Gymnema sylvestre (GS)

Ofgymnema the 80 %  of the world’s population who use herbs, many live in countries such as India. Although, GS is not widely known in the US it is part of the Ayurveda (India’s health system) compendium of herbs (1).

The gymnema plant can be found in both the African and Indian continent. Although,  it is more prominent in India. The leaves of the gymnema plant can be eaten fresh to block the sweet taste buds (This works – personal experience).  The herbs of Ayurveda have been used for over 2,000 years. The name gymnema sylvestre means “Sugar destroyer.”  Even the Hindi name of gumar refers to the destruction of sugar. These definitions lead us to the obvious use for this herb – diabetes.  GS has the ability to lower blood sugar.

Science: See table for chemical constituents of GS (2,3,4).

You will find one other name for gymnema sylvestre – GS4 when looking at research (1,2).  The best clinical trials will use a standardized extract of whatever herb they are investigating.

Gymnema Sylvestre main constituents

  • gymnemic acid (saponins)
  • tartaric acid
  • gumarin
  • calcium oxalate
  • glucose
  • stigmasterol
  • betaine
  • choline
Taken from article: 4-7

Herbs can only work if they are able to be absorbed. This is known as the bioavailability. Saponins make up the majority of the gymnemic acid which appears to work well in spite of the low bioavailability (5).  One of the constituents has the chemical shape very similar to glucose which is probably why it can block the sweet taste buds. More importantly this is the same mechanism the plant uses to block absorption of glucose in the GI tract (6). The active component for these phenomena is believed to be gumarin (6,7).

There is a general acceptance of gymnema as a safe herb from an empirical perspective, although, today there are also several scientific studies which support the empirical evidence.

We don’t always have good human studies to look at for support of an herbs safety. However, often an LD50 has been established in rats (lethal dose at which 50% of rats tested died). The LD50 levels can give a general idea of the level of toxicity we can expect in humans. The lower the LD50 is for a substance the more likely to be toxic. If it is high it means it would take a lot of it to be dangerous. Gymnema is considered non-toxic because the LD50 for gymnema in rats is very high (8).

Does it work? Yes.  – speak to your doctor

Personal communications and experience:

  • Co-worker: Morning glucose was 143; evening glucose 163. 34 days on gymnema and glucose dropped to: 114/116.
  • Co-worker: extremely bad condition. 2 months after starting gymnema was much better and his doctor (who refused to put him on the herb) started 8 patients on the herb.
  • Family experience: blood glucose of 101- which is pre-diabetic – 45 days on gymnema glucose 78-90.
  • Also lowers cholesterol

Does it work for everyone?  No. Show the science to your doctor so you can make the decision together. Your blood glucose must be monitored especially if you are on a diabetic medication.

References:

  1. Ayurvedic Medicine: An Introduction. National Center for Complementary and Alternative Medicine [Internet]. 2004 Available from: http://nccam.nih.gov/health/ayurveda
  2. Baskaran K, Kizar Ahamath B, Radha Shanmugasundaram K, Shanmugasundaram ER. Antidiabetic effect of a leaf extract from Gymnema sylvestre in non-insulin-dependent diabetes mellitus patients. Journal of ethnopharmacology. 1990 October;30(3):295–300.
  3. Shanmugasundaram ER, Gopinath KL, Radha Shanmugasundaram K, Rajendran VM. Possible regeneration of the
    islets of Langerhans in streptozotocin-diabetic rats given Gymnema sylvestre leaf extracts. Journal of ethnopharmacology. 19
    90 October;30(3):265–79.
  4. Manni PE, Sinsheimer JE. Constituents from Gymnema sylvestre leaves. Journal of pharmaceutical sciences. 1965 October;54(10):1541–4.
  5. Murakami N, Murakami T, Kadoya M, Matsuda H, Yamahara J, Yoshikawa M. New hypoglycemic constituents in “gymnemic acid” from Gymnema sylvestre. Chemical & pharmaceutical bulletin. 1996 February;44(2):469–71.
  6. Kanetkar P, Singhal R, Kamat M. Gymnema sylvestre: A Memoir. Journal of clinical biochemistry and nutrition. 2007 September;41(2):77–81.
  7. Lemon CH, Imoto T, Smith D V. Differential gurmarin suppression of sweet taste responses in rat solitary nucleus neurons. Journal of neurophysiology. 2003 August;90(2):911–23.
  8. Bone K. Gymnema: A Key Herb in the Management of Diabetes. Townsend Letter for Doctors & Patients. 2002;December.