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26-06-2018

Nutranews condemns the media disinformation targeting dietary supplements

supplements A study published in June in the Journal of the American College of Cardiology has prompted one of the worst examples of skewed reporting by the media in recent years.


This kind of large-scale media distortion occurs when genuine information gets reported incorrectly or in a biased way by the vast majority of media, within a short time period. The principle is simple: one news agency or newswire publishes an incomplete report and all the rest rush to circulate the same information without checking it, putting it into context or critically analysing it, while at the same time writing ever more sensational headlines or ‘clickbait’ to make their stories stand out from the competition.

So dietary supplements are useless?

It was the publication of a meta-analysis that sparked this flood of inaccurate media coverage: dozens of articles appeared on the same day, all claiming that vitamins and dietary supplements are ‘completely worthless’. These articles were published by all types of media including the populist Mail Online and the quality newspaper The Guardian.


They all said much the same thing – that dietary supplements do not provide health benefits:


Bad news for those who take dietary supplements: the most popular vitamins and minerals may be worthless. That’s the conclusion of a new study conducted by Canadian researchers, published recently in the Journal of the American College of Cardiology. [from the website Maxisciences].


Vitamins C and D, magnesium and iron:  some people take dietary supplements to boost their health. But according to a recent meta-analysis, they may be completely useless! [from the website Futura-Sciences].


Point by point, you’ll see how none of the journalists responsible for these articles took the time to actually read the study itself. An observation as shocking as it is dangerous given the potential influence of this type of health disinformation and the indelible print it leaves on the web.


The worst thing about this is that history is repeating itself: three years ago, a study looking at the role chance plays in the development of cancer had sparked a similar level of media hype. This disinformation phenomenon was even analysed in the French health journal Les Tribunes de la Santé (1) a few months later.

How can we be sure the journalists didn’t read the review in question?

1) The meta-analysis only looked at the risks of cardiovascular disease and mortality.

While most of the articles give the impression that dietary supplements are useless for our health in general, the study on which they’re based only looked at cardiovascular problems.


The title of the meta-analysis is pretty unequivocal: Supplemental Vitamins and Minerals for CVD Prevention and Treatment.


And if we turn to the study’s abstract and conclusion, we see that in no way did its authors reach the conclusion that dietary supplements were totally ineffective at preventing cardiovascular problems:


The meta-analysis showed moderate to weak evidence for the preventive benefits of vitamin B9 (folic acid) for total cardiovascular disease, and of B-vitamins for stroke, no effect for multivitamins, vitamin C, vitamin D, beta-carotene, calcium and selenium, and increased risk for niacin [with a statin] for all-cause mortality.


The authors even add that the only new findings thrown up by their meta-analysis were the preventive effects of vitamin B9 and B complex vitamins in relation to stroke (a 20% decrease in risk). The remaining data was already ‘out there’, accessible via numerous scientific data bases.

In other words, the study’s conclusions are actually positive.


Positive effects were not expected to be found for vitamin C or selenium in relation to cardiovascular problems since no serious study has so far demonstrated such benefits.
What the review did show, however, was that there is a body of evidence supporting vitamin B9’s effects on the risk of stroke, and this was indeed something new.


If the journalists involved had actually read the meta-analysis (we’re assuming they didn’t act dishonestly), they would therefore have chosen a more informative headline:


Vitamin B9 supplements may reduce the risk of stroke

2) The review excluded 88% of studies conducted on the subject

A meta-analysis is a synthesis of research results which already exist: scientists combine and analyse several studies published within a defined period, so that they can draw an overall conclusion when studies appear to contradict each other.


In this particular meta-analysis, the authors identified 1497 studies that had investigated nutritional supplements in relation to the prevention and treatment of cardiovascular disease and overall mortality. But they actually retained only 179, barely 12 % of those identified. This was either because the studies were not in English, or they affected a particular section of the population or they were not randomised controlled trials (RCTs).


Randomised controlled trials are the gold standard of clinical trials: among a group of similar people, certain participants receive the treatment being tested (therapeutic intervention), while others are given a placebo, ie, containing no active principle. Nobody – not the participants, nor those conducting the trial - know which group has received which ‘treatment’. In theory, this type of study minimises bias and is therefore of greater scientific value.


