Green Tea? Funny You Should Ask

Like all good public servants (and bloggers seeking to build loyal audiences), we here at the Truth Squad are responsive to our visitors. And so today we jump right on a recent reader request for the straight dope on green tea. Happily, this is something I've looked into quite closely lately.

Bottom line first
Most claims made for the benefits of green tea--which range from fighting cancer and heart disease to enhancing weight loss and (inevitably) improving sex life--have not been scientifically established. Most of the claimery rises from self-interested promoters and out-of-context reports of inconclusive studies.

Best stuff
As usual, our friends at The Natural Standard have produced the most independent, thoroughgoing report.

The Natural Standard green tree report, updated in August 2006, reveals that there is "unclear scientific evidence" (which they grade "C" on their A-through-F scale) for the following uses: arthritis, asthma, cancer prevention, dental cavity prevention, diabetes, fertility, heart attack prevention, high blood lipids, memory enhancement, menopausal symptoms, mental performance/alertness, prostate cancer treatment, sun protection/damage mitigation; and weight loss. Anxiety gets a "D."

That's pretty much a clean sweep dismissal of all the popular claims made for green tea and the potent antioxidant EGCG, thought to be the source of tea's possible benefits.

Let me rush to add that failing to prove a benefit is not the same as disproving it. For each of the claims above, there is some evidence of benefit--from test-tube or animal studies, or from observational or lower quality experiments in people. But none rises to the level of what NS or other legit researchers consider "good" or "strong" scientific evidence.

The cancer question
Due to a health issue in my extended family, I recently dug deep into the research about anti-cancer properties of green tea. The venerable Mayo Clinic is carrying out a gold-standard clinical trial on patients with chronic lymhpocytic leukemia (CLL), a blood cancer. Here's a report on the preliminary research that provided groundwork for the clinical trial.

This is one of those neat Internet successes: A patient/doctor-maintained Web site, CLL Topics, helped sponsor the study. Read that inspiring CLL story here. The fact that Mayo is on the case suggests serious people think a link to cancer prevention or treatment is possible.

Key facts

• Nearly all responsible authorities report that moderate amounts of green tea (up to 4 cups per day is what's usually cited) are safe. Ditto most dietary supplements taken per label recommendations.
  
• High blood pressure, diabetes, liver disease, pregnant, or taking warfarin? Proceed with great caution and only with a doctor's okay.
  
• Green tea and supplements contain caffeine, so take the usual precautions (or enthusiasm). If green tea has any metabolic and/or weight loss effects, this is suspected to be the reason.
  
• All teas contain EGCG, but green tea includes more than black (oolong, orange pekoe, Earl Gray, etc.). Several bottled green teas have been tested and found to have tiny, likely inconsequential amounts of EGCG.
• Still want more info? The Department of Agriculture has produced an excellent green tea report on continuing research, updated in June 2006.
• Bottom line: Enjoy some green tea of you like it. Eating healthy, exercising regularly and not smoking are, as usual, the most important things you can do to minimize disease risk. Ignore any claims you hear to the contrary, especially from folks who are selling supplements or green tea products. The Truth Squad will keep you posted
  

For Heart Disease, a Prevent Defense

Great report yesterday in the New England Journal of Medicine analyzing how many lives have been saved by improved prevention and treatment of heart disease. A few key points are worth knowing.

Bottom line first
Less invasive and less costly heart disease interventions saved more lives over the past 20 years than angioplasty or open heart surgery did. But obesity and diabetes cut into those gains significantly.

This study in 50 words or less
Researchers analyzed data from previous studies on heart disease treatments and compared it to demographic data on heart disease and death. They arrived at estimates--which they admit are quite rough--of numbers of lives saved by various methods.

Yes, but. . .
This is a classic example of the old question, Is the ventricle half full or half empty?

If you look at whether treatment or prevention of heart disease saved more lives, treatment wins. But if you compare pills-and-lifestyle vs. expensive bodily invasion, the easier/cheaper methods (aspirin, controlling high blood pressure and cholesterol with diet, exercise and meds, quitting smoking) win by a long shot.

