Many dietary supplements are heavily promoted for the prevention of chronic diseases, including cardiovascular disease (CVD) and cancer. But do they actually work or are they just raising false hopes? The evidence on this subject is confusing and proponents of both camps produce data which seemingly support their claims. In this situation, we need an independent analysis of the totality of the evidence to guide us. And one such review has just become available
The purpose of this article was to systematically review evidence for the use of multivitamins or single nutrients and functionally related nutrient pairs for the primary prevention of CVD and cancer in the general population.
The authors searched 5 databases to identify literature that was published between 2005 and January 29, 2013. They also examined the references from the previous reviews and other relevant articles to identify additional studies. In addition, they searched Web sites of government agencies and other organizations for grey literature. Two investigators independently reviewed identified abstracts and full-text articles against a set of a priori inclusion and quality criteria. One investigator abstracted data into an evidence table and a second investigator checked these data. The researchers then qualitatively and quantitatively synthesized the results for 4 key questions and grouped the included studies by study supplement. Finally, they conducted meta-analyses using Mantel-Haenzel fixed effects models for overall cancer incidence, CVD incidence, and all-cause mortality.
103 articles representing 26 unique studies met the inclusion criteria. Very few studies examined the use of multivitamin supplements. Two trials showed a protective effect against cancer in men; only one of these trials included women and found no effect. No effects of treatment were seen on CVD or all-cause mortality.
Beta-carotene showed a negative effect on lung cancer incidence and mortality among individuals at high risk for lung cancer at baseline (i.e., smokers and asbestos-exposed workers); this effect was persistent even when combined with vitamin A or E. Trials of vitamin E supplementation showed mixed results and altogether had no overall effect on cancer, CVD, or all-cause mortality. Only one of two studies included selenium trials showed a beneficial effect for colorectal and prostate cancer; however, this trial had a small sample size. The few studies addressing folic acid, vitamin C, and vitamin A showed no effect on CVD, cancer, and mortality. Vitamin D and/or calcium supplementation also showed no overall effect on CVD, cancer, and mortality. Harms were infrequently reported and aside from limited paradoxical effects for some supplements, were not considered serious.
The authors’ conclusion are less than encouraging: there are a limited number of trials examining the effects of dietary supplements on the primary prevention of CVD and cancer; the majority showed no effect in healthy populations. Clinical heterogeneity of included studies limits generalizability of results to the general primary care population. Results from trials in at-risk populations discourage additional studies for particular supplements (e.g., beta-carotene); however, future research in general primary care populations and on other supplements is required to address research gaps.
A brand-new RCT provides further information, specifically on the question whether oral multivitamins are effective for the secondary prevention of cardiovascular events. In total, 1708 patients aged 50 years or older who had myocardial infarction (MI) at least 6 weeks earlier with elevated serum creatinine levels were randomly assigned to an oral, 28-component, high-dose multivitamin and multi-mineral mixture or placebo. The primary end point was time to death, recurrent MI, stroke, coronary revascularization, or hospitalization for angina. Median follow-up was 55 months. Patients received treatments for a median of 31 months in the vitamin group and 35 months in the placebo group. 76% and 76% patients in the vitamin and placebo groups completed at least 1 year of oral therapy, and 47% and 50% patients completed at least 3 years. Totals of 46% and 46% patients in both groups discontinued the vitamin regimen, and 17% of patients withdrew from the study.
The primary end point occurred in 27% patients in the vitamin group and 30% in the placebo group. No evidence suggested harm from vitamin therapy in any category of adverse events. The authors of this RCT concluded that high-dose oral multivitamins and multiminerals did not statistically significantly reduce cardiovascular events in patients after MI who received standard medications. However, this conclusion is tempered by the nonadherence rate.
These findings are sobering and in stark contrast to what the multi-billion dollar supplement industry promotes. The misinformation in this area is monumental. Here is what one site advertises for heart disease:
Vitamin C could be helpful, limit dosage to 100 to 500 mg a day.
