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Diet/Exercise (12 posts)  RSS

Can eating chocolate prevent cancer?

February 12, 2014

By Ted Gansler, MD, MPH

 

In the course of my routine medical journal reading last year, I came across a short article in The Lancet Oncology about chocolate and cancer prevention. I saved that file on my computer (without reading it), thinking that it might serve as the point of departure for a lighthearted and slightly romantic Valentine's Day essay on this blog.

With that deadline only a few days away, I opened the file and read the article, as well as a few others. The good news is that chocolate does not cause cancer and that moderate consumption of dark chocolate may have a positive impact on heart disease risk. The rest is more complicated.

If you try an Internet search for words like "chocolate prevents cancer," you will find several thoughtful summaries of the available evidence. You will also find some cute but misleading articles implying that eating a lot of chocolate candy prevents cancer. And, you will find a lot of articles with cute headlines and introductions that save their unsweetened facts for the conclusion.

My favorite scientific reviews of cancer and chocolate evaluate information from pre-clinical studies, observational epidemiological studies, and clinical trials separately, and I will follow this approach to get the most thorough view of the topic.

What lab studies can tell us

 

Most pre-clinical studies are experiments that use lab animals (in this case, mice and rats) or cells growing in lab dishes. The theme of the cell experiments involves adding specific chemicals from chocolate (such as polyphenols, catechins, and proanthocyanidins) and observing what they do to various cell processes that are known to have an effect on cancer formation, growth, spread, etc. Some of the rat and mouse experiments added specific chemicals from chocolate to the animals' food, whereas others used liquid chocolate extracts or unsweetened cocoa powder. More...

Filed Under:

Diet/Exercise | Ted Gansler

Does drinking alcohol increase the risk of cancer?

June 26, 2013

By Susan M. Gapstur, PhD, MPH


Do you enjoy an occasional, or even a daily, glass of wine, beer, or other drink that contains alcohol? Many adults do. Indeed, 37% of adults in the U.S. report drinking low to moderate amounts, which is, on average, up to 1 drink per day if you are a woman, and 2 drinks per day if you are a man. Another 28% of adults drink more each day, which is considered heavy drinking. A drink of alcohol is generally defined as 12 ounces of beer, 5 ounces of wine, or 1.5 ounces of 80-proof distilled spirits.

Modest Benefit but Many Risks Associated with Alcohol Drinking


While low to moderate alcohol consumption is linked to a reduced risk of heart disease, drinking too much alcohol can increase risk of high blood pressure, heart failure, sudden death and stroke. Overall, alcohol consumption is one of the top 10 contributors to sickness and death from injuries, motor vehicle crashes, homicides and suicides, sexual assaults, sexually transmitted infections from unsafe sex, falls, birth defects, depression, disorders of the gastrointestinal tract, and sleep disorders.

Additionally, there is a lot of evidence that drinking alcohol increases the risk of several cancers. In 2007, a working group of experts convened by the World Health Organization's International Agency for Research on Cancer (IARC) reviewed the scientific evidence on alcohol and cancer risk for 27 different anatomic sites. They found sufficient evidence that alcohol drinking is a cause of cancers of the mouth, pharynx, larynx, esophagus, liver, colon, rectum, and female breast. And for cancers of the mouth, larynx, and esophagus, when people drink and use tobacco, the risks are combined to be greater than either tobacco use or alcohol use alone! More...

Filed Under:

Diet/Exercise | General

The obesity-cancer connection, and what we can do about it

February 28, 2013

By Lewis E. Foxhall, MD

It's almost impossible to get through the holiday season without gaining a few pounds, and for many of us that means we are even more likely to be over our ideal body weight.  Sure, we all want to look good in our clothes, but being obese is not just a condition that affects our appearance.  And in March, during National Nutrition Month, it's a good chance to talk about it.

Weight gain happens when we take in more calories from food (energy) than we use up through our basic biological requirements and exercise. After a while, enough fat stores up and makes us obese. Our bodies are very efficient at taking in energy and storing it for times when it is hard to find, but in our modern environment this is working against us and our health.  For most of us it is easy to get as much food as we want, and most of us do not need to exert ourselves much for work or daily living activities.


