Expert-reviewed by Ashwini S.Kanade, Registered Dietician and Certified Diabetes Educator with 17 years of experience.
Anywhere between 1/6th to 1/3rd of the diabetic population take herbal medications, and about half of them does so in addition to conventional prescription medicines, almost always without consulting pharmacists or physicians.[1,2]
However, natural does not mean safe. Individuals who self-medicate with herbal supplements, especially together with conventional medicines, risk getting some severe side effects.
Care and treatment for type 2 diabetes is virtually a life-long process, during which there are ups and downs — even among the most compliant patients. This increases the frustration levels associated with the disease, and patients tend to look for alternative sources of relief. There is a general tendency to assume that alternative medicines, particularly herbal formulations, are safe and without side effects. Herbal medicines are getting more visibility and their popularity has risen over the years. The media promotes the use of such alternative medicines directly or indirectly. Herbal preparations tend to be more advertised, at least partly because individuals do not need a prescription to buy them, and companies selling them cash in on this.
Want to go natural? Try these research-backed home remedies to control blood sugar levels instead.
Are herbal supplements bad in general?
Herbal supplements against diabetes have a blood glucose-lowering action, which is not unlike how most allopathic anti-diabetic medications work. They contain one or more ingredients that achieve this, such as active components of garlic, cinnamon, ginseng, aloe, cabbage juice, pomegranate flower, mulberry leaves, blueberry and so on [1,2]; all of these reduce the blood glucose levels by one or more mechanisms. While the fact that at least some of them work cannot be denied, the word herbal does not mean free from side effects.
What are the side effects?
Herbal medications are not always standardized, which makes regulating or fixing a dose practically impossible. Also, they may be contaminated with harmful compounds. Approximately 50% of individuals taking herbal medicines consume them along with conventional prescription medicines and without informing their doctor. When taken without medical supervision, the unregulated doses and/or combination with other medicines (such as metformin) may reduce blood glucose concentration more than the acceptable lower limit. For instance, karela (bitter melon), when used with the standard dose of metformin or glibenclamide, sharply decreases blood glucose. This is potentially dangerous and may give rise to a range of complications such as [1,3]
- mild to a severe headache
- feeling uncomfortable or malaise
- cold sweats
- hunger pangs
- tinnitus or ringing in the ears
In severe cases, the individual may fall unconscious and go into a hypoglycemic coma. One survey of individuals with diabetes who used herbal supplements found that as many as 70% of them had experienced symptoms of low blood glucose! Some medicines can have more specific effects when taken in large doses: agitation, nervousness, and insomnia with ginseng; nausea, burning sensation in the gut, and itching with garlic; and so on.
Many herbs affect the liver enzymes that process the medicinal compounds; as a result, the metabolism of allopathic diabetic or non-diabetic medications may increase or reduce, thereby leading to rising in drug toxicity or lowered effect, respectively. The Ayurvedic herb Kalmegh (king of bitters) can slow down the removal of glimepiride and similar anti-diabetes drugs.
Should I not take herbal supplements at all?
Herbal medicines are by themselves not harmful, and there is evidence that they work. Some studies have shown certain combinations of allopathic medications with herbal supplements to work better than either of them alone, but this should be taken only after consultation. Also, it is certainly challenging to check the quality and assess the safety of herbal supplements. Patients with diabetes, and people, in general, should be more aware of the dangers of herbal self-medication. If you want to take herbal medicines, do it only after talking to your doctor. If possible, consult a herbal medicine specialist who will customise the supplement according to your need. Check out our article on why self-medication (allopathic or otherwise) in general is a bad idea, and why and how you can avoid it.
- Damnjanovic I, Kitic D, Stefanovic N, et al. Herbal self-medication use in patients with diabetes mellitus type 2. Turk J Med Sci. 2015;45(4):964-71. Available at: http://journals.tubitak.gov.tr/medical/issues/sag-15-45-4/sag-45-4-36-1410-60.pdf
- Aydin Y, ÖNDER E. Herbal self-medication use in Type 2 diabetes mellitus. Turkish journal of medical sciences. 2016;46(4):1275-6. Available at: http://journals.tubitak.gov.tr/medical/issues/sag-16-46-4/sag-46-4-50-1507-97.pdf
- Singh J, Singh R, Gautam CS. Self-medication with herbal remedies amongst patients of type 2 diabetes mellitus: A preliminary study. Indian J Endocrinol Metab. 2012;16(4):662. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3401782/
- Gupta RC, Chang D, Nammi S, Bensoussan A, Bilinski K, Roufogalis BD. Interactions between antidiabetic drugs and herbs: an overview of mechanisms of action and clinical implications. Diabetol Metab Syndr. 2017;9(1):59.
- Ekor M. The growing use of herbal medicines: issues relating to adverse reactions and challenges in monitoring safety. Frontiers in pharmacology. 2014;4:177. Available at: https://www.frontiersin.org/articles/10.3389/fphar.2013.00177/full