The search for an effective treatment of obesity is understandably intense. Many scientists are looking in the plant kingdom for a solution, but so far none has been forthcoming – as we have already discussed on this blog before (e. g. here, and here). One herbal slimming aid is currently becoming popular: Yerba Mate also called Ilex paraguariensis, a plant many of us know from teas and other beverages. Our review concluded that the evidence for it was unconvincing but that it merited further study. This was 10 years ago, and meanwhile the evidence has moved on.
The aim of a recent study was to investigate the efficacy of Yerba Mate supplementation in subjects with obesity. For this purpose, a randomized, double-blind, placebo-controlled trial was conducted. Korean subjects with obesity (body mass index (BMI) ≥ 25 but < 35 kg/m(2) and waist-hip ratio (WHR) ≥ 0.90 for men and ≥ 0.85 for women) were given oral supplements of Yerba Mate capsules (n = 15) or placebos (n = 15) for 12 weeks. They took three capsules per each meal, total three times in a day (3 g/day). Outcome measures were efficacy (abdominal fat distribution, anthropometric parameters and blood lipid profiles) and safety (adverse events, laboratory test results and vital signs).
During 12 weeks of Yerba Mate supplementation, statistically significant decreases in body fat mass and percent body fat compared to the placebo group were noted significant. The WHR was significantly also decreased in the Yerba Mate group compared to the placebo group. No clinically significant changes in any safety parameters were observed.
The authors concluded that Yerba Mate supplementation decreased body fat mass, percent body fat and WHR. Yerba Mate was a potent anti-obesity reagent that did not produce significant adverse effects. These results suggested that Yerba Mate supplementation may be effective for treating obese individuals.
These are encouraging results, but the conclusions go way too far, for my taste. The study was tiny and does therefore not lend itself to far-reaching generalisations. What would be helpful, is a review of other evidence. As it happens, such a paper has just become available. Its authors evaluated the impact of yerba maté on obesity and obesity-related inflammation and demonstrate that yerba maté suppresses adipocyte differentiation as well as triglyceride accumulation and reduces inflammation. Animal studies show that yerba maté modulates signaling pathways that regulate adipogenesis, antioxidant, anti-inflammatory and insulin signaling responses.
The review authors concluded that the use of yerba maté might be useful against obesity, improving the lipid parameters in humans and animal models. In addition, yerba maté modulates the expression of genes that are changed in the obese state and restores them to more normal levels of expression. In doing so, it addresses several of the abnormal and disease-causing factors associated with obesity. Protective and ameliorative effects on insulin resistance were also observed… it seems that yerba maté beverages and supplements might be helpful in the battle against obesity.
I am still not fully convinced that this dietary supplement is the solution to the current obesity epidemic. But the evidence is encouraging – more so than for most of the many other ‘natural’ slimming aids that are presently being promoted for this condition by gurus like Dr Oz.
What we needed now is not the ill-informed, self-interested voice of charlatans; what we need is well-designed research to define efficacy, effect size and risks.
While my last post was about the risk following some naturopaths’ advice, this one is about the effectiveness of naturopathic treatments. This is a complex subject, not least because naturopaths use a wide range of therapies (as the name implies, they pride themselves of employing all therapeutic means supplied by nature). Some of these interventions are clearly supported by good evidence; for instance, nobody would doubt the effectiveness of a healthy diet or the benefits of regular exercise. But what about all the other treatments naturopaths use? The best approach to find an answer might be to assess not each single therapy but to evaluate the entire package of the naturopathic approach, and not a single study but all such trials.
This is precisely what US researchers have recently done. The purpose of this interesting, new systematic review was to compile and consolidate research that has investigated the whole practice of naturopathic medicine as it is practiced in community settings in order to better assess the quantity and quality of the research, and clinical effect, if any.
In order to get included into the review, studies had to report results from multi-modal treatment delivered by North American naturopathic doctors. The effect size for each study was calculated; no meta-analysis was undertaken.