Link between obesity and cancer


The problem with being overweight or obese, as measured by weight and height, is that it raises our risk of chronic diseases like diabetes and heart disease.  But did you know that being obese can actually increase our risk of getting cancer and may even worsen our chances of surviving after a cancer diagnosis?  In fact, the American Cancer Society Cancer Prevention Study II showed significant increases in cancer occurrence in people who are the most overweight.  This link is stronger in some cancer types --including breast cancer after menopause, and cancers of the colon and rectum, pancreas, kidney, esophagus, and endometrium -- and can be associated with a major increase in risk. More...

The Bottom Line on Soy and Breast Cancer Risk

August 02, 2012

By Marji McCullough, ScD, RD

 

EDITOR'S NOTE: Dr. McCullough added the following statement 4/8/14 in response to questions related to sources of isoflavones:

Research on soy and cancer is highly complex, controversial, and evolving.

When concerns about soy are raised, they generally focus on findings from rodent models of cancer which tend to use isolated soy compounds like soy protein isolate or high doses of isoflavones (compounds found in soy).  However, soy is metabolized differently in humans than it is in mice and rats, so findings in rodents may not apply to people. (See: http://www.ncbi.nlm.nih.gov/pubmed/16614407 for more on this.)(Setchell, AJCN, 2011).  There is no evidence in the medical literature that soy protein isolate is bad for humans, compared to other forms of soy. Soy protein isolate is often used as a supplement in randomized studies of the effects of soy on health and none of these studies have shown harm.

Most of the studies suggesting benefits of soy consumption in people have measured how much soy foods people are eating, including tofu, soybeans, and soy milk.  These foods are more commonly eaten in Asian countries. In the U.S., purified forms of soy are used in the food supply, including in energy bars and soy hot dogs.  The few US studies that have measured these forms of soy do not suggest harm.    

More research is needed to understand the relationship between specific forms of soy and doses of isoflavones on cancer risk and recurrence. We also need to learn more about childhood exposure to isoflavones and risk of cancer. Until more is known, if you enjoy eating soy foods, the evidence indicates that this is safe, and may be beneficial (but note that miso, a fermented soy product, is high in sodium.)  It is prudent to avoid high doses of isolated soy compounds found specifically in supplements, as less is known about their health effects. As for other "hidden" sources of soy proteins, the evidence to date does not suggest harm or benefit. However, if you are concerned about these products, you can choose to avoid them.  


 

Before writing a blog about soy and breast cancer, I took an informal poll of a few friends to get a sense of what women believe about soy.  I asked them, "What do you know about eating soy food?  Is it good for you? Not good for you?" (I didn't even mention breast cancer.)  The responses I got were,  "I think it acts like estrogen in the body"; "Consuming any soy products increases the risk of breast cancer"; "I don't eat it a lot because I heard something negative but I can't remember what it was;" and "I've heard you should only have it in moderation."  Apparently, people are hearing that soy may not be good. But what's the truth? In this blog I'll walk you through what we know and what we don't know about soy and breast cancer, and give you some practical tips on eating soy. More...

ACS Nutrition and Physical Activity Guidelines Evolve

January 10, 2012

By Colleen Doyle, MS, RD


Today, the American Cancer Society released its 2012 Guidelines on Nutrition and Physical Activity Cancer Prevention. Based on sound science and strong evidence, our best advice to the general public to help reduce their risk of cancer through nutrition and physical activity is to:

  • achieve and maintain a healthy weight throughout life
  • adopt a physically active lifestyle
  • consume a healthy diet, with an emphasis on plant foods
  • limit consumption if you drink alcoholic beverages


As a matter of fact, for the majority of us who don't smoke, these are the most important ways to reduce cancer risk. More...

Jump on the 'bran wagon' for better health

November 03, 2011

By Colleen Doyle, MS, RD


It may be time to jump on the "bran wagon," if you're not already on it.

 

In a study published earlier this year in the Journal of the American Medical Association, researchers report that eating a high fiber diet reduces the risk of dying at an early age from a variety of causes, including heart disease, respiratory and infectious diseases, and among men, cancer.

 

During a 9-year study looking at diet and health, more than half a million AARP members between the ages of 50 and 71 completed a survey about their eating habits. Those who reported eating the most fiber (about 30 grams a day for men, and 26 grams a day for women) were 22% less likely to die from any cause during the study compared to those consuming the least amount (about 13 grams for men and 11 grams for women). More...

