Diabetes and Complementary Medicine: A look at three plant-based remedies

This is part two of a two-part article on complementary medicine. Click here to read part one, Diabetes and Complementary Medicine: is there more than what Western medicine has to offer?

There are many plant-based remedies used for the treatment of diabetes.

Today, we’ll look at three common treatments and how they stack up: milk thistle, fenugreek and bitter melon.

Before we begin, please remember: fenugreek and bitter melon are not recommended for children.

For each of these remedies, we’ll look at these questions:

  • What is it?
  • What are its uses?
  • Which parts of the plant are useful?
  • What are possible mechanisms of action?
  • Is there any evidence this works?
  • What are the known side-effects?

These are questions you should always ask any time you consider an alternative medicine.

Milk Thistle

What is it? A flowering herb common in the Mediterranean.  Its other common names are Mary thistle, silymarin and holy thistle.

Uses: Mainly used as a treatment for liver disease,  it is also indicated for lowering cholesterol levels and lowering blood glucose levels in type 2 diabetes complicated by cirrhosis.

Useful part: Seeds which are turned into capsules, extracts, powders and tinctures.

Possible mechanism of action: Silymarin, the active ingredient in milk thistle, acts as an antioxidant help, preserving the ability of the pancreas to produce insulin.

Evidence: Results have been mixed with most studies poorly designed.

Side effects: Mild gastrointestinal discomfort, headache and allergic reactions. People who are allergic to plants such as ragweed, chrysanthemum, marigold and daisy have a greater chance of developing an allergy to milk thistle which is a member of the same family of plants.  There have been several reports of anaphylactic shock in people who have used milk thistle products.


What Is It? Fenugreek is a white flowering plant of the legume family.

Uses: It has been used in Asia and the Mediterranean for centuries as a treatment for many medical conditions including diabetes, high cholesterol levels, and digestive ailments.   It is also used as an aid to stimulate milk flow in breast-feeding women.

Useful parts: Leaves and seeds.

Possible mechanisms of action: 4-hydroxyisoleucine (an amino acid derived from fenugreek) may help stimulate the secretion of insulin and reduce insulin resistance by slowing absorption of glucose in the intestine.

Evidence: There is limited evidence from a few small studies indicating fenugreek may help lower blood glucose levels.  One study using a very high dose of fenugreek in the form of seed powder found a small decrease in fasting blood glucose levels.

Side Effects: Gas, bloating and diarrhea and respiratory symptoms such as nasal congestion and cough.  Fenugreek can cause allergic reactions in susceptible individuals.  When applied topically it can irritate the skin.

Bitter Melon

What Is It? Bitter melon is an edible, bumpy-textured gourd resembling a cucumber grown throughout Asia, Africa and the Caribbean. The fruit can be eaten both raw and cooked with the pith becoming sweeter as the fruit ripens.

Uses: As a digestive aid for the treatment of stomach upset and constipation and also as a treatment for malaria and viral infections.

Useful parts: Seeds, pulp, fruit and leaves.

Possible mechanisms of action: Substances located in the stem and fruit, called triterpenoids, are postulated to be responsible for its glucose-lowering ability through activation of an enzyme system which promotes glucose uptake by the cells.  In addition, the melon contains a lectin that is purported to work by lowering insulin resistance in the peripheral cells and suppressing hunger signals in the brain.

Evidence: Most evidence comes from in vitro and animal studies.   Bitter melon has been found to reduce postprandial hyperglycemia and improve insulin sensitivity.  However, there are few human clinical trials and those that exist generally do not meet the standards of clinical research due to poor study designs, small number of test subjects and lack of a control population.  Currently there is not enough evidence to recommend bitter melon as an adjunct treatment.

Side effects: Bitter melon is generally well tolerated.  It is counterindicated in pregnant women as it has been linked to abnormal bleeding, and the seeds may also induce favism (a condition caused by a deficiency of phosphate dehydrogenase, an enzyme in red blood cells).  When certain foods such as fava beans are eaten by people with this condition, a severe anemia can result, possibly progressing to coma.

REMEMBER — Safety First

People perceive herbal supplements as natural and therefore not harmful.   But as they say, not all that glitters is gold nor all that’s natural safe.   Many herbal supplements have side effects as dangerous as or more dangerous than many commercial drugs.  For example, comfrey and kava can cause liver damage. Or supplements that are safe for adults may not be for children; two supplements used for diabetes, fenugreek and bitter melon, are not recommended for children.

Herbal supplements are not in the same class as drugs and are not regulated as drugs.  The U.S. Food and Drug Administration (FDA) has oversight over dietary supplements and views them as foods.

The FDA has established quality standards for identity, purity, strength, and composition of dietary supplements, but is not directly checking that what is written on the label is in the bottle for every supplement. Many reviews have shown that not all supplements contain the amount of product indicated on the label.  This makes it very important to buy from a reputable manufacturer.

No herbal supplement can cure a disease.

There are no double-blind, controlled clinical trials in the United States that have found that herbal supplements can replace standard diabetes medications in achieving glycemic control.

This is not to say that some of these supplements don’t have an effect on blood glucose levels.   Manufacturers of herbal supplements are not allowed to make disease treatment claims for their products.  Instead, similar to what you may find on food labels, you will find structure/function claims on botanicals.   For example, a supplement may say that it helps maintain blood glucose levels but not that it is a treatment for diabetes.

Be cautious about taking herbal supplements if you take the following types of drugs.

  • Drugs to treat depression, anxiety or other psychiatric problems
  • Anti-seizure drugs
  • Blood thinners
  • Blood pressure medicine
  • Heart medicine
  • Drugs to treat diabetes
  • Cancer drugs

Before you decide to take a supplement:

  1. Know what you are taking and why you are taking it.
  2. Know the best dose of the supplement for your condition.
  3. Know the best form of the supplement to take. Many supplements are made from more than one source (for example, the product may be processed from the bark, leaves and fruits but only the leaves have shown effectiveness).
  4. Talk to your health care provider before taking any supplement. Herbals can interact with Western medications.


If you decide to take one:

  1. Continue to take your prescribed medications. Herbal supplements are not intended to fully treat any disease.
  2. Stop taking herbal supplements at least two weeks before surgery, as they can interfere with anesthesia and contribute to bleeding.
  3. Buy supplements from a reputable vendor, one that displays the United States Pharmacopeia (USP) or NSF International seal.  These seals indicate that the product contents are truthfully described on the label.

Where to go for more information:


Photo: http://www.flickr.com/photos/avlxyz/

Be the first to comment

Leave a Reply

Your email address will not be published.