2008 Clinical Practice Guidelines - Canadian Diabetes Association

Complementary and Alternative Medicine
in the Management of Diabetes
Canadian Diabetes Association Clinical Practice Guidelines Expert Committee
The initial draft of this chapter was prepared by Jeannette Goguen MD MEd FRCPC
KEY MESSAGES
• Up to 30% of patients with diabetes use complementary
and alternative medicine (CAM) for various indications.
• Most CAM studies have small sample sizes and are of
short duration, and therefore may have missed harmful
side effects.
• Certain CAM in common use for disorders other than
diabetes can result in side effects and drug interactions.
INTRODUCTION
Complementary and alternative medicine (CAM) has been
defined as “medicine that does not conform to the standards
of the medical community, is not widely taught
in North American medical schools and is not available in
North American hospitals” (1). It involves the use of herbal
medications as well as dietary supplements, including minerals,
vitamins and other micronutrients.When used in a traditional
system (e.g. Chinese,Tibetan,Ayurvedic), an herb is often only
one of a number of interventions, which could also include
acupuncture, yoga and multiple other herbs.
MANAGEMENT
CAM in the management of diabetes has been included in
these guidelines, as it includes potential new therapeutic
agents, and because studies have suggested that up to 30% of
patients with diabetes use CAM for multiple indications (2),
leading to potential side effects, drug interactions and
increased cost to the patient. In 1 Canadian study in predominantly
Caucasian subjects, the most commonly used alternative
trace element for glycemic control was chromium (6%),
followed by magnesium (2.2%) and vanadium (1%) (2).
Herbs were rarely used.
There are several issues unique to CAM that have implications
in the assessment of the evidence for its use: trials are
typically of short duration, with small sample sizes and unique
patient populations that may not be generalizable (3); publications
are often difficult to access, with only 10% referenced in
MEDLINE (4); and there is a lack of standardization and purity
of available compounds, including their contamination with
regular medications and toxic compounds (5).
The following herbs have been shown to improve glycemic
control in adults with type 2 diabetes: Aloe vera (6,7); Ipomoea
batatas (caiapo) (8); Coccinia indica (9); Ganoderma lucidum (10);
Gymnema sylvestre (11); Ocimum tenuiflorum (holy basil or tulsi)
(12); Salacia reticulata (13); pinitol (14); touchi (15); and
Pterocarpus marsupium (vijayasar) (16). However, as all of the
studies were small and of short duration, it is premature to
recommend the use of these agents.
The following herbs have been shown to be ineffective for
glycemic control in adults with type 2 diabetes: Syzgium cumini
(17); Tinospora crispa (18); French maritime pine bark (19);
garlic (20); and soy phytoestrogens (21).The following dietary
supplements have been shown to be ineffective: coenzyme
Q10 (22) and vitamin E (23-26). Glucosamine sulfate, used to
treat osteoarthritis, does not affect glycemic control (27).
The following herbs have conflicting evidence with
regards to glycemic control in adults with type 2 diabetes:
Cinnamomum cassia (Chinese cinnamon) (28-31); Momordica
charantia (bitter melon or bitter gourd) (32,33); Trigonella
foenum-graecum (fenugreek) (34,35); and ginseng (36,37).The
following dietary supplements have conflicting evidence:
chromium (38-46); vanadium (47); magnesium (48-52);
lipoic acid (53); vitamin C (52,54); and carnitine (55,56).
Studies have examined the combinations of herbs as used
by traditional practitioners. These studies included Tibetan
traditional medicine (57), Chinese plants (58,59) and
Ayurvedic pancreas extract (60). Methodological concerns
make the results of these studies difficult to interpret.
COMPLICATIONS
It is important to consider potential harm from the use of
CAM. Most studies were of small sample size and short duration,
and thus may have missed harmful side effects.The use
of Tinospora crispa was associated with markedly elevated liver
enzymes in 2 patients and should be avoided (18).Alternative
medications should not be used in pregnancy – some are
abortificants (e.g. Momordica charantia) (61).As well, there are
case reports of severe hypoglycemia with the use of bitter
melon in children (61).
Impurities of substances are another concern.
Contamination with regular medications and with heavy
metals has been documented in several publications (5).
Finally, certain CAM in common use for disorders other than
diabetes can result in side effects and drug interactions.
Agents that have been associated with elevations in blood
pressure include the following: ginseng, licorice, yohimbine
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MANAGEMENT