Friday, December 28, 2012

Glycemic Load, Overall Health, and a New Study on Colon Cancer Survival

"Glycemic index."  It's a term that likely rings a bell, but unless you're a dietician or research scientist, you can certainly be excused for not knowing exactly what it is and why it's even important.  But, like a lot of similar concepts, it's really not that complicated once you look into it a little bit.

Basically, the glycemic index is a lot like the speedometer in your car.  While a speedometer measures how fast you're moving, the glycemic index measures how fast a food you eat gets converted into glucose in your body.  The higher the number, the more quickly and strongly the food boosts blood glucose levels, which can cause a host of reactions that over the long run can lead to weight gain and an increased risk of heart disease and diabetes. Some studies have also linked diets filled with high glycemic index foods to an increased risk of some cancers, but this link isn't perfectly clear and is an active area of research.

Adding to this science base, is a new study in the Journal of the National Cancer Institute that links diets high in high glycemic index foods and carbohydrates with the return of cancer and earlier death in patients with stage III colon cancer (study).

The study, part of the federally-sponsored Cancer and Leukemia Group B trial, followed a thousand colon cancer survivors for an average of seven years and looked at the carbohydrate intake and overall glycemic load of patients' diets to see how this related to cancer recurrence and survival.  What the researchers found was that those patients with the highest overall glycemic load diets were almost twice as likely to have their cancer return (recurrence) compared to those with the lowest glycemic load diets. Overall carbohydrate intake had a similar effect.  Looking at overall survival, high glycemic load diets and high carbohydrate intake diets increased the risk of dying by 75 - 80 percent.  In the United States, the large majority of carbohydrates eaten are refined carbohydrates, which have a high glycemic index, so it's not surprising that the results for carbohydrate intake tracked closely to those of overall glycemic load.

Exactly how a high glycemic load diet may promote cancer recurrence is unknown.  But, high glycemic index foods can cause spikes in blood glucose and insulin, which can have wide-ranging effects throughout the body that some lab studies suggest can lead to cancer cell growth and inhibit cancer cell death.

Though this study doesn't provide concrete evidence that a high glycemic load diet hurts survival in colon cancer patients, it does add to overall evidence that a diet filled with low glycemic index foods is a healthy choice for everyone, and there's good evidence that it'll lower the risk of heart disease and diabetes, which are important concerns even for most cancer survivors.

In general, a diet with a lower glycemic load includes a lot of whole grains (like oatmeal, whole wheat, and wild rice) and whole fruits and vegetables. It's also low in refined grains (like white bread, white rice, and regular pasta) and sugary foods (like sweets and soda). (See figure).

For more on healthy steps after a cancer diagnosis, see Cancer Survivors' 8ight Ways to Stay Healthy After Cancer.  For general healthy steps, see 8ight Ways to Stay Healthy and Prevent Disease.

Glycemic Index of Selected Foods

(Over 65)
(45 – 65)
(Under 45)
Glucose 100
Raisins 65
Grapes 43
Carrots 92
Coca cola 63
Dried Beans (cooked) 42
Molasses 87
Jelly 63
Pear 41
Pancakes 83
Bananas (Ripe) 62
Orange 40
Cornflakes 80
Sweet Corn 61
Apples 39
Cheerios 74
Bran Muffins 60
Chocolate 36
Baked potato 73
Table sugar 59
Wine 35
White Rice 72
Honey 58
Beer 35
Dark bread 72
Oatmeal (cooked) 58
Chocolate Milk 34
Watermelon 72
Kiwis 58
Milk 34
Corn chips 70
Muesli Cereal 56
Yogurt 33
White bread 69
Cookies (general) 55
Ice cream (full fat) 30
Bagels 69
Oatmeal Cookies 55
Strawberries 25
Pita Bread 69
Special K Cereal 54
Barley (uncooked) 25
Cornmeal 68
Orange Juice 53
Cherries 22
French fries 67
Peas 52
Peanut butter 13
Brown Rice 66
All Bran Cereal 51
Walnuts 13
Pineapple 66
Pasta 50
Broccoli 9

Ice Cream (low fat) 50
Spinach (cooked) 9

Grapefruit Juice 48
Lettuce 9

Cake 47
Eggs 0

Fish 0

Hamburger 0

Hard cheese 0
Source: Nurses Health Study Nutrient Database

Friday, December 21, 2012

Going for the gold: Olympic medalists live longer than the rest of us

The Christmas issue of the British Medical Journal (BMJ) is always high in entertainment value, containing as it does a number of off-kilter papers that still manage to inform.  The 2012 issue is marked by papers like, Why Rudolph's nose is red and The tooth fairy and malpractice.  One of the more straightforward pieces, which still managed to be fairly entertaining though it dealt directly with mortality, was a study looking at longevity in former Olympic games medallists.