Vitamin E works better with CoQ10 to reduce inflammation in heart disease. Limit vitamin E to maximum 30 to 200 units a few times a week. Use a natural vitamin E complex rather than synthetic products.
CoQ10 may be helpful in heart disease, especially in combination with vitamin E. I would recommend limiting the dosage of Coenzyme Q10 to 30 mg daily or 50 mg three or four times a week.
Curcumin protects rat heart tissue against damage from low oxygen supply, and the protective effect could be attributed to its antioxidant properties. Curcumin is derived from turmeric, which is often used in curries.
Garlic could be an effective treatment for lowering cholesterol and triglyceride levels for patients with a history or risk of cardiovascular disease, especially as a long term strategy.
Terminalia arjuna, an Indian medicinal plant, has been reported to have beneficial effects in patients with ischemic heart disease in a number of small studies. Arjuna has been tested in angina and could help reduce chest pain.
Magnesium is a mineral that could help some individuals. It is reasonable to encourage diets high in magnesium as a potential means to lower the risk of coronary heart disease.
Danshen used in China for heart conditions.
And in the area of cancer, the choice is even more wide and audacious as this web-site for example demonstrates.
So, the picture that emerges from all this seems fairly clear. Despite thousands of claims to the contrary, dietary supplements are useless in preventing cardiovascular diseases or cancer. All they do produce, I am afraid, is rather expensive urine.
There are numerous types and styles of acupuncture, and the discussion whether one is better than the other has been long, tedious and frustrating. Traditional acupuncturists, for instance, individualise their approach according to their findings of pulse and tongue diagnoses as well as other non-validated diagnostic criteria. Western acupuncturists, by contrast, tend to use formula or standardised treatments according to conventional diagnoses.
This study aimed to compare the effectiveness of standardized and individualized acupuncture treatment in patients with chronic low back pain. A single-center randomized controlled single-blind trial was performed in a general medical practice of a Chinese-born medical doctor trained in both western and Chinese medicine. One hundred and fifty outpatients with chronic low back pain were randomly allocated to two groups who received either standardized acupuncture or individualized acupuncture. 10 to 15 treatments based on individual symptoms were given with two treatments per week.
The main outcome measure was the area under the curve (AUC) summarizing eight weeks of daily rated pain severity measured with a visual analogue scale. No significant differences between groups were observed for the AUC (individualized acupuncture mean: 1768.7; standardized acupuncture 1482.9; group difference, 285.8).
The authors concluded that individualized acupuncture was not superior to standardized acupuncture for patients suffering from chronic pain.
But perhaps it matters whether the acupuncturist is thoroughly trained or has just picked up his/her skills during a weekend course? I am afraid not: this analysis of a total of 4,084 patients with chronic headache, lower back pain or arthritic pain treated by 1,838 acupuncturists suggested otherwise. There were no differences in success for patients treated by physicians passing through shorter (A diploma) or longer (B diploma) training courses in acupuncture.
But these are just one single trial and one post-hoc analysis of another study which, by definition, cannot be fully definitive. Fortunately, we have more evidence based on much larger numbers. This brand-new meta-analysis aimed to evaluate whether there are characteristics of acupuncture or acupuncturists that are associated with better or worse outcomes.
An existing dataset, developed by the Acupuncture Trialists’ Collaboration, included 29 trials of acupuncture for chronic pain with individual data involving 17,922 patients. The available data on characteristics of acupuncture included style of acupuncture, point prescription, location of needles, use of electrical stimulation and moxibustion, number, frequency and duration of sessions, number of needles used and acupuncturist experience. Random-effects meta-regression was used to test the effect of each characteristic on the main effect estimate of pain. Where sufficient patient-level data were available, patient-level analyses were conducted.
