The history and development of conventional medicine is what ties it to complementary and alternative (CAM) therapies used today. But how did this development occur and why then are CAM therapies frowned upon or at least not considered ‘first-line’ by conventional healthcare professionals? 

After Carina Harkin’s presentation at a 2012 multidisciplinary diabetes study day, themed ‘Shifting sands in diabetes management and care delivery’, of the naturopathic angle on diabetes management, endocrinologist Prof Richard Firth presented some of the current evidence of the benefits of CAM therapies. The first point he made was that over 200 current medications used by healthcare professionals are derived from plants, and so the link to CAM is not so distant (see Table 1). 

Looking at the history of ‘medicine’, herbal or plant-derived medicine was the mainstay of therapy until the 18th century, when it started declining due to the scientific revolution, said Prof Firth. In fact, in the first edition of the US Pharmacopoeia in 1820, botanicals still represented over two-thirds of the entries.

“It was only in the 20th century that standardised pharma drugs started properly replacing herbal therapies as they were more effective (read potent) and more profitable,” said Prof Firth.

CAM also includes mind-body medicine such as yoga, tai chi and meditation; manipulation and body-based practices such as chiropractic therapy, osteopathy and massage; and energy medicine such as reiki, qigong and therapeutic touch. However, from a safety point of view, it is the ingested therapies that are of most concern to conventional healthcare professionals.

“The use of CAM is a bigger issue than we think, because for example, in the US over 40% of adults use CAM, with $4.8 billion used on CAM therapies from the pocket. While in Europe we use over $5 billion on over the counter CAM therapies.

“It is also interesting to see that the reasons for use of CAM include ‘enhancing health’ and helping with common chronic symptoms such as memory loss, arthritis and fatigue. These are the very things that conventional medicine cannot treat – how many times have you heard of a patient complaining about being tired? 

“That is why there is huge potential use [of CAM] by people for these things that we [conventional medical practitioners] cannot address,” added Prof Firth. See Table 2 for the most popular natural products used.

Regulation of herbal supplements

When it comes to the safety of CAM, whatever is ingested is probably of most concern, and therefore, Prof Firth concentrated on supplements.

Herbal supplements would in Ireland be regulated by either the Food Safety Authority of Ireland (FSAI) or the Irish Medicines Board (IMB) depending on whether the herbal supplement contains a substance which is subject to medicinal control, Prof Frith explained.

He added that according to an EU Directive from 2004, all OTC herbal products:

• Are to be registered with the European Agency for Evaluation of Medicinal Products

• Need to have pre-market evaluation of quality and safety

• Need to have post-market surveillance and reporting of adverse events.

This is apparently much more regulated than in the US.

Safety of herbal supplements

There are a number of factors that affect the safety of herbal supplements (which would not be the case with industrially produced medicines). These are:

• Plant species used  – echinacea, which is used for the common cold, has at least three easily available sub-species, which must have slightly different properties and therefore effects when considering treatment

• Plant parts used – different parts of a plant (leafs, roots, flowers) may have a very different effect and may lead to potential problems

• Harvesting and storage – time of harvesting, storage time, climactic conditions, etc.,  will all affect the product collected as will possible microbial contamination in storage

• Processing – some are homogenised, some are extracted for solvents, some are dried, encapsulated, made into liquid tinctures, teas, poultices, creams, etc., and the way in which it is processed will of course affect the end-product drastically

• Accuracy of labelling – some products, eg. ginseng, may vary from 0-300% of the labelled concentration, and studies have found that, eg. of valerian products, 4/17 had no valerinic acid. Of 880 samples of the 10 most purchased herbs, 43% were consistent with benchmarks, while 37% were not consistent or insufficiently labelled.  “The more you pay for your recommended daily dose, the better the product you get, and it doesn’t matter where you buy it from, but it is the price you pay,” said Prof Firth.

• Standardisation – what are the active ingredients in a complex herbal system when there can be many complex active ingredients in one herb, eg. ginkgo extracts are standardised to 24% flavonoids glycosides and 6% terpenoids and this is what is aimed for.

• Purity – there are some concerns about the purities of some supplements, eg. the FDA in the US  found lead, mercury and arsenic in imported traditional Chinese and Indian medicines. 

“This is not only because the products were contaminated with these metals, but also because they would actually be used in some traditional medicines. But they are a source of potential safety issues.”

Efficacy of herbal supplements

When Prof Firth moved on to the efficacy of herbal supplements, he made a point first of talking about the studies in which the efficacy of these products have been tested. There has only been a few randomised controlled trials (RCTs) of complementary medicine, and therefore, studies often lack detail in design, results and reporting, thus leading to inconclusive results. 

“There is no money in plant medicine. And because of that, there has been no big, very expensive randomised controlled trials using thousands of patients. And this is no fault of complementary medicine, but it is just a fact, and unfortunately we have very little evidence base for complementary medicine,” said Prof Firth.

This is because there is no potential monetary profit to be made if it is found that, eg. garlic can ‘cure’ hypertension; Prof Firth pointed out that it has in fact been shown in pooled data that garlic can significantly lower systolic blood pressure. However, its use in diabetes is very limited.

