Complementary Medicines: The Evidence is Food for Thought

Articles that proclaim there is no evidence behind complementary medicine are not only wrong but also confusing, especially when they are written by academics that have access to many scientific databases, writes Dr Lesley Braun PhD, Director of Blackmores Institute.

The vast majority of complementary medicine products (CMs) available in Australian pharmacies are vitamin and mineral supplements, food concentrates (such as fish oil and fibre) and western herbal medicines. The, now common usage and ease of availability of these products stemmed from  naturopathic practice in this country which sees diet and lifestyle modification together with nutritional supplementation and herbal medicines as cornerstones of treatment.  

The keen interest in nutritional supplementation arose from the recognition that food is medicine and therefore key components in foods, such as nutrients, are important for good health. Western herbal medicine was first used on a basis of traditional evidence but now is very much guided by scientific evidence. These low risk treatments have been dispensed in naturopathic clinics for decades yet their inclusion in the pharmacist and general practitioner treatment armament is relatively recent. 

In 1993, David M. Eisenberg MD, the Bernard Osher Distinguished Associate Professor of Medicine at Harvard Medical School and Associate Professor of Nutrition at the Harvard School of Public Health, in the United States, and his colleagues, coined the term ‘unconventional medicine’.

They defined this as "interventions neither taught widely in medical schools nor generally available in US hospitals" [1]. 

At the time, the term was used to describe various complementary and alternative medicine practices but it inadvertently set up an artificial barrier between different medicines. However, times have certainly moved on and many medical doctors now routinely prescribe once unconventional substances such as fish oils, probiotics and glucosamine to patients while hospital formularies include coenzyme Q10 and omega 3 fatty acids. In addition, many medical schools in North America now teach complementary medicine in their under-graduate courses and some hospitals are offering acupuncture, meditation and massage. 

Regardless of whether they are conventional or complementary, any medicines that promote good health, prevent and treat disease, ease discomfort and are safe are simply ‘good medicines’. The low risk nature of most complementary medicines means they have attracted a different regulatory framework compared to higher risk medicines, which need many more safeguards. This lower risk means they can be more accessible to the public and are more appropriate for use in self-care. 

Detractors of CM often argue that Australians are eating a healthy diet which is sufficient to meet optimal nutritional requirements and therefore have no need to “waste their money” on supplements.  But this is far from the case. Peer-reviewed literature reports that many adolescents and Australian adults fail to meet the recommended intakes for dairy products [2]; and only 11% of adults meet the minimum recommendations for both fruit and vegetables [3]. A recent cross-sectional study using data from the Australian Longitudinal Study on Women's Health has reported similar findings. 

The study, involving over 18,000 women, showed that less than 2% were achieving the recommendation of five daily servings of vegetables, 32% of young women failed to meet fruit intake recommendations and only 22% of pregnant women met intakes for dairy products [4].

Results such as these consistently demonstrate that despite Australians living in a first-world country with access to fresh produce, most are not making good dietary choices. Multivitamins are amongst the most popular over the counter CMs being sold and it’s easy to understand why. They will never replace a good diet but they will at least prevent frank deficiency in people at risk, which appears to be the majority of Australians.  

Beyond poor dietary intake, we also know that nutritional deficiencies can occur due to secondary factors such as polypharmacy, drug interactions, alcoholism, malabsorption syndromes and other pre-existing comorbidities. This is an area which should be of particular interest to pharmacists and medical practitioners. 

There is also a growing evidence base indicating that pharmaceutical medicines significantly disrupt the nutritional status of patients. This is of particular concern amongst elderly people taking medication long term. For example, proton pump inhibitors (PPIs) have long been linked to an increased risk of vitamin and mineral deficiencies impacting vitamin B12, vitamin C, calcium, iron and magnesium metabolism [5]. A recent article identified that the use of PPIs is of critical concern as it not only predisposes patients to hypomagnesaemia but to prolonged hospitalisation irrespective of their underlying morbidity [6]. A systematic review also identified that the use of ACE inhibitors and angiotensin 2 receptor antagonists or thiazide diuretics have the potential to reduce zinc levels in hypertensive patients [7].