Fifteen studies met the authors’ inclusion criteria. They covered a wide range of chronic diseases. Most studies had low to medium risks of bias including acknowledged limitations of pragmatic trials. Effect sizes for the primary medical outcomes varied and were statistically significant in 10 out of 13 studies. A quality of life metric was included in all of the RCTs with medium effect size and statistical significance in some subscales.
The authors concluded that previous reports about the lack of evidence or benefit of naturopathic medicine (NM) are inaccurate; a small but compelling body of research exists. Further investigation is warranted into the effectiveness of whole practice NM across a range of health conditions.
This sounds like good news for naturopathy! However, there are several important caveats:
- the authors seem to have only looked at US studies (naturopathy is a European tradition!),
- the searches were done three years ago, and more recent data were thus omitted,
- the authors included all sorts of investigations, even uncontrolled studies; only 6 were RCTs,
- rigorous trials were very scarce; and for each condition, they were even more so,
- the authors mention the PRISMA guidelines for systematic reviews implying that they followed them but, in fact, they did not.
My biggest concern, however, is something else. It relates to the interventions tested in these studies. The authors claim that their results table provides full details on this issue but this is unfortunately not true. All we have by way of an explanation is the authors’ remark that the interventions tested in the studies of their review included diet counseling and nutritional recommendations, specific home exercises and physical activity recommendations, deep breathing techniques or other stress reduction strategies, dietary supplements including vitamins, hydrotherapy, soft-tissue manual techniques, electrical muscle stimulation, and botanical medicines.
Survey data from two US states tell us that the most commonly prescribed naturopathic therapeutics are botanical medicines (51% of visits in Connecticut, 43% in Washington), vitamins (41% and 43%), minerals (35% and 39%), homeopathy (29% and 19%) and allergy treatments (11% and 13%). They also inform us that the mean length of a consultation with an US naturopath is about 40 minutes.
I think, this puts things into perspective. If I advise a patient with diabetes or hypertension or coronary heat disease to follow an appropriate diet, exercise and to adhere to some stress reduction program, if in addition I show empathy and compassion during a 40 minute consultation and make sure that my advise is taken seriously and subsequently adhered to, the outcome is likely to be positive. Naturopaths may elect to call this package of intervention ‘naturopathy’, however, I would call it good conventional medicine.
The problem, I think is clear: good therapeutic advice is effective but it is not naturopathy, and it cannot be used to justify the use of doubtful interventions like homeopathy or all sorts of dodgy supplements. Testing whole treatment packages of this nature can therefore lead to highly misleading results, particularly if the researchers draw unwarranted conclusions about specific schools of health care.
Discussions about the dietary supplements are often far too general to be truly useful, in my view. For a meaningful debate, we need to define what supplement we are talking about and make clear what condition it is used for. A recent paper meets these criteria well and is therefore worth a mention.
The review was aimed at addressing the controversy regarding the optimal intake, and the role of calcium supplements in the treatment and prevention of osteoporosis. The authors demonstrate that most studies on the subject show little evidence of a relationship between calcium intake and bone density, or the rate of bone loss. Re-analysis of data from the placebo group from the Auckland Calcium Study demonstrates no relationship between dietary calcium intake and rate of bone loss over 5 years in healthy older women with intakes varying from <400 to >1500 mg per day .
The authors argue that supplements are therefore not needed within this range of intakes to compensate for a demonstrable dietary deficiency, but might be acting as weak anti-resorptive agents via effects on parathyroid hormone and calcitonin. Consistent with this, supplements do acutely reduce bone resorption and produce small short-term effects on bone density, without evidence of a cumulative density benefit. As a result, anti-fracture efficacy remains unproven, with no evidence to support hip fracture prevention (other than in a cohort with severe vitamin D deficiency) and total fracture numbers are reduced by 0-10%, depending on which meta-analysis is considered. Five recent large studies have failed to demonstrate fracture prevention in their primary analyses.
