Recent media coverage focused on the failed attempt by Mead Johnson to introduce a chocolate flavored drink for toddlers. Mead Johnson launched its Enfagrow vanilla flavor in July, 2009, and chocolate was added in February, 2010. The product was for toddlers who have been weaned off breast milk or infant formula. The formula was especially designed for finicky toddlers who may not get enough vitamins and nutrients through their diet, according to the company. 
Parents, nutritionists, and food bloggers, however, immediately voiced concern over the 19 grams of sugar found in each 6-ounce serving, saying products like this contribute to the current obesity epidemic surrounding the nation. When infants are ready to be weaned, sometime after 12 months old, they are ready for nutritious table food, not formula, according to nutritionists, who encourage parents to expose toddlers to a wide range of foods. Critics asserted that infants and toddlers do not need formula–instead, they need to transition from mother’s milk to eating nutritious table foods, drinking milk, and developing healthy eating behaviors. Toddlers are unpredictable, and what they need are patience, understanding, and plenty of fruits and vegetables, whole grains, protein, and dairy, not an expensive formula supplement drink. Critics claimed that, with obesity rampant around the world, children should not be introduced at young ages to hyper-sweet and hyper-palatable foods like sugar-sweetened fortified chocolate milk. 
Following the outcry, Mead Johnson announced on June 9, 2010, that it would pull its Enfagrow Premium chocolate toddler formula off store shelves. The chocolate version was discontinued after four months because of “the whole emotional evocative nature of chocolate,” said Mead Johnson spokesman Chris Perille. “It’s more associated with candy and sweets and things potentially not as beneficial. Flavor was more in conflict with a nutritious product.” In a prepared statement, Mead Johnson said there had been “some misunderstanding and mischaracterization regarding the intended consumer” of the product. “The resulting debate has distracted attention from the overall benefits of the brand.” 
The controversy made me curious about the capacity of infants to taste and differentiate between flavors. How and when do they develop that capacity, and do flavors really have a significant impact on what they are willing to eat?
A 2001 study tested the hypothesis that experience with a flavor in amniotic fluid or breast milk modifies the infants’ acceptance and enjoyment of similarly flavored foods at weaning. Pregnant women who planned on breast-feeding their infants were randomly assigned to 1 of 3 groups, consuming various combinations of carrot juice and water for 3 consecutive weeks during the last trimester of pregnancy and then again during the first 2 months of lactation. The infants were later videotaped as they were fed cereal prepared with water or carrot juice. The results demonstrated that the infants who had exposure to the flavor of carrots in either amniotic fluid or breast milk behaved differently in response to that flavor in a food base than did non-exposed control infants. The study concluded that prenatal and early postnatal exposure to a flavor enhanced the infants’ enjoyment of that flavor in solid foods during weaning. These very early flavor experiences could provide the foundation for cultural and ethnic differences in cuisine. 
A study published in 2004 sought to determine why early experience by infants with formulas establishes subsequent preferences. Infants whose parents had chosen to formula-feed them were randomized into 1 of 4 groups by the second week of life. One group was fed a milk-based formula, whereas another was fed a particularly unpleasant tasting protein hydrolysate formula. The remaining groups were fed the unpleasant formula for 3 months and the milk-based formula for 4 months. After 7 months of exposure, infants were videotaped on 3 separate days while feeding on the different formulas. The results indicated that previous exposure to the unpleasant tasting formula significantly enhanced its subsequent acceptance, and that seven months of exposure led to greater acceptance than did 3 months. The study concluded that such early variation in feeding, including varying exposures to different flavors in amniotic fluid and mothers’ milk, may underlie individual differences in food acceptability throughout the life span. 
The responses of children to certain tastes differ markedly from adults, including heightened preferences for sweet tasting and greater rejection of bitter tasting foods. A 2005 study tested the hypothesis that genetic variations in a newly discovered taste gene, as well as cultural differences, are associated with differences in sensitivity to bitter taste and preferences for sucrose and sweet-tasting foods. The results indicated that variations in the taste receptor gene accounted for a major portion of individual differences in bitterness perception in both children and adults, as well as a portion of individual differences in preferences for sweet flavors in children but not in adults. These findings underscore the genotype effects on behavioral outcomes in children, especially as they relate to taste preferences, and that cultural forces may sometimes override the genotypic effects in adults. New knowledge about the molecular basis of food likes and dislikes in children may suggest strategies to overcome diet-induced diseases. 