Researchers from Australia, the United States, and the Netherlands compared the lifespan of 15,000 medalists from nine difference countries (including among others, the United States, Russia, Norway, and Germany) to the lifespan of average folks of the same age and gender from the same countries.

What they found was that on average Olympic medalists lived nearly three years longer than the average person.  And that the color of the medal (gold, silver, or bronze) didn't didn't further effect survival.  In other words, gold medalists - despite the added glory - didn't live any longer than either the silver or bronze medalists.  What did seem to make a distinction among medalists, however, was the type of sport a medal was won in.  Events with an endurance component were linked to a greater survival advantage than power events, like weight lifting.   Though, medaling in power events was still linked to boosted longevity compared to the average person in a population, even though the advantage was fairly slight.

The lifespan distinction between endurance and power events certainly suggests that cardiovascular fitness and regular endurance activity is a likely reason that Olympians live longer than most people. And there are certainly good data showing that exercise boosts longevity overall.

Of course, Olympians, and especially medallists, are far from normal people when it comes to fitness and physiology, so a study like this may be more fun than informing, especially because it didn't set out to answer why the distinctions exist.  Perhaps the authors are saving that for Christmas 2013.

Beyond issues of fitness and activity level, any number of other factors could also account for medalists living longer.  There's genetics.  There's financial standing, with successful athletes able to earn more money than they otherwise might and therefore afford better medical care and the time to look after their health.  And there's simply a broader focus on overall healthy living that many Olympians adhere to.

Whatever it is, Olympians seems to, once again, embody an ideal to strive for.  And perhaps that's something to keep in mind as we hop from holiday party to holiday party, and maybe why the BMJ published it in the first place.

Tuesday, December 18, 2012

AHA's 2012 Heart Disease Advances and What They Mean for Cancer

The American Heart Association (AHA) just released its top 10 list of research accomplishments for 2012.  Most are quite heart-specific (unsurprisingly), but two of the ten highlight something we've often highlighted on this blog and in our risk assessment app and websites: that major chronic diseases share many of the same risk factors.

"6. Why children and adolescents should 'just say no' to sugary drinks"

This advance highlighted the results of two large, well-designed clinical trials that "provided definitive evidence" that drinking sugary drinks can increase excess weight gain in youth.  Both studies found that  youth who reduced the amount of sugary drinks they consumed kept excess weight off to a greater degree than those who kept drinking sugary drinks as they normally would.  While this may not seem like news per se, given all the media chatter on the topic and the recent ban on large-sized sodas in New York City, these studies do provide even more of a solid scientific backing to the links seen between sugary soda and weight gain.  

If there's one overarching chronic disease risk factor - apart from tobacco - it's overweight.  There are the obvious links with diabetes and heart disease and stroke, but also the lesser known links with numerous cancers (at least seven).  One recent paper - of which CNiC's Graham Colditz was a co-author - estimated that obesity directly cost the nation $99 billion (in 1995 dollars) and consumed close to six percent of all health care costs.

Though recent data show some progress on the childhood obesity front, much work remains to be done.  Obesity rates shot up so drastically over the past two decades that it'll take many years of concerted efforts to make sustainable and general progress against it.  But recent trends showing rates leveling off and even dropping in some areas is a great sign that awareness and action may finally be translating to real results.  Working to further curb sugary soda consumption is one important effort that can help keep things moving in the right direction.

"9. Ideal cardiovascular health practices lead to longer life, lower risk"

At number nine on the AHA list were two studies showing "the huge impact lifestyle factors can have in lowering heart disease and stroke risk and in helping people extend their lives."  One of these studies, which followed 7600 adults for close to six years, found that an overall healthy lifestyle - like, not smoking, keeping a healthy weight, eating healthfully, and watching cholesterol and blood pressure - could lower the risk of dying from cardiovascular disease by almost 90 percent and dying overall by almost 80 percent.  

While the public largely understands that heart disease is highly preventable, fewer understand that cancer is as well.  Yet overall, 50 percent of cancers can be prevented by most of the same behaviors that also lower heart disease risk.  For colon and lung cancers, this percentage is much higher - 70 percent or more (see figure). 

