Back-and-Forth Foods

Do certain foods or drinks help your health or hurt it? With the conflicting scientific results they produce, how can you tell their real place on your plate?

On some days, they are hailed for their edible health virtues; on others, their culinary curse. Some studies boast of their abundance of life-extending antioxidants, while others warn of the poisons, fats, or other dangers they also contain.

They are those "back-and-forth" foods and drinks that keep making news for different reasons -- adding to a recipe for confusion when it comes to their real role in your health.

There's chocolate, which has been found to promote heart health -- while also clogging its arteries. Wine that dulls the senses but may also keep the mind sharp. Coffee that can cause nervousness, hand trembling, and rapid heartbeat while exciting researchers for apparently lowering risk of diabetes, Parkinson's disease, colon cancer, and even cavities. Wild salmon are known to be swimming with heart-healthy fatty acids -- and possibly, cancer-causing toxins, as well.

Why these conflicting findings?

"Science is evolutionary -- not revolutionary," says dietitian Kathleen Zelman, MPH, RD, director of nutrition for WebMD's Weight Loss Clinic, who also runs a private practice in Atlanta. "Generally, one study does not make a difference in the grand scheme of a certain food's role in your diet. But that doesn't stop it from making headlines."

Especially when the latest findings suggest there are healthful properties in some of the most notorious vices in your kitchen, or possible dangers in foods that are generally praised for their nutritional gold.

Read Between the Headlines

So how do you know the real story behind the headlines to better determine how they should rate on your plate?

"A lot depends on how, where, and with whom the study was conducted," says Marilyn Tanner, RD, spokeswoman for the American Dietetic Association and pediatric dietary study coordinator at Washington University School of Medicine in St. Louis. When you hear the latest health finding about these or any foods, she suggests you note these factors:

· Where it's published. Bigger medical journals tend to publish better quality studies. "If it's published in the big journals -- The Journal of the American Medical Association, The New England Journal of Medicine or the Journal of the American Dietetic Association -- it means something, and you should weigh those findings more than a study posted on a food manufacturer's web site," Tanner tells WebMD.

· Where it was conducted. "Studies done in university settings are more likely to be trustworthy than those done at private labs or in the sponsoring companies' own lab," she says. "In multicenter studies, you've got different races, ethnic backgrounds, and populations, which can make food findings even more important. For instance, in the East and West Coasts, there is tons of fresh seafood, which would play a role in eating habits and health effects compared to doing a fish consumption study in the Midwest."

· Its length and size. Generally, the larger and longer the study, the greater its credibility, and the more one can apply the results of the study to the general population.



Should You Have It or Not?

That said, here is the latest lowdown on some controversial cuisine:

Coffee

In recent decades, some 19,000 studies have examined coffee's impact on health. "Overall, research shows that coffee is far more healthful than it is harmful," says Tomas DePaulis, PhD, research scientist at Vanderbilt University's Institute for Coffee Studies. Among the benefits noted in multiple studies: Compared to non-drinkers, having two to three cups a day translates to a lower risk of Parkinson's, colon cancer, gallstones, and liver cirrhosis. One recent Harvard study showed that six cups daily reduced diabetes risk 54% in men and 30% in women.

But that doesn't mean coffee is for everyone: Heart patients, pregnant women, and those with GERD or at risk for osteoporosis are often advised to limit or avoid coffee and other caffeine sources because it speeds heart rhythm, can trigger acid reflux, and leech calcium from bones.

"With teens, the issue over coffee is really about weight gain, because they tend to load a cup of coffee with sugars, cream, and fancy syrups," says Zelman. While coffee itself has 0 calories, the "tall" versions of these specialty coffees can contain 800 calories or more -- nearly two meals worth -- thanks to these extras.

Advice: Two cups of joe daily is enough for the average Joe to wake up and reap most of the health benefits without caffeine overload. And drinking that amount in slow sips throughout the day keeps you alert better than gulping it in one sitting, suggests one recent study.