A 2007 study sought to evaluate the effects of breastfeeding and dietary experiences on acceptance of a fruit and a green vegetable by 4- to 8-month-old infants. Forty-five infants, 44 percent of whom were breastfed, were assigned randomly to 1 of 2 treatment groups. One group was fed green beans, and the other was fed green beans and then peaches at the same time of day for 8 consecutive days. Acceptance of both foods, as determined by a variety of measures, was assessed before and after the home-exposure period. The study results indicated that breastfeeding confers an advantage in initial acceptance of a food, but only if mothers eat the food regularly. Once weaned, infants who receive repeated dietary exposure to a food eat more of it and may learn to like its flavor. However, because infants initially display facial expressions of distaste in response to certain flavors, caregivers may hesitate to continue offering these foods. The study concluded that parents should be encouraged to provide their infants with repeated opportunities to taste fruits and vegetables, and should focus not only on their infants’ facial expressions but also on their willingness to continue feeding. 
These findings regarding the impacts of flavor tasting by infants and children on their eating habits take on greater importance given the acknowledged overweight and obesity epidemic afflicting our children. The rapid increase in the prevalence of childhood obesity has alarmed public health agencies, health care clinicians, health care researchers, and the general public. On the basis of measured heights and weights from US children assessed approximately every 5 years, obesity prevalence has increased from roughly 5 percent in 1963 to 1970 to 17 percent in 2003 to 2004. The obesity epidemic has also disproportionately affected some racial/ethnic groups. In 2003-2004, the prevalence rates were particularly high among African American girls (24 percent) and among Mexican American boys (22 percent). Rates have also increased among Native American and Asian American youths. Generally, greater obesity prevalence among adolescents has also been associated with poverty. 
A 2009 study in fact demonstrates the likely association with rapid early weight gain and subsequent obesity. The goal of the study was to
examine the associations of weight-for-length at birth and at 6 months with obesity at 3 years of age. The study concluded that more rapid increases in weight for length in the first 6 months of life were associated with sharply increased risk of obesity at 3 years of age. Changes in weight status in infancy may thus influence risk of later obesity more than weight status at birth. 
The potential impact of early exposure by infants and toddlers to enhanced sweet flavors could thus significantly affect their life-long food predispositions and related health aspects. Some more double chocolate fudge ice cream, kids?
1. “Chocolate Toddler ‘Formula’ Pulled After Sugar Uproar”, Susan Donaldson James, ABC NEWS, June 10, 2010.
2. http://www.theatlantic.com/food/archive/2010/05/chocolate-formula-baby-doesnt-know-best/56919 . The Atlantic Monthly Group, May 19, 2010.
3. Julie A. Mennella, PhD, Coren P. Jagnow, MS, and Gary K. Beauchamp, PhD, “Prenatal and Postnatal Flavor Learning by Human Infants”, Pediatrics, Vol. 107 No. 6, June 2001.
4. Julie A. Mennella, PhD, Cara E. Griffin, and Gary K. Beauchamp, PhD, “Flavor Programming During Infancy”, Pediatrics, Vol. 113 No. 4, April 2004.
5. Julie A. Mennella, PhD, M. Yanina Pepino, PhD, and Danielle R. Reed, PhD, “Genetic and Environmental Determinants of Bitter Perception and Sweet Preferences”, Pediatrics, Vol. 115 No. 2, February 2005.
6. Catherine A. Forestell, PhD, and Julie A. Mennella, PhD, “Early Determinants of Fruit and Vegetable Acceptance”, Pediatrics, Vol. 120, No. 6, February 2007.
7. Sarah E. Barlow, MD, MPH, and the Expert Committee, “Expert Committee Recommendations Regarding the Prevention, Assessment, and Treatment of Child and Adolescent Overweight and Obesity: Summary Report”, Pediatrics, Vol. 120, Supplement 4, December 2007.
8. Elsie M. Taveras, Sheryl L. Rifas-Shiman, Mandy Belfort, Ken Kleinman, Emily Oken and Matthew Gillman, “Weight Status in the First 6 Months of Life and Obesity at 3 Years of Age”, Pediatrics, Vol. 123, Number 4, April 2009.