Pill Pushing©

The herb industry - Based on fact or fiction? - (7/1/2018)

By Dr. Ron Gasbarro 

The herb industry – Based on fact or fiction?

Susie was browsing the herbal supplement aisle when she asked the pharmacist where the pau d’arco was. “I hear it is a great antibiotic and it can also stop cancer from forming!” Susie exclaimed. This pharmacist worked for a chain of stores across the country. As an employee, he had little say in what was stocked in the pharmacy. Corporate wanted to beef up their herbal supplement sales, so they erected a virtual altar to hundreds of types of herbs. Susie got her pau d’arco, happy as a clam!

The pharmacist knew, however, that many, if not most of these herbs, have never been tested on humans. In fact, in the case of pau d’arco, the only research has been done on mice. So, how did Susie hear about it? From a friend, a neighbor, a relative. Because the pharmacist did not know Susie, he had no way of knowing if she was on other medications, or what her medical history is. And that could be dangerous for Susie. 

The perils of herb supplements

Nearly half of all adult Americans take herbal and dietary supplements, presumably in a quest to get or stay healthy. However, new research finds many of them may be harming themselves. For example, liver injury caused by herbals and dietary supplements increased from 7% to 20% in an American study group over a 10-year period, according to a study published in Hepatology, a journal of the American Association for the Study of Liver Diseases [Bonkovsky, 2017]. The products caused the loss of bile ducts – a number of long tube-like structures that carry bile, necessary for digestion.  

Surprisingly, bodybuilders and endurance athletes are not the most affected by dietary supplements. Rather, liver injury caused by non-bodybuilding supplements occurs more often in middle-aged women and more frequently results in death or the need for transplantation than liver injury from bodybuilding supplements or conventional medications.

Drug interactions
Even though herbal supplements may be from plant or herb sources, the active ingredients can still be potent chemicals. Because of this, herbal supplements can interact with drugs, with each other, or with food or alcohol. Unfortunately, these products are not labeled with safety warnings, and it is difficult for a consumer to know if an interaction may occur.

Herbal interactions with prescription medications or other chemicals can:
Interfere with how the drug may be broken down in the body
Enhance side effects of prescription medications
Block the intended therapeutic effect of a drug.

If you take digoxin, diuretics, hypoglycemics, nonsteroidal anti-inflammatory drugs, spironolactone, or warfarin, do not use the following supplements without first checking with your doctor.

Name of remedy



Ephedra (Ephedra sinica, also called Ma-Huang)

To treat coughs and obesity

Dangerous and life-threatening increases in heart rate and blood pressure; has potentially fatal interactions with many cardiac medicines

Garlic (Allium sativum)

To lower cholesterol; to prevent and treat colds and certain infections

Increases the risk of bleeding when taken with blood-thinning drugs

Ginkgo (Ginkgo biloba)

To improve memory, circulation, and mental function as well as to prevent altitude sickness

Increases the risk of excess bleeding when taken with blood-thinning drugs

Goldenseal (Hydrastis canadensis)

To alleviate constipation; acts as an anti-inflammatory

May decrease or increase blood pressure; Berberine (ingredient of goldenseal) has also been associated with heart rhythm abnormalities; Increases the risk of bleeding when taken with blood-thinning drugs.

Hawthorn (Crataegus species)

To alleviate congestive heart failure and high blood pressure

Increases the risk of bleeding when taken with blood-thinning drugs

Licorice root (Glycyrrhiza glabra)

To treat coughs, cirrhosis, and stomach ulcers

May increase blood pressure and has been associated with heart rhythm abnormalities

Many of the drug interactions result from the fact that the herbs contain naturally-occurring compounds called coumarins that are anticoagulants. In fact, warfarin is a coumarin, as its trade name, Coumadin®, implies. 

High levels of vitamin K are also a problem for people who take anticoagulants because vitamin K reverses the effects of warfarin. Patients who take warfarin should avoid excessive amounts of alfalfa, as well as agrimony, plantain, and stinging nettle. Since vitamin K is also found in green, leafy vegetables, they should also be avoided.

