臨床試驗——金本位或白色大象?

這些試驗的價值食品行業是不可否認的,但往往營養被斷章取義,遵循同樣的方法用於測試的藥物。但是讓我們不要忘記,按照藥物模型我們補充營養飲食與一個或兩個,每個單劑量,一組一段時間。時間控製的隨機試驗真的可以捕獲一生的消費對慢性疾病嗎?隨機臨床試驗的工作通過隨機分配一組誌願者接受一個活躍的化合物,是一種藥物或營養(s),或一個不活躍的比較,是一個不活躍的形式的活性化合物或安慰劑。觀察性研究,顧名思義,觀察人口和膳食攝入的食物和營養相關疾病的發生。我們需要考慮科學作為一個整體,而不是信號燈自己與一個大的臨床試驗的結果,不管花費多少錢,什麼大學。食品,通常不會形成通常的食物鏈的一部分,隨機臨床試驗是最好的最好的,因為這樣的化合物可以測試和測試成功。植物甾醇、益生菌或植物補充劑,例如,歸入這一類。事實上,臨床試驗植物甾醇顯示一次又一次,日常消費的1.5到3克的植物固醇/固醇可以降低總膽固醇水平8 - 17%,代表顯著減少心血管疾病的風險。研究如何將這些結果轉移到實際生活無拘束的人口支持臨床試驗,顯示穩定的膽固醇水平在某些人群。 So we know the benefit of clinical trials. But when we start using this approach for vitamins, minerals, antioxidants and other nutrients, we come a little unstuck. Some may say that I'm over-reacting, but let's just look at the report published in the New Scientist magazine that slammed antioxidant supplements as myth. Despite a vast body of observational/ epidemiological studies linking an increased dietary intake of antioxidants from fruits and vegetables to reduced risks of a range of disease, including cancer, cardiovascular disease and diabetes, when such antioxidants have been extracted and put into supplements, the results, according to RCTs, do not produce the same benefits and may even be harmful. So the author of the article, Dr. Lisa Melton from the London-based registered charity, the Novartis Foundation, concluded that antioxidant supplements are too good to be true. Is this really the answer or is it due to poor study design? Would a two-year trial of vitamin E, let's say, really produce a reduction in the risk of a chronic disease? To illustrate this point further, we only need to go back to last year's Women's Health Initiative (WHI) trial that followed 18,176 post-menopausal women taking calcium (1000 mg) and vitamin D (400 IU) supplements. A similar population (N=18,106) was given a placebo. The subjects were followed for about seven years and the researchers reported that the supplements 'had no effect' on the risk of colorectal cancer. None of the women had the cancer at the start of the study and colorectal cancer has a long latency period of 10 to 20 years, which begs the question - could we really have expected to see an effect? We also need to remember that nutrients often work in synergy with one another and exert effects on multiple body tissues, unlike pharmaceuticals. Additionally, many randomised clinical trials look at the effect of nutrients in diseased populations. Surely the damage of a lifetime's poor nutrition has already been done. When we obtain negative or null results from such trials, should we really be surprised? The power of nutrients is in the prevention, not cure, of disease. So what should we do? I don't pretend to have any answers. These are for ladies and gentlemen with infinitely bigger brains than me. Realistically, there are no viable alternatives out there at present. Randomisation is the best way of limiting bias that creeps into every study, and controlling, specifically with placebo, is the best way to make comparisons. For those times where randomised trials clearly aren't the best option, then we probably need to look at the observational studies and mechanistic studies in greater depth, and place more value on them. The research community as a whole must work together to re-evaluate how to get the most from research into nutrition. Lots of different types of studies are out there. Let's make the most of what we already have.斯蒂芬·丹尼爾是食品科學記者NutraIngredients.com和FoodNavigator.com。他有一個貝爾法斯特女王大學化學博士學位,並在荷蘭和法國的研究工作。如果你想要評論這篇文章請聯係stephen.daniells特'decisionnews.com讀者的評論謝謝你出版這個完整性檢查。我們的符合,目前我們的研究是如何進行的。特別是流行病學,結果越來越越來越提前的決定結果是什麼想要的然後工作測試,以證明這一點。我已經失去了信心在今天的科學“證據”。- Susan R. Feldman, President, Susan Feldman Consulting LLC., Alexandria, VA. USA Just read your article on the limited that view clinical trials produce on the effectiveness of vitamins, minerals, etc. and couldn't agree more with what you are saying. Just wanted to let you know that I enjoyed your article and I think the points you raise deserve serious attention by those who conduct such trials and offer opinions to the public as a result. - Terry, Australia