According to the data, in the year 2000 aspirin saved about 23,000 lives. Statins saved 9,000. Bypass surgery and angioplasty together saved just over 3,000.

The bad news: about 60,000 additional people died due to increased obesity and diabetes in 2000.

Still, the total number of heart related deaths per 100,000 people dropped from 543 to 267 among men over the 20 years studied, and from 263 to 134 per 100,000 for women. (This data thanks to a very good report on the study by USA Today's Steve Sternberg.)

So what are you going to do about it?
To the extent a study dealing with large populations and sketchy estimates can be useful, this one suggests:

• It's vital to find out which (if any) preventive meds you should take--statins, aspirin, ACE inhibitors, etc.--and then comply. (Remember how former President Clinton had a heart attack after he stopped taking his statins?)
• If you've had a heart attack already, change your life and take your pills.
  
• Among lifestyle factors, quitting smokng is the most important.
• Diet and exercise are of secondary importance, but they have the advantage of being really cheap. They also cut your risk sharply of diabetes and obesity, which are bigger killers than most of the things studied are life-savers.
• For a good dose of heart disease prevention, the American Heart Association has a detailed, if a bit stern, page on the latest targets and risk factors. An easier-to-digest downboil is provided by the American Academy of Family Physicians.
  
• Calculate your 10-year heart disease risk here, using this tool from the Cleveland Clinic. It's fast, it's fun, and it may alarm you into making some useful changes.
  

Sunny News on Cancer? Not Really

I'm beginning to feel like I'm picking on the hardworking folks at Reuter's all the time. But today's report on the link between more sun and less lymphoma needs some clarification. Especially since it begins with this annoying sentence: "At last, some positive health effects of sitting in the sun!"

Bottom line first
Greater exposure to sunlight may reduce risk of some types of lymphoma, a name used to describe a wide variety of cancers that begin in the lymph system.

This study in 50 words or less
German researchers studied over 700 people with malignant lymphomas, and gathered data about their lifestyles, in particular how much they were exposed to the sun via work, outdoor recreation, climate, etc. The risk for some forms of lymphoma was less with more exposure to sunlight (even tanning beds).

Yes, but. . .
As always with studies that find associations but not cause-and-effect, the implications are limited. This study does not prove that exposing yourself to the sun will lower your lymphoma risk. Exposure to sunlight may be a marker for some other aspect of lifestyle that was not measured in this study.

So what are you going to do about it?

• Nothing. If you're looking for good reasons to make like George Hamilton, you're not going to get it from The Truth Squad--or the International Journal of Cancer, for that matter.
• Still, realize that lymphoma (about 19,000 deaths this year) kills more than melanoma (about 8,000 deaths). More cancer data here.
• There is a very interesting issue about whether Americans are low in Vitamin D--due in part, perhaps, to our decreased exposure to the sun, thanks to more SPF 30 and skin cancer awareness generally. (Vitamin D is manufactured by the human body when the skin is exposed to the sun; it plays an essential role in immune function.) Of course, dermatologists hate this, because they fear people will go out and get more skin cancer if the stay-out-of-the-sun message gets blurred. There's an excellent article on the Vitamin D/skin-cancer hoo-ha here.
• The non-hysterical view appears to be that healthy people can expose, say, their arms or legs to up to 10 minutes of sun most days to make sure they have plenty of Vitamin D without extra melanoma risk.

Fish Oil, Weight Loss, Coffee, and Thou

Today's newsfeed doesn't have a single study that's really worth digging into deeply. So let me just mention a few headlines that advance our understanding a bit.

Headline: Many Americans Maintain Weight Loss
Details: A federal survey suggests some people who lose weight can keep some of it off. Why is this not dismissed quickly to the Duh Files? A detail suggested that exercise seemed to be the key to keeping weight off. Sedentary weight losers were more likely to put the pounds right back on.

