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Today, The Visible Embryo is linked to over 600 educational institutions and is viewed by more than 1 million visitors each month. The field of early embryology has grown to include the identification of the stem cell as not only critical to organogenesis in the embryo, but equally critical to organ function and repair in the adult human. The identification and understanding of genetic malfunction, inflammatory responses, and the progression in chronic disease, begins with a grounding in primary cellular and systemic functions manifested in the study of the early embryo.

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Pregnancy Timeline by SemestersFetal liver is producing blood cellsHead may position into pelvisBrain convolutions beginFull TermWhite fat begins to be madeWhite fat begins to be madeHead may position into pelvisImmune system beginningImmune system beginningPeriod of rapid brain growthBrain convolutions beginLungs begin to produce surfactantSensory brain waves begin to activateSensory brain waves begin to activateInner Ear Bones HardenBone marrow starts making blood cellsBone marrow starts making blood cellsBrown fat surrounds lymphatic systemFetal sexual organs visibleFinger and toe prints appearFinger and toe prints appearHeartbeat can be detectedHeartbeat can be detectedBasic Brain Structure in PlaceThe Appearance of SomitesFirst Detectable Brain WavesA Four Chambered HeartBeginning Cerebral HemispheresFemale Reproductive SystemEnd of Embryonic PeriodEnd of Embryonic PeriodFirst Thin Layer of Skin AppearsThird TrimesterSecond TrimesterFirst TrimesterFertilizationDevelopmental Timeline
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Home | Pregnancy Timeline | News Alerts |News Archive March 21, 2014


Children who were tall for their age preferred sweeter solutions,
and children with higher amounts of body fat preferred saltier soups.

WHO Child Growth Charts




Child's preference for sweet or salty linked

Biology predisposes us to like and consume calorie-rich sweet foods and sodium-rich salty foods, and this is especially true for children.

Scientists from the Monell Chemical Senses Center have found that children who prefer high levels of sweet tastes also prefer high levels of salt taste and, in general, prefer sweeter and saltier tastes than adults. Taste preferences relate not only to food but also to growth measurements — important to understand in efforts to change children's diets.

Many illnesses of modern society are related to poor food choices. As children consume far more sugar and salt than recommended, which contributes to poor health, understanding the biology behind children's preferences for these tastes is crucial to reducing their intake.

"Our research shows that liking salty and sweet tastes, in part, reflects the biology of the child. Growing children's preferences for sweet and salty tastes make them more vulnerable to our modern diet, different from our past when salt and sugar were rare and expensive commodities."

Julie Mennella, PhD, biopsychologist at Monell, and lead author.

In the study, published online at PLOS ONE, Mennella and colleagues tested 108 children between 5 and 10 years old, and their mothers, for salt and sweet taste preferences.

The method used for both were tasting broth and crackers that varied in salt content, and sugar water and jellies that varied in sugar content. Mennella and her colleagues at Monel developed a procedure to determine taste preferences, even in very young children. First, they have adults and children compare two different levels of a taste, pick their favorite, and then compare that favorite with another, again and again until the most favorite taste is identified. Very much like an optomitrist uses differences between lenses to capture the best suited lense combination to improve your vision.

Researchers also estimated daily sodium, calorie, and added sugar intake from foods eaten by their subjects in the past 24 hours. Finally, adults and children gave a saliva sample, which was typed for a sweet receptor gene, and a urine sample to measure levels of Ntx, a marker for bone growth. Weight, height, and percent body fat were measured for all.

Analyses of all the data showed that not only were sweet and salty preferences correlated in children — and higher overall than those in adults — but also children's taste preferences related to their growth and development measurements.

Children who were tall for their age preferred sweeter solutions, and children with higher amounts of body fat preferred saltier soups.

There was also some indication that higher sweet liking related to spurts in bone growth, but that result needs confirmation in a larger group of children.

Sweet and salty preferences were correlated in adults as well. In adults — but not in children — a sweet receptor genotype was related to a preference for sweetness. "There are inborn genetic preferences that affect the liking of sweet by adults," says collaborator Danielle Reed, PhD, "but for children, other factors – perhaps the current state of growth – are stronger influences than genetics."

Both children and adults who preferred higher levels of salt in food also reported consuming more dietary salt in the past 24 hours, but no such relationship was found between sweet preferences and sugar intake. This difference may reflect parents exerting control over their children's diet more for added sugar than for added salt. Or it could reflect an increased use of artificial sweeteners in foods geared towards children — in other words, the sweetness of some foods doesn't reflect their sugar content.

Current intake of sodium and added sugars among US children is in excess of recommendations.

For almost all 2- to 8-year-olds, added sugars account for more than half of their discretionary calories (130 total discretionary calories are allowed for children of this age).

For 4- to 13-year-olds, sodium intake is more than twice adequate levels (1200-1500 mg/day is allowed for children of this age).

The children studied, two-thirds of whom were overweight or obese, also consumed twice adequate levels of sodium, and their added sugar intake averaged almost 20 teaspoons, or 300 calories, each day.

Guidelines from leading authorities, including the World Health Organization, American Heart Association, U.S. Department of Agriculture, and Institute of Medicine, recommend significantly cutting sugar and salt intake for children, but this can be very difficult.

Commenting on the implications of her research, as lead author Mennella notes: "The present findings reveal that the struggle parents have in modifying their children's diets to comply with recommendations appears to have a biological basis."

Understanding the basic biology that drives the desire for sweet and salty tastes in children illustrates their vulnerability to the current food environment. But on a positive note, Mennella observed, "it also paves the way toward developing more insightful and informed strategies for promoting healthy eating that meet the particular needs of growing children."

The present study aimed to determine if salty and sweet taste preferences in children are related to each other, to markers of growth, and to genetic differences.

Children preferred higher concentrations of salt in broth and sucrose in water than did adults, and for both groups, salty and sweet taste preferences were significantly and positively correlated. In children, preference measures were related to reported intake of sodium but not of added sugars. Children who were tall for their age preferred sweeter solutions than did those that were shorter and percent body fat was correlated with salt preference. In mothers but not in children, sweet preference correlated with TAS1R3 genotype.

Conclusions and Relevance
For children, sweet and salty taste preferences were positively correlated and related to some aspects of real-world food intake. Complying with recommendations to reduce added sugars and salt may be more difficult for some children, which emphasizes the need for new strategies to improve children's diets.

Also contributing to the study, which can be accessed at http://dx.plos.org/10.1371/journal.pone.0092201, were Susana Finkbeiner, Sarah V. Lipchock, and Liang-Dar Hwang, all from Monell. Research reported in the publication was supported by grants from The Eunice Shriver National Institute of Child Health and Human Development (R01HD37119), the National Institute on Deafness and Other Communication Disorders (R01DC011278, P30DC011735, T32DC000014) and the National Center for Research Resources (UL1RR024134), all of the National Institutes of Health. Other support came from the Pennsylvania Tobacco Research Settlement Fund, the Pennsylvania Department of Health. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health or the Pennsylvania Department of Health.

The Monell Chemical Senses Center is an independent nonprofit basic research institute based in Philadelphia, Pennsylvania. For 46 years, Monell has advanced scientific understanding of the mechanisms and functions of taste and smell to benefit human health and well-being. Using an interdisciplinary approach, scientists collaborate in the programmatic areas of sensation and perception; neuroscience and molecular biology; environmental and occupational health; nutrition and appetite; health and well-being; development, aging, and regeneration; and chemical ecology and communication. For more information about Monell, visit http://www.monell.org.