Dr. Ayala's Open Salon Blog

Non-caloric sweeteners on the rise: Should we be concerned?

Wed, 30 May 2012 09:05:01 -0400

Americans eat a lot of sugar – 15 percent of daily calories are from added sugar alone. Sugar’s high caloric price as well as its rising market cost are moving consumers and food makers to replace sugar with ever rising amounts of low-calorie sweeteners such as Equal, NutraSweet, Splenda, Sweet'N Low, Stevia and many others. Replacing sugar with no-calorie sugar substitutes potentially saves many calories, but also raises concerns about what happens when you dissociate sweetness from energy: how does non-caloric sweetness affect appetite, eating habits and weight?

And since the sugar-substitute experiment is long underway, it’s a good idea to stop and see how the trial is faring: are low caloric sweeteners helping in the obesity fight?

Food and nutrition experts met in the spring of 2011 in Washington DC to do just that in a workshop called: “Low-Calorie Sweeteners, Appetite and Weight Control: What the Science Tells Us”. The presentations of this workshop are summarized in a upcoming supplement of the Journal of Nutrition and make for some interesting reading.

Does sweetness promote overeating?

Tasting something sweet activates pleasure centers in the brain. Do you know what else activates these neural reward pathways? Addictive drugs such as alcohol and opiates work on the same brain mechanisms. That of course doesn’t mean that drug addiction and our affection for sweet food are the same thing – but it does help explain how strong and well conserved our sweet preference is. Loving sweet is innate and present even before birth. It probably served our species well, leading babies to crave mother’s milk and all other aged humans to seek ripe fruit.

A few interesting findings from the article about sweetness and food preference:

· Sweet taste makes pain go away: a Cochrane review showed that sweet tasting solutions reduced the reaction to pain in babies. Sweetness continues to act as an analgesic in childhood.

· We sense sweet taste through taste receptors in the mouth, but receptors are present also in our intestine and our pancreas. Stimulating these receptors leads to a cascade of physiologic reactions, including insulin and other hormone secretion, stomach emptying, appetite control and gut motility. These receptors can’t tell caloric sweeteners and non-caloric sweeteners apart -- they react to both, to a degree that isn’t completely understood.

· Young kids prefer super sweet -- the sweeter the better. They’ll always gravitate to sweet rather than plain. Kids can also discriminate between sweet-tasting foods differing in energy content, preferring those that are more energy dense.

· Preferring sweetness is natural, but also learned: babies and young kids exposed to sweet foods and drinks prefer sweet foods, and eat more of them. Through their experience with food kids ‘learn’ what should and shouldn’t taste sweet. Repeated exposure to sweet drinks leads to preference of sweet drinks.

· The ready availability of sweet, highly rewarding foods, can promote overeating and weight gain. Adding sweetness (caloric or non-caloric) to foods that are not naturally sweet -- think cereal, water, yogurt or milk -- creates dietary habits of overconsumption. It’s just human nature.

The science of non-caloric sweeteners

Thanks for hanging in there up until now. I bet you’re curious to know the bottom line verdict of this workshop. Two years ago, the new Dietary Guidelines for Americans concluded that:

“The replacement of sugar-sweetened foods and beverages with sugar-free products should theoretically reduce body weight. Yet many questions remain, as epidemiologic studies show a positive link with use of nonnutritive sweeteners and BMI. Additionally, whether use of low calorie sweeteners is linked to higher intake of other calories in the diet remains a debated question.”

I’m afraid not much has changed.

The workshop concluded that the bulk of epidemiologic, observational studies, but not all of them, reported that use of low-caloric sweeteners is associated with obesity and weight gain. However, association doesn’t prove causality. Real evidence, the experts say, can only come from well-performed randomized controlled clinical trails, in which people will be assigned randomly to consume either non-caloric sweeteners for long periods of time, or serve as controls.

Until then, the large-scale non-randomized population experiment is ongoing, we’re all part of it, and I don’t think it’s going too well. I choose to be in the control group.

Dr. Ayala

Full disclosure: I’m vice president of product development for Herbal Water, where we make organic herb-infused waters that have zero calories and no sugar or artificial ingredients. I’m also a pediatrician and have been promoting good nutrition and healthy lifestyle for many years.

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The health and weight of the (young) nation

Wed, 23 May 2012 09:05:14 -0400

It has been many a pediatrician’s nightmare prediction: rising obesity rates are likely to cause an increase in type 2 diabetes in teens, in much the same way these two conditions are linked in adults.