Prof Firth also looked at the therapeutic uses of aloe vera, ivy gourd, bitter melon, prickly pear cactus, ginseng, fenugreek, gymnema, cinnamon, ALA, chromium,  magnesium, omega -3 fatty acids and vanadium, some of which overlapped the commonly used herbal and vitamin remedies for diabetes presented by Carina Harkin.

Where there was an overlap, it was interesting to note the different effects and warnings reported by the two authors. What Prof Firth pointed out about the overlapping products were:

• Cinnamon – the active ingredient is hydroxychalcone, which is thought to enhance insulin action. Some studies have shown a reduction in blood glucose (BG) and improvement in cholesterol and triglycerides, but have shown no effect in A1c. Side-effects include allergy (rare), contact dermatitis and hypoglycaemia and care needs to be taken in liver disease due to coumarin content

• Gymnema (‘the sugar destroyer’) – used in ayurveda for diabetes for more than 200 years. A gymnema leaf extract used in non-RCTs as adjuvant therapy in type 1 and type 2 diabetes resulted in a fall in fasting blood glucose (FBG) and A1c levels which was not seen in controls, however, the studies lacked between group comparison and randomisation. It is also proposed as an insulin secretagogue, but may interact with hypoglycaemics

• Fenugreek – used in Indian and Chinese medicine, including for diabetes. Mechanisms proposed are decreased carbohydrate absorption and increased insulin secretion. Potential effect seen in studies of type 1 and type 2 diabetes, but the studies are of poor quality

• ALA – is an antioxidant and is used in Germany for peripheral neuropathy. ALADIN trials at 600-1,800mg/day IV improved some symptoms of peripheral neuropathy, but there is no evidence to show that it prevents or alters natural history of diabetic peripheral neuropathy. Side-effects include hypoglycaemia, rash and thiamine deficiency and it may interact with medicines for thyroid disease

• Chromium – is an essential trace element required for glucose metabolism, enhancing insulin action. Severe states of chromium deficiency is associated with reversible diabetes due to insulin resistance. A meta-analysis of 14 RCTs (n = 381) showed changes in glucose metabolism after chromium supplementation. Earlier meta-analysis showed little effect, and the authors commented on poor quality of studies. Dosing is 400-800µg/day. Excessive intake can lead to liver and renal failure, thrombocytopaenia, haemolysis and skin reactions. There are also multiple drug interactions

• Magnesium – is abundant in humans and has many functions, including glucose metabolism. A meta-analysis of nine RCTs (n = 370) in type 2 diabetes for 4-16 weeks with 15mg/day resulted in a fasting plasma glucose decrease of 0.56mmol/l, but no changes in HbA1c. It may have a preventive role in onset of type 2 diabetes. A meta-analysis of seven prospective cohort studies collected dietary data, 100mg/day increase in magnesium intake led to a relative risk of 0.85 for development of type 2 diabetes.

Mind-body medicine

According to Prof Firth, there is more clinical evidence for the use of mind-body medicine such as yoga, tai-chi and meditation; however, not for the purposes of treating diabetes itself, rather for teaching people with disease how to cope and improve mood and quality of life. 

“These would be considered low to moderate intensity exercise and – bearing in mind that ADA recommends more than 150 minutes of moderate-intensity exercise per week – in controlled clinical trials, neither yoga or tai chi have shown significant long-term improvement in glycaemic control.

“However, these techniques may have something to contribute to the improvement of quality of life and mood and reducing stress in people with diabetes,” said Prof Firth.

Risks with these therapies are also minimal, but the quality of published research to date is poor, added Prof Firth.

Counselling patients

So why do physicians need to be aware of the use of CAM? Prof Firth pointed out that according to a US study, 63% of patients did not disclose CAM use to their doctor. Of these, 61% felt that it was not important for the doctor to know and 60% reported that the doctor never asked.

“There is a risk in this because people believe that because CAM therapies are usually old remedies, they are safe, and there is also a belief that ‘more is better’,” said Prof Firth

But as herbs may be pharmacologically active with potential positive and negative impacts on patient health, the healthcare professional treating a patient with diabetes needs to be aware of possible CAM usage.

“Discussing it with the patient may also provide insight into patient concerns. Someone taking PUFAs (omega-3) may be harbouring phobia of heart disease and it allows you to investigate this situation.”

What advice to give

Finally, Prof Firth advised on what to do if a patient insists on using a herbal product against advice:

• A non-judgemental reaction should be adopted and the professional relationship should not be terminated

• The choice of brand should be one that is used in clinical trials; brands should be made by manufacturers practising GMP; single-product supplements display`ing quantity and standardised content should be used; and imported products should be avoided when possible

• Special precaution should be taken in pregnant patients, children and the elderly.

“At this stage, it is difficult to recommend herbal products and dietary supplements on the basis of the evidence of their efficacy, quality and safety, but this is not meant to down alternative medicine, it is an indictment of conventional medicine as well,” said Prof Firth.

“The longer you are in medicine, the more cynical you get about clinical trials: they are wonderfully done, very expensive, they are all randomised, but the questions that are asked are dubious. 

“For instance, you will not see very many studies looking at direct head-to-head comparison between an ACE inhibitor and an ARB, because the companies that make one make the other one too.”