Thus, there can be no argument that nutritional supplementation has an important place in our community and these are the products that make up the majority of OTC CMs sold in Australia.

Western herbal medicines are also used in complementary medicine products. An understanding of phytochemistry and herbal pharmacology provides a rational basis for their use in various health conditions.  In other words, they provide biological plausibility. By understanding the underlying pathological processes and biochemical changes in the body as a result of disease, it is possible to see how herbs with relevant mechanisms of action can be useful in that disease. For example, St John’s wort contains several constituents that elicit pharmacological effects that are consistent with antidepressant activity [8].  A recent review of RCTs yet again confirmed it is comparable to paroxetine, is beneficial in the treatment of core symptoms of depression, and has a very favourable safety profile. Adverse event rates similar to placebo and lower than that of synthetic antidepressants make it a very well tolerated medicine [9]. Interestingly, St John’s wort has been used as a traditional medicine since the days of Hippocrates and was once believed to chase ‘evil spirits away’, possibly a medieval description of its significant mood changing effects. 

There are many other traditional herbal medicines that have been subject to scientific investigation, shown to have multiple pharmacological actions and significant clinical effects such as pygeum in BPH [10], pelargonium in acute bronchitis[11], saffron in depression [12], kava kava and anxiety [13], garlic and hypertension [14], black cohosh and menopause [15]. Interestingly, many pharmaceutical drug therapies are derived from plants such as dithranol and methoxsalen (8-methoxypsoralen) which are standard treatments in psoriasis [16]; morphine, quinine, digoxin, cocaine, podophyllin, corticosteroids, metformin, taxol and numerous other chemotherapeutic drugs. 

As with all medicines, RCTs can only guide practice and the information needs to be contextualised for the individual patient. Additionally, the absence of evidence is not the same as negative evidence; it just means the work has yet to be done. 

Creating evidence requires money, lots of it. In a situation where less than 0.2% of the nation’s health and medical research budget for 2014 - 2018 was allocated to CM [17] and the pharmaceutical industry has no incentive to fund expensive trials due to the lack of patent protection, creating evidence for non–patentable treatments is always a major problem. Ask the pharmaceutical drug companies that lose interest in undertaking research when their drugs go off patent. 

Evidence is changing all the time and in a constant state of flux. This is true across the board for all medicines. The changing evidence base for paracetamol [18], hormone replacement therapy and cardiovascular risk factors in women [19] and the TGA revision that OTC cough and cold treatments should not be given to children under that age of six years are just a few examples [20].

It is hard for medical practitioners and pharmacists to keep up to date and it’s no surprise that some would be unfamiliar with the evidence base regarding OTC CMs, instead believing the baseless arguments that there is no evidence for these medicines. This isn’t helped when under-graduate medical and pharmacy education includes very little about nutrition, nutritional supplementation and evidence-based herbal medicines. 

Clearly there is a need for more scientific investigation to uncover new and novel mechanisms of action and clinical effectiveness of CM but we are by no means starting with a blank sheet. Anyone who proclaims there is no evidence behind complementary medicines has not done their homework, or is using the term ‘complementary medicine’ very liberally. There is no denying that some treatments used in the community do not have clear biological plausibility and worse, can be dangerous, but these are not the mainstream complementary medicines. They are not typical of the common usage of CM and should therefore not be portrayed as representative of all complementary medicines. 

Adopting the attitude that there is no evidence is unhelpful to your patients in light of surveys that show between 60- 70% of Australians use CMs [21, 22].  It is also unhelpful when they report getting good results from their treatment and a medical practitioner remarks, but there’s no evidence. Clearly, patients deserve better. Good medical practice means respecting patient autonomy, using your clinical acumen and experience, becoming informed about the evidence and promoting patient safety.  It also means admitting when you aren’t familiar with a treatment, such as CM, and referring to credible resources, talking with more informed colleagues or personally up-skilling with good education so patients get the advice they deserve. 

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Source: www.blackmoresinstitute.org/opinion/blog/CM-%20the-evidence-is-food-for-thought, Friday 5 September 2014