It's only natural that health organizations focus on specific diseases or specific risk factors since it can help with funding, messaging, and research.  However, it's also important that organizations don't become too isolated in their specific fields and explore, when possible, more unified approaches that can optimize the links between the range of common risk factors and common chronic diseases.  

#  #  # 
Full list of AHA's top research advances for 2012 include:
  1. Extended CPR saves lives
  2. Converting “non-beating” heart cells into “beating” heart cells
  3. Biopsied heart cells improved heart function and reduced scars
  4. “Disconnecting” the kidneys might be the key to treating high blood pressure
  5. Progress for children in transplant bridging and Kawasaki Disease
  6. Why children and adolescents should “just say no” to sugary drinks
  7. Global impact: ECHO screening for rheumatic heart disease
  8. Devices for stroke
  9. Ideal cardiovascular health practices lead to longer life, lower risk
  10. Bypass surgery vs. drug-coated stents for diabetes patients

Thursday, December 13, 2012

Dept. of Diversity: Cancer-Related Risk Factors in Hispanics

A report last month in the American Cancer Society's journal CA detailed the rates of cancer-related risk factors in US Hispanics/Latinos (report), and one of the parts of the report that stood out to us were the rates of certain behaviors in adolescents that could have implications for cancer risk later in life.

As we've written about previously (most recently here), early life is being seen as an increasingly important time in the development of some cancers (see figure).  This is particularly so for breast cancer, but with the development of the HPV vaccine, it's also an important time for combatting later cervical cancer risk (more on this here). And even if certain risk factors don't have a unique age-dependent impact, they can be lifestyle choices - like smoking and eating an unhealthy diet - that have a high likelihood of getting cemented in youth and carried through adulthood.

What the new report found was that Hispanic/Latino kids had risky levels of a number of key cancer risk factors.  A little over 23 percent of Hispanic adolescents were obese, compared to 16 percent of non-Hispanic whites.  Only 56 percent of Hispanic adolescent girls who started the series of HPV vaccinations got all the needed shots, compared to 75 percent of whites.  And although rates of cigarette use (18 percent) and alcohol use (43 percent) were better than those of non-hispanic whites, they were only slightly so, and still high enough to be of concern.

While these numbers point to an increased cancer burden if they remain unchanged, on average they aren't much worse or much better compared to other groups in the United States.  But, they do show that Hispanic adolescents have unique risk profiles, and any efforts to improve these numbers must also take into account Hispanic adolescents' unique social and cultural environment.

It's a reminder that we're a diverse country - racially/ethnically, economically, geographically - and to make real and lasting strides in improving the nation's health, we need make sure we understand not only what is going on in the nation as a whole, but also what is going in specific populations that make up the whole - and tailor efforts appropriately.

Wednesday, December 12, 2012

Go Ahead, Enjoy that Java: Coffee and Health

Maybe it's the devotion it garners; or that it can cause the jitters; or simply that so many people enjoy it so much.  But for a very long time, coffee's been assumed to be on the healthy lifestyle black list.  And even as more and more evidence comes out that it has very few, if any, bad health effects - and may even have some benefits - it continues to exist in a kind of health grey area.

But, things are starting to change.  Jane Brody wrote a nice New York Times piece this summer on the links between coffee and health (Having Your Coffee and Enjoying It To).  And just yesterday, the American Institute for Cancer Research (AICR) posted a piece on its blog about coffee and cancer (Prevent Cancer with Your Morning Joe?), which along with information on cancer studies, includes tips for dealing with some aspects of specialty coffee drinks that could actually be improved  - the extra calories and saturated fats. The post also links to AICR's detailed page on coffee and cancer (Foods That Fight Cancer: Coffee).

So as we enter the shortest days of the year and you feel like you need a boost, go ahead and enjoy that  cup of coffee - just be sure to hold the whip cream.

Monday, December 10, 2012

Researchers ask "Is everything we eat linked with cancer?"

The answer's "No," but here's why it can seem that way

In the early 80's, the singer/songwriter Joe Jackson captured in the refrain of his song "Cancer" a frustrated sentiment many people were feeling back then - and not surprisingly still do now - that: "Everything gives you cancer."

Even in the 80's - at the cusp of the information revolution - the amount of health news filling newspaper pages and airwaves was overwhelming.  On top of this, stories could oftentimes seem conflicting, and at times, just plain arbitrary.  It's a trend that's only gotten worse as we make our way toward a world of universal information access, little context, and not nearly enough studied curators.