But they have their limitations: a randomised clinical trial cannot continue for a long time as it would be too expensive.

The authors themselves acknowledge this in a section of the meta-analysis headed “Strengths and weaknesses”: “RCTs are often of shorter duration, whereas cohorts of longer duration might be required to fully capture chronic disease risk”.


This is indeed a pertinent remark. The latency period between exposure to risk factors and the onset of cardiovascular disease is very long (between 10 and 40 years): is it possible, therefore, to judge the efficacy of dietary supplements in just a few months? This question arises more in the case of supplements aimed at boosting the antioxidant system such as vitamin C and carotenoids. These are not designed to treat or prevent disease in the short-term but to combat the effects of oxidative stress over the much longer term.


Below we list the duration of some of the studies used by the authors, which led to antioxidant supplements being labelled as ineffective:


McKeown-Eyssen et al., 1988: 137 participants, 2 years of supplementation (2).

Girodon et al., 1997: 81 participants, 2 years of supplementation (3).

Plummer et al., 2007: 1980 participants (“at very high risk”), 3 years of supplementation (4).

Jacobson et al., 2000: 121 participants, 6 months of supplementation (5).

3) The meta-analysis only looked at 15 supplements

How were these journalists able to say that supplementation has no effect on health when the study only looked at 15 supplements?


The authors of the meta-analysis concentrated on the most ‘popular’ supplements, without taking into account that most of them are not aimed at improving the cardiovascular system. Suppose they had demonstrated that paracetamol has no effect against long-sightedness. Would we expect to see media headlines such as “Painkillers are ineffective”?


What can be described, at the very least, as an ambiguous selection of supplements becomes a patently inappropriate one when we discover that omega-3 supplements, were not included, despite being very popular. Of all the dietary supplements available, omega-3 have without doubt been the most widely-documented in scientific publications in relation to cardiovascular risk.


Their use for optimising blood pressure and maintaining normal triglyceride levels – two key factors in cardiovascular disease – has been scientifically recognised by the European Food Safety Authority. Not unlike the authors of this review, the EFSA based their advice and opinion on several meta-analyses (6-11) (see).


The Panel considers that the following wording reflects the scientific evidence: “DHA and EPA contribute to the maintenance of normal triglyceride concentrations”.


Neither did the authors include increasingly popular natural health products, such as extracts of maritime pine, hawthorn and notoginseng, despite them having featured in traditional systems of medicine for thousands of years, and the fact that their use for reducing cardiovascular risk factors has been under review by the EFSA since 2011.


So in fact, a more accurate headline to describe this far from ground-breaking review might be:


An inappropriate selection of dietary supplements has been shown to have little efficacy in the short-term on risk of cardiovascular disease (with the exception of folic acid and B vitamin formulations)


But would you be tempted to click on this to read the whole article? Almost certainly not – which is another reason for this type of selective reporting by the media …

Supplementation has, on the contrary, proven its worth

The most worrying aspect of this story is not even that the journalists did not take the time to read the actual meta-analysis: it’s their level of knowledge of the subject.


To claim that dietary supplements have no effect on health is to ignore not only millions of scientific studies, but also the scientific views of government authorities and agencies whose duty it is to interpret them.


These agencies include the European Food Safety Authority (EFSA), the scientific committee of which is responsible for providing science-based advice to EU member states so that they can make informed decisions on health policy.


Since 2011, the members of this committee have looked at the scientific literature in great detail to enable them to confirm whether a supplement offers a particular health benefit. Their criteria are extremely stringent: all the studies have to come to similar conclusions, with no doubt remaining, before the value of a supplement is scientifically-recognised.


This committee has already confirmed241 links between dietary supplements and genuine health benefits. Of these, 24 concern metabolism, 22 the health of bones or teeth, 14 heart health and 12 relate to all the mechanisms involved in skin health.


Vitamins D, A, B9, C and E, as well as calcium, iron, zinc, magnesium and selenium, all of which are included in this meta-analysis, have all been scientifically-recognised as beneficial for health by the EFSA.


Vitamin D, for example, has been proven to optimise bone health and aid muscle function, to improve immune system function and help reduce the risk of falls associated with muscle weakness and postural instability (12).


