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Herbal supplements often contain hidden ingredients

A recent study led by Chapman University has found that some supplement companies may mislead customers with unproven health claims and undeclared ingredients. The researchers focused on herbal supplements purported to treat or prevent COVID-19 and other respiratory illnesses. During the pandemic, the use of dietary supplements surged globally. 

“There was a big spike in purchase and use of these types of supplements during the pandemic,” said senior author Rosalee Hellberg, an associate professor of food science at Chapman. “Whenever there’s an increase in demand, there’s also an increased chance for fraud to occur.”

Ayurvedic herbal supplements 

The researchers collected 54 supplements containing Ayurvedic herbs, a type of alternative medicine from India, which were claimed to treat COVID-19. 

These herbs included ashwagandha, cinnamon, ginger, turmeric, tulsi, vacha, amla, guduchi, and tribulus. The products were sourced from online and local retailers in Orange and Los Angeles counties, CA.

DNA barcoding 

The researchers employed DNA barcoding techniques to verify the plant species in the supplements. DNA barcoding uses a short DNA sequence to identify an organism’s species. 

The researchers noted several concerning results, indicating the need for increased scrutiny of these products. In 60% of the products, the expected ingredient was not detected. 

However, Hellberg noted that this might not necessarily indicate fraud, as the novel use of DNA barcoding may struggle to detect degraded DNA, meaning a negative result does not confirm the absence of the species.

Hidden ingredients in herbal supplements 

Another limitation of DNA barcoding is that it does not quantify the detected species’ ingredients. Additional research is required to verify the amount of each ingredient, Hellberg said. 

“If the ingredients were present at a higher amount, that is where the concerns can arise,” explained Hellberg. “Also, any time you’re detecting things that aren’t on the label, that can indicate some quality control issues. That could also suggest that there are other health risks going on or maybe things aren’t being handled properly.”

The scientists also found 19 products with undeclared plant species. Common fillers such as rice and other materials were identified, along with other unlisted Ayurvedic herbs. 

“So these could be used in a fraudulent manner,” said Hellberg. “Instead of having 100% of the declared species on the label, some manufacturers might mix in filler because it’s cheaper.”

Broader implications of the study

Undeclared species and ingredients in supplements pose risks to consumers, who could ingest substances causing allergic reactions and other health issues. However, the study did not determine the exact risk level, as it could not detect the amount of each ingredient. 

This study – published in the journal Phytochemical Analysis – highlights the importance of increased regulation and scrutiny of dietary supplements to ensure consumer safety and prevent misleading health claims.

More about herbal supplements 

Herbal supplements are products made from plants for their therapeutic or medicinal properties. They are commonly used to improve health, boost immune function, and prevent or alleviate various ailments. 

Herbal supplements can be found in various forms, such as pills, powders, teas, extracts, or capsules.

Traditional medicine

The use of herbal supplements dates back thousands of years as part of traditional medicine practices across the world, such as Ayurveda and Traditional Chinese Medicine. 

Commonly used herbs include echinacea, used to prevent colds; ginseng, used for energy and cognitive function; and St. John’s wort, often used for depression.

Lack of regulation 

While many find herbal supplements beneficial, their effectiveness can vary widely. In many countries, they are not strictly regulated like prescription drugs. This lack of regulation can lead to inconsistencies in potency and purity. 

Side effects

Users should also be aware of potential side effects and interactions with other medications. Some of the general side effects and risks associated with herbal supplements include:

Allergic reactions

Some people may experience allergies to certain herbs, manifesting as rashes, hives, swelling, or difficulty breathing.

Gastrointestinal issues

Many herbal supplements can cause nausea, vomiting, diarrhea, or upset stomach.

Sleep disturbances

Supplements such as ginseng and ginkgo can cause insomnia or restlessness.

Bleeding risks

Herbs like garlic, ginkgo, and ginseng have blood-thinning properties and can increase bleeding risk, particularly if taken with other blood thinners like warfarin.

Heart issues

Some herbs can interfere with heart medications and affect heart rhythms. For example, St. John’s wort can interact with heart medications like digoxin.

Liver damage

Supplements such as kava and comfrey have been linked to liver damage.

Drug interactions

Many herbs can interact with prescription medications, either decreasing or increasing their effects, which can be dangerous. For instance, St. John’s wort can reduce the effectiveness of birth control pills, antidepressants, and other medications.

It’s crucial for individuals to discuss any herbal supplements they are considering with a healthcare provider to ensure they are appropriate and safe, especially if they have underlying health conditions or are taking other medications.


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