Tag Archives: obesity

Fizzy Drinks and Sugar Intake

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A report on the “Effect of Carbonation on Brain Processing of Sweet Stimuli in Humans” (Gastroenterology 2013; 145: 537-39) highlights how the addition of carbonation could lead to increased consumption of sugar products.  The authors examined neural activity in response to carbonated beverage consumption with the aid of functional MRI.  An easy-to-read analysis of this study can be found at this link:  Carbonation affects brain processing of sweet stimuli : Family …

An excerpt:

Carbonation produces a decrease in the neural processing of sweetness-related signals, particularly those from sucrose, a small functional neuroimaging study shows.

The findings, which suggest that the combination of CO2 and sucrose might increase consumption of sucrose, could have implications for dietary interventions designed to regulate caloric intake, according to Dr. Francesco Di Salle of Salerno (Italy) University and his colleagues.

To assess the interference between CO2 and perception of sweetness, as well as the differential effects of CO2 on sucrose and aspartame-acesulfame, (As-Ac, an artificial sweetener combination commonly used in diet beverages), the investigators performed two functional magnetic resonance imaging (fMRI) experiments to evaluate changes in regional brain activity…

The first experiment, performed in nine volunteers, analyzed the effect of carbonation in four sweet Sprite-based solutions, including one carbonated and sweetened with sucrose, one noncarbonated and sweetened with sucrose, one carbonated and sweetened with As-Ac, and one noncarbonated and sweetened with As-Ac. The second experiment evaluated the spatial location of the strongest neural effects of sour taste and CO2 within the insular cortex of eight subjects.

On fMRI, the presence of carbonation in sweet solutions “independently of the sweetening agent, reduced neural activity in the anterior insula (AI), orbitofrontal cortex (OFC), and posterior pons … the effect of carbonation on sucrose was much higher than on perception of As-Ac,” they noted, explaining that “at the perceptual level … carbonation reduced the perception of sweetness and the differences between the sensory profiles of sucrose and As-Ac.”

This effect may increase sucrose intake, but is also favorable to diet beverage formulations being perceived as similar to regular beverage formulations, the investigators reported…

It may be that taste and CO2-related information influence food choices and intake through integration in the tractus solitarius with input from the gastrointestinal tract, they suggested, explaining that “the reduced discrimination between sucrose and As-Ac induced by CO2 would promote the consumptions of low-calorie beverages and would converge with CO2-induced gastric distention in limiting caloric intake.”

This study was supported in part by the Coca-Cola Company. One author, Dr. Rosario Cuomo, was sponsored by the Coca-Cola Company. The remaining authors reported having no disclosures.

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Could antibiotics make you fat?

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Studies in mice have shown that those exposed to antibiotics had higher total fat mass/body fat without additional weight gain.  In addition, a study of infants indicated that early antibiotic exposure may also be a risk factor for increased weight gain.

From Gastroenterology and Endoscopy News, June 2013: http://www.gastroendonews.com/ViewArticle.aspx?d=In%2bthe%2bNews&d_id=187&i=June+2013&i_id=961&a_id=23385

“Ilseung Cho, MD, MS, assistant professor of medicine, associate program director, Division of Gastroenterology, NYU School of Medicine, New York City, said, “Many investigators who study the gut microbiome think that it plays a significant role in the obesity epidemic in concert with a variety of other risk factors, such as poor dietary habits or a sedentary lifestyle. The microbiome plays a key role in a variety of host functions, including immune response and metabolism.”

Effect of Antibiotics

Dr. Cho was the lead investigator on a study in mice that demonstrated that antibiotics altered the gut microbiome in such a way as to affect murine metabolism and cause increased adiposity (Cho I et al. Nature 2012;488:621-626). Investigators administered subtherapeutic doses of penicillin, vancomycin, penicillin plus vancomycin, or chlortetracycline to young mice in their drinking water; a control group received no antibiotics. There were 10 mice per group. After an exposure period of seven weeks, the mice did not differ significantly in weight gain, but all four antibiotic-exposed groups had significantly higher total fat mass (P<0.05) compared with controls, and most (with the exception of the vancomycin group) had higher percent body fat (P<0.05).

The antibiotic exposure caused taxonomic changes in the microbiome, with the ratio of the phylum firmicutes to the phylum Bacteroidetes elevated in the antibiotic-exposed mice. Additionally, there was evidence of metabolic changes. For example, glucose-dependent insulinotropic polypeptide was elevated in the antibiotic-exposed mice, and glucose tolerance tests showed a trend toward hyperglycemia.