These facts, the authors argue, must be balanced against the possible harm. The risks of regularly taking calcium supplements include an increase in gastrointestinal side effects (including a doubling of hospital admissions for these problems), a 17% increase in renal calculi and a 20-40% increase in risk of myocardial infarction. Each of these adverse events alone neutralizes any possible benefit in fracture prevention.
The authors draw the following detailed conclusions: “Concern regarding the safety of calcium supplements has led to recommendations that dietary calcium should be the primary source, and supplements reserved only for those who are unable to achieve an adequate dietary intake. The current recommendations for intakes of 1000–1200 mg day−1 are not firmly based on evidence. The longitudinal bone densitometry studies reviewed here, together with the new data included in this review relating to total body calcium, suggest that intakes in women consuming only half these quantities are satisfactory and thus, they do not require additional supplementation. The continuing preoccupation with calcium nutrition has its origin in a period when calcium balance was the only technique available to assess dietary or other therapeutic effects on bone health. We now have persuasive evidence from direct measurements of changes in bone density that calcium balance does not reflect bone balance. Bone balance is determined by the relative activities of bone formation and bone resorption, both of which are cellular processes. The mineralization of newly formed bone utilizes calcium as a substrate, but there is no suggestion that provision of excess substrate has any positive effect on either bone formation or subsequent mineralization.
Based on the evidence reviewed here, it seems sensible to maintain calcium intakes in the region of 500–1000 mg day−1 in older individuals at risk of osteoporosis, but there seems to be little need for calcium supplements except in individuals with major malabsorption problems or substantial abnormalities of calcium metabolism. Because of their formulation, costs and probable safety issues, calcium supplements should be regarded as pharmaceutical agents rather than as part of a standard diet. As such, they do not meet the standard cost–benefit criteria for pharmaceutical use and are not cost-effective. If an individual’s fracture risk is sufficient to require pharmaceutical intervention, then safer and more effective measures are available which have been subjected to rigorous clinical trials and careful cost–benefit analyses. Calcium supplements have very little role to play in the prevention or treatment of osteoporosis.”
Clear and useful words indeed! I wish there were more articles like this in the never-ending discussion about the complex subject of dietary supplements.
NATURAL NEWS announced the death of Nicholas Gonzalez with the following words:
It is with great sadness that we report the death of health freedom advocate and individualized nutrition specialist Dr. Nick Gonzalez, who on the eve of July 21 died from an alleged heart attack. Dr. Gonzalez’ contributions to anticancer nutrition protocols and an array of other nutritional therapies have been invaluable, and we would like to honor this pioneering natural healer by recognizing his benevolent legacy…
In contrast to the conventional cancer treatment model, Dr. Gonzalez’s approach was always about helping individuals heal through individualized care. Along with fellow colleague Dr. Linda Isaacs, Dr. Gonzalez helped build a repository of dietary protocols to help patients overcome their specific conditions through advanced nutritional therapies. His methodology centered around detoxification, supplementation with healing foods and nutrients, and specialized enzyme therapy…
Dr. Gonzalez was always a strong adherent to sound science, and he was never in it for the money. His humble, cogent approach to helping people heal naturally without drugs or surgery is a legacy worth remembering and passing on, and we’re thankful to have gotten to know this honorable man during his time on this earth…
This sounds as though Gonzalez was some kind of medical genius and scientific pioneer. Most cancer experts would disagree very sharply with this. Here is what Louise Lubetkin wrote on this blog about him, and I very much encourage you to read her whole post.
Those who recognize and appreciate a fine example of pseudoscientific baloney when they see one know that there is no richer seam, no more inexhaustible source, than the bustling, huckster-infested street carnival that is alternative medicine. There one can find intellectual swindlers in abundance, all offering outrageously implausible claims with the utmost earnestness and sincerity. But the supreme prize, the Fabergé egg found buried among the bric-a-brac, surely belongs to that most convincing of illusionists, the physician reborn as an ardent advocate of alternative medicine…
So what are we to make of Gonzalez? Is he a cynical fraud or does he genuinely believe that coffee enemas, skin brushing and massive doses of supplements are capable of holding back the tsunami of cancer?