And this fear has come to pass. Type 2 diabetes, unheard of in kids just a few decades ago (it used to be called adult-onset-diabetes for just that reason!), has become unexceptional in pediatric practice.

But what we’ve seen so far seems to be just the tip of the iceberg. A new article in Pediatrics looked at a group of about 3400 nationally representative teens (aged 12-19), and found that diabetes and pre-diabetes nearly tripled in less than 10 years, jumping from 9 percent in 1999-2000 to 23 percent in 2007-2008.

The authors, led by Ashleigh May, warn that these results should be interpreted cautiously: Diabetes and pre-diabetes were diagnosed by a single fasting blood sugar test. The true prevalence of type 2 diabetes in kids is hard to know unless blood tests are done because the disease can have little or no symptoms for a very long time. The numbers do look high, and it’s going to be interesting to see if other large-population studies corroborate them.

Teens at serious cardiovascular risk

High blood sugar wasn’t the only cardiovascular risk factor facing the teens in the study. Overweight and obesity were common – 16 percent of the kids were overweight and another 18 percent were obese.

On top of that, 14 percent of kids had pre-hypertension or hypertension, 22 percent had borderline or high LDL (bad) cholesterol, and 6 percent had low HDL (good) cholesterol.

All these above mentioned risk factors were seen much more frequently among the kids with overweight and obesity, in fact, among obese teens 61 percent had at least one cardiovascular risk factor on top of their weight status, and 8 percent of the obese teens had 3 or more of the tested risk factors. But even among normal weight teens 37 percent had a cardiovascular risk factor (the most common of which was high LDL), showing that even when teens aren’t overweight they can benefit from interventions promoting a better diet and more physical activity.

A bit of good news if I may: it seems like obesity rates have leveled off and they haven’t changed much during the 9 years covered in this study. For overweight and obesity to level off at a third of the pediatric population is of little comfort, though

Diabetes in teens carries extra burden

Kids with diabetes not only have more years to accumulate the disease’s serious complications – the longer one has diabetes the more likely heart, kidney, eye, nerve and other body systems are to suffer its consequences. Type 2 diabetes is also proving to be much harder to treat in young patients according to recent studies.

It doesn’t have to be so!

I assume that the vast majority of the kids in this study had pre-diabetes – a condition that if left unattended can, and often will, develop into diabetes (the article doesn’t differentiate between diabetic and pre-diabetic teens). But pre-diabetics can reverse their metabolic state with just modest weight loss and exercise.

And for all of us, type 2 diabetes is mostly a lifestyle disease. It is really up to us to feed kids better and help them become more active so they’re not doomed to develop totally preventable disease and disability as young adults.

What to do? HBO’s excellent Weight of the Nation looks at this complex issue in depth and with compassion. If you haven’t seen it yet, I highly recommend the Children in Crisis chapter (I actually think it’s a good idea to watch the chapters out of order – I found the first installment, Consequences, to be so depressing that I have a feeling some viewers might have just given up on both the series and on dealing with obesity before that chapter was over).

As Dr. Tom Frieden, CDC director, says: The weight of the nation is not healthy. And to get it healthy, we’re all going to have to do our part.

Dr. Ayala

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Study proves school nutrition standards work

Wed, 16 May 2012 09:05:58 -0400

School meals are far from perfectly nutritious, even after the long awaited and very welcome changes put in place earlier this year.

The good news is that under the new guidelines kids will hopefully double their fruit and veggie intake, will be served more whole grains, all milk will be low fat, and there’ll be upper limits to salt, trans-fat and calories in the school meal. The not so great reality is that kids will continue to eat lots of highly processed foods – very few schools actually cook food from scratch – and tomato paste on pizza counts as a vegetable.

But school food isn’t just the subsidized school lunch; competing with it are the foods sold in schools -- in vending machines, school stores, and a-la-carte in the cafeteria -- which make a big part of what kids actually eat while they’re in school.

The USDA administers and regulates the school lunch program, and is developing nutrition guidelines for the foods and drinks sold at schools. (The Healthy, Hunger-Free Kids Act, passed in 2010, gives the Agriculture Department authority to set health standards for all foods sold on school property — including those in vending machines). Right now, the only existing federal restriction is that foods of “minimal nutritional values”, such as candy and soda, won’t be sold in the cafeteria during meal times. That of course doesn’t mean they can’t be sold right outside the cafeteria doors.