“In our paper, we describe a model where, by exposing mice to low-dose antibiotics, we were able to alter their microbiome,” said Dr. Cho. “Altering their microbiome resulted in a metabolic change in the mice that led to increased adiposity. The paper demonstrates that we are able to affect host metabolism by altering the gut microbiome.”

Around the same time that Dr. Cho and his colleagues published their results, a related paper about antibiotic exposure in infants was published in advance online (Trasande L et al. Int J Obes 2012 Aug 21 [Epub ahead of print]).

“Knowledge of the importance of the microbiome in human development raises new issues about antibiotic use in children, as such exposures may disrupt the microbial ecology,” the authors wrote.

In the longitudinal birth cohort study, investigators analyzed data from 11,532 children. Exposure to antibiotics during three early-life time periods (ages <6 months, 6-14 months, 15-23 months) was assessed by questionnaires that had been administered to the parents near the measured time interval. Body mass indices (BMIs) were examined at five time points (six weeks, 10 months, 20 months, 38 months and seven years).

Exposure to antibiotics during the period before 6 months of age—and only during that period, of those studied—was consistently associated with increases in BMI from 10 to 38 months. At 38 months, children who had been exposed to antibiotics before 6 months had significantly higher standardized BMI scores (P=0.009) and were 22% more likely to be overweight than children who had not been exposed (P=0.029). The researchers controlled for known social and behavioral risk factors for obesity.”

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Lunchroom Makeover

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A recent pilot study indicates that $50 and three hours can increase the chances that teens will eat their fruits and vegetables (J Pediatr 2013; 162: 867-9).  While the US Department of Agriculture has mandated alterations in what foods that schools offer for lunch, schools cannot force students to eat specific foods.  As such, the authors tried changing the convenience, attractiveness, and ‘normative nature of healthy foods’ in the lunchroom. These changes are part of a behavioral science called “libertarian paternalism.”

These field studies took place at two schools in western New York with students at 7-12 grade levels.  After implementing changes in the lunchrooms, researchers recorded tray waste on multiple dates.

Specific changes included the following:

Improved convenience:

  • “Healthy convenience line” with only submarine sandwiches and healthier sides (fruits/vegetables)
  • Salad served in see-through to-go containers

Improved attractiveness:

  • Lunch menu posted with nice color photos of fruits and vegetables
  • Fruit displayed in nice bowls or tiered stands

Normative behavior:

  • Verbal prompts by staff: “Would you like to try…”, “No veggie? How about…” “You can get another side with your meal. How about grabbing a piece of fruit?”
  • “Last chance for Fruit” sign displayed next to fruit basket at the cash register

The impact of the “smarter lunchroom:” actual fruit consumption increased by 18% and vegetable consumption increased by 23%.  The limitations of this study: no control school, did not track individual consumption, and small number of measured days.

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How to gain too much weight –attend daycare?

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According to a provocative study (J Pediatr 2013; 162: 753-8), receiving childcare as opposed to parental care was associated with increased weight.

1649 children were enrolled in a prospective birth cohort in Quebec.  Information about childcare was completed by their mothers at ages 1.5, 2.5, 3.5 and 4 years.  In addition, body mass index (BMI) was checked at ages 4, 6, 7, and 10 years of age.

Compared with care at home, children who attended a center-based childcare or were cared for by a relative were at increased risk of being overweight or obese, with odds ratios of 1.65 for center-based care and 1.5 for relative-based care.  Furthermore, increased hours away from home was associated with increased odds; every 5 hours increased the likelihood by 9% in the first decade of life.

These associations could not be explained by a number of potential confounding factors including socioeconomic status, breastfeeding, maternal employment, and maternal BMI (along with many other factors). In addition, the authors note in their discussion that these results are in line with other large studies from a number of countries.  One hypothesis for relative-based care has been that this may involve less physical activity, especially by grandparents.

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Food Marketing Detectable on Functional MRI

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The applications of functional magnetic resonance imaging (MRI) are burgeoning.  One recent usage has been on the effect of food logos on brain activation in obese and healthy children (J Pediatr 2013; 162: 759-64 & editorial 672-73).

