Top Researchers Say Tofu A Powerful Aphrodisiac!

by Dave Way (Originally published in the November/December 2004 issue of Canada EarthSaver)

Today in the newspaper you read a study claiming that people eating large amounts of artichokes have less cancer of the nose. Simultaneously an internet news item reported that high consumption of chick peas is associated with spontaneous human combustion. Is that artichoke hummus worth eating or not?

We live in a world of information overload, with so many forms of media competing for the public's attention. To keep that attention, they need to supply a constant diet of interesting and hopefully useful stories. So when the benefits of oat bran are not news, any study that suggests the opposite is welcome, to stir things up. The media are not necessarily intending to misrepresent the facts, but they are often ill prepared to determine whether a study is trust-worthy and what the actual results are.

So how can one read about a medical study and understand it without a university degree? It is hard but here are some hints: the most important point is that 'correlation does not prove causation'. That is, there may be a relationship between two things, but one might not cause the other. For example, if the highest heart attack rate in North America is in Tucson, Arizona, can we conclude that this locale is dangerous to heart health? A more likely explanation is that those with heart disease are encouraged by their doctors to move from other parts of the country to Tucson for climate reasons. They eventually die of heart disease anyway, leading to the high statistics. So science can't generally answer the question of 'did my behaviours or other factors cause my medical condition?' Rather it can just show that there is a relationship between the two. Most studies reported in the media are correlational only.

Another issue with studies is the scientific rigour of their design. Some works are basically an analysis of a small group of patients after the fact. Other than being authored by an MD, they are not much more use than the anecdotal gossip of your friends or neighbours about who seems to be gaining the most weight.
How can one determine if a link is 'strong enough'?

Statistics! Yes, that's right, math is the answer. There is no point in doing a 'scientific study' of 12 vegetarians if the results could later be explained away as easily as coincidence. Better to figure out that you need 150 at the outset and not sabotage the work.

Size and design of a study is often determined ahead of time by statistical methods. It is also necessary to make sure that the group in question is actually giving different results than the general population. In a 'cohort study', the group of interest is compared to a normal group. This is often called the 'control'. One example might be to look at a bunch of veggies versus nonveggies to see how much heart disease they have. Another form of design is sort of the reverse of this: in a 'case-control study', one would look at a group with a certain outcome, say heart disease, and a healthy group. We would then ask 'is there more meat consumption by those that got the disease than in the healthy group?'

Even if the study appears to be large and well-designed, there could be flaws or misrepresentations. One of the main defenses against this is the standard of peer-reviewed or refereed journals. The idea is 'who better than an eminent immunologist to analyze and critique an immunological study?' One example of where this was not done is the Eat Right 4 Your Type book, in which author and naturopathic doctor Peter D'Adamo claims that your blood cell markers make certain foods appropriate or not for you. Since he talks about only one type of blood marker (the ABO groups) out of several, and reports associated responses to foods that no one else in the medical field has found, it's all a bit suspect. When one reads the footnotes, it turns out that most of his 'clinical studies' or evidence have been reported in a nutrition journal (read magazine) that he himself edited. No peer review was going on, therefore no one to keep it trustworthy. All of the more famous scientific journals (Lancet, Nature, Science, JAMA) are trusted because of this peer review and their rigorous standards.

An equally important consideration is the author bias. Do they seem determined to persuade the audience, or do they qualify their views by acknowledging opposing views? What do they have to gain from the acceptance of their study? Are they selling products? Books? A religion? In the case of the Atkins diet, all three?

If the author seems to be free of commercial associations, it's worth checking who they work for or who sponsored the study. The BC Dairy Foundation employs certified nutritionists, but it's hard to imagine these folks giving any publicity to a study they come across that associates dairy intake with a medical ailment. It's just not in the interests of their employer, whose mandate is to increase consumption of dairy products for their members. Admittedly, a writer for EarthSave may have a bias too.

If you want to get a better handle on this issue, there is an article on the internet called 'Getting the Story Straight on Nutrition' which was written to help reporters and editors look for bias and report scientific studies accurately. Really keen? Try Manfred Kroger's book Studies Show: A Popular Guide to Understanding Scientific Studies.

In addition, you can go closer to the source and search on PubMed, a portal to summaries of thousands of actual medical and scientific journal articles. Good luck and remember, one study is not enough to make significant life decisions (like eating only blue foods). It's just a starting point for more research.

Reprinted by permission from the Canada Earthsaver.

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