October 13, 2011 by  
Filed under Health Blog, Nutrients For Life

A recent study on the so-called effects of nutrient supplementation was so substandard, it is surprising that it was even published.   

The study found that some supplements, particularly iron (when taken in excess of 200mg/per day), could be harmful to older women’s health whereas they found that calcium supplementation may reduce their risk of mortality. However, none of the data can be taken seriously.

The study was totally dependent on older women relying on their memory to complete questionnaires about their diet and nutrient intake over the past 19 years. Furthermore, it was not a double blind, placebo controlled study (which is the gold standard in scientific research) and twice the amount of supplement takers in the study were also taking Hormone Replacement Therapy (HRT), compared to the non-supplement takers – and HRT has known risks of increased mortality through breast cancer, heart attacks and strokes. In addition, the researchers admitted that their study could not distinguish whether the participants were taking supplements to fight diseases they already had or not. As many people only begin taking supplements in response to the symptoms of illness such as fatigue or other signs of disease, it is highly likely that the elderly supplement-taking participants were already suffering from ill-health. Indeed, the researchers themselves admit that the results may be due to pre-existing underlying health conditions rather than the supplements themselves – making this research totally unreliable.

There are also a number of other significant flaws with this study such as the absurdly high levels of iron supplementation that participants were taking (which was far higher than the Recommended Dietary Intake) and there was also no reference to the quality of the supplements being taken (whether they were cheap, synthetic products filled with harmful additives and in forms that were not bio-available or beneficial to the body); whether the women self-prescribed the supplements or whether
they sought expert advice (to determine what their biologically-unique body required); and many other factors that make this study unreliable.

 The research does not provide reliable evidence of the effects of nutrient supplementation at all. As Dr. David Herber, Director of the UCLA Center for Human Nutrition said “I wouldn’t recommend anyone change what they’re doing based on this study.”

The Research                                                                                                                                                                                                                                                                                                                     The research was called ‘The Iowa Women’s Health Study’ and was published in the Arch Intern Med. 2011;171(18):1625-1633. The study involved researchers analyzing data from questionnaires that were completed by older female participants which relied on their memory regarding their dietary and supplement intake. The average age of the women was 62yo at the start of the 19 year study and over 81yo by the end of the study.  The study conclusions were that there ‘may’ be a slightly increased risk of mortality in older women taking certain nutrient supplements especially iron (but only if taking more than 200mg per day) but calcium supplementation seemed to decrease the risk of mortality by 9% in older women. There was no mention of the scientifically-proven health benefits of fish oils, probiotics, Vitamin D supplementation or other nutrient supplementation despite there being a vast amount of clinical trials proving that these supplements can prevent and treat certain chronic disease.

Why This Research Is Questionable:                                                                                                                                                                                                                                                                             Besides the large number of issues with this research described above, one of the main problems with the study is the high intake of iron supplementation. The results of the research indicated that iron was the main culprit (out of all the supplements reviewed) when taken at levels higher than 200mg per day but the study showed there were no negative health effects when taken at 200mg per day or less. Of course it is potentially harmful to take more than 200mg per day of iron! In fact, I have no idea why anyone would take that much. Added to that, there was no mention whether it was organic iron or inorganic (The latter is well known to be harmful to the body as it is more likely to be stored rather than utilized). As a practitioner for over 18 years, if I prescribe iron to a client as a result of determining they have a deficiency (and after ruling out the client does not have Hemochromatosis – which the researchers failed to check), I only ever prescribe iron at a dose of 100mg per day (equivalent to 20mg per day) and I only prescribe a totally organic (plant-based) source of iron. I have never recommended more than 200mg of iron per day to anyone so it concerns me that these are the levels that the researchers are basing their results on as I don’t imagine too many people are taking such excessive amounts of iron. I can only assume that the women taking such large doses of iron were self-prescribing their own supplements and dosages and did not seek expert advice. Furthermore, the researchers admit that they “Cannot rule out the possibility that the increase in mortality rate was caused by illnesses for which use of iron supplements is indicated,” they wrote. “Chronic disease, major injury, and/or operations may cause anemia, which is then treated with supplemental iron”. In addition, if any of the participants had Hemochromatosis (which largely goes undiagnosed), their body accumulates iron (rather than utilizes it) until it builds to dangerously high levels and causes serious disease. This was not taken into consideration in this study. Copper can also accumulate in those with Wilson’s syndrome but again, this was not considered by the researchers. Note: This is why it always best to consult a trained Naturopath to find out which nutrients you should be taking to prevent disease and which ones you need to avoid.

