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The evidence on super-sized soft drinks

October 26, 2012 By 1 Comment

Next year, New York City residents must say good-bye to their super-sized sodas and Double Big Gulps.  Beginning in March, the city will limit to 16 ounces the size of soft drinks sold at restaurants, street carts, movie theaters and sporting venues. The New York City Board of Health passed the proposal last month in an effort to reduce the consumption of sugary drinks thought to contribute to the nation’s obesity epidemic.

But what evidence do we have about sugary soft drinks and weight gain and harm our health?  We know that sugar-sweetened drinks account for nearly half of the total added sugars Americans consume and 7 percent of our total calories. But what impact does that have on our health?

New York Times writer Jane Brody also provides an overview of some of the evidence on this topic in her column this week. There are also several systematic reviews that tell the story:

  • A 2007 meta analysis in the American Journal of Public Health reviewed 88 studies that examined the association between soft drink consumption and nutrition and health outcomes. The analysis found consuming soft drinks led to increased energy intake and body weight, and was associated with lower intakes of milk, calcium, and other nutrients.  It also found an association between soda intake and diabetes.
  • Another systematic review, published in the American Journal of Clinical Nutrition in 2006 – which included 30 cross-sectional, prospective and experimental studies looking at the relationship between sugary soft drink consumption and weight gain – concluded that sugary soft drinks are associated with weight gain and obesity.
  • A third review published in Cambridge University’s Nutrition Research Reviews in 2008 came up with inconclusive results. The review examined 44 epidemiological studies and interventions and six meta-analyses – all looking at the relationship between sugary soda consumption and obesity. The author concluded that while sugary soft drinks are a source of calories, there is little evidence that they cause more weight gain than other sources of calories.  He said the impact of sugary sodas on weight gains depends on variables including how much soda is consumed each day and the formulation of the specific drink. His review also concluded that consuming large amounts of sugary soft drinks on a daily basis is most directly associated with weight gain.

So, did the New York City Board of Health make an evidence-based decision in limiting sugary soft drink sizes?  I think the answer is yes. While there is some mixed data on the association of soft drink consumption and weight gain, the evidence makes it abundantly clear that consuming large amounts of soda is the major problem. By limiting soft drinks sizes, the City is essential legislating the old adage, “Moderation in all things.”

Filed Under: Evidence-Based Living, Health and Wellness, In The Media Tagged With: , , , , ,

The evidence on arsenic and rice

October 9, 2012 By 2 Comments

The magazine Consumer Reports released a study last month that revealed low levels of arsenic – a chemical element that is toxic when consumed in higher doses – in rice and rice products grown across the world.

The study tested 223 types of rice and rice products – such as rice-based cereals and rice milk – purchased in the United States in April, May and August of this year. It found arsenic in every product it tested, and dangerous levels of inorganic arsenic in dozens of products. Consumer Reports the story points out that their study is “a spot check of the market and “too limited to offer general conclusions about arsenic levels in specific brands within/across rice product categories.”  Nevertheless, their article raises some surprising questions about toxins in our food supply.

Following the Consumer Reports study, the U.S. Food and Drug Administration released some preliminary results of a long-term study on arsenic levels in our food supply. Their study found levels of arsenic in rice similar to the Consumer Reports study.

So, what’s a rice-lover to do?  Consumer Reports recommends limiting consumption of rice and rice products, while the FDA is not recommending any limits on rice consumption.

Since the FDA and Consumers Reports found the same level of arsenic in food, the question in my mind is: Exactly how dangerous is low-level exposure to arsenic? A search of systematic reviews yielded some interesting results.

  • One meta-analysis found consuming arsenic in drinking water is associated with a higher risk of lung cancer.
  • Another analysis found chronic arsenic exposure can lead to mental retardation and developmental disabilities such as physical, cognitive, psychological, sensory and speech impairments – although in higher levels that measured in the rice products tested by Consumer Reports and the FDA.
  • Other analyses found inconclusive results on the relationship between arsenic exposure and diabetes and arsenic exposure and cardiovascular disease – although both of these reviews identified limitations in the study methodology and called for additional research.