For its part, vitamin C is acknowledged as optimising immune function during exercise, as well as collagen formation in the skin, bones, joints and blood vessels, helping to maintain the nervous system, reducing fatigue, and above all, helping to protect cells from oxidative stress (13).


The list is long and is available on-line. What’s more, just because certain claims have not yet been recognised by this agency doesn’t make them unfounded: it just means that either there is not yet sufficient scientific data to pass definitive judgement or that results have been inconsistent. Added to which, the EFSA has a heavy workload with 2500 claims pending, most of which concern plant-based dietary supplements. Across the Atlantic, it’s the US Food and Drug Administration that fulfils this role, arriving at largely the same conclusions as its European counterpart.


To claim that dietary supplements have no effect on our health is also to ignore decades of experience on the part of therapists and those that take them.


We’ve known since the 18th century that vitamin C supplements prevent and treat scurvy, a disease that was widespread among sailors in times gone by. But what incredible progress has been made since this discovery!


Though many people don’t realise it, nutritional supplements are nowadays added to many food products to help prevent deficiency in several micronutrients in the form of food fortification.


Thus salt is routinely fortified with iodine to prevent intellectual disability and hypothyroidism, flour and cereals with vitamin B9 in the US (a measure first taken in 1992 which has helped to significantly reduce the incidence of infant deformities) (14), bread with vitamin B3 to prevent pellagra, milk with vitamin D, and plant-based drinks and fruit juices are often fortified with calcium …


Fortification of these foods has followed the establishment of health programmes based on the inexorable observation that today’s populations are lacking in many micronutrients and that these shortfalls have very real effects on health . Such measures help prevent more serious deficiencies (and the diseases associated with them) but they are by no means enough to compensate for all of them...


In the case of vitamin D, for example, it’s estimated that a billion people worldwide may be deficient. A study published 20 years ago showed that deficiency was present among 80% of elderly people in the West and the situation is not getting any better (16).


Such deficiency is calculated on the basis of requirements for vitamin D estimated by several different scientific bodies such as the US Endocrine Society (2011), the Groupe de recherche et d’information sur les ostéoporoses (France 2011), the Canadian Medical Association (Canada 2010), the Académie Nationale de Médecine (France 2012) and the UK Scientific Advisory Committee on Nutrition.


There’s no doubt that a lack of vitamin D significantly increases the risk of osteoporosis, osteomalacia (associated with generalised bone pain) and muscle weakness. A statistical relationship has actually been found between low vitamin D levels and many other diseases but evidence of causality is not yet sufficiently strong to make definitive claims.


Deficiency is a problem for many other micronutrients essential for good health, including minerals and vitamins B9 and B12 (17).


To claim that dietary supplements have no effect on our health is also to ignore these common-sense observations.


In an ideal world, everyone would obtain the micronutrients they need from a healthy, balanced, micro-local diet, but the fact is this not the case. Or to be more precise, this is no longer the case.


Encouragingly, there are many people who are realistic about the situation: in the US and certain European countries, almost 50% of people say they’ve taken supplements during the year. And this percentage appears to be higher among those working in the health sector: a study published in 2006 showed that 80% of 1250 health professionals questioned had taken at least one supplement in the preceding week (18).


A finding consistent with those of other previously-published studies on the same subject (19-24).


If you would like to read the meta-analysis behind this media distortion, it is available at: https://www.sciencedirect.com/science/article/pii/S0735109718345601?via%3Dihub


And remember when you read media articles in the future, you need to apply two essential elements: clear-headedness and a critical eye.


Références

1. Chevrel, S. (2016). Cancer et hasard. Une dérive médiatique passée au crible. Les Tribunes de la santé, 53,(4), 103-110. doi:10.3917/seve.053.0103.

2. McKeown-Eyssen G, Holloway C, Jazmaji V, Bright-See E, Dion P, Bruce WR. A randomized trial of vitamins C and E in the prevention of recurrence of colorectal polyps. Cancer Res 1988;48:4701–5

3. Girodon F, Lombard M, Galan P, et al. Effect of micronutrient supplementation on infection in institutionalized elderly subjects: a controlled trial. Ann Nutr Metab 1997;41:98–107.

4. Plummer M, Vivas J, Lopez G, et al. Chemoprevention of precancerous gastric lesions with antioxidant vitamin supplementation: a randomized trial in a high-risk population. J Natl Cancer Inst 2007;99:137–46.