At the end of the day it hardly matters: either way, he’s a dangerous man.
Personally, I believe much more in the text of Louise Lubetkin. How about you?
Soy isoflavone supplements are used to treat several chronic diseases, although the data supporting their use are limited. Some data suggest that supplementation with soy isoflavone may be an effective treatment for patients with poor asthma control. In fact, genistein, one of the isoflavones in soy, is a powerful anti-inflammatory agent and as such it might help control asthma symptoms. But speculation and wishful thinking does not lead anywhere. What we need is a good study to test the efficacy of soy in asthma patients.
Yes, you guessed it: such an investigation has just been published, The objective of this trial was to determine whether a soy isoflavone supplement improves asthma control in adolescent and adult patients with poorly controlled disease.
The study was designed as a multi-centre, randomized, double-blind, placebo-controlled trial conducted between May 2010 and August 2012 at 19 pulmonary and allergy centres in the American Lung Association Asthma Clinical Research Centers network. Three hundred eighty-six patients aged 12 years or older with symptomatic asthma while taking a controller medicine and low dietary soy intake were randomized, and 345 (89%) completed spirometry at week 24.
Participants were randomly assigned to receive soy isoflavone supplement containing 100 mg of total isoflavones (n=193) or matching placebo (n=193) in 2 divided doses administered daily for 24 weeks.
The primary outcome measure was change in forced expiratory volume in the first second (FEV1) at 24 weeks. Secondary outcome measures were symptoms, episodes of poor asthma control, Asthma Control Test score (range, 5-25; higher scores indicate better control), and systemic and airway biomarkers of inflammation.
Mean changes in pre-bronchodilator FEV1 over 24 weeks were 0.03 L (95% CI, −0.01 to 0.08 L) in the placebo group and 0.01 L (95% CI, −0.07 to 0.07 L) in the soy isoflavone group. The difference was not significantly different. Mean changes in symptom scores on the Asthma Control Test, number of episodes of poor asthma control, and changes in exhaled nitric oxide did not significantly improve more with the soy isoflavone supplement than with placebo. Mean plasma genistein level increased from 4.87 ng/mL to 37.67 ng/mL (P < .001) in participants receiving the supplement.
The authors concluded that among adults and children aged 12 years or older with poorly controlled asthma while taking a controller medication, use of a soy isoflavone supplement, compared with placebo, did not result in improved lung function or clinical outcomes. These findings suggest that this supplement should not be used for patients with poorly controlled asthma.
This is a good study and a squarely negative finding. As far as I can see, there is no dietary supplement that is of proven effectiveness for asthma. Yet, the hype and bogus claims in this realm continue unabated. This trial provides solid evidence, but will it change much? I doubt it. Supplement manufacturers will simply say: THEY USED THE WRONG PRODUCT/DOSE/TREATMENT SCHEDULE !!! And the exploitation of asthma patients will continue just as before.
Few alternative remedies are more popular than colloidal silver, i.e. tiny particles of silver suspended in a liquid, and few represent more irresponsible quackery. It is widely promoted as a veritable panacea. Take this website (one of thousands), for instance; it advertises colloidal silver in the most glowing terms:
Here are some of the diseases against which Colloidal Silver has been used successfully Acne, Allergies, Appendicitis, Arthritis, Blood parasites, Bubonic plague, Burns (colloidal silver is one of the few treatments that can keep severe burn patients alive), Cancer, Cholera, Conjunctivitis, Diabetes, Gonorrhoea, Hay Fever, Herpes, Leprosy, Leukaemia, Malaria, Meningitis, Parasitic Infections both viral and fungal, Pneumonia, Rheumatism, Ringworm, Scarlet Fever, Septic conditions of eyes, ears, mouth, throat, Shingles, Skin Cancer, Syphilis, all viruses, warts and stomach ulcer.In addition it also has veterinary uses, such as for canine Parvo virus. You’ll also find Colloidal Silver very handy in the garden since it can be used against bacterial, fungal / viral attacks on plants.It would also appear highly unlikely that any germ warfare agents could survive an encounter with CS, as viruses such as E Bola and Hanta are in the end merely viruses and bacteria.Colloidal Silver is non-toxic, making it safe for both children, adults and pets. Colloidal Silver is in fact a pre 1938 healing modality, making it exempt from FDA jurisdiction.