After a pilot validation study to select food and nonfood logos, the authors recruited 10 healthy children with mean body mass index (BMI) at 50th percentile and 10 obese children with mean BMI at the ~98 percentile.  After completing reports on measures of self-control, the children underwent functional MRI while viewing food and nonfood logos.

The key findings were that healthy weight children, when viewing food logos, demonstrated greater activation in brain regions associated with cognitive control/self-control including Brodmann’s area 10 and the inferior frontal gyrus bilaterally.  Obese children showed greater activation in ‘reward’ regions of the brain when shown food logos.

While these studies should be considered preliminary due to the small sample size, they are intriguing nevertheless.  The editorial takes these findings and places them into context.

  • Children view ~6000 commercials annually; the majority feature calorie-dense and nutrient poor foods
  • “Any food can be marketed in any way, to any age group, and even the most vulnerable demographic groups can be targeted.”
  • “It is tempting to suggest interventions…to help resist marketed foods.”  However, the author notes that this strategy will fail due to increases in the “toxic influence” of advertising.
  • “Food brands are already commonplace in …sporting facilities, schools..in online advergaming..and in social media.”
  • “Targeted advertising has been related to greater consumption of high-calorie foods (eg. fast foods) by African-American and Hispanic children”
  • Policy initiatives “to turn back the tide of childhood obesity” are needed; studies that show a direct impact on children’s brains may be persuasive in compelling change.  Without these changes, companies will continue doing neuroscience research and will exploit their findings.

Bottom-line:  If one uses an analogy to tobacco, it is not quite 1964 for the food industry.

“In 1964 the Surgeon General of the U.S. (the chief doctor for the country) wrote a report about the dangers of cigarette smoking. He said that the nicotine and tar in cigarettes cause lung cancer. In 1965 the Congress of the U.S. passed the Cigarette Labelling and Advertising Act. It said that every cigarette pack must have a warning label on its side stating ‘Cigarettes may be hazardous to your health.'” History of Tobacco – Health & Literacy Special Collection

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Life Cut Short by Obesity

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When someone is too heavy, everyone knows that this is associated with numerous health risks.  A recent estimate on the amount of life lost due to obesity has been published (Obesity 2013; 21: 405-12).

Using data from the National Health and Nutrition Examination Survey (NHANES) I (1971-75), II (1976-80), and III (1988-94), the author was able to follow-up for 15 years and prospectively analyzed the data to calculate the relative risk of death and the “advancement period” of death due to obesity.  Stratification of death was adjusted for covariates including pre-existing illness, smoking, and older age.

The study focused on otherwise healthy nonsmokers to isolate the effects of obesity on mortality.  The averages of the cohorts was 46-48 years of age. While the author studied only 37,632 patients who had 8,791 deaths during the study, these results are relevant to about one-third of American adults.

Key finding: Compared to reference weight (BMI 23-25 kg/meter-squared), mortality was likely to occur 9.44 years earlier for those who were obese (BMI ≥ 30).

When the data was divided by weight, overweight (BMI 25-30 kg/meter-squared), mild obesity (BMI 30-35 kg/meter-squared), and obesity grades 2-3 (BMI >35 kg/meter-squared), the results were 4.40 years, 6.69 years, and 14.16 years respectively. The effect on advancement period mortality was less in older age groups (>55 years).

The main limitation of the study was its reliance on statistical analysis.  For those without a statistical background, Figure 2 which describes the mortality risk advancement period formula could as easily be written in Chinese.  Nevertheless, in the discussion the author underscores that these estimates are consistent with prior studies.

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Childhood Obesity and Consensus Recommendations

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Everyday pediatric gastroenterologists care for obese children; in fact, the prevalence is approximately 17% in the United States (JAMA 2010; 303: 242-9).  The types of problems include the entire spectrum of pediatric gastroenterology, though some problems like encopresis and gastroesophageal reflux are more prevalent in this population.  Whether during visits for other problems or at clinic visits focused on obesity, there may be opportunities to improve the health of these patients.

A recent consensus statement provides some guidance on the problems and treatment approaches (JPGN 2013; 56: 99-109).