Other supplements are known to cause heart problems, whether or not the consumer is also taking heart medications. These include:
Aloe - used internally to relieve constipation and externally to soothe irritated skin and burns. When taken internally, aloe can cause abnormal heart rhythms with prolonged use.
Arnica (Arnica montana) - applied externally to reduce pain from bruising, aches and sprains, and to relieve constipation. Arnica is potentially toxic to the heart and can raise blood pressure if taken internally.
Black cohosh (Cimicifuga racemosa) - Used to relieve menopausal symptoms. Can cause lowered blood pressure when taken at high doses.
Feverfew (Tanacetum parthenium) - Believed to prevent and treat migraines, arthritis, and allergies. Feverfew can interfere with blood clotting when taken internally.
Ginger - Purported to alleviate nausea and motion sickness, lower blood cholesterol, decrease platelet aggregation, and as a digestive aid and antioxidant. Ginger can interfere with blood clotting and increase the risk of bleeding when taken with blood-thinners. High dose has been associated with abnormal heart rhythm and blood pressure changes.
Ginseng (Panax ginseng) - Supposed to slow aging, increase mental and physical capacity, increase sexual performance, and boost immunity. It should not be taken by people with hypertension. Ginseng can interfere with blood clotting and increase the risk of bleeding when taken with blood-thinners.
Stinging nettle (Urtica dioica) - Thought to fight urinary tract infections, kidney and bladder stones, and rheumatism. It is used externally to control dandruff. Nettle should not be taken by people with fluid retention caused by reduced heart or kidney function.

Unlike prescription medications, herbal remedies are classified as dietary supplements and, thus, bypass the tight Food and Drug Administration (FDA) scrutiny that prescription medications must undergo. To make matters worse, computer software used by pharmacists to alert them to potentially dangerous drug interactions do not recognize adverse interactions with herbal products. If the lure of, say, improved memory or relief from arthritis pain seems strong, do your heart a favor and talk to your doctor before trying a "safe" herbal remedy.

Aren’t there laws to protect the consumer?

The US Food and Drug Administration (FDA) regulates herbal supplements, but not as drugs or as foods. They are placed under a category called dietary supplements. The rules for dietary supplements are as follows:
Manufacturers do not have to seek FDA approval before selling dietary supplements as they would if the product was classified as a drug. 
Companies can claim that products address a nutrient deficiency, support health or are linked to body functions if they have supporting research and they include a disclaimer that the FDA has not evaluated the claim.
Companies are not allowed to make a specific medical claim. An example of a specific medical claim might be, "This herb reduces the frequency of urination due to an enlarged prostate."
Manufacturers must follow good manufacturing practices to ensure that supplements are processed consistently and meet quality standards. These regulations are intended to keep the wrong ingredients and contaminants out of supplements, as well as make sure that the right ingredients are included in appropriate amounts.
The FDA is responsible for monitoring dietary supplements that are on the market. If the FDA finds a product to be unsafe, it can take action against the manufacturer or distributor or both, and may issue a warning or require that the product is to be removed from the market.
These regulations provide assurance that herbal supplements meet certain quality standards. The FDA can intervene to remove dangerous products from the market. However, the rules do not guarantee that herbal supplements are safe for anyone to use. That is a green light to herb manufacturers who generate all sorts of herbal supplements without a hint of how they work or what they do.

The bottom line
Like hairstyles, herbs come and herbs go. They rise in popularity and then eventually poop out as new fads unfold. Yet, unlike mullets, beehives, or flips, herbs can compromise your health.  Do your homework before you add any herbal supplements to your diet. Check PubMed to see if the supplement you are considering has been studied in humans. Or, have they only been tested in animals? In that case, they may never get tested in humans because pharmaceutical companies will not pay for the clinical studies needed to prove they work or to determine which dose is safe and which dose is not. Particularly if you take other medications, check with your pharmacist to see if there are any herb-drug interactions. 


Bonkovsky HL, Kleiner DE, Gu J, et al; U.S. Drug-Induced Liver Injury Network Investigators. Clinical presentations and outcomes of bile duct loss caused by drugs and herbal and dietary supplements. Hepatology. 2017;65:1267-77.

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