What got us here at CNiC thinking about these things was the recent publication of an intriguing and entertaining paper seemingly inspired by Mr. Jackson's song, called Is everything we eat associated with cancer? A systematic cookbook review.

The authors, Jonathan Schoenfeld of Harvard Medical School and John Ioannidis of the Stanford Prevention Research Center, picked 50 food ingredients from random recipes in a basic cookbook and reviewed the scientific literature to see which of the items had been studied and what the prevailing results of each were.  Food items included in the study were things like, veal, salt, carrots, mushrooms, milk, cheese, cinnamon, tea, and raisins.  Most were items that could easily be found in kitchen cupboards and refrigerators.

What the study found was that of the individual studies of these foods, over 70 percent found that the food either increased or decreased the risk of cancer.  Only 23 percent of studies showed no effects.  This means that the vast majority of studies looking at common foods found some link with cancer.

On the positive side, Schoenfeld and Ioannidis also looked at the results of meta-analyses of the same items.  Meta-analyses collect and analyze the results from many different studies, and they provided a more measured view on the food list's link with cancer.  Whereas 72 percent of individual studies found links with cancer, only 36 percent of meta-analyses did.  The larger size of a meta-analysis and its usual attention to design takes into account much of the noise or marginal results from the individual studies, providing something that is likely more solid.

Of course, it can be tall order for most people to delineate the niceties of such results, which places a greater burden on reporters and scientists to spend extra time to place results into context, to not overreach with conclusions, to spend time thinking about how the messages will be received (for more on this, see a recent editorial of ours).

Until then, though, there are a few simple tips readers can use to help bring some clarity to the cluttered world of diet and health news.  When trying to figure out what the latest health findings in the news mean for you, ask these simple questions:
Was the story about a study done in humans or animals?  Animal/lab studies have less importance than human studies when it comes to health choices. 
Was the story about the results of a single study?  The results of single studies are usually not important enough to base health choices on.  
Was the story about new recommendations or guidelines based on many studies? Recommendations or guidelines developed by the federal government or other reputable organizations are usually best for guiding health choices.  They are made by experts in the field using the entire weight of scientific evidence on a topic.

For more tips on understanding health news and information, visit these sites:
How to Evaluate Health Information on the InternetOffice Dietary Supplements, National Institutes of Health 
MedlinePlus Guide to Healthy Web SurfingNational Library of Medicine, National Institutes of Health

Thursday, December 6, 2012

Top Cancer Prevention and Screening Advances in Context

Earlier this week, the American Society of Clinical Oncology (ASCO) published their 2012 annual report on key clinical advances in cancer. Though the document's largely focussed on breakthroughs in treatment and diagnosis, it does highlight three important results in prevention and screening.

Colon Cancer Screening
First are findings from the Prostate, Lung, Colorectal, and Ovarian Cancer (PLCO) Screening Study that further bolstered the benefits of colon cancer screening.  We've written extensively on this blog about the benefits of regular screening tests for colorectal cancer -  whether with the fecal occult blood tests (FOBT), sigmoidoscopy, colonoscopy, or other recommended tests.  Data have consistently borne out the benefits of screening, and not just for finding cancer early, when it's more treatable, but in actually preventing disease in the first place.  The large study by Schoen and colleagues highlighted by ASCO found that screening with flexible sigmoidoscopy at regular intervals could lower the risk of dying from colon cancer by 26 percent and of developing colon cancer by 21 percent.  Though similar to colonoscopy, flexible sigmoidoscopy is a less involved procedure that is quicker to perform and only examines the lower part of the intestine, rather than the full length as with colonoscopy.

Of course, compelling findings alone don't insure that people will follow a new healthy behavior, like getting screened.  Moving from science to action to real world impact usually takes a broad-based, concerted, and often long-term effort to succeed.  Years after colon cancer screening won approval for coverage by Medicare and other health insurers, rates of use still vary greatly across the US.  Massachusetts had the highest uptake of screening in the nation in 2010, capping off a multi-year effort by state and local governments, universities, health insurers, physicians, NGOs and others to make a screening a priority as well as a reality in the state - a successful effort highlighted in a previous post.