5. Jacobson JS, Begg MD, Wang LW, et al. Effects of a 6-month vitamin intervention on DNA damage in heavy smokers. Cancer Epidemiol Biomarkers Prev 2000;9:1303–11.

6. Appel LJ, Miller ER, 3rd, Seidler AJ, Whelton PK, 1993. Does supplementation of diet with 'fish oil' reduce blood pressure? A meta-analysis of controlled clinical trials. Arch. Intern. Med. 153, 1429-1438.

7. Morris MC, Sacks F, Rosner B, 1993. Does fish oil lower blood pressure? A meta-analysis of controlled trials. Circulation 88, 523-533.

8. Geleijnse JM, Giltay EJ, Grobbee DE, Donders AR, Kok FJ, 2002. Blood pressure response to fish oil supplementation: metaregression analysis of randomized trials. J. Hypertens. 20, 1493-1499.

9. Jacobsen TA, 2008. Role of n-3 fatty acids in the treatment of hypertriglyceridemia and cardiovascular disease. Am. J. Clin. Nutr. 87, 1981S-1890S

10. Grimsgaard S, Bonaa KH, Hansen JB, Nordoy A, 2007. Highly purified eicosapentaenoic acid and docosahexaenoic acid in humans have similar triacylglycerol-lowering effects but divergent effects on serum fatty acids. Am. J. Clin. Nutr. 66, 649-659.

11. Balk EM, Lichtenstein AH, Chung M, Kupelnick B, Chen P, Lau J, 2006. Effects of omega-3 fatty acids on serum markers of cardiovascular disease risk: A systematic review. Atherosclerosis 189, 19-30.

12. EFSA opinion 2009;7(9):1226, 2010;8(10):1815

13. EFSA opinion 2009;7(9):1227, 2011;9(6):2203

14. Williams J, Mai CT, Mulinare J, Isenburg J, Flood TJ, Ethen M, Frohnert B, Kirby RS, Centers for Disease C, Prevention. Updated estimates of neural tube defects prevented by mandatory folic Acid fortification – United States, 1995-2011. MMWR Morb Mortal Wkly Rep 2015;64(1):1-5.

15. Holick MF. Vitamin D deficiency. N Engl J Med 2007;357:266-81

16. Van Der Wielen RP, Löwik MR, van Den Berg H, et al. Serum vitamin D concentrations among elderly people in Europe. Lancet 1995;346:207-10.

17. Allen LH. How common is vitamin B-12 deficiency? Am J Clin Nutr 2009;89:693S–696S.

18. Gardiner P, Woods C, Kemper KJ. Dietary supplement use among health care professionals enrolled in an online curriculum on herbs and dietary supplements, BMC Complementary and Alternative Medicine, https://doi.org/10.1186/1472-6882-6-21

19. Lee YK, Georgiou C, Raab C: The knowledge, attitudes, and practices of dietitians licensed in Oregon regarding functional foods, nutrient supplements, and herbs as complementary medicine. J Am Diet Assoc. 2000, 100 (5): 543-548. 10.1016/S0002-8223(00)00169-3.

20. Worthington-Roberts B, Breskin M: Supplementation patterns of Washington State dietitians. J Am Diet Assoc. 1984, 84 (7): 795-800.

21. Wilkinson JM, Simpson MD: Complementary therapy use by nursing, pharmacy and biomedical science students. Nurs Health Sci. 2001, 3 (1): 19-27. 10.1046/j.1442-2018.2001.00067.x.

22. Howard N, Tsourounis C, Kapusnik-Uner J: Dietary supplement survey of pharmacists: personal and professional practices. J Altern Complement Med. 2001, 7 (6): 667-680. 10.1089/10755530152755225.

23. Tracy MF, Lindquist R, Savik K: Use of complementary and alternative therapies: a national survey of critical care nurses. Am J Crit Care. 2005, 14 (5): 404-414. quiz 415–416

24. Muntwyler J, Hennekens CH, Manson JE, Buring JE, Gaziano JM: Vitamin supplement use in a low-risk population of US male physicians and subsequent cardiovascular mortality. Arch Intern Med. 2002, 162 (13): 1472-1476. 10.1001/archinte.162.13.1472. Jul 8

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