So why haven’t you heard of it? It’s suspected that the user friendly economics of Colloidal Silver may have something to do with its low profile in the media. Colloidal Silver shines a spotlight on the over expensive and deadly nature of the pharmaceutical industry, who are larger than the Pentagon economically.
That’s right, plenty of bogus claims (it goes without saying that there is no good evidence to support any of them) and, for good measure, some conspiracy theory as well – the perfect mix for making a fast buck!
But sometimes things do not work out as planned. The following text was recently published on the website of Essex County Council:
A man claiming to sell a cure for cancer has been fined £750 following an investigation by Essex Trading Standards. Steven Cook, 54, of East Road, West Mersea, was charged with an offence under the Cancer Act after suggesting Colloidal Silver was a treatment for cancer.
Mr Cook pleaded guilty at Colchester Magistrates’ Court on Friday 12 September. Magistrates imposed a fine of £750 and ordered him to pay £1,500 costs. Cllr Roger Hirst, Essex County Council’s cabinet member for Trading Standards, said: “Trading Standards’ advice to people who are considering whether to take any substance not prescribed for a medical purpose, either preventative or as a treatment, is to consult their doctor first.
“I hope the public feel safer knowing that Essex Trading Standards will take action where traders are trying to sell products which are neither medically proven nor safe.”
Mr Cook runs a website, www.colloidalsilveruk.com, selling various products containing silver. One of the products on sale was “Ultimate Colloidal Silver”, a liquid containing silver that Mr Cook made in his own home. Trading Standards said the website implied that the product can cure cancer – and this is an offence under the Cancer Act. Mr Cook has now updated the website and removed any claims that colloidal silver can cure some cancers.
So, there is some hope! Occasionally, fraudsters are being found out and punished. But the bad news, of course, is that this sort of thing occurs far too rarely and when it does happen, the punishment is far too lenient. Consequently, the public’s protection from fraudsters exploiting the most vulnerable patients is woefully insufficient.
Poor sleep quality during pregnancy is a frequent problem. Drug treatment can be problematic due to possible adverse effects for mother and embryo/foetus. Many pregnant women prefer natural treatments and assume that ‘natural’ equals harmless.
In the present study, the sedative effects of Bryophyllum pinnatum were investigated. This remedy is a phytotherapeutic medication predominantly used in anthroposophic medicine. In previous clinical studies on its tocolytic effect, B. pinnatum showed a promising risk/benefit ratio for mother and child. A recent analysis of the prescribing pattern for B. pinnatum in a network of anthroposophic physicians revealed sleep disorders as one of the most frequent diagnosis.
In this prospective, multi-centre, observational study, pregnant women suffering from sleep problems were treated with B. pinnatum (350mg tablets, 50% leaf press juice, Weleda AG, Arlesheim, dosage at physician’s consideration). Sleep quality, daily sleepiness and fatigue were assessed with the aid of standardised questionnaires, at the beginning of the treatment and after 2 weeks. Possible adverse effects perceived by the patients during the treatment were recorded.
The results show that the number of wake-ups, as well as the subjective quality of sleep was significantly improved at the end of the treatment with B. pinnatum. The Epworth Sleeping Scale decreased, indicating a reduction in tiredness during the day. There was, however, no evidence for a prolongation of the sleep duration, reduction in the time to fall asleep, as well as change in the Fatigue Severity Scale after B. pinnatum. No serious adverse drug reactions were detected.
From these data, the authors concluded that B. pinnatum is a suitable treatment of sleep problems in pregnancy. The data of this study encourage further clinical investigations on the use of B. pinnatum in sleep disorders.
