Helping the medicine go down

August 21, 2008
Helping the medicine go down
A cross-section of a rabbit's taste buds. Credit: Henry Gray's Anatomy of the Human Body

Getting little Doug and Debbie to take a spoonful of medicine is more than just a rite of passage for frustrated parents. Children's refusal to swallow liquid medication — and their tendency to vomit it back up — is an important public health problem that means longer or more serious illness for thousands of kids each year. In the case of HIV and AIDS pediatrics, missing a dose can be a life or death scenario.

In a report presented at the 236th National Meeting of the American Chemical Society, Julie A. Mennella, Ph.D., described how knowledge from basic research on the chemical senses explains why a child's rejection of bitter medicine and nutritious but bitter-tasting foods like spinach and other green vegetables is a reflection of their basic biology.

"Children's rejection of unpalatable medications and bitter-tasting foods is a complex product of maturing sensory systems, genetic variation, experiences and culture," says Mennella, a researcher with the Monell Chemical Senses Center in Philadelphia.

She says that children are born with a much stronger preference for sweet flavors, naturally attracting infants to mother's milk. This heightened preference for sweets continues even in their teenage years. By late adolescence, kids start to outgrow their sugary predilection.

"A better understanding of the sensory world of the child – and the scientific basis for distaste and how to ameliorate it – is a public health priority," states Mennella.

Mennella investigates the role of early experience as a child develops their unique sense of taste and smell. In the process, she ultimately hopes to find ways of creating more palatable medicines and getting kids to eat their greens more readily.

"The number one reason for non-compliance among children when taking medicine or eating vegetables is that they don't like the taste," says Mennella. "Just look at a child's face when they're eating some of these things!"

The root of this bitter problem lies in human taste buds, or taste receptors. While there are only a few receptors for sweet flavors, evolution imbued man with about 27 for bitterness. In prehistoric times, this heightened sensitivity to bitterness prevented early humans from eating toxic plants or other unsavory and possibly poisonous fare. "Bitter taste is a sensation that evolved to make you not want to ingest something," says Mennella.

Unfortunately, most of the chemicals in the pharmacist's cookbook are plant-derived and therefore inherently bitter. Some of more potent drugs like certain AIDS medications for children are even less pleasant – they often smell bad and cause mouth irritation.

For some medications, masking the bitterness is possible by encapsulating the bitter chemical in pill or tablet form, or by using special "bitter blockers" that numb the tongue's receptors. But many children have trouble swallowing pills, so liquid formulations are needed. Adding sweet tastes and flavors that children like helps the medicine go down.

Unfortunately, Mennella says its extremely difficult to mask the flavors of some of the truly bitter liquid medicines. A better understanding of bitter taste receptors may yield new ways of overcoming these unpleasant flavors.

A recent explosion in taste and smell research led to the identification of genes that code for certain bitter taste receptors. Mennella's team showed that a variation in the TAS2R38 gene is linked to the perception of bitterness in children and their parents. The researchers found that while parents with this variation were sensitive to certain bitter compounds, their children were most sensitive of all.

"It is interesting because it may suggest that children have heightened bitter sensitivity compared to adults," states Mennella.

Babies begin developing their unique tasting profile while still in the womb. What a mother eats while pregnant and nursing enhances a newborn's acceptance of foods. "We find that the more a mother eats fruits when she's pregnant, the more a child will accept fruits and vegetables," says Mennella.

The culture that a child grows up in also plays a huge role in their development of taste and smell. For evidence, Mennella points to the flavorings found in children's medicine around the world. "In England, there is a lot of lemon flavor added to children's medicine. It's a cultural phenomenon. Bubblegum and cherry are popular in the United States," according to Mennella.

When children cannot or will not take medicines in encapsulated form, methods to reduce the bitterness in liquid medications become medically significant. Failure to consume medication may do the child harm, and in some cases, may be life threatening, according to Mennella. She says that pharmaceutical companies will benefit from more basic research on bitter taste and how to ameliorate it.

"It is one of the fundamental mysteries of human behavior – why do we grow to like these foods and flavors that we initially rejected?"

Source: American Chemical Society

Explore further: Unique sensory responses to the pediatric HIV medication Kaletra

Related Stories

Unique sensory responses to the pediatric HIV medication Kaletra

December 13, 2017
Bad taste can lead to rejection of life-saving medicines by infants and young children, who require liquid formulations because they are unable to swallow pills yet lack the language to explain why something does not taste ...

Got a picky eater? How 'nature and nurture' may be influencing eating behavior in young children

October 3, 2017
For most preschool-age children, picky eating is just a normal part of growing up. But for others, behaviors such as insisting on only eating their favorite food item—think chicken nuggets at every meal—or refusing to ...

Study identifies genes responsible for diversity of human skin colors

October 12, 2017
Human populations feature a broad palette of skin tones. But until now, few genes have been shown to contribute to normal variation in skin color, and these had primarily been discovered through studies of European populations.

Interaction of genes and environment influences obesity in children

November 1, 2012
(Medical Xpress)—Neither genes nor the environment alone can predict obesity in children, but when considered together a strong relationship emerges, according to researchers at Penn State, St. Luke's Roosevelt Hospital ...

Bitter sensitive children eat more vegetables with help of dip

December 1, 2011
There's an existential crisis that often happens at dinner tables across the country: why won't kids eat their vegetables? Research has found that one reason could be a sensitivity to bitterness, fairly common among children ...

A spoonful of sugar or a bitter blocker?

February 7, 2012
Dr Hannah Newton, an historian of science with an interest in how previous generations coped with childhood illness, digs up some 17th century tips for making medicine taste better and finds evidence for common sense and ...

Recommended for you

Drug for spinal muscular atrophy prompts ethical dilemmas, bioethicists say

December 11, 2017
When the Food and Drug Administration approved the first drug for people with spinal muscular atrophy a year ago, clinicians finally had hope for improving the lives of patients with the rare debilitating muscular disease. ...

FDA's program to speed up drug approval shaved nearly a year off the process

December 7, 2017
Speeding the pace at which potentially lifesaving drugs are brought to market was a rallying cry for Donald Trump as a candidate, and is a stated priority of his Food and Drug Administration commissioner, Dr. Scott Gottlieb. ...

Dangers of commonly prescribed painkillers highlighted in study

December 6, 2017
Commonly prescribed painkillers need to be given for shorter periods of time to reduce the risk of obesity and sleep deprivation, a new study has revealed.

Viagra goes generic: Pfizer to launch own little white pill

December 6, 2017
The little blue pill that's helped millions of men in the bedroom is turning white. Drugmaker Pfizer is launching its own cheaper generic version of Viagra rather than lose most sales when the impotence pill gets its first ...

Surgery-related opioid doses can drop dramatically without affecting patients' pain

December 6, 2017
Some surgeons might be able to prescribe a third of opioid painkiller pills that they currently give patients, and not affect their level of post-surgery pain control, a new study suggests.

Four-fold jump in deaths in opioid-driven hospitalizations

December 4, 2017
People who end up in the hospital due to an opioid-related condition are four times more likely to die now than they were in 2000, according to research led by Harvard Medical School and published in the December issue of ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.