Lung Cancer Screening
Next on the ASCO list are findings also confirming something long-suspected, that regular screening with chest X-rays doesn't lower lung cancer mortality rates. Though it seems intuitive that a regular X-ray would help find lung cancer early when it's most treatable - and therefore save lives - the numbers just did not support this.  In a study of over 150,000 people, half of whom received annual chest x-rays over a four year period and half of whom did not, there was no difference between the two groups in the rates of people dying from lung cancer.

Unfortunately, this is how things often play out for potential cancer screening tests.  While on paper they can seem promising, there are many avenues where new tests can fall short and miss a key criteria for an effective test: saving lives.  (See our Cancer Screening page for more on why finding good, new tests can be difficult.)

There is, however, some promise on the lung cancer screening front with spiral CT scans.  In smokers, results from the Lung Cancer Screening Study found that screening with spiral CT could reduce deaths from lung cancer by 20 percent.  It's a significant number but many unanswered questions remain about who exactly should be screened, how often, and what the risks may be.  Tobacco prevention and cessation efforts remain the surest and most cost-effective way to lower the death rate from lung cancer, as we touched on in a previous post.

Regular Aspirin Use
Finally, aspirin.  A new analysis of over 51 different studies found that regular aspirin use for just three years could lower the risk of developing cancer by around 25 percent, and the risk of dying from cancer by 15 percent.  With five or more years of use, cancer deaths dropped by 37 percent. These findings build on results we've written about previously (here, here, and here) showing that long term use of aspirin can significantly and sustainably lower the risk of colon cancer (see figure).  This new analysis, though, shows benefits from relatively short-term use, and given the heart-health benefits of aspirin - and some intriguing new results for liver cancer - it seems it may be time to reassess prevention-oriented recommendations for aspirin that currently largely apply just to those at high risk of heart attack and begin to consider it for a broader swath of the population as well.

Challenges are a constant in the quest to prevent cancer.  But each year we make progress, honing our understanding of the issues and crafting better and more effective ways to improve health and lower risk.  This past year was no exception, and it seems assured that 2013 won't be either.

Tuesday, December 4, 2012

Taking the Stairs - For Fun

Yesterday, we wrote a post about the growing use of stand-up desks as a way to cut down on the amount of time workers sit throughout the day.   That an everyday item, like a desk, could help affect a key health behavior, made the trend a good example of how important our environment (those people, places, and things that surround us) can be when it comes to influencing many of the choices we make.

Shortly after writing that post, I harkened back to a video made in 2009 in Sweden that illustrates wonderfully - if anecdotally - that point as well.  It also shows that public health isn't all equations and Brussels sprouts and journal articles.  Sometimes there's no better driving force than a bit of fun.

Monday, December 3, 2012

Becoming a Stand-Up: Fighting Disease with Desks

It was hard to miss the headlines this summer telling us that a new federal study confirmed what many disgruntled office workers had long suspected - that their desk jobs may just be killing them.  While the headlines were a bit overblown, they did capture the essence of what more and more evidence is showing, being consistently sedentary for long stretches of time increases the risk of heart disease, cancer, and early death.

In this latest study, women who sat for six hours or more each day were nearly 40 percent more likely to die during the 14 year study period than those who sat less than three hours per day.  Men who sat for six hours or more were 20 percent more likely to die.  

Perhaps most surprising to many, hitting the gym, walking, or doing other physical activities didn't counteract the effects of sitting, though not exercising certainly made the effects of sitting even worse, more than doubling the risk of dying.

With these results, many office workers and their bosses have taken note, and there seems to be a move in corporate America - as well as in home offices - to try to improve health by cutting back on sit-time, largely through innovations in desks. alone ran at least five stories over the past spring and summer on stand-up desks, including one reviewing some of the current crop that may be seen in both corner offices and cubicles alike.  In October, Wired magazine posted specs on what to look for in stand up desks, including home-spun inexpensive alternatives. And this past Sunday, the New York Times ran an article on the growing acceptance of stand-up desks in the workplace - even the space-gobbling and pricey treadmill desks.

It's a common refrain here on CNiC that our surroundings can have a profound impact on the health choices we all make - or don't make.  It's hard to exercise if there are no sidewalks or parks in your neighborhood.  It's hard to eat healthy food during the day if there's nothing but fast food choices around your school or workplace.

With around 80 percent of US jobs now requiring little if any physical activity, beginning to change the office environment and culture around sitting could have an important impact on employee wellness as well as nationwide health.  Of course, we still need more sidewalks, parks, and produce stands but more stand up desks is still a good move in the right direction.