In the meantime some states have developed their own regulations. Studying the effects of different sets of regulations and their enforcement can teach us what’s been successful – and what doesn’t work.

Vending machines with fewer calories

California was one of the first states to implement rules for vending and selling foods in schools; these rules limit the caloric content, fat and sugar in snacks and ban soda and sweetened beverages.

A new study in the Archives of Pediatric & Adolescent Medicine compared California high school students’ daily intake to the intake of students from 14 states without any school nutrition standards.

California kids ate fewer calories per day at school -- 170 fewer – compared to high school students in other states. California kids also consumed less fat and sugar.

Did the kids load up the ‘lost’ calories on their way home or once they got there? It doesn’t seem so. Although California students ate more of their daily calories out of school when compared to the kids from the “no rules” states, the Golden State’s students took in 158 fewer calories a day, overall.

And a reduction of 158 calories is a big deal. We gain weight very gradually, and reducing even 100 calories a day can prevent weight gain and put a dent in the obesity crisis.

Fewer calories, perhaps no better nutrition

California students ate fewer calories from fat and sugar, but the study found that their intake of nutrients such as vitamins and minerals was unchanged compared to the students from the other states.

The authors suggest that the reason lies if the food laws themselves: the laws limit sugar fat and salt, they don’t require whole grains, fruits or vegetables. Replacing full fat chips with baked low-salt ones can only do so much.

Providing truly healthy substitutes is obviously the next step, but since obesity – too many calories -- and the abundance of sugar, fat and salt in kids’ diets are the main nutrition problem facing us, I’d conclude that California kids seem to enjoy better nutrition according this study.

Does public policy impact kids’ health?

While there are plenty of studies that show policies have a positive impact on kids’ eating habits, there are definitely studies that show that they don’t. I shared a recent study that showed that in schools that banned only soda, kids bought the other vended sugary beverages instead. In schools that banned all sugary drinks kids indeed consumed fewer sugary drinks at school, but their consumption did not decrease overall; kids were able to find sugary drinks out of school, and filled the sugar gap before and after school. In other words, school vending policies only changed the school environment, and didn’t seem to be enough to change kids’ access and behavior overall.

I’d argue that even if the regulations don’t have the immediate nutrition-improving outcome we’d hoped for, it’s still imperative to apply nutrition rules for educational reasons. It’s impossible to advocate for safe driving while holding a cellphone with one hand and the wheel with the other.

School should have a central role in nutrition education, and you can’t teach healthy nutrition while benefiting from the sale of junk food within school walls.

Kids spend half their waking hours in school and consume much of their daily calories while on campus. Changing school food should be a critical part of the effort to combat obesity.

Dr. Ayala

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Put those fruits and veggies a little closer

Wed, 9 May 2012 09:05:18 -0400

Much of our eating is mindless and automatic. That’s why environmental changes can lead us to overeat. Many argue that what’s at the root of the obesity epidemic is the transformation in our environment, which gradually changed into an obesity-promoting one.

Proximity and convenience affect food choices. Food makers know that the closest, easiest to grab, and most noticeable food items will sell more, that’s why they place the products that they want you to buy on an eye-level shelf, near the checkout and in an open case. Previous studies have shown that when candy is placed closer and is in a clear rather than an opaque bowl, people eat more of it.

Could proximity and visibility promote good-for-you foods just as well?

Gregory Privitera and Heather Creary tested how distance and visibility affect apple and carrot consumption. Their new study appears in the Environment and Behavior Journal.

The 96 healthy students in the study were not aware that eating behavior was the purpose of the experiment, and were assigned randomly to have a bowl of the fruit or the veggie in one of these four settings:

• Within arm’s reach and in a clear bowl

• Within arm’s reach and in an opaque closed bowl

• On a table about 2 yards away in a clear bowl

• On a table about 2 yards away in an opaque closed bowl

The students watched the researcher take the food out of a sealed bag (this was done to ensure the participants knew the food’s fresh and good to eat), and the researcher then excused himself for 10 minutes, with a cover story of “I’ll be right back with some questionnaires”, and an invitation to munch on the carrots or apples.

