Pill-Taking Posture

It’s a wild guess, but I bet you didn’t think about your posture the last time you took a pill. Well, maybe you should have. Posture has a significant effect on how quickly our bodies absorb a pill’s contents. 

Welcome back. Popping a pill is the most common choice for drug administration, offering convenience, low cost and high patient compliance.

Most pills don’t start working until they’ve dissolved and passed through the stomach into the duodenum, the first part of the small intestine. The closer a swallowed pill lands to the last part of the stomach, the faster it starts to dissolve and empty its contents into the duodenum.

Simple stomach diagram (from pharmacyimages.blogspot.com/2020/09/Simplestomachdiagram-Stomachstructure-stomachanatomy.html).

Posture is critical If you’d like to get the pill down there fast. How critical? That was investigated by a team of researchers affiliated with Johns Hopkins University.

“StomachSim”
The researchers used in-vivo imaging data available from the Virtual Population library to construct StomachSim, an anatomical model of a human stomach.

Using StomachSim, they observed and quantified pill dissolution, mixing in the stomach, and gastric emptying of the dissolved active pharmaceutical ingredient into the duodenum, modulated by gastric motility, physical properties of the pill and stomach contents.

StomachSim also allowed tracing the trajectory of the pill motion, which is induced by a complex interplay of stomach motility, gastric fluid dynamics, gravity and, yes, posture.

Testing Postures
To compare the effect of posture on drug availability, they considered four different postures keeping other parameters constant: upright, leaning right, leaning left and leaning back.

Rather than rotate the stomach with posture, they changed the direction of the gravitational force. Because the pill is denser than the dissolution medium, the effect of direction significantly affects pill motion and thus the rate of dissolution and pharmaceutical ingredient release. 

Diagram showing original position and different relative positions of the stomach with respect to the direction of gravity (Fig. 4 from aip.scitation.org/doi/full/10.1063/5.0096877).

Swallowing pills while lying on the right side was by far the best posture, sending pills into the deepest part of the stomach 2.3 times faster than even an upright posture. Lying on the left side was the worst. A pill that needs 10 minutes to dissolve when lying on the right side, could take 23 minutes to dissolve in an upright posture and over 100 minutes when lying on the left side.

Volumetric distributions of dissolved active pharmaceutical ingredients in the stomach and duodenum regions for different postures at three time periods (t, seconds)(from Fig. 5 of aip.scitation.org/doi/full/10.1063/5.0096877).

The team also considered pill dissolution by stomachs that aren’t functioning at full strength due to gastroparesis caused by diseases such as diabetes and Parkinson’s Syndrome. The impact of stomach disease on drug dissolution was similar to that of posture.

Wrap Up
The findings have important implications when accounting for posture in clinical studies of drug dissolution and to consider posture as a factor modulating the release of a pharmaceutical concentration. This is particularly relevant for narrow absorption window drugs, absorbed mainly in the upper part of the gastrointestinal tract. It also has important implications for the rate of drug absorption by bedridden patients or elderly adults.

Next on the research team’s agenda are how changes in the biomechanics of the stomach affect drug absorption, how food is processed in the stomach and the effect of posture and gastroparesis on food digestion. Stay tuned and thanks for stopping by.

P.S.
Study of effects of posture in Physics of Fluids journal: aip.scitation.org/doi/full/10.1063/5.0096877
Article on study on EurekAlert! website: www.eurekalert.org/news-releases/961853
Virtual Population library: www.semanticscholar.org/paper/Development-of-a-new-generation-of-high-resolution-Gosselin-Neufeld/d8b3865ca3ef524f9177f15e73b5747365ab1141

Head Tilt for Dominance

Welcome back. Years ago, in a blog post that warned scientists to do a better job at garnering the public’s trust, I wrote:

All this time I thought people didn’t trust science and scientists because of lobbyists, biased or clueless media, politics and contrarians. Nope. It’s because scientists are cold fish…scientists may be respected by the public but not necessarily trusted; and it’s all because scientists are not perceived as warm (from Trust a Scientist).

Seeking ways to assist not only warn scientists, I then blogged about an older study on facial evaluation; in essence, certain facial features tend to convey trust. I described how those researchers developed models for representing facial trustworthiness and dominance (from Trust a Scientist Addendum).

Judgments of 300 emotionally neutral faces found that certain facial features tend to convey trust (from www.pnas.org/content/105/32/11087.full).

I wasn’t suggesting plastic surgery or other such tweaks. I just thought scientists might use a mirror to practice certain facial expressions or use makeup to raise their inner eyebrows. Or maybe not.

From Trust to Dominance
Today, instead of trust, I’m going for dominance. And this pertains to everyone, even those who failed science in school.

Researchers from the University of British Columbia demonstrated that the perception of dominance need not focus on facial evaluation. In a series of tests involving over 1,500 participants, they found head movements--tilting one’s head downward with eyes looking forward--increased the perception of dominance.

