We're used to media pieces that warn us of the nutritional inadequacies of our diet or suggestions that intensive farming strips our food of nutritional value to the point where we would all be well-advised to take supplements. Lots of lifestyle media advise us to be wary of pharmaceutical preparations and to consider 'safer, natural' alternatives. The New York Times
has published an interesting essay: Diet Supplements and Safety: Some Disquieting Data
(use Bug Me Not
if it asks for a log-in and read the correction
) that is taken from Dan Hurley's Natural Causes: Death, Lies and Politics in America’s Vitamin and Herbal Supplement Industry
. I haven't seen the book but it has attracted some adverse comments from interested parties on amazon.com (which is why I've given the US rather than UK link). I'll return to these comments.
Senator Orrin G. Hatch famously defended herbal remedies, saying that they
have been on the market for centuries. In fact, most of these have been on the market for 4,000 years, and the real issue is risk. And there is not much risk in any of these products.
I'm flabbergasted by the notion that there was much competition for herbal remedies on the market over those 4000 years or that the consumers implied by this market had much alternative at all or the luxury to be concerned about relative safety, but I digress. It seems as if Senator Hatch was mistaken. Apparently, there is
some risk and children are particularly vulnerable. The American Association for Poison Control Centers
has been logging reports of poisoning, including those that involve vitamins, minerals, essential oils and homeopathic remedies. Unsurprisingly, the supplements linked to the most reactions were ordinary vitamins (more than half of all the reports in 2005). Minerals were linked to about half as many total reports but were linked to more deaths.
Injuries to children under 6 account for nearly three-quarters of all the reports of adverse reactions to dietary supplements, according to the poison centers. In 2005, the most recent year for which figures are available, 48,604 children suffered reactions to vitamins alone, the ninth-largest category of substances associated with reactions in that age group.
The standard advice from medical authorities and government agencies is that healthy children do not need vitamin or mineral supplements. However, possibly responding to the the media scare stories that Sandy discusses over at Junk Food Science
, Hurley reports a study that found that 54% of parents of preschool children gave them a vitamin or mineral supplement at least three days a week.
It is particularly interesting to note that when there are adverse reactions to prescription drugs, somewhere between 3-4% occur at the recommended dose levels. Adverse reactions to vitamins, minerals and essential oils occurred at comparably low levels when people took the recommended amounts. However,
adverse reactions linked to the recommended levels of herbs, homeopathic products and other dietary supplements accounted for 10.3 percent of all reactions to those products reported to the poison centers — about three times the level seen for most drugs.
Reading this, it occurred to me that I have no idea how the manufacturers of these products establish their recommended doses but I assume that there are no well-validated therapeutic trials. I was interested enough to scamper into a local self-styled health food shop as well as my local pharmacy that stocks some of these products. I didn't find any patient information inserts to alert me to the signs of overdosing or to inform me of the range of side-effects and the likelihood of experiencing them. I looked about on the internet and the following FAQ answer
(half-way down) is quite typical:
Homeopathy can be safely taken with over-the-counter drugs or prescription medications. People using other therapies can also use homeopathy. Conventional medicines when combined with other medicines cause side effects and serious to life threatening results. Homeopathy works in a different way and does not interfer [sic] with other therapies, drugs, herbs, vitamins or supplements. Homeopathy is safe to use in conjunction with other medications or with other homeopathic remedies. Homeopathy is without side effects. [My emphasis.]
At a time when the MHRA in the UK is allowing homeopathic remedies to indicate the conditions for which they can be used
and when GPs are allowed to prescribe these remedies on the NHS
it is cheering to note that the US Congress has approved a measure to require the manufacturers of dietary supplements and over-the-counter drugs to report serious adverse events to the FDA. However, I do wonder how many consumers will report such adverse events when they are repeatedly told that "homeopathy is without side effects" and the like.
I haven't seen Hurley's book so I can't comment on it. According to the commenters on Amazon he has made some irritating mistakes
. At the time of writing, the book has 2.5 stars which is a little surprising when the book received positive reviews in the trade press. One editorial review mentions that
Hurley wraps up with a refreshingly tough-love conclusion: the bamboozled have to accept some of the blame themselves for wanting a quick-fix promise of good health without having to do the work of a salubrious lifestyle.
