A study has indicated that reclining on your right side after taking a pill can accelerate absorption. If you lie on your right side following pill ingestion, absorption can occur approximately 13 minutes faster than when sitting with