After reviewing epidemiology and etiology, the consensus reviews common comorbidities which include

  • NAFLD/NASH
  • Cardiovascular: Hypertension, Hyperlipidemia   Screen: Blood pressure, fasting lipids
  • Pulmonary: Obstructive sleep apnea  Screen: assess snoring
  • Psychiatric: Depression, Bullying   Screen: assess clinically
  • Orthopedic: Blount disease (pain at medial aspect of knee) and difference in leg length, SCFE
  • Endocrine: Diabetes/insulin resistance, Polycystic ovarian syndrome  Screen: look for acanthosis nigricans, fasting glucose, hemoglobin A1c.  For PCOS, inquire about oligo/amenorrhea, look for hyperandrogenism, consider pelvic ultrasound

Besides looking for these comorbid conditions, the authors discuss treatment.  “Overall, multidisciplinary, behavior-based programs should be used when lifestyle modification counseling has not worked.”  Also, the authors recommend motivational interviewing, lifestyle interventions (healthy activity and diet =”mainstay of weight management”), possibly using Orlistat, and possibly bariatric surgery.

These consensus recommendations are sensible.  Will they make a difference?

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Challenging the Obesity Myths

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A recent provocative article highlights the myriad misconceptions regarding obesity (NEJM 2013; 368: 446-54).

According to the authors, many of the obesity recommendations are fallacies:

  • Myth: “Small sustained changes in energy intake will produce large long-term weight changes.” Fact: Because of changes in body mass, the energy requirements change which results in only modest improvement.
  • Myth: “Setting realistic goals for weight loss is important.” Fact: Setting realistic goals has not been shown to improve outcomes over more ambitious goals.
  • Myth: “Rapid weight loss is associated with poorer long-term weight-loss outcomes, as compared with slow, gradual weight loss.”  Fact: Ultimate success in terms of body weight is better with greater initial weight loss.
  • Myth: “It is important to assess…diet readiness.” Fact: Readiness does not predict the magnitude of weight loss or treatment adherence among those who sign up for behavioral programs or undergo weight loss surgery.
  • Myth: “Physical-education classes…play an important role in reducing or preventing childhood obesity.” Fact: Physical education, as typically provided, has not been shown to reduce or prevent obesity.
  • Myth: “Breast-feeding is protective against obesity.” Fact: “Studies with better control for confounding..involving more than 13,000 children who were followed for more than 6 years provided no compelling evidence of an effect of breast-feeding on obesity.”
  • Myth: “Sexual activity burns 100-300 kcal for each participant.” Fact: “Incremental benefit of one bout…is plausibly on the order of 14 kcal.”  (This is going to dampen the all-you-need-to-lose weight is to become a pornography star craze.)

Presumptions -also not proven:

  • Eating breakfast is protective against obesity
  • Early childhood learning regarding exercise and eating influence our weight throughout life
  • Eating more fruits and vegetables will result in weight loss
  • Snacking contributes to weight gain
  • Availability of parks and sidewalks influence the development of obesity

Facts:

  • Reducing energy intake (dieting) can be effective.
  • Increased exercise improves health.
  • Programs that involve parents promote greater weight loss.
  • Some pharmaceutical agents can help.
  • Bariatric surgery can be lifesaving treatment in some cases.
  • Heritability is not destiny.  Moderate sustained environmental changes can be effective.

 

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Improvement in obesity rate?

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In case you didn’t see it, this article link, OBESITY IN YOUNG IS SEEN AS FALLING IN – THE NEW YORK TIMES, appeared in multiple news outlets (December 10, 2012) and suggests that in some cities there has been a modest reduction in obesity rates of 3-5%.

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Skipping breakfast –boomerang effect for obesity

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A recent article shows unfavorable biochemical variables associated with skipping breakfast in obese children and adolescents (J Pediatr 2012; 161: 871-4).

After recruiting 174 Brazilian subjects (6-16 years) through advertising, the investigators assessed their body composition with dual-energy-dray adsorptiometry and assessed fasting blood glucose and lipid profiles.  Face-to-face interviews with parents determined the frequency of skipped meals.  The median BMI in the cohort was 27.

Results:

  • Skipping breakfast was commonplace.  Only 46% of subjects consumed breakfast daily.  Skipping lunch or dinner was infrequent, approximately 10% and 22% at times skipped lunch and dinner respectively.
  • Consumption of breakfast was inversely correlated with the odds of obesity (OR 0.73).
  • Skipping breakfast was correlated with increased glucose, triglycerides, and very low density lipoprotein cholesterol.

The authors speculate that a prolonged period of fasting in the morning could affect ghrelin secretion which promotes increased food intake.  In addition, ghrelin could affect pancreatic insulin secretion.

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