A Summary of Why This Research Was Flawed     

1) The study was not a double blind, placebo controlled study which is the gold standard in scientific research and interestingly is also the standard that the medical field demand when it comes to the complementary medicine field providing evidence of the benefits of natural remedies. Footnote: There are thousands of independent scientific research trials that have demonstrated the effectiveness of certain herbal medicines and nutrient therapies.

2) The study was totally reliant on older women (from 62yo to over 81yo) filling out questionnaires. Therefore the study only showed an association – not cause and effect – which is not scientifically reliable especially as it was reliant on the memory of the elderly participants.

3) The researchers admitted that their data cannot distinguish whether the women they studied were taking supplements to fight  diseases they already had or simply to maintain health. This is a significant  flaw as many people that suffer from illness start taking supplements in  response to the fatigue or other symptoms that clinical disease causes. The researchers acknowledged that the slight increases in death risk (which were  extremely small and may not even be clinically meaningful) – may have actually  been due to pre-existing underlying health conditions rather than the supplements themselves – making this research totally unreliable.

4)  Twice the amount of  supplement takers in the study were also taking Hormone Replacement Therapy (HRT), compared to the non-supplement takers. As HRT has known risks of increased mortality through breast cancer, heart  attacks and strokes, this could account for the results in the increased  mortality risk in older women.

5)  It is not known whether the supplement-taking participants only took supplements that were self-prescribed (i.e. Not prescribed by a health professional) and therefore may not have been required by their body.  Good Naturopaths always recommend individual health screening to determine which nutrients each person requires based on their unique, biological requirements.

6) It is not known whether the study participants only took cheap and/or  inorganic, synthetic supplements which are known for their toxicity, their  cheap harmful fillers and additives and their lack of health benefits (Which is why trained Naturopaths never recommend nutrient supplements from health food shops, pharmacies, supermarkets or other retail outlets).

7) The study was carried out by the nutrition department  at Iowa university which means the researchers quite possibly had a bias towards proving that food should be enough for good health and that  supplements are not required (which is what most nutritionists believe). While believing that we can derive all the nutrients we require from food alone is a nice idealistic philosophy – it’s not consistent with logic when you consider that a vast amount of clinical research has shown that the majority of humans have multiple nutrient deficiencies and that long-term nutrient deficiencies result in (preventable) disease. From over 18 years of clinical practice and testing a vast number of clients for nutrient deficiencies, even those eating a healthy, organic diet almost always still lack certain nutrients. Studies in agriculture are also showing the dramatic decline in nutrient values in modern foods so how do dieticians propose that the average person derives sufficient amounts of a variety of nutrients from food alone?

8) The researchers admit that their study was limited by the possibility of residual confounding (confusion), the inability to exclude the chance that some supplements were taken in response to pre-existing symptoms or clinical disease, the lack of data on nutritional status, any details on the supplements used or changes in supplement use during the study (Yes, I don’t suppose any of the participants took the same supplements every day for 19 years and no doubt wouldn’t have remembered what they did actually take over that length of time!).

In conclusion, in my opinion, this research is neither scientifically reliable nor useful but it does point out the need for people to seek expert health advice when it comes to individual nutrient supplementation. Instead of  ‘self-prescribing’ or purchasing supplements just because a celebrity on the TV said they were a good idea or accepting advice from untrained staff in health
food stores and other retail outlets or being sold supplements from pharmacists or their staff – who have very limited training in nutrient supplementation you may want to consult a
qualified Naturopathic Physician who has studied health and nutritional science for many years, is trained in appropriate testing to determine which nutrients you really need (rather than being
sold something that could be harmful), who understands the pathology underlying chronic disease, who will spend an extended amount of time with you to find out what your individual requirements are so you can achieve optimum health and prevent disease and will prescribe you nutrient supplements that are of the highest grade possible and have proven effectiveness – not inferior, sub-standard products that may not offer you any benefits at all or worse, could be dangerous to your health.


Please see your health practitioner for advice.

Yours In Great Health,

Sar Rooney BHSc., ND., DC., DASc., GDSc. (Hons), MATMS, MNHAA, MHATO

Naturopathic Medicine Practitioner, Lecturer, Researcher


Earth Medicine TM


Email: [email protected]



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Sar Rooney is a Naturopathic Medicine Practitioner specialising in Anxiety and Depression |Women’s Health| Hormonal Imbalances | Thyroid Disorders | Digestive Health | Genetic Polymorphisms (MTHFR/Pyroluria) | Nutritional Medicine | Optimal Wellness & Disease Prevention 

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