Within arm’s reach

Leaving the apples and the carrots close, within arm’s reach of where the student sat, increased intake significantly. The transparent bowl trick worked only with apples; carrot intake wasn’t significantly increased when the bowl showed though. The researchers suggest an explanation:

“apple slices may be more visually appealing than carrots in that seeing sweet-tasting apple slices (vs. bitter-tasting carrots) induces a stronger wanting to consume those foods.”

I’m here to defend the meager carrot: carrots are generally not bitter! I wonder where the researchers got their veggies, or when they last tasted a good carrot. Carrots actually have high sugar content, and are very tasty! They’re pretty, too.

Anyway, I suppose most moms knew this intuitively, but here’s some experimental proof showing that making fruits and veggies readily available can get us closer to the minimum recommended 5-a-day.

Another thing that caught my eye in this study is the background information on the study group. The students were about 19 years of age, and their average body mass index (BMI) was about 27. A BMI of above 25 puts a person in the overweight range. The study sample is a small one, and quite random, but what we see again and again is that even among young students, being overweight has become the norm. Every year of being overweight adds to the risk of chronic diseases such as type 2 diabetes and heart disease, and that’s why the overweight and obesity epidemic among kids and young people is especially worrisome.

Eating more fruits and veggies is important to health, as well as for healthy weight maintenance; so let’s think up some clever fruit and veggie placements!

Dr. Ayala

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Preschoolers suffering nature and exercise deficits

Wed, 2 May 2012 09:05:44 -0400

A happy day, I think, is one in which some time is spent outdoors.

Dog owners take their dogs out daily, and pediatricians suggest we extend the same kindness to our kids.

No, seriously, kids need the outdoors quite critically. Outdoors translates to physical activity and fitness, and the more time kids spend outdoors the less likely they are to become obese. Kids don’t exercise in gyms; they have bursts of intense, vigorous, heart racing activity while playing in a large open space, when they’re chasing a friend or a squirrel, or repeatedly going up and down a slide. Playing outdoors also helps kids’ development and growth and does wonders to their vision, coordination, vitamin D levels and mood!

Experts say that free play — especially outdoors — is crucial to a kid's health, but chances to play outside have been on the decline over the past few decades. Busy lives, over anxiety about safety, screen based entertainment and lack of awareness are keeping kids indoors.

Not enough outdoors time

A new study in the Archives of Pediatrics & Adolescent Medicine looked at the frequency at which parents took their kids to play outside. The authors, led by Pooja Tandon, used a nationally representative sample of about 9,000 4-year-olds, whose parents were asked how often they took their kid out to play.

They found that about half of the preschoolers were taken out by their parents daily.

Is another caregiver taking these kids out? Possibly — daycares are supposed to take kids out. But even among the 20 percent of children in the study who didn’t attend any day care or preschool at all, only 58 percent went outside daily with mom or dad.

Is safety the issue?

An important barrier to spending time outdoors could be perceived or actual concern for safety. This study found that the vast majority of parents thought that their neighborhood was either very safe (58 percent) or fairly safe (35 percent), with just 5 percent assessing their area as fairly unsafe and only 2 percent as very unsafe. So dangerous neighborhoods were not the issue.

Has TV replaced playing outdoors? The researchers found that the 4-year-olds in the study spent almost 4 hours a day in front of a screen — which is a lot, and almost double the (generous) American Academy of Pediatrics’ suggested upper limit — nevertheless, screen time wasn’t correlated with how often parents took their kids out to play.

There was also no correlation with household income or mom’s marital status.

There were, however, two interesting variables that increased the odds of getting regular fresh air: boys were taken out more often than girls, and moms who exercised regularly were more likely to the take their kids out.

It seems like active parents raise their kids to be more active, and perhaps the known statistic that boys are generally more active than girls can be partly explained by the fact that boys are given more opportunities for activity.

Get outside!

Being active starts at home and with the parents.

Barring dangerous weather, kids — and adults — I do believe, will do themselves some good by spending some time outdoors every day. Regardless of what happened at day care or school, parents should encourage kids to go out, run around, look at trees and birds, meet some insects, get dirty and come back tired. I can’t think of a better way to take a break from work, media and chores than to leave them all behind and go out with the kids. Soon enough these young kids will be able to enjoy the outdoors without adult supervision, and if you’ve collected some great outdoor memories you’ll be rewarded with outdoor enthusiasts for life.

Dr. Ayala

“Sunshine is delicious, rain is refreshing, wind braces us up, snow is exhilarating; there is really no such thing as bad weather, only different kinds of good weather.” ~John Ruskin

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