Tests of Perceived Dominance
For one online test with 101 participants, the researchers generated avatars with neutral facial expressions in one of three head positions, tilted up or down 10 degrees or looking straight ahead.

The participants judged the dominance of each avatar image, rating their agreement with statements including “This person would enjoy having control over others” and “This person would be willing to use aggressive tactics to get their way.”

Avatars with downward head tilt were rated most dominant.

In a similar online test with images of humans instead of avatars, 570 participants had the same results. An important additional finding from that test was that the part of the face around the eyes and eyebrows was both necessary and sufficient to produce the dominance effect. 

Images of avatars (top row) and humans (other rows) with neutral facial expressions and heads looking straight ahead (center images) or tilted 10 degrees (from journals.sagepub.com/doi/abs/10.1177/0956797619838762).

Other tests showed that the angle of the eyebrows drove the effect. Tilting the head downward can have the same effect on perception as lowering one’s eyebrows. The eyebrows appear more “V shaped,” even if they have not moved from a neutral position.

The researchers point out that “Brow Lowerer” is Upper Face Action Unit 4 in the Facial Action Coding System, which I blogged about in Facial Expressions Addendum. 

Upper Face Action Units (AU) from the Facial Action Coding System for human expressions (from what-when-how.com/face-recognition/facial-expression-recognition-face-recognition-techniques-part-1/).

Wrap Up
Clearly, social judgments about faces are derived not only from facial shape and musculature but also from head movements.

The researchers are continuing to pursue the topic, exploring whether the effects might extend beyond perception of dominance to how we interpret facial expressions of emotion. They’re hoping to define practical implications for our everyday social interactions.

Appearing dominant is a good start, at least for some of us. Thanks for stopping by.

P.S.
Study of head tilt perception of dominance in Psychological Science journal: journals.sagepub.com/doi/abs/10.1177/0956797619838762
News release on study from Assoc. for Psychological Science: www.psychologicalscience.org/news/releases/head-tilt-dominance.html

Posture Affects Taste

Welcome back. Do you want to eat less? Eat standing up. Do you have guests for dinner and the food didn’t turn out right? Have them eat standing up. Do your kids balk at eating veggies? Let them eat the veggies standing up. 

Standing while eating at home
(from recipes.timesofindia.com).

What’s all this standing to eat about? It turns out that posture, specifically sitting versus standing, affects how the taste of food is perceived. At least that’s what researchers from the University of South Florida and Louisiana State University found.

Why Does Posture Matter?
We normally evaluate food with our visual, olfactory, gustatory, haptic and auditory senses. To these five senses, the researchers added a sixth. They demonstrated that our vestibular sense, the one responsible for balance, posture and spatial orientation, also plays a major role.

Standing causes physical stress and subdues taste buds. As gravity pulls blood lower in the body, the heart works harder to pump blood upward. This stimulates the hypothalamic-pituitary-adrenal axis, a major neuroendocrine system, and produces increased concentrations of the stress hormone cortisol. These reactions reduce sensory sensitivity, impacting taste evaluation, food temperature perception and overall consumption.

Standing versus Sitting Tests
The researchers conducted a series of tests to confirm the importance of the vestibular sense.

In one, they had 350 participants rate the taste of pita chips. Participants who were standing gave a lower rating than participants who sat in a padded chair.

In a second test, they had participants eat bite-size brownies, baked locally and considered pleasant tasting. Participants who ate the brownies while sitting rated them most delicious. The baker then made a new batch, adding extra salt to make the taste less pleasant. Participants who ate the saltier brownies while standing didn’t notice. They rated the brownies more favorable than participants who ate the brownies while sitting.

In another test, participants had to sample a fruit snack while carrying a shopping bag. The intent was to simulate what occurs when a shopper tries samples at a grocery store or in a food court. Sitting and standing participants both found the added weight made the food taste worse.

To test the effect of posture on food temperature perception and consumption, participants drank hot coffee. Those sitting found the coffee to be hotter than did those standing, yet they drank more, which suggests the stress of standing suppressed their appetite. Standing rather than sitting while eating food also leads to lesser amounts consumed.

Standing while eating at a restaurant (from
ny.eater.com/2017/2/20/14570352/ikinari-steak-nyc-opens).

Wrap Up
The researchers are affiliated with university marketing departments. They judge that their study findings have conceptual implications for expanding sensory marketing as well as the effects of sensory systems on food taste perceptions.

Of particular interest are the practical implications of standing while eating for the environmental design of restaurants, retail and other food services. Of course, one could also stand just to eat less. Thanks for stopping by.

P.S.
Study of vestibular sensations and food taste in Journal of Consumer Research: academic.oup.com/jcr/advance-article-abstract/doi/10.1093/jcr/ucz018/5488173
Article on study on ScienceDaily website: www.sciencedaily.com/releases/2019/06/190607091031.htm
Wikipedia description of hypothalamic–pituitary–adrenal axis: en.wikipedia.org/wiki/Hypothalamic%E2%80%93pituitary%E2%80%93adrenal_axis