Scientific Studies Coming to Terms

ou've read news reports of nutrition studies. But what do all the terms mean?

Bias. Problems in the study design that affect the reliability of the results; perhaps the subjects weren't chosen right.

Blind (single or double) study. Study (single blind) where the subjects don't know if they're in the experimental or placebo group until after the study's over; study (double blind) where the researchers don't know either, so they can't influence the outcome.

Clinical trial. Studies done to directly show the effectiveness and the safety of a supplement, medication, or treatment with a selected group of people.

Confounding variable. A "hidden" and related variable (perhaps an unknown phytonutrient) that the researcher attributes to something different.

Control group. The study group that doesn't have the treatment. A control group is used to know if a treatment has an effect.

Correlation. An association between two research variables, such as eating lycopene and reduced risk for prostate cancer. A correlation does not prove cause and effect, but may suggest further study.

Epidemiological study. Study of the incidence and prevalence of a health condition among a specific group of people, such as neural tube defects among newborns.

  1. Describes how much research results apply to the general population of people who are like the studies' subjects.
  2. How many new cases of a disease or health condition as of a specific date, for a defined population.

In vitro study. Laboratory study with cells or tissue samples, usually done before an in vivo study.

In vivo study. Study with living subjects, either animal or human research.

Meta-analysis. A way to pool quantitative data from many studies to see what overall conclusions can be drawn, such as the pooling of more than forty studies on oats and more than twenty-five studies on soy protein to show their links to cholesterol-lowering.

  1. Number of deaths in relation to a population.
  2. Number of people with an illness in relation to a population.

Observational study. Study that identifies a link between a health condition and behavior, such as overweight and TV-watching, but doesn't prove cause and effect.

Placebo. A "fake" treatment, perhaps a sugar pill, that appears to be the same as the treatment under study. It's used to remove bias when study subjects don't know which treatment they have.

Placebo effect. Positive results among subjects who think they're getting the real treatment.

Prevalence. How many existing cases of a disease or a health condition as of a specific date, for a defined population.

Prospective study. Study that poses the research questions, then follows groups of people, often for decades.

Random sample. A way to choose study subjects whereby anyone from a target population has an equal chance to be picked. In that way the results can be more easily generalized to a larger group.

Reliability. Describes research that is carefully controlled so the data can be reproduced. In other words, the researcher would get the same result with the same study subject several times.

Retrospective study. Study that uses recorded data or recall of the past. Because the study relies on memory or some variables that can't be easily controlled, this type of research has limitations.

Risk. The probability that something (perhaps a heart attack, stroke, cancer, diabetes, osteoporosis) will happen. "Risk" doesn't necessarily mean something will happen.

Risk factor. A factor that's statistically linked to the incidence of disease, such as a high BMI as a risk factor for heart disease. Again, it doesn't necessarily mean cause and effect.

  1. The accuracy or truthfulness of the study's conclusion, and if the study measured what it meant to study.
  2. A factor such as age, gender, or food choices in a study that differs among the people being studied. An independent variable is the one being studied; a dependent variable, perhaps lower blood sugar level or LDL cholesterol level, happens as a result of the treatment.

Adapted from source: Reprinted with permission of the International

Food Information Council Foundation, Washington, D.C.

  • Have an educational purpose, or only a hidden guise of sound nutrition advice? If it's promotional, the information is likely biased or reframed for marketing and sales. Assess information within the context of total nutrition. Be aware: Online charlatans sell products and "cures" with unfounded benefits or harmful side effects!
  • Indicate regular updates and postings? Credible Web sites are updated often to offer the most current advice. Caution: Being current doesn't necessarily make it accurate. If the links don't work, it's likely old.
  • Provide sound information, not just "bells and whistles"? Is it free of advertising, including pop-up ads?
  • Pass other credibility tests? See "Read between the Headlines" in this chapter. Anyone can launch a site. Like any media report, being on the Internet doesn't ensure reliability.
  • Have a nutrition expert as a host for forums and chatrooms? Many unsponsored bulletin boards bring interested people together, with chat from undisclosed sources who often aren't experts. Be wary!

"Well" Connected Links

Search engines list legitimate and less reliable Web sites side-by-side; you need skills to sort them out. That's why it's wise to tap health-related resources that indicate high standards:

  • To speed your search use gateway sites that link to responsible organizations—for example, the U.S. government's site (www.nutrition.gov). The U.S. Department of Health and Human Services' Healthfinder (www.healthfinder.gov) hyperlinks to hundreds of responsible sites, as does the gateway in the American Dietetic Association's site (www.eatright.org).
  • Review more than one Web site on the same nutrition topic; use several search engines. With information "sound bites," usually one site isn't complete enough.
  • Look for sites with the HONcode symbol, showing they adhere to the HONcode (Health On the Net Foundation) principles. An example: the WebMD Web site, which

IHHHI

Have You Ever Wondered

. . . how to judge food scares that circulate through e-mail? Being 100 percent sure about these food scares takes research. What appears in your e-mail is likely a hoax (1) if it wasn't written by the e-mail sender, (2) if you're asked to forward the e-mail, (3) if it claims not to be a hoax or an urban legend, (4) if it appeals to your emotions, and (5) if it doesn't cite a legitimate source or a credible Web site. Read critically for obvious false claims, poor logic, and lack of common sense. If you're still not sure, you might want to check Web sites such as www.quackwatch.com or www.urbanlegends.com that debunk food myths.

provides online, consumer-focused health information (www.webmd.com). These sites voluntarily comply with a code of conduct for health and medical Web sites. HON is an honor symbol and system, so still be a careful online consumer.

• Ask a nutrition expert, such as an RD or a DTR, who has a quick ability to see nuances of Web site bias and inaccuracy. If you find news of interest on the Internet, such as about a phytonutrient link to health, or a dietary supplement, print the information with the name and address of the Web site; take it to your healthcare provider or a nutrition expert for a perspective.

To find reliable nutrition and health Web sites, see "Resources You Can Use" at the back of this book.

E-Nutrition Advice: Just for You

With a few mouse clicks, you can calculate your BMI, assess your food choices, even tie in to online weight control counseling. But consider this:

  • If you wish, use quick, online assessments and counseling on your food choices, physical activity, and health issues, but don't replace your healthcare provider. For a reliable diagnosis and prescribed eating plan, work with a qualified healthcare provider in person, who can review your medical history. Today many registered dietitians do online counseling.
  • For the same reasons, get advice or a prescription for a dietary supplement from your doctor. As an aside, buying supplements online may, or may not, cost less, and the quality is uneven.
  • Even on trustworthy healthcare sites that do online nutrition assessments and counseling, there's a wrinkle: privacy. To protect the privacy of your records and avoid a Pandora's box of e-marketing, provide personal data on encrypted, or secured, sites only. If a "closed padlock" appears on the Web page, the data you provide are encrypted and secure. And pay attention to "alarms" on the site that warn that you're moving from secure to insecure parts of the Web site.

As you surf the Internet, keep track of your path. You may be unaware when you pass from a reliable to an unreliable source of information.

Your Heart and Nutrition

Your Heart and Nutrition

Prevention is better than a cure. Learn how to cherish your heart by taking the necessary means to keep it pumping healthily and steadily through your life.

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