My plan is to think more carefully about the rice products my family consumes.  I’m not going to throw out the brown rice in my pantry, and we will still enjoy stir fry and sushi on a regular basis. But I certainly plan to steer way from rice cereals and other rice products at the grocery store.

Filed Under: Evidence-Based Living, Health and Wellness, policy Tagged With: , , , , , , ,

What we know – and what we don’t – about Omega-3 fatty acids

October 4, 2012 By 2 Comments

Over the past four decades, there have been thousands of studies examining the health benefits of Omega-3 fatty acids – building blocks our bodies use to create cell membranes and maintain the connections between brain cells.

The medical community’s excitement over this nutrient began when observational studies of non-western diets – in Japan and among Eskimos in Greenland, for example – found significantly lower rates of heart disease and other chronic medical conditions.  (Humans can’t produce omega-3 fatty acids, so we must get them by eating fish, walnuts, flaxseed and green vegetables.)

Dozens have studies have identified these types of correlations. But earlier this year, a meta-analysis published in the Journal of the American Medical Association, which included 20 clinical trials involving nearly 70,000 people, concluded omega-3 fatty acids did not prevent heart attacks, strokes or deaths from heart disease.

Proponents of omega-3s point out that the authors of the JAMA analysis used the an especially strict standard to determine statistical significance. (Using the typical standard would have found a 9 percent reduction in cardiac deaths.)

But other systematic reviews – like this one by the Cochrane Collaboration – found it unclear whether omega-3 supplements reduce the risk of cardiac deaths.

So, what’s the bottom line?  This is one case where the evidence is truly unclear. One challenge is that longitudinal diet studies are difficult to perform because there are so many variables in what people eat over long periods of time. The it can be tough to differentiate between omega-3s consumed as part of a diet versus those taken in a supplement.  It is clear that foods like salmon, tuna and green vegetables are good for us – and including them in our diets is a step in the right direction. But we need more evidence to determine their exact effects, and to establish whether it’s worthwhile to take omega-3 supplements.

Filed Under: Cornell Cooperative Extension, Evidence-Based Living, Health and Wellness Tagged With: , , , ,

Coffee update: It’s actually good for you

September 26, 2012 By Leave a Comment

Here at EBL, we’ve written about coffee before. But given that more than 60 percent of Americans consume coffee on a daily basis, we think it’s an important to understand its effects. We were excited to come across a new systematic review on America’s favorite drink and its relationship to heart failure.

The review included five prospective studies of more than 140,000 people in total measuring the relationship between regular coffee consumption and the risk of heart failure. Across all of the studies, more than 6,500 participants suffered heart failure.

According to the analysis, consuming a moderate amount of coffee was inversely related to risk of heart failure: people who drank four servings of coffee a day had the smallest risk of heart failure.  Those who drank significantly more or less than four servings a day were found to have a higher risk heart failure. The review found there were no variance between men and women, or for participants who had a history of heart attack or diabetes.

Clearly, there is more to this story, and further study is warranted on the health benefits of coffee are warranted. But to date, the evidence indicates that drinking coffee regularly isn’t risky and may actually protect you against heart failure.

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Slimming it down? New evidence on low-calorie diets

September 4, 2012 By 5 Comments

Over the past few years, you may have heard the buzz about the potential for a low-calorie diet to prolong life and prevent chronic medical conditions like heart disease and cancer.

While the concept of restricting calories has been around for decades, a longitudinal study of monkeys published in 2009 seemed to provide definitive evidence that eating less was good for you. The study by researchers at the University of Wisconsin found a diet of moderate caloric restrictions over 20 years lowered the incidence of aging-related deaths and reduced the incidence of diabetes, cancer, cardiovascular disease, and brain atrophy.

But last week, a new longitudinal study of different species of monkey raised questions about the idea of restricting calories to improve health. The study included 121 monkeys split into two groups. The experimental group was fed 30 percent fewer calories than the control group.

