January 24

Bias in nutritional studies


As Julius Caesar said with the knife buried in him: “Et tu, Brute?” I feel a little the same way after this paper from PLoS, but I guess I shouldn’t be surprised.
It’s long been known and reported on that there is major bias in studies funded with drug company money. Now it appears that there is the same kind of bias when published nutritional studies are funded by food companies. There may be even more bias than there appears to be due to the fact that many negative studies are not published. If a company pays to underwrite a study on one of its products, and that study turns out to not support the claims that company makes for its product, typically the study isn’t submitted for publication. When you see a study that offers evidence that the companies products promote better health, it doesn’t necessarily mean that the study is false or wasn’t well done. But what you don’t know is whether there are a half dozen more studies showing the product negatively that never saw the light of day.
The Editor’s Summary of the PLoS study:


Much of the money available for doing medical research comes from companies, as opposed to government agencies or charities. There is some evidence that when a research study is sponsored by an organization that has a financial interest in the outcome, the study is more likely to produce results that favor the funder (this is called “sponsorship bias”). This phenomenon is worrying, because if our knowledge about effectiveness and safety of medicines is based on biased findings, patients could suffer. However, it is not clear whether sponsorship bias extends beyond research into drugs, but also affects other types of research that is in the public interest. For example, research into the health benefits, or otherwise, of different types of food and drink may affect government guidelines, regulations, and the behavior patterns of members of the public. Were sponsorship bias also to exist in this area of research, the health of the wider public could be affected.

Why Was This Study Done?

There is not a great deal of evidence about whether sponsorship bias affects nutritional research (scientific studies that look at the relationship between food and/or drink, and health or disease states). Therefore, the group of researchers here set out to collect information from published nutritional research papers, to see if the type of sponsorship for the research studies was in any way linked with whether the main conclusions were favorable or unfavorable to the sponsor.

What Did the Researchers Do and Find?

The research study reported here used the scientific literature as a source of data. The researchers chose to examine one particular area of nutrition (nonalcoholic drinks including soft drinks, juices, and milk), so that their investigation would not be affected too much by variability between the different types of nutritional research. Using literature searches, the researchers identified all original research and scientific review articles published between January 1999 and December 2003 that examined soft drinks, juices, and milk; described research carried out in humans; and at the same time drew conclusions relevant to health or disease. Then, information from each published article was categorized: the conclusions were coded as either favorable, unfavorable, or neutral in relation to the health effects of the products being studied, and the article’s funding was coded as either all industry (ie, food/drinks companies), no industry, or mixed. 206 published articles were analyzed and only 54% declared funding. The researchers found that, overall, there was a strong association between the type of funding available for these articles and the conclusions that were drawn. Articles sponsored exclusively by food/drinks companies were four to eight times more likely to have conclusions favorable to the financial interests of the sponsoring company than articles which were not sponsored by food or drinks companies.

What Do These Findings Mean?

These findings suggest that a high potential for bias exists in research into the health benefits or harms of nonalcoholic drinks. It is not clear from this research study why or how this bias comes about, but there are many different mechanisms that might cause it. The researchers suggest that certain initiatives might help to reduce bias, for example, increasing independent funding of nutrition research.

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  1. MRE,
    “Were sponsorship bias also to exist in this area of research, the health of the wider public could be affected.”
    Geez! I guess so! Anecdotal evidence suggests that there’s a whole lotta trouble in River City’s favorite buffets and fast-food joints!
    I’m not a scientist (actually, I’m an artist and curator), but I’ve trudged through just enough research material to realize that if it weren’t already difficult enough, ascertaining the hidden agenda(s) of the sponsors makes it downright depressing.
    Mike, is there much hope for a flowering of independently sponsored nutrition studies, or will the political and economic interests of the sponsors always have to play a role in the evaluation of evidence?
    Hi Richard–
    I’m afraid that until we get independent funding, we’re going to have to deal with the bias in published studies. Who is going to independently fund nutritional studies? That is the $64,000 question. If our leaders in Washington really gave a rat’s hind end about the health of the nation, they would see that the NIH funded more nutritional studies. I mean, what could be more important than the discovery of the optimal diet for man. I’m not holding my breath.

  2. Oh, it doesn’t look good at all. Nutrition research begins with the knowledge gained from “basic” research, i.e., discovering how the cells work (not to be confused with drug discovery, clinical research, etc.). My husband is a research scientist (biochemist) in basic research. One of his main areas is apoptosis, which is “programmed cell death”, sort of like cell suicide. All cells have this death process programmed to happen at a particular time (lifespan of a cell varies by cell type), but when the timing is wrong (too early or too late) then problems occur (cancer with cell proliferation or neurodegenerative disease with early cell die-off, for example). He has discovered many aspects of how this process is turned on or off, and is it quite an exciting field for many reasons. Much of what he and his colleagues learn about apoptosis is already being applied to disease research and treatment by other researchers and clinicians.
    Most of his funding is from NIH grants. He is quite worried about the state of funding 5 years from now, when his current grants are up for renewal or ending (not just for his lab employees, for even perhaps for himself). Peer-reviewed grant funding has always been quite competitive, but with good grant-writing skills, an outstanding track-record of scientific achievement, and a good reputation among his peers, he has been successful in earning grants and developing an outstanding lab at an excellent non-profit research institute (ok, I’m very proud of him). The competition tends to make the good scientists better, and weed out the less competant (for the most part). 🙂
    But now, even the best scientists are having trouble getting grants funded or renewed at all. It is only going to get worse if Congress and the President continue to underfund NIH (all govt departments have taken budget hits to fund the war in Iraq & Afghanistan). Basic research may be seriously compromised in the US if NIH funding continues to be reduced. Much of the current medical research is based on this basic research, sort of like a trickle down effect. Good scientists are leaving the country and going to places like Singapore & China (& the UK, to a lesser extent), where the funding is generous (especially in Asia) and stem cell research is less restricted.
    Yes, I have a personal stake in this because it is my husband’s livelihood, but we also see a dark cloud ahead for basic science (and all the good stuff that trickles down from it). Drug companies will pick up the slack with more basic research perhaps, but there may be a huge price to pay for that, because then the research is patented and decisions to pursue certain areas of knowledge will be more frequently based on profit, rather than the pursuit of pure knowledge. Additionally, there will be a huge brain drain as the top folks leave the non-profit US science communities for profit based organizations or other countries, just to keep working at what they love. Most people in the NIH-funded non-profit research institutes are not in it for riches (in fact it is a long, low paying process of higher education and apprenticeship, not to mention weeding out less competitive candidates, before one earns his/her own lab and research grants), and most do it because they are extremely intellectually curious and a life pursuing knowledge is very satisfying.
    Ok, off my soap box.
    San Diego, CA
    Hi Anna–
    We are indeed in trouble with worse to come, I fear.  It’s going to be tough to get the Big Pharma to pony up for basic science research unless it gets them something in return.  And with NIH becoming stingier by the minute, I don’t know where it’s all heading, but it doesn’t look good. t would be great to see the extremely wealthy (Bill Gates and/or Warren Buffet, for example) to use their charities to fund basic science research, but I guess that doesn’t get the warm and fuzzies for them.
    Let’s keep our fingers crossed.

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