Healthy Children

Hello and welcome to Nutrition Facts – the podcast that brings you the latest in evidence-based nutrition research.  I’m your host, Dr. Michael Greger.

I know that facts have been in the news a lot lately, both real and fake.  The concept of alternative facts is nothing new in the field of nutrition though, where powerful commercial interests have tried to not only keep people in the dark, but actively try to confuse them.  That’s why I stick to the science:  What’s the best available balance of evidence published in peer-reviewed medical journals right now?    That’s why I wrote my New York Times best-selling book, “How Not to Die”, why I created my nonprofit site NutritionFacts.org and, now, this podcast.

Today we’re going to look at children’s health and we’re going to start with some sobering news.  Recent research indicates that the current generation of American kids may be one of the first generations to be less healthy and have a shorter lifespan than their parents.  We know that coronary artery disease doesn’t just magically appear; the disease begins during early childhood, progressing unrecognized for several decades to its often final and unexpected endpoint of chest pain, disability, or simply death. 

We need to remind ourselves that atherosclerosis begins in childhood as fatty streaks in the arteries, which are the precursors of the advanced lesions that ultimately kill us.  By our 20s, 20% of the inner surface of the artery coming off the heart is covered in fatty streaks.  So, fifty years ago, pathologists started raising the question of whether heart disease is best handled by cardiologists or by pediatricians, because by their 30s, many young adults already have advanced coronary atherosclerosis.  An intervention from our thirties on is actually what’s called secondary prevention, just trying to mediate the ravages of the disease rather than prevent the disease itself, because advanced atherosclerosis is likely already present.

And, we’re exporting the problem around the world.  Young, thin, apparently healthy individuals, yet 97% of their collected arteries looked like this.  So, even in developing countries, where they’ve acquired our eating habits, we’re seeing an epidemic of heart disease and sudden death—that is, if you’re not shot first.

Moreover, the risk factors that correlate with the extent of such early lesions are the same risk factors that correlate with heart attacks later in life.  In other words, it’s the same disease, just in the early stages. So, pathologists, the ones doing the autopsies on all these young people, and seeing all this coronary artery disease, began urging many years ago that preventive measures should be instituted earlier in life.

We’ve known that fatty streaks exist in young children for over a century, but it wasn’t until 1994 that a task force convened by the government came up with a radical idea:  The strategic key, and the greatest opportunity in preventing cardiovascular disease, is to prevent the development of risk in the first place.

In my video, Heart Disease Starts in Childhood, I noted that fatty streaks, the first stage of atherosclerosis, were found in the arteries of nearly 100% of kids by age 10 raised on the Standard American Diet. In recognition of this fact, the latest Academy of Pediatrics’ recommendation is that all kids get their cholesterol tested starting between the ages of 9 and 11.  Of course, this has drug companies salivating at the thought of slipping statins into Happy Meals, but long-term drug intervention is costly and may be associated with adverse effects.  They’re talking about lifestyle modification.

In my video, How Many Meet the Simple Seven?, I revealed the  breathtaking statistic that only about one in 2,000 U.S. adults met the seven American Heart Association criteria for a heart-healthy lifestyle.  What about American teenagers?  Of the 4,673 adolescents aged 12 through 19 that were studied, zero made the cut.  What was the main sticking point?  Well, you know, most teen boys and girls don’t smoke.  The white bars show the percentage meeting the criteria.  Most aren’t overweight, but almost no one ate a healthy diet.  Less than one percent of young men and women met a minimum of healthy diet criteria.

This sorry state of affairs is what’s behind this controversial paper suggesting that the current generation of U.S. children and adolescents—our children—may be one of the first generations to be less healthy and have a shorter lifespan than their parents.

In a recent study conducted in California, researchers found that levels of arsenic, banned pesticides, and dioxins exceeded cancer benchmarks in the 364 children who were tested.  Which foods were the primary sources of toxic pollutants for preschoolers and their parents?  Here are some answers.

Recently, the diets of California children, ages two through seven, were analyzed to determine the cancer and non-cancer health effects from food contaminant exposures.  Food may be the primary route of exposure to toxic heavy metals, persistent pollutants, and pesticides.  Though foodborne toxic contaminants are a concern for all ages, they are of greatest concern for children, who are disproportionately impacted because they’re still developing and have greater intake of food and fluids relative to their weight.  Pediatric problems that have been linked to preventable environmental toxin exposures include cancer, asthma, lead poisoning, neurobehavioral disorders, learning and developmental disabilities, and birth defects.

But, the good news is changing one’s diet can change one’s exposure.  A diet high in fish and animal products, for example, results in greater exposure to persistent pollutants, like DDT and dioxins and heavy metals, than does a plant-based diet because these compounds bioaccumulate up the food chain and plants are at the bottom of the food chain.  But, this sample of California kids was not eating a plant-based diet and cancer benchmark levels were exceeded by all 364 children for arsenic, the banned pesticide dieldrin, a metabolite of DDT called DDE, and dioxins.

Children exceeded safety levels by a greater margin than adults.  This is especially of concern for children because all of these compounds are suspected endocrine disruptors and thus may impact normal development.  Cancer risk ratios were exceeded by over a factor of 100 for arsenic and dioxins.