When comparing acupuncture to sham controls, there was little evidence that the effects of acupuncture on pain were modified by any of the acupuncture characteristics evaluated, including style of acupuncture, the number or placement of needles, the number, frequency or duration of sessions, patient-practitioner interactions and the experience of the acupuncturist. When comparing acupuncture to non-acupuncture controls, there was little evidence that these characteristics modified the effect of acupuncture, except better pain outcomes were observed when more needles were used and, from patient level analysis involving a sub-set of 5 trials, when a higher number of acupuncture treatment sessions were provided.
The authors of this meta-analysis concluded that there was little evidence that different characteristics of acupuncture or acupuncturists modified the effect of treatment on pain outcomes. Increased number of needles and more sessions appear to be associated with better outcomes when comparing acupuncture to non-acupuncture controls, suggesting that dose is important. Potential confounders include differences in control group and sample size between trials. Trials to evaluate potentially small differences in outcome associated with different acupuncture characteristics are likely to require large sample sizes.
My reading of these collective findings is that it does not matter which type of acupuncture you use nor who uses it; the clinical effects are similar regardless of the most obvious potential determinants. Hardly surprising! In fact, one would expect such results, if one considered that acupuncture is a placebo-treatment.
Alternative medicine thrives in the realm of common chronic conditions which conventional medicine cannot cure and which respond well to treatment with placebos. Irritable bowel syndrome (IBS) is such a condition, and IBS-sufferers who are often frustrated with the symptomatic relief conventional medicine has to offer are only too keen to try any therapy that promises help. There is hardly an alternative therapy which does not claim to be the solution to IBS-symptoms: herbal medicine, mind-body interventions, homeopathy (the subject of my next post), acupuncture, even ‘MOXIBUSTION‘.
Moxibustion is a derivative of acupuncture; instead of needles, this method employs heat to stimulate acupuncture points. Proponents believe that the effects of moxibustion are roughly equivalent to those of acupuncture but many acupuncturists feel that they are less powerful. One website explains: Moxibustion is a traditional Chinese medicine technique that involves the burning of mugwort, a small, spongy herb, to facilitate healing. Moxibustion has been used throughout Asia for thousands of years; in fact, the actual Chinese character for acupuncture, translated literally, means “acupuncture-moxibustion.” The purpose of moxibustion, as with most forms of traditional Chinese medicine, is to strengthen the blood, stimulate the flow of qi, and maintain general health.
Many proponents of moxibustion claim that their treatment works for IBS. The evidence is, however, far less clear. Two recent meta-analyses might tell us more.
The first systematic review and meta-analysis was published by Korean researchers and aimed at critically evaluating the current evidence on moxibustion for improving global symptoms of IBS. The authors conducted extensive searches and found a total of 20 RCTs to be included in their analyses. The risk of bias in these studies was generally high. Compared with pharmacological medications, moxibustion significantly alleviated overall IBS symptoms but there was a moderate inconsistency among the 7 RCTs. Moxibustion combined with acupuncture was more effective than pharmacological therapy but a moderate inconsistency among the 4 studies was found. When moxibustion was added to pharmacological medications or herbal medicine, no additive benefit of moxibustion was shown compared with pharmacological medications or herbal medicine alone. One small sham-controlled trial found no difference between moxibustion and sham control in symptom severity. Moxibustion appeared to be associated with few adverse events but the evidence is limited due to poor reporting.
The authors concluded that moxibustion may provide benefit to IBS patients although the risk of bias in the included studies is relatively high. Future studies are necessary to confirm whether this finding is reproducible in carefully-designed and conducted trials and to firmly establish the place of moxibustion in current practice.
The way I see it, these conclusions are far too optimistic. There was only one RCT that controlled for placebo-effects, and the results of that study were negative. Thus I would conclude that some studies report effectiveness of moxibustion for IBS, yet the effects seem not to be caused by the treatment per se but are most likely due to a placebo-effect.
