com/databases/food,-herbs-supplements/professional.aspx?productid=1126

Examine.com. Peppermint. Retrieved June 18, 2024, from https://examine.com/supplements/peppermint/

Therapeutic Research Center. Peppermint. Natural Medicines. Retrieved June 18, 2024, from https://naturalmedicines.therapeuticresearch.com/databases/food,-herbs-supplements/professional.aspx?productid=705

Examine.com. Curcumin. Retrieved June 18, 2024, from https://examine.com/supplements/curcumin/

Therapeutic Research Center. Turmeric. Natural Medicines. Retrieved June 18, 2024, from https://naturalmedicines.therapeuticresearch.com/databases/food,-herbs-supplements/professional.aspx?productid=662

Examine.com. Ashwagandha. Retrieved June 18, 2024, from https://examine.com/supplements/ashwagandha/

Therapeutic Research Center. Ashwagandha. Natural Medicines. Retrieved June 18, 2024, from https://naturalmedicines.therapeuticresearch.com/databases/food,-herbs-supplements/professional.aspx?productid=953

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Examine.com. Silymarin. Retrieved June 18, 2024, from https://examine.com/supplements/silymarin/

Therapeutic Research Center. Milk Thistle. Natural Medicines. Retrieved June 18, 2024, from https://naturalmedicines.therapeuticresearch.com/databases/food,-herbs-supplements/professional.aspx?productid=138

Examine.com. Elderberry. Retrieved June 18, 2024, from https://examine.com/supplements/elderberry/

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Efficacy of berberine in patients with T2DM. Retrieved September 9, 2024, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2410097/

https://www.usp.org/dietary-supplements-herbal-medicines

https://www.nsf.org/

https://www.npanational.org/