Beating Lunchbox Boredom the Healthy Way

September 13, 2011

By Colleen Doyle, MS, RD


I read a recent study from a group of Harvard researchers who wanted to determine what foods and/or beverages are most likely to cause that slow and steady weight gain that many of us see over time as we get older - those things we eat or drink that may contribute to the number on our scale inching up ever so slightly year after year.


Interestingly enough, what topped the list were potato chips, potatoes (especially french fries), sugar-sweetened beverages and processed meats (think hot dogs).  And that got me thinking about my kids and what they eat at school. More...

Filed Under:

Colleen Doyle | Diet/Exercise

Will a vitamin a day keep cancer away?

August 16, 2011

By Marji McCullough, ScD, RD

 

Editor's note: Dr. McCullough added the following statement 12/20/13 in response to new studies being released:

Recent findings on multivitamin supplements published after the posting of this blog deserve mention. In 2012, the results of a randomized controlled trial (RCT) of a daily multivitamin supplement were published, showing a small but statistically significant lower risk of all cancers combined in male physicians followed over 11 years.  The supplement included 30 nutrients at levels similar to that found in a regular diet in the United States (≤100% recommended daily allowance (RDA)).  The U.S. Preventive Services Task Force (USPSTF) recently updated their review of vitamin and mineral supplements for the primary prevention of cancer and cardiovascular disease (CVD) and found there isn't much evidence that multivitamins or supplements help prevent cancer or CVD. But they add that a small benefit from multivitamin supplements on cancer in men was found, based on this study and an earlier RCT in France. The study in France found lower rates of cancer in men, but not women. The authors speculate that this may have been due to worse nutritional status - a generally less nutritious diet in the men - but more research is needed. In the study with the male physicians mentioned above, they all were well nourished but still saw some benefit.

There are still questions to answer about multivitamins and cancer from the RCTs: why only in men? Does whether you have a nutritious diet matter, and to what degree? Are these findings able to be replicated? Longer follow-up from these trials (to see long term effects) may provide more clues. In the meantime, these studies show that lower-dose multivitamins (with ≤100% RDA) appear safe and don't raise risk of cancer or CVD. Still, the best way to get nutrients is through a healthy diet, and the cost of multivitamins can add up. People should discuss the pros and cons of supplement use with their health care professional.

 

Original blog, 8/16/2011


Can popping vitamin pills prevent cancer? The simple answer is no, based on what we know so far. In fact, some vitamin supplements have even shown harm. What I'm talking about mostly are pills containing individual nutrients in amounts that are greater than that found in food. Before you stop reading, thinking this is simply another "just eat your vegetables" message, let me give you a little history.


Toward the end of the last century, scientists observed that people with healthy diets, and with higher levels of certain phytochemicals ("phyto" for plant) in their bloodstream, such as beta-carotene, had lower rates of cancer. But observations don't prove cause and effect.


So, after careful evaluation of promising dietary compounds, the scientists began planning randomized, placebo controlled clinical trials ("RCTs") with tens of thousands of healthy people to see if taking supplements of individual phytochemicals could actually prevent cancer. RCTs are considered by most to be the gold standard for proving something works. Most of the supplements tested were antioxidants, which are chemical compounds that combat "free radicals" in the body that can damage DNA and possibly lead to cancer. More...

From the Pyramid to the Plate

June 02, 2011

By Colleen Doyle, MS, RD


Today, the United States Department of Agriculture (USDA) unveiled a new graphic, a new icon designed to help make it easier for all of us to eat a healthier diet.  Called "MyPlate," this icon replaces the Food Guide Pyramid that, in one form or another, has been around since 1992. And it is a huge improvement. Especially because we eat off plates, not pyramids. More...

Another Reason to Have a Second Cup of Coffee?

May 25, 2011

By Colleen Doyle, MS, RD

I admit it; I'm a java junkie. I LOVE my morning (and mid-morning) cups of coffee.  So any study that looks at the potential health benefits of coffee gets my adrenaline pumping, whether I'm revved up on caffeine or not.


A study just published in the Journal of the National Cancer Institute looked at whether or not coffee consumption was related to prostate cancer risk. The researchers were particularly interested in whether or not coffee consumption reduced the risk of advanced prostate cancer (by advanced, they mean that the cancer has spread beyond the prostate at the time of diagnosis).  As a matter of fact, this study is the first of its kind looking specifically at the relationship between coffee consumption and advanced prostate cancer.  While prostate cancer is one cancer I don't need to personally worry about, on behalf of all the men in my life, I took a look. More...

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