The second systematic review and meta-analysis was published by Chinese researchers and aimed at evaluating the clinical efficacy and safety of moxibustion and acupuncture in treatment of IBS. The authors included randomized and quasi-randomized clinical trials in their analyses and were able to include 11 trials. Their meta analysis suggests that the effectiveness of the combined methods of acupuncture and moxibustion is superior to conventional western medication treatment. The authors concluded that acupuncture-moxibustion for IBS is better than the conventional western medication treatment.
While the first meta-analysis was at least technically sound, the second seems to have too many flaws to mention: the search methodology was flimsy, many available studies were not included, their risk of bias was not assessed critically, the conclusions are based more on wishful thinking than on the available data, etc.
If we consider that moxibustion is a method of stimulating acupoints, we have to assume that it can at best be as effective as acupuncture, quite possibly slightly less. Thus it is relevant to see what the evidence tells us about acupuncture for IBS. The current Cochrane review of acupuncture for IBS shows that sham-controlled RCTs have found no benefits of acupuncture relative to a credible sham acupuncture control for IBS symptom severity or IBS-related quality of life.
I think I rest my case.
Australian researchers wanted to know whether acupuncture is effective for alleviating the symptoms of fibromyalgia, a common painful condition for which no universally accepted treatment exists. For this purpose, they conducted a Cochrane review. After extensive literature searches, they identified 9 RCTs, extracted their data and assessed risk of bias.
The results show that all studies except one were at low risk of selection bias; five were at risk of selective reporting bias; two were subject to attrition bias (favouring acupuncture); three were subject to performance bias (favouring acupuncture) and one to detection bias (favouring acupuncture).
Three studies utilised electro-acupuncture (EA) and the remainder manual acupuncture (MA) without electrical stimulation.
Low quality evidence from one study (13 participants) showed EA improved symptoms with no adverse events at one month following treatment.
Moderate quality evidence from six studies (286 participants) indicated that acupuncture (EA or MA) was no better than sham acupuncture, except for less stiffness at one month. Subgroup analysis of two studies (104 participants) indicated benefits of EA. Mean pain was 70 points on 0 to 100 point scale with sham treatment; EA reduced pain by 13% (5% to 22%).
Low-quality evidence from one study suggested that MA resulted in poorer physical function: mean function in the sham group was 28 points (100 point scale); treatment worsened function by a mean of 6 points.
Moderate quality evidence from one study (58 participants) found that, compared with standard therapy alone (antidepressants and exercise), adjunct acupuncture therapy reduced pain at one month after treatment.
Low quality evidence from one study (38 participants) showed a short-term benefit of acupuncture over antidepressants in pain relief.
Moderate-quality evidence from one study (41 participants) indicated that deep needling with or without deqi did not differ in pain, fatigue, function or adverse events.
Four studies reported no differences between acupuncture and control or other treatments described at six to seven months follow-up.
No serious adverse events were reported, but there were insufficient adverse events to be certain of the risks.
The authors draw the following conclusions: There is low to moderate-level evidence that compared with no treatment and standard therapy, acupuncture improves pain and stiffness in people with fibromyalgia. There is moderate-level evidence that the effect of acupuncture does not differ from sham acupuncture in reducing pain or fatigue, or improving sleep or global well-being. EA is probably better than MA for pain and stiffness reduction and improvement of global well-being, sleep and fatigue. The effect lasts up to one month, but is not maintained at six months follow-up. MA probably does not improve pain or physical functioning. Acupuncture appears safe. People with fibromyalgia may consider using EA alone or with exercise and medication. The small sample size, scarcity of studies for each comparison, lack of an ideal sham acupuncture weaken the level of evidence and its clinical implications. Larger studies are warranted.
What does all that mean? In my view, it means that there is no sound evidence base for acupuncture as a treatment of fibromyalgia – or as we expressed it in our own systematic review of 2007: The notion that acupuncture is an effective symptomatic treatment for fibromyaligia is not supported by the results from rigorous clinical trials. On the basis of this evidence, acupuncture cannot be recommended for fibromyalgia.