Clinical trials of anthroposophic remedies, i.e. remedies which are based on the school of medicine founded by Rudolf Steiner, are very rare. Therefore this trial could be important.
B. pinnatum is a plant used in traditional Tai medicine against hypertension, and to some extend this makes sense: it contains cardiac glycosides which might help lowering elevated blood pressure. The reason for its use as a hypnotic, however, is not clear.
So, is B pinnatum really a ‘suitable treatment of sleep problems in pregnancy’? I doubt it for the following reasons:
- the effects documented in this study are far from convincing,
- we would need much more solid data to issue such a general recommendation,
- cardiac glycosides can cause very serious adverse effects,
- the sample size of the study is at least one dimension too small for assuming that it is safe,
- we know nothing about its potential to cause harm to the foetus.
Personally, I find it irresponsible to draw conclusions such as the ones above on the basis of data which are flimsy to the extreme. I ask myself, to what extend wishful thinking might be a regrettable characteristic for the entire field of anthroposophic medicine.
Multivitamins are widely used, mainly for disease prevention, and particularly cardiovascular disease (CVD). But there are only few prospective studies investigating their association with both long- and short-term risk. In view of these facts, new evidence is more than welcome.
The objective of this study was to investigate how multivitamin use is associated with the long- and short-term risk of CVD. A prospective cohort study was conducted of 37,193 women from the Women’s Health Study aged ≥45 y and free of CVD and cancer at baseline who were followed for an average of 16.2 y. At baseline, women self-reported a wide range of lifestyle, clinical, and dietary factors. Women were categorized into 1) no current use and 2) current use of multivitamins. Duration and updated measures over the course of the follow-up to address short-term effects were also considered. Women were followed for major CVD events, including myocardial infarction (MI), stroke, and CVD death.
During the follow-up, 1493 incident cases of CVD [defined as myocardial infarction (MI), stroke, and CVD death] occurred. In multivariable analyses, multivitamin use compared with no use was not associated with major CVD event, stroke, or CVD death. A non-significant inverse association was observed between baseline multivitamin use and major CVD events among women aged ≥70 y (P-interaction = 0.04) and those consuming <3 servings/d of fruit and vegetables (P-interaction = 0.01). When updating information on multivitamin use during the course of follow-up, no associations were observed for major CVD events, MI, stroke, and CVD death.
The authors concluded that, in this study of middle-aged and elderly women, neither baseline nor time-varying multivitamin use was associated with the long-term risk of major CVD events, MI, stroke, cardiac revascularizations, or CVD death. Additional studies are needed to clarify the role of multivitamins on CVD.
Even the most enthusiastic vitamin fan will find it hard to argue with these findings; they seem rock solid. Vitamins have their name from the fact that they are vital for our survival – we all need them. But, in developed countries, we all get them through our daily food. Any excess of water-soluble vitamins is swiftly excreted via the urine. Any excess of fat-soluble vitamins is stored in the body and may, in some cases, even represent a health risk.
Exceptions are vulnerable groups such as children, the elderly, pregnant women and patients with certain diseases. These individuals can suffer from hypovitaminoses, the only reason for regularly using vitamin supplements. But for the vast majority of the population, the only effects of regular vitamin supplementation are that we enrich the manufacturers and render our urine expensive.
Well, not everywhere actually; if you go on Medline, for instance, and search for ‘detox’, you hardly find anything at all on detox as used in alternative medicine. This is because there is no science behind it (for the purpose of this post, ‘detox’ means the alternative detox that is supposed to rid us from environmental poisons and, more relevant to the Christmas season, of the effects of over-indulgence). Notwithstanding this lack of science and evidence, detox is currently being heavily promoted in magazines, newspapers and, of course, via the Internet.