Headline: Coffee Associated with Lower Liver Cancer Risk
Details: So you're actually going to drink coffee (more than 2 cups per day) because it's linked to a 43 percent lower risk of liver cancer? We didn't think so. This was a meta-analysis suggesting an association only, not cause and effect. If you have a family history of liver cancer, there's nothing here: The link is not proven, merely a hypothesis for more research. Like coffee? Drink it.

Headline: Folic Acid Doesn't Prevent Polyps
Details: But it may contribute to them. This JAMA study proves once again that you should not fool with vitamins beyond a multi unless you've talked to your doctor and really know what you're doing.

Have GERD? Check Your Pants Size

We've written before about the link between big waist circumference, high BMI and risk for a number of undesirable outcomes, including Death Itself. Today comes a new report, published in Gut (prizewinner in the Great Medical Journal Title Competition) that explores the role of waist size in GERD--gastro-esophageal reflux disease, commonly known as acid reflux.

Bottom line first
For white males, a bigger waist was a risk factor for GERD, independent of Body Mass Index (BMI). Previous research has found a link between high BMI and GERD.

This study in 50 words or less
Kaiser Permanente identified patients with GERD symptoms (regurgitation, heartburn) via physicals and questionnaires. They found a direct link between waist size and GERD symptoms. The roundest white males had 85 percent higher risk of GERD than their slimmest counterparts. High BMI added to the risk.

Yes, but. . .
The study was designed to explore the role of waist circumference and BMI in various ethnic groups, not simply the link itself. (Specific hypotheses like that often make any generalizations that emerge less reliable.) The link was less strong for white women, and not observed in Asians or blacks. The abstract (the only part of the study freely available) makes it hard to tell what waist sizes and BMIs were the tipping points.

So what are you going to do about it?

• The study doesn't prove that losing belly circumference would reduce those symptoms. Still, losing girth cannot do harm. If you're a big white guy with GERD, dropping a pants size or two could relieve symptoms.
• Previous studies have found the greatest risks for abdominal obesity at 40 inches and above for men, and 35 and above for women. Regarding BMI, various risks begin to accumulate at 27 and above.

Elsewhere today around the Personal Health Webscape

• Life Two has an excellent report on a new study about women and depression at midlife
• And the often policy-heavy Health Care Blog has a great item today about how some people prefer sharing their sorrows online rather than with a live therapist. Fascinating stuff.

Longer Exercise Linked to Improved HDL Cholesterol

A decent report in Archives of Internal Medicine suggests that doing longer exercise sessions improves your HDL, or "good" cholesterol more than fewer, shorter ones.

Bottom Line First
Longer workout sessions that burn about 900 calories per week in total (about 2 hours of exercise total) appear to be more effective at raising HDL cholesterol than shorter, fewer workouts.

This study in 50 words or less
Researchers analyzed 25 clinical trials of exercise and HDL. The benefits of exercise on HDL rise were modest: about 2.5 mg/dL, enough to reduce heart disease risk by 5 percent in men and 8 percent in women.

Yes, but. . .
Like any meta-analysis, the results may be confounded by variations in methodology and rigor. Still, only randomized, controlled trails were included--high-quality science. Grade in terms of potentially applicability: B

So what are you going to do about it?

• The results showed that for every 10 minutes consistent workouts were extended, HDL rose an additional 1.4 mg/dL. Intensity or frequency didn't matter: So: Do fewer, longer workouts that total about 2 hours a week if you want to boost your HDL. (HDL under 40 is generally considered to raise heart disease risk; here's more HDL detail from the American Heart Association.)
• Researchers suggest the benefits accrue less to people with a body mass index of under 28 (over 25's overweight, over 30's obese) and total cholesterol of under 220. Which is to say: people who are boderline overweight with high but not severely elevated cholesterol. Alas, there's a good chance that's you.
• If you haven't exercised in a while, take this questionnaire which helps determine whether you really should go see your doc before you start an exercise program.
• If you've been sedentary, walking is by far the best way to start. Here's a great guide to starting a walking program--from, of all places, Runner's World Magazine.