In 2010, NICE recommended acupuncture for chronic low back pain (cLBP). Acupuncturists were of course delighted; the British Acupuncture Council, for instance, stated that they fully support NICE’s (National Institute for Health and Clinical Excellence) decision that acupuncture be made available on the NHS for chronic lower back pain. Traditional acupuncture has been used for over 2,000 years to alleviate back pain and British Acupuncture Council members have for many many years been successfully treating patients for this condition either in private practice or working within the NHS. In effect, therefore, these new guidelines are a rubber stamp of the positive work already being undertaken as well as an endorsement of the wealth of research evidence now available in this area.
More critical experts, however, tended to be surprised about this move and doubted that the evidence was strong enough for a positive recommendation. Now a brand-new meta-analysis sheds more light on this important issue.
Its aim was to determine the effectiveness of acupuncture as a therapy for cLBP. The authors found 13 RCTs which matched their inclusion criteria. Their results show that, compared with no treatment, acupuncture achieved better outcomes in terms of pain relief, disability recovery and better quality of life. These effects were, however, not observed when real acupuncture was compared to sham acupuncture. Acupuncture achieved better outcomes when compared with other treatments. No publication bias was detected.
The authors conclude that acupuncture is an effective treatment for chronic low back pain, but this effect is likely to be produced by the nonspecific effects of manipulation.
In plain English, this means that the effects of acupuncture on cLBP are most likely due to placebo. Should NICE be recommending placebo-treatments and have the tax payer foot the bill? I think I can leave it to my readers to answer this question.
One of the best-selling supplements in the UK as well as several other countries is evening primrose oil (EPO). It is available via all sorts of outlets (even respectable pharmacies - or is that supposedly respectable?), and is being promoted for a wide range of conditions, including eczema. The NIH website is optimistic about its efficacy: “Evening primrose oil may have modest benefits for eczema.” Our brand-new Cochrane review was aimed at critically assessing the effects of oral EPO or borage oil (BO) on the symptoms of atopic eczema, and it casts considerable doubt on this somewhat uncritical view.
Here is what we did: We searched six databases as well as online trials registers and checked the bibliographies of included studies for further references to relevant trials. We corresponded with trial investigators and pharmaceutical companies to identify unpublished and ongoing trials. We also performed a separate search for adverse effects. All RCTs investigating oral intake of EPO or BO for eczema were included.
Two experts independently applied eligibility criteria, assessed risk of bias, and extracted data. We pooled dichotomous outcomes using risk ratios (RR), and continuous outcomes using the mean difference (MD). Where possible, we pooled study results using random-effects meta-analysis and tested statistical heterogeneity.
And here is what we found: 27 studies with a total of 1596 participants met our inclusion criteria: 19 studies tested EPO, and 8 studies assessed BO. A meta-analysis of results from 7 studies showed that EPO failed to improve global eczema symptoms as reported by participants and doctors. Treatment with BO also failed to improve global eczema symptoms. 67% of the studies had a low risk of bias for random sequence generation; 44%, for allocation concealment; 59%, for blinding; and 37%, for other biases.
Our conclusions were clear: Oral borage oil and evening primrose oil lack effect on eczema; improvement was similar to respective placebos used in trials. Oral BO and EPO are not effective treatments for eczema.
The very wide-spread notion that EPO is effective for eczema and a range of other conditions was originally promoted by the researcher turned entrepreneur, D F Horrobin, who claimed that several human diseases, including eczema, were due to a lack of fatty acid precursors and could thus be effectively treated with EPO. In the 1980s, Horrobin began to sell EPO supplements without having conclusively demonstrated their safety and efficacy; this led to confiscations and felony indictments in the US. As chief executive of Scotia Pharmaceuticals, Horrobin obtained licences for several EPO-preparations which later were withdrawn for lack of efficacy. Charges of mismanagement and fraud led to Horrobin being ousted as CEO by the board of the company. Later, Horrobin published a positive meta-analysis of EPO for eczema where he excluded the negative results of the largest published trial, but included results of 7 of his own unpublished studies. When scientists asked to examine the data, Horrobin’s legal team convinced the journal to refuse the request.
