Skeptoid PodcastSkeptoid on Facebook   Skeptoid on Twitter   Skeptoid on Stitcher   iTunes   Google Play

Members Portal

Store

 

Get a Free Book

 

SKEPTOID BLOG:

"Salty Foods Make Kids Want Sugary Drinks"

by Stephen Propatier

December 12, 2012

Share Tweet Reddit

Donate "Salty Foods Make Kids Want Sugary Drinks" is the title of an article on the medical website MedPage Today. In my opinion the article is a complete science reporting fail. The webpage ignores the real conclusions of the research. It draws conclusions that are not supported by the research. Realistically the title should be; Salty food makes kids thirsty, and overweight kids tend to favor sugary drinks. This is not compelling or surprising. Which is probably why he did not use it.

This is yet another example of a news media outlet failing to capture the true purpose of published research. For some reporters it is not their fault. Many science publishers attempt to capture public attention. In this case the author appears to be at fault. It was not written by some general reporter trying to write fluff filler. This is a medically reviewed webpage that is marketed as a resource for medical professionals. Based on the webpage's own information it was medically reviewed "Reviewed by Robert Jasmer, MD; Associate Clinical Professor of Medicine, University of California, San Francisco and Dorothy Caputo, MA, BSN, RN, Nurse Planner". I admit I am uncertain as to what a Nurse Planner does, but Dr. Jasmer is a critical care and pulmonary MD. Given the research disconnect, I am certain he did not spend a lot of time reviewing this article.

Mr. Petrochko writes "A cross-sectional study of Australian children ages 2 to 16 found salt consumption was positively associated with drinking sugar-sweetened beverages (P<0.001) and increased obesity risks by 26% (95% CI 1.03 to 1.53), according to Caryl Nowson, PhD, of Deakin University in Victoria, Australia, and colleagues.". Calling the Pediatric article a "study" is at best stretching it. It is published as an article. It is based on Cross-sectional data from a self reported survey. A systematic selection of data points from a voluntary survey. That is significantly different from a rigorous study. A good study experimentally asks specific questions and controls for variables. Even assuming the data is valid it does not support his conclusions.

The author proposes, "Kids and teens who eat salty foods are more likely to wash them down with sugary drinks, potentially raising their risk for obesity, researchers found."

Actual abstract,"Cross-sectional data from the 2007 Australian National Children's Nutrition and Physical Activity Survey. Consumption of dietary salt, fluid, and SSB was determined via two 24-hour dietary recalls. BMI was calculated from recorded height and weight. Regression analysis was used to assess the association between salt, fluid, SSB consumption, and weight status.".

The researchers conclusions:" Dietary salt intake predicted total fluid consumption and SSB consumption within consumers of SSBs." That is a reasonable conclusion.

Petrochko writes "And the more salt they ate, the more sugary drinks they drank -- every 1 g/day of salt consumed was significantly associated with an additional 17 g/day of sugar-sweetened beverages drank (P<0.001), they wrote online in Pediatrics.". True but that does not mean they sought out and drank sugary drinks over non-sweetened beverages. That is not a supported conclusion.

His next observation is not what I would call insightful,"They noted that after a patient consumes dietary salt, "there is a subsequent rise in the plasma sodium concentration, and to maintain body fluid homeostasis, thirst is stimulated, thus promoting fluid intake.". Wow, ground breaking research. Salt makes you thirsty I am amazed.

I am not sure what his point is here, but I think he is indicating that they gained immediate weight,"The researchers studied associations between salt intake and overall fluid consumption, as well as salt and sugary beverage consumption and the effect of that on weight status in a sample of 4,283 Australian children over the day prior to data collection.". Yes, salt retains fluid gaining water weight.

The author paraphrases weak supporting data for his conclusion."Among children who drank a sugary drink, each additional gram of salt consumed in a day was associated with an additional 30 grams of sugary beverages. The authors noted that "salt intake alone accounted for 11% of the variance in sugar-sweetened beverage consumption. Additionally, children who drank more than one sugary beverage a day were 34% more likely to be overweight or obese (95% CI 1.12 to 1.60, P<0.001).". That is not what the article proposed. The obese kids ate more salt and drank more sweetened beverage, compared to unsweetened beverage. When the data is presented like this it appears to support causation for the obesity. It is not. It is true to say that heavy kids eat more salt and drink more SSB.

He tries to ends the article with a description of the limitations. Even that I would classify as a fail. "The study was limited by the use of self-reported recall data; potentially absent additional salt measures (such as through table salt); lack of accounting for seasonal variation in fluid consumption; and the clustering of unhealthy dietary behaviors.". That, as my uncle would say, is putting lipstick on the pig.

My interpretation, older kids and heavy kids chose sweetened drinks, the salt made everyone drink more. The older kids and the heavy kids drank a greater amount of sweetened drinks. One plausible conclusion is that sweetened drinks taste better, and that is why they drank more. Older bigger kids have the capacity to drink more. Overweight children are as likely to over drink as they are to over eat.

My review of the research limitations is a little more specific. This a non-blinded, non-randomized, voluntary survey, that was data mined. There was no control group or consideration of confounding variables. Where did they eat, home or out; what are the school lunch options, to name a few relevant variables.

Calling the pediatric article "science" is a borderline description. I would call it interesting not science. Writing this web article with that title is a complete fail. The title and the tone is giving parents the false impression that overeating and high calorie beverages are not at fault for childhood obesity. Rather eating salty food makes you crave sugar beverages. The data shows that kids that eat food high in salt might tend to be more thirsty. Kids that overeat and make poor food choices also make poor drink choices. Correlation not causation. The authors of Pediatrics article gives no indication that they thought there was a relationship with salt and craving sugar in beverages.

What did I learn from this study? Salt makes kids thirsty and heavy kids tend to make poor dietary choices. Not exactly front page material. It does demonstrate another case of poor science reporting in the media. By extrapolating from the results to achieve some perceived "wow" factor, he could cause very real harm. If you allow parents to disconnect responsibility from the underlying problems you perpetuate the poor behavior.

Childhood obesity is a complex problem. Children who eat too many calories, and have poor dietary choices will not benefit by blaming salt. I can already see the fast-food lawsuits. Followed by NYC outlawing salt on french fries,"Think of the Children". SSB as a dietary option for overweight kids is by itself the problem. Giving your Kid a cola and taking the salt shaker off the table does little to eliminate weight issues.

The truth of weight loss is very simple, less calories in and more calories out. Everything else is just window dressing to distract us. If you are told that something other than extra calories is the primary cause for your healthy child's obesity. You have good cause to be skeptical.
References:

(doi: 10.1542/peds.2012-1628)

 

by Stephen Propatier

Share Tweet Reddit

@Skeptoid Media, a 501(c)(3) nonprofit

 

 

 

Donate