Some comments accuse Hurley of being selective in choosing his studies (he mentions some well-received meta-analyses in the NYT
piece) and ignoring others: there is some speculation that he is "somehow receiving financial or material support from Big Pharma". One commenter does have the grace to conclude his negative review with the information that he is an "attorney specializing in food in drug law. Many of my clients are in the dietary supplement/natural products industry".
Other commenters are 'outed' for their own special interests in the comments on their comments. One 'outed' commenter is Suzanne Shelton who wrote:
Anyone without an agenda who has done a little research knows there are a number of supplements that are very safe and extremely beneficial. Alas, none of those studies are in the book. There are even Lewin Group studies on the cost savings of disease prevention through supplement use, but they aren't in this book either. Dont be mislead, this is not an objective examination of the supplements world, it is the work of someone with a set agenda.
In the spirit of fairness, I consulted the Lewin Group website to see if I could identify these studies. Perhaps I didn't look hard enough because I could only find this one about Multivitamins and Public Health: Exploring the Evidence
. At the risk of being pedantic, the report predicts that there would be potential
healthcare savings associated with daily use of a multivitamin by the elderly; it would have been premature to have included this study in the book as its predictive model runs until 2008.
I'm also not entirely sure how many of the studies in the literature review on which they grounded the model were speculative or observational rather than large-scale prospective studies. In the fact sheet summary of the study
(pdf), the authors single out an article by Drs. Fletcher and Fairfield who they summarise as saying that "suboptimal intake of some vitamins (above levels causing classic vitamin deficiency) is a risk factor for chronic diseases and common in the general population, especially the elderly. Fletcher and Fairfield call multivitamin dosages "safe and inexpensive," and directly "recommend that all adults take one multivitamin daily."
Now, it is true that those recommendations can be culled from the Fletcher and Fairfield Clinical Applications paper
if you don't have access). However, the Fletcher and Fairfield Scientific Review
(Entrez PubMed abstract
if you don't have access) paper in the same issue is more nuanced and less emphatic about the mulitivitamin message. The concluding paragraph was:
Although the clinical syndromes of vitamin deficiencies are unusual in Western societies, suboptimal vitamin status is not. Because suboptimal vitamin status is associated with many chronic diseases, including cardiovascular disease, cancer, and osteoporosis, it is important for physicians to identify patients with poor nutrition or other reasons for increased vitamin needs. The science of vitamin supplementation for chronic disease prevention is not well developed, and much of the evidence comes from observational studies.
Far from being "common in the general population", the authors highlight that it is particular groups such as
elderly people, vegans, alcohol-dependent individuals, and patients with malabsorption [who] are at higher risk of inadequate intake or absorption of several vitamins.
Throughout the paper, the authors advise testing for various conditions where appropriate, they do not only
propose supplementation. Fairfield and Fletcher are scrupulous about qualifying some of their recommendations:
Since the existing evidence is entirely from observational research, it should be viewed with caution until randomized trial results become available.
In their discussion of the benefits of a higher folate intake to reduce breast cancer risks, the authors specify that current evidence only shows a benefit for women who have "low folate levels and consume alcohol".
Even in the Clinical Applications paper, the authors acknowlege that:
Foods contain thousands of compounds that may be biologically active, including hundreds of natural antioxidants, carotenoids, and flavonoids. For these reasons, vitamin supplementation is not an adequate substitute for a good diet.
Suzanne Shelton accuses Hurley of using "selective studies" and having a "set agenda". It is (presumably) this Lewin Group study (or similar) that she castigates Hurley for omitting and it seems as if they, too, may have been selective.
Diet supplements, homeopathic and herbal preparations may have small reported risks but they do have risks (we may not have a clear idea of any risks because it has been widely promulgated that they don't have side-effects and the manufacturers are not obliged to discuss them in information inserts): it seems as if children are especially vulnerable. The general advice is that healthy children do not need such supplements: if parents choose to administer them to their children, they would be well-advised to discuss them with the children's doctors. But, before you buy these supplements, read Junk Food Science
and consider the quality of the evidence that is suggesting that your children need them.
Labels: adverse reactions, Hatch, herbal remedy, homeopathic remedy, homeopathy, Hurley, minerals, supplements, vitamins