The evidence for EPO is negative not just for eczema. To the best of my knowledge, there is not a single disease or symptom for which it demonstrably works. Our own review of the data concluded ” EPO has not been established as an effective treatment for any condition”
Our new Cochrane review might help to put this long saga to rest. In my view, it is a fascinating tale of a scientist being blinded by creed and ambition. The results of such errors can be dramatic. Horrobin misled all of us: patients, health care professionals, scientists, regulators, decision makers, businessmen. This caused unnecessary expense and set back research efforts in a multitude of areas. I find the tale also fascinating from other perspectives; for instance, it begs the question why so many ‘respectable’ manufacturers and retailers are still allowed to make money on EPO. Is it not time to debunk the EPO-myth and say it as clearly as possible: EPO helps only those who financially profit from misleading the public?
This week is acupuncture awareness week, and I will use this occasion to continue focusing on this therapy. This first time ever event is supported by the British Acupuncture Council who state that it aims to “help better inform people about the ancient practice of traditional acupuncture. With 2.3 million acupuncture treatments carried out each year, acupuncture is one of the most popular complementary therapies practised in the UK today.“
Right, let’s inform people about acupuncture then! Let’s show them that there is often more to acupuncture research than meets the eye.
My team and I have done lots of research into acupuncture and probably published more papers on this than any other subject. We had prominent acupuncturists on board from the UK, Korea, China and Japan, we ran conferences, published books and are proud to have been innovative and productive in our multidisciplinary research. But here I do not intend to dwell on our own achievements, rather I will highlight several important new papers in this area.
Korean authors just published a meta-analysis to assess the effectiveness of acupuncture as therapy for gouty arthritis. Ten RCTs involving 852 gouty arthritis patients were included. Six studies of 512 patients reported a significant decrease in uric acid in the treatment group compared with a control group, while two studies of 120 patients reported no such effect. The remaining four studies of 380 patients reported a significant decrease in pain in the treatment group.
The authors conclude “that acupuncture is efficacious as complementary therapy for gouty arthritis patients”.
We should be delighted with such a positive and neat result! Why then do I hesitate and have doubts?
I believe that this paper reveals several important issues in relation to systematic reviews of Chinese acupuncture trials and studies of other TCM interventions. In fact, this is my main reason for discussing the new meta-analysis here. The following three points are crucial, in my view:
1) All the primary studies were from China, and 8 of the 10 were only available in Chinese.
2) All of them had major methodological flaws.
3) It has been shown repeatedly that all acupuncture-trials from China are positive.
Given this situation, the conclusions of any review for which there are only Chinese acupuncture studies might as well be written before the actual research has started. If the authors are pro-acupuncture, as the ones of the present article clearly are, they will conclude that “acupuncture is efficacious“. If the research team has some critical thinkers on board, the same evidence will lead to an entirely different conclusion, such as “due to the lack of rigorous trials, the evidence is less than compelling.“
Systematic reviews are supposed to be the best type of evidence we currently have; they are supposed to guide therapeutic decisions. I find it unacceptable that one and the same set of data could be systematically analysed to generate such dramatically different outcomes. This is confusing and counter-productive!
So what is there to do? How can we prevent being misled by such articles? I think that medical journals should refuse to publish systematic reviews which so clearly lack sufficient critical input. I also believe that reviewers of predominantly Chinese studies should provide English translations of these texts so that they can be independently assessed by those who are not able to read Chinese – and for the sake of transparency, journal editors should insist on this point.
And what about the value of acupuncture for gouty arthritis? I think I let the readers draw their own conclusion.