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Herbal Supplements and Diabetes
Be careful when taking these unproven substances

Dietary supplements are a type of complementary and alternative medicine (CAM).  The term “dietary supplement” as defined by law encompasses vitamins, minerals, herbs or other botanicals, and amino acids as well as their related metabolites, concentrates, constituents and extracts. They are not a conventional food, nor are they meant to be eaten as a total meal or diet.   In this article, I will focus on herbal and other botanical dietary supplements which I will call “herbs,” and which are used by approximately 22% of people with diabetes.

Dietary supplements, including botanicals, are regulated by the Food and Drug Administration (FDA) as food. This means that, unlike pharmaceutical drugs, manufacturers do not need to prove a supplement’s safety, effectiveness or quality before it goes on the market, and that the FDA can address problems with them only after they are being sold.  Therefore, you cannot be assured that what is in the bottle will do what you think it should, will contain the quantity of each ingredient on the label, will not be contaminated, or will not cause harm.  But you can learn how to make informed choices about supplement use.

10 Tips to Using Herbs Wisely

Weigh the pros and cons

If you are considering adding an herb to your diabetes plan, start by making a list of the pros and cons. Many herbs have not been studied by researchers and for those that have, results are mixed.  However, if after following the steps below, you conclude that the herb seems safe and affordable and your health care team is supportive, you may decide to give it a try.  Monitor your progress to see if the herb produces the results you desire.

“Natural” does not equal safe.

Milk ThistleThere are many factors that can affect whether a specific herb or a brand of that herb is safe for you.   Interactions with other medications or herbs you are taking can put you at risk.  As a couple of examples, American ginseng is likely to reduce the effectiveness of Coumadin (a blood thinner), and aloe vera can interfere with positive effects of Digoxin (a heart medication).  If you take any prescription medications, talk to your physician or pharmacist before starting an herbal supplement.   

Use of specific herbs can also be unsafe if you have problems with your liver or kidneys.  Some herbs can cause damage to these organs at certain doses, so pre-existing problems can be worsened.  If you have concerns, talk to your health care team.  Safety concerns also arise when products are contaminated.  There have been news reports of herbs containing hazardous trace metals and/or even prescription diabetes medications.  To minimize this risk, consider avoiding products produced in other countries.

Safety for you is not safety for all

Some herbs have safety concerns for specific populations such as children and pregnant or lactating women.  So don’t share your herbal supplements with others.  Be especially cautious if you are considering giving a supplement to a child.  Fenugreek and bitter melon are just two of the supplements not recommended for children.

Herbs can act like prescription medications

Many herbs used for diabetes are believed to lower blood sugar through the same mechanisms as various prescription medications. So approach their use in the same way you would use prescription drugs.  Learn how it may affect your blood sugar.  The difference between herbs and prescription medications is that there can be hundreds of components in herbs that contribute to their effectiveness.  Scientists have not yet identified most of these components, which makes research on herbs difficult.  

Select brands wisely

SteviaYou can not assume that the amount of the active ingredient in an herbal product matches that listed on the label. As an example, of 11 brands of milk thistle tested by an organization called ConsumerLab, only 5 brands contained the expected amount of the active ingredient, silymarin.  To maximize the chances that the contents match the label, look for products that display either a USP or NF seal. Also, seek brands that have been tested independently. Avoid those that make outlandish claims. The Federal Trade Commission regulates claims made by supplement manufacturers in advertisements, while the FDA regulates statements made on supplement labels.  Manufacturers cannot claim that a supplement treats or cures a specific disease.  But beware.   It takes some time for the market to address these claims if they are made.        

Follow dose recommendations only when made by reliable source

If you read labels on supplements you will see a great variation in the recommended dose.  There are several legitimate reasons for these differences including the form of the herb in the product and the purpose for which it is being taken.  Be careful, though, because there are products that promote potentially harmful mega doses.  Seek independent advice from your pharmacist, dietitian or physician or use the resources cited below.

Aloe veraBe knowledgeable about potential side effects

Herbs can cause side effects. In most cases they are mild, but there are exceptions. Learn what the side effects are so you will be prepared to notice them.  Add only one herb to your diabetes plan at a time so you can pinpoint side effects more easily. Remember that if you are taking an herb to assist with lowering your blood sugar, be sure you know how to treat a hypoglycemic episode. 

Popular Herbs Used for Diabetes

Below are herbs most often used by people with diabetes.  Inclusion on this list is not an endorsement for their use.  Follow the steps in this article to decide if an herb is right for you.
Aloe vera           Ginseng
Banaba             Gymnema sylvestre
Bitter melon       Milk thistle
Chia                  Nopal
Cinnamon          Salacia oblonga
Fenugreek         Stevia


Talk to your doctor first

Your doctor can help you determine if an herb is safe for you and then incorporate it into your diabetes care. It is important not to stop or decrease the dose of your prescription medications without the guidance of your physician.  If you notice that the herb you are taking lowers your blood sugar, ask your physician if your diabetes medication can be adjusted.  There is a misconception that conventional medical practitioners are opposed to the use of supplements. Due to limited research your doctor may be skeptical about the effectiveness of a supplement, but might support you if the risks are low. 

Inform all health professionals about your use of herbs

Anyone who needs to know about your medications also should know about your use of herbs. This includes all members of your diabetes team, and the staff of any hospital to which you are admitted. Letting them know will reduce the risk of dangerous side effects.

Get information from reputable sources

Ask your dietitian, pharmacist or physician for detailed information about any herbs that interest you.  You can also study various Web sites, which often provide more current information than books, although you may need to pay a subscription fee. Some sites to explore include:

NIH Office of Dietary Supplements

National Center for Complimentary
and Alternative Medicine

Natural Medicines Comprehensive



About the Author

Lynn BaillifLynn Baillif is currently Coordinator of Diabetes Education at Saint Agnes Hospital in Baltimore, MD, has been a registered dietitian for 15 years and a certified diabetes educator for 7 years.  She has been a member of the National Federation of the Blind since 1987 when she was a national scholarship winner.