Which foods were the worst?  For preschoolers, the number one food source of arsenic was poultry, though for their parents it was tuna.  The number one source for lead was dairy and for mercury it was seafood, and the number one source of the banned pesticides and dioxins was dairy.  

They didn’t split up the groups by gender, but a similar study in Europe found that men had higher levels of some of these pollutants than women; for example, levels of the banned pesticide chlordane, but women who never breastfed were right up there closer along with men, with the lowest levels found in women who had breastfed more than 12 months.  It is therefore likely that the lactation-related reduction in blood pollutant levels partially explains the lower body burdens among women compared to men.  So, cows can lower their levels by giving some to us, then we pass it along to our children.

What non-cancer effects might some of these pollutants have?  They can affect the immune system.  Studies clearly demonstrate the ability of dioxins and related compounds to have a long-lasting and deleterious effect on immune function.  This manifests as increased incidences of respiratory infections, ear infections, cough, and sore throat.  At first, most of the data was for during infancy, but now we have follow-up studies showing that the immunosuppressive effects of some of these toxins may persist into early childhood.  So, we should try to reduce our exposure as much as possible.  How do we do that?  Because these pollutants accumulate in animal fat, consuming a plant-based diet, decreasing meat, dairy, and fish consumption may reduce exposure for children and adults alike.

Our next story may make you reach for a long, tall glass of water and it should make you hand one to your kids as well.  A recent study found that most children don’t drink water from the time they wake up, until they go off to school.  Interventional trials show this mild state of dehydration may negatively affect scholastic performance.  Here’s the story.

What is the hydration status of healthy children in the United States?  Preventing cellular dehydration is integral to hormonal, immune, neurological, cardiovascular, gastrointestinal, muscle and skeletal function.  So, researchers recently got urine samples from a group of 9- to 11-year olds in L.A. and Manhattan on their way to school to see how they were doing.  Fifty bucks to pee in a cup—not bad!

The study was motivated by recent studies in Israel showing children did not seem to be hydrated enough but Israel’s in a desert.  So, that’s why they repeated the study under cooler and less arid conditions; yet, U.S. kids did just as bad as the Israeli kids.

The urine from nearly two-thirds of the kids was considered too concentrated—an indicator that they were dehydrated.  Why?  They weren’t drinking enough water.  Three-quarters of the kids did not drink water between when they woke up and when they went off to school.  But, most did eat breakfast, so they must have been drinking something.

The problem is that other beverages are not as hydrating.  The levels of sodium, sugars, and amino acids in milk and juice can shrink cells, and trigger the release of the hormone that signals dehydration.

So what, though?  I mean, is there any actual negative impact of mild dehydration on their ability to function at school?  Historically, most of the studies on hydration and mental functioning were done on adults under extreme conditions, like having people exercise in 113-degree heat, or giving people powerful diuretics, like Lasix, and putting them on a treadmill, and most of the studies on hydration and cognitive performance have been performed on military personnel to evaluate soldiers’ ability to function in extreme circumstances.  It is easy to imagine that a soldier fighting in the desert with a heavy rucksack and a protective suit must be physically and cognitively at their best.  It is, however, very difficult to translate this knowledge to normal real-life circumstances.  But, three new studies did just that.

Simple study.  Take a group of schoolchildren, randomly allocate them to drink a cup of water, or not, and then just give them all a test, and see who does better and the winner was the cup-of-water group.  Conclusion:  The results of the present study suggest that even children in a state of mild dehydration, not induced by intentional water deprivation or by heat stress or living in an extreme climate, can benefit from drinking more water and improve their cognitive performance.

So, water worked for second- and third-graders.  What about first grade?  Same experimental design, but this time, instead of forcing kids in the water group to drink a cup, the water group was just given some water, and told to drink as much as they wanted and, again, found significant improvement in their performance on various tasks, leading to the same conclusion:  Even under circumstances of mild dehydration, children’s cognitive performance can be improved by having a drink of water.

In the latest study that just came out, the largest to date, which really put it all together.  They, too, also found a remarkable proportion of children were in a state of mild, voluntary dehydration at the beginning of the school day, found a significant negative correlation between dehydration and, for example, the ability to remember numbers.  They offered a randomized group some water and those kids, on average, felt better and performed better.  Though dehydration might affect some cognitive abilities more than others, it is an adverse state that might render the school day more challenging for children.

Even doctors often apparently fail to realize the connection.  A recent study found that healthcare professionals under-recognized the importance of proper hydration for mental health.  Who would care enough about the importance of human hydration to even do such a study?  The European Hydration Institute, founded in part by the Coca-Cola Company.

Significant improvement in cognitive performance, but not with Coke and not with Ritalin or some new drug either, just plain water.  Think how much drug companies could make if they could sell sugar pills, but just tell kids to take the fake pill with a glass of water.

To see any graphs, charts, graphics, images, or studies mentioned here, please go to the Nutrition Facts podcast landing page.  There, you’ll find all the detailed information you need plus links to all the sources we cite for each of these topics.

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Thanks for listening to Nutrition Facts.  I’m Dr. Michael Greger.