Take the heir to our thrown, Prince Charles, for instance; he famously marketed his Duchy Originals ‘DETOX TINCTURE’. And he has competition from thousands who also exploit the gullible with similar placebos. One website even claimed that “2014 was the year of the cleanse diet. Celebrities swear by them and more and more people have been getting in on the action, whether it’s to detox diet, brighten skin, lose weight, or get a fresh start. And nowhere is that more evident than in Yahoo’s Year in Review, where different health cleanses consistently topped the site’s most popular stories lists. Here, the year’s top 10 most popular cleanses.”
The author then continues by promoting 10 different forms of detox:
1. A Colon Cleanse.
2. A Liver Cleanse.
3. The Master Cleanse.
4. The 10-Day Green Smoothie Cleanse.
5. A Juice Cleanse.
6. Detox Cleanse.
7. Slendera Garcinia and Natural Cleanse.
8. Dherbs Full Body Cleanse.
9. Blueprint Cleanse.
10. Isagenix Cleanse for Life.
These treatments seem diverse but they all have one thing in common: they do not work; they do not eliminate poisons from the body, they merely eliminate cash from your wallet.
But being so very negative is not the way forward, some might argue. Why does he not tell us which forms of detox do actually work?
Because it is Christmas, I will do just that and provide my readers with a full list of detox treatments that are effective. If you are looking for a specific type of detox and it is not on the list, it means you should spend your money on something else, stop over-indulging yourself and adopt a sensibly health lifestyle.
HERE WE GO – THIS IS MY COMPLETE LIST OF EFFECTIVE FORMS OF DETOX:
MERRY CHRISTMAS EVERYONE
The regular consumption of fish-oil has a potentially favourable role in inflammation, carcinogenesis inhibition and cancer outcomes. An analysis of the literature aimed to review the evidence for the roles of dietary-fish and fish-oil intake in prostate-cancer (PC) risk, aggressiveness and mortality.
A systematic-review, following PRISMA guidelines was conducted. PubMed, MEDLINE and Embase were searched to explore PC-risk, aggressiveness and mortality associated with dietary-fish and fish-oil intake. 37 studies were selected.
A total of 37-studies with 495,321 participants were analysed. They revealed various relationships regarding PC-risk (n = 31), aggressiveness (n = 8) and mortality (n = 3). Overall, 10 studies considering PC-risk found significant inverse trends with fish and fish-oil intake. One found a dose–response relationship whereas greater intake of long-chain-polyunsaturated fatty acids increased risk of PC when considering crude odds-ratios [OR: 1.36 (95% CI: 0.99–1.86); p = 0.014]. Three studies addressing aggressiveness identified significant positive relationships with reduced risk of aggressive cancer when considering the greatest intake of total fish [OR 0.56 (95% CI 0.37–0.86)], dark fish and shellfish-meat (p < 0.0001), EPA (p = 0.03) and DHA (p = 0.04). Three studies investigating fish consumption and PC-mortality identified a significantly reduced risk. Multivariate-OR (95% CI) were 0.9 (0.6–1.7), 0.12 (0.05–0.32) and 0.52 (0.30–0.91) at highest fish intakes.
The authors concluded that fish and fish-oil do not show consistent roles in reducing PC incidence, aggressiveness and mortality. Results suggest that the specific fish type and the fish-oil ratio must be considered. Findings suggest the need for large intervention randomised placebo-controlled trials.
Several other recent reviews have also generated encouraging evidence, e.g.:
…omega-3 fatty acids may exert their anticancer actions by influencing multiple targets implicated in various stages of cancer development, including cell proliferation, cell survival, angiogenesis, inflammation, metastasis and epigenetic abnormalities that are crucial to the onset and progression of cancer.
If I was aiming for a career as a cancer quack, I would now use this evidence to promote my very own cancer prevention and treatment diet. As I have no such ambitions, I should tell you that regular fish oil consumption is no way to treat cancer. It also is no way to prevent cancer. If anything, it might turn out to be a way of slightly reducing the risk of certain cancers. To be sure, we need a lot more research, and once we have it, fish oil will be entirely mainstream. Raising false hopes regarding ‘alternative cancer cures’ based on fairly preliminary evidence is counter-productive, unethical and irresponsible.