Chocolate

Yes, it can be a great source of flavonoids, those antioxidants known to protect against free radicals that damage arteries and trigger the buildup of plaque, which can lead to atherosclerosis. But bite-for-bite, chocolate is among the highest sources of saturated fats -- and therefore, it can lead to high cholesterol and weight gain.

The caveat: Most studies indicate that it's dark chocolate that offers the antioxidant bounty, not white or milk chocolate. And take this cue from a small study last year that showed eating 3.5 ounces of chocolate each day helped lower blood pressure: The study participants were asked cut back on 480 calories each day to so they didn't gain weight from the daily candy bar.

Advice: Satisfy your cravings, without guilt -- but not necessarily your appetite. "Chocolate is a nice treat that can be enjoyed, but realize the health benefits don't outweigh its high amounts of sugar and fat. There are better ways to eat more antioxidants," says Zelman. "When you treat yourself, do it with one of those miniature bars, not a movie-sized one."

Wine

Last year, a well-publicized study with all the right ingredients -- done by a respected Harvard team that tracked 38,000 people over 12 years (and published in a top journal) -- showed that the more often men drank, the less likely they were to have heart attacks. But that's the key: How often, not how much.

Virtually every finding suggests the heart- and mind-helping effects of wine and other alcohol comes from moderate amounts of wine -- one to two drinks a day. It's OK to have this amount daily, but don't down it in one sitting. In fact, a recent finding suggests that regularly having three or more drinks daily can damage the brain.



"All alcohol is OK; that's not to say you should start drinking to become healthier," says Zelman. In fact, people with high blood pressure, diabetes, or who are pregnant shouldn't drink at all.

Advice: If you do drink, stop at two per day. "And be aware that alcohol can have a lot of calories, especially if you mix it with kahula, Bailey's, or other sweet liquors," she says.

Salmon

There's no question that salmon is a treasure chest of disease-fighting nutrients. "Some foods have magic bullet qualities and salmon is one of them, with numerous scientific papers showing that omega-3 fatty acids are probably more abundant in salmon than anything else, and it's an excellent source of lean protein."

But what about reports of its dangerous levels of PCBs -- synthetic chemicals released through industry activity? PCBs have been banned in the U.S. since 1976 because they are thought to cause cancer and birth defects in even small doses. "I've done research on PCBs, and it's really an issue between what the FDA believes are safe levels and what the EPA says should be looked at," says Zelman. "Thus far, the association between salmon and potential cancer is theoretical at best."

Advice: Unless you're a grizzly bear in feeding season, it's highly unlikely you'd get enough PCBs from salmon to cause problems. Many experts, including Zelman, contend salmon is safe in the often recommended two-or-so servings per week.

Eggs

Forget those worries that eggs cause high cholesterol. Despite the fact that a single egg has 213 mg of cholesterol -- two-thirds the daily recommended levels -- newer research indicates that it also contains a substance that, in laboratory animals at least, actually blocks the absorption of cholesterol from entering the bloodstream.

"Eggs are incredibly nutritious and can be worked into every meal," says Zelman.

Advice: Most experts agree that it's completely safe for most people to have one egg a day.

The bottom line of it all: "All foods can fit into your diet, but often it's a question of how much of them you should have," says Tanner.

Published May 24, 2004.





SOURCES: Kathleen Zelman, MPH, RD, director of nutrition, WebMD Weight Loss Clinic. Marilyn Tanner, RD, pediatric dietary study coordinator, Washington University School of Medicine, St. Louis; spokeswoman, American Dietetic Association. Tomas DePaulis, PhD, research scientist, Vanderbilt University's Institute for Coffee Studies, Nashville. Wyatt, J.K. Sleep, May 2004; vol 27. Taubert, D. The Journal of the American Medical Association, Aug. 27, 2003; vol 290: pp 1029-1030. Serafini, M. Nature, Aug. 28, 2003; vol 424: p 1013. Mukamal, K. The New England Journal of Medicine, Jan. 9, 2003, vol 348; pp 109-118.

http://my.webmd.com/content/article/87/99550.htm

>>"Where it's published. Bigger medical journals tend to publish better quality studies. "

As long as they chime in with the current paradigm.

...and one egg per day?