In the study published last week, which was sponsored by the National Institute on Aging, the monkeys on restricted diets did not live any longer than those with normal diets. Rates of cancer and heart disease were the same for monkeys on restricted diets and normal diets. While some groups of monkeys on restricted diets had lower levels of cholesterol, blood sugar and triglycerides, they still did not live longer than the monkeys who ate normally.

The study is interesting from a health perspective because it raises questions about the notion of restricting calories to improve health. But it’s also a prime example of why it’s important to collect data from more than one study.

“This shows the importance of replication in science,” Steven Austad, interim director of the Barshop Institute for Longevity and Aging Studies at the University of Texas Health Science Center, told the New York Times. Austad, who was not involved in either study, also explained that the first study was not as conclusive as portrayed in the media.

The take home message: It’s important to collect evidence from multiple studies before drawing conclusions, even when the data seems extremely convincing.

Filed Under: Evidence-Based Living, Health and Wellness Tagged With: , , , , ,

New evidence: Vitamin D helps prevent falls

August 9, 2012 By 1 Comment

Vitamin D is one of those supplements that makes it into the news media frequently. Here on EBL, we’ve written before about the U.S. Institute of Medicine’s recommendations on Vitamin D intake.

Now there is a new recommendation that taking Vitamin D supplements can help prevent falls in people over 65 years old with a higher risk of falling.

In a review of nine separate studies, the United States Preventative Services Task Force came to the conclusion a daily dose of 800 international units reduced the risk of falling by about 17 percent, compared with those who did not take the vitamin.

“The exact mechanism is not known, but it seems to help muscle strength and balance,” Dr. Al Siu, vice chairman of the task force and chairman of the geriatrics and palliative medicine department at Mount Sinai School of Medicine, told the New York Times.

The panel also made two other recommendations.  Doctors should do a comprehensive assessment of patients’ risk of falling – including asking about falling history and observing patients stand up and walk – to identify those at higher risk. And patients’ should exercise to improve strength and balance.

Falls are the leading cause of injury in adults 65 and older. While there’s no sure-fire way to prevent them, we have evidence that some interventions do work. That’s important information for all of us to know.

Filed Under: Evidence-Based Living, Health and Wellness, policy Tagged With: , , , , ,

Evidence-based Olympics: The science of sport

August 3, 2012 By 1 Comment

Much of the world is watching the 2012 Olympics with excitement as athletes attempt to swim faster, jump higher and dive more gracefully than humans ever have before.  The casual spectator might be surprised at the amount of science that goes into competition at the Olympic level.

Here at EBL, we tracked down a round-up of media on scientists working with Olympic athletes to help them become the best they can be.

Among the interesting research is a study trying to determine the most efficient freestyle stroke technique for swimmers. A mechanical engineering professor at John Hopkins University used laser body scans and underwater video of two Olympic-level swimmers to create a computational fluid dynamic model to compare the two different freestyle strokes. His work determined that a method known as the “deep-thrust” swimming style is the most effective way to swim freestyle.

Another professor of biomedical engineering at the University of California is using physics to help elite divers. She installed force sensors on diving platforms to measure the forces divers use when they begin their dives. “The athletes feel the forces and the coaches see the effect of the forces,” Professor Jill L. McNitt-Gray explained. “By measuring forces, they could both get a sense of what they actually are.”

And a mechanical engineer at Sheffield Hallam University in the United Kingdom studies the role technology has played in the history of sport. He’s written extensively this year on the effects of rule changes and technology on sporting performance over time.

Certainly, there are many more examples of science in sport such as aerodynamic helmets used in cycling and the biological effects of endurance sports, to name two.

When it comes down to individual competitions, luck and human spirit certainly do play a role – especially at the Olympics. But it’s interesting to take a look behind the scenes to see the role that science plays as well.

Filed Under: Evidence-Based Living, Health and Wellness, In The Media Tagged With: , , , , ,

Alcohol consumption: the benefit is in the dose

June 29, 2012 By 3 Comments

We know that excessive alcohol consumption is dangerous. It is well-documented that drinking leads to motor vehicle accidents, serious diseases, and a weakened immune system.

But there’s a saying first coined by Parcelsus in the 1500s : “The  difference between a drug and a poison is the dose.”  And it certainly applies to alcohol consumption. Two important new meta-analyses underscore this point.

In the first article, the authors included 84 studies that look at the connections between cardiovascular risk and alcohol consumption. They came to the conclusion that the evidence is now so clear that moderate drinking reduces cardiac risk that no further meta-analyses are necessary. Instead “debate should centre now on how to integrate this evidence into clinical practice and public health messages. In the realm of clinical practice, the evidence could form a foundation for proposing counseling for selected patients to incorporate moderate amounts of alcohol into their diets to improve their coronary heart disease risk.”

But they didn’t stop there. They also conducted a second meta-analysis of “feeding studies” (where alcohol is experimentally administered). These studies eliminate the concerns about confounding in the observational studies, and can thus point to mechanisms by which alcohol protects against heart disease.

The finding? “Moderate alcohol consumption had favourable effects on levels of high density lipoprotein cholesterol, apolipoprotein A1, adiponectin, and fibrinogen. These results strengthen the case for a causal link between alcohol intake and reduced risk of coronary heart disease.”

“We don’t need any more studies examining this association,”  said Dr. Cary Reid, a geriatrician at Weill Cornell Medical College. “This meta analysis is well conducted and is one of many conducted over the past decade that has shown a consistent protective effect of moderate alcohol consumption on cardiovascular outcomes.”

The challenge, Reid says, is communicating the evidence to patients. “It remains unclear whether this finding will be translated into clinical practice given clinicians’ concerns about increased alcohol use – particularly among older people – and the associated effects of falls, fractures, and decreased psychological functioning.”

The key message is “moderate.” And there are some specific guidelines about what that means issued by the National Institute on Alcohol Abuse and Alcoholism. (The rule of thumb is one drink a day for women and two drinks a day for men.)

So raise a glass – but just one of two, and not if you’re driving – to your health.

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The media gets it right: The health effects of coffee

June 26, 2012 By 2 Comments

Here at EBL, we love it when a major media outlet takes a fair and balanced look at the evidence.  As we’ve written about before, mainstream publications don’t always present all of the evidence.  But this week, the New York Times published an excellent update on the health effects of coffee.

Health writer Jane Brody first wrote up a thorough review of the health effects of coffee in 2008.

Among the findings she reported:

  • Drinks with fewer than 550 milligrams of caffeine, which includes a Grande brew from Starbucks, are equally as hydrating as drinking pure water. (Many previous reports have touted coffee’s diuretic effects.)
  • There is very little evidence that coffee increases your risk of heart attack or abnormal heart rhythms.
  • Coffee causes a small, temporary rise in blood pressure, but there’s no evidence that it leads to chronic hypertension.
  • And on a positive note, coffee is found to increase alertness, happiness and endurance in aerobic activities. It also helps blunt the feeling of pain. (No wonder so many Americans love it so!)

Brody’s update, published this week, was based on a study published in May in the New England Journal of Medicine. Here’s how she summed it up:

“When smoking and many other factors known to influence health and longevity were taken into account, coffee drinkers in the study were found to be living somewhat longer than abstainers. Further, the more coffee consumed each day — up to a point, at least — the greater the benefit to longevity.”

That’s good news on two fronts: Coffee drinkers the world over can enjoy brews without worry, and the New York Times gets accolades for balanced, comprehensive reporting.

Filed Under: Evidence-Based Living, Health and Wellness, In The Media Tagged With: , , ,

Disney takes its cues from the evidence

June 11, 2012 By Leave a Comment

In major news this week, the Walt Disney Co. banned the advertising of junk foods from its television, radio and Internet programming. Under the new guidelines, advertisers who want to promote food and beverages on Disney programming for children must meet guidelines on serving size, calories, and fat and sugar content.

While it’s inspiring that such a large company is interested in promoting health among kids, I was even more inspired that Disney created a policy based on real evidence. Because, in fact, there is a growing body of evidence that links media consumption – and specifically advertisements – with negative health outcomes for children.

This systematic review, for example, looked at 173 studies examining the relationship between media consumption and health outcomes among children. In 80 percent of the studies, more media exposure was associated with a negative health outcome, and childhood obesity had the strongest correlation. This analysis considered the quantity of media that children watched, but not the content.

Another meta-analysis found a significant association between the proportion of children overweight and the number commercials per hour on children’s television, especially ads that promoting junk foods. The study used data from surveys of advertising on children’s television and estimates of the prevalence of overweight among children, in the U.S., Australia and eight European countries. It concluded the quantity and content of advertising on children’s television programs has a specific effect on children.

It’s great to see a major company taking cues from the evidence in an effort to improve the health of children!

Filed Under: Evidence-Based Living, Health and Wellness, policy Tagged With: , , , , ,

Energy drinks: Bad for kids, bad for your teeth

May 8, 2012 By 3 Comments

Brightly-colored, sugar-filled energy and sports drinks are everywhere – in vending machines, cafeterias and gas stations.

While they may seem like a healthy alternative – athletes drink them, after all – most lack nutritional value, and many contain caffeine. The evidence actually shows these drinks can be detrimental to kids and harmful to teeth.

First off, a systematic review commissioned by the American Academy of Pediatrics found that sports drinks – which don’t contain caffeine, but do have a lot of sugar – lead to obesity and tooth decay among children. And energy drinks – which do contain caffeine – can interfere with sleep, lead to anxiety and cause dehydration.

A more recent study published in the journal General Dentistry and covered by National Public Radio found both energy and sports drinks contain high levels of citric acid, which erodes tooth enamel, leaving teeth more prone to cavities and decay.

There’s certainly a place for sports drinks – specifically to replace electrolytes and energy stores in both children and adults who exercise vigorously for more than an hour at a time. But for the public at large, these drinks are essentially empty calories.

So help to discourage children from downing sports drinks unless they’re actually playing a sport.  And the next time you’re picking up a beverage to go with that sandwich or need to quench your thirst on a long drive, stick with water.  It’s the healthier choice.

Filed Under: Evidence-Based Living, Health and Wellness, Youth Development Tagged With: , , , ,

The buzz on red meat

March 20, 2012 By 3 Comments

Last week, the headlines on meat consumption were inflammatory to say the least.

The Los Angeles Times: All red meat is bad for you, study finds Fox News: Red meat linked to premature death, research finds
The BBC: More Red Meat, More Mortality
The New York Times: Red Meat Increases Death, Cancer and Heart Risk

The researchers, from the Harvard School of Public Health, followed the diets and health outcomes of 37,000 men and 83,000 women over more than two decades. The found those who ate protein sources other than red meat were more likely to live longer. But what’s really at work here?

I found several systematic reviews on red meat consumption that give a broader look at this issue.

One published in the journal Circulation found 20 case-controlled studies and randomized controlled trials that assessed the effect of red meat consumption on health and concluded that eating processed meats, but not red meat, is associated with higher incidence of heart disease and diabetes.

Another review looked at the link between red meat consumption and colorectal cancer, and found eating red meat on a daily basis is associated with an increased risk of colorectal cancer and eating processed meats regularly is associated with an even higher risk of colorectal cancer.

And a third review found little evidence available on the links between red meat consumption and stroke risk.

As much as I love a good burger or juicy steak, the available evidence shows that eating red meat regularly is bad for your health. It is worth noting ,though, that in each study, the conclusions were drawn based on participants consuming red meat every day.

Personally, I’m going to stick with my motto of everything in moderation, and still enjoy a nice cut of beef once in a while.

Filed Under: Evidence-Based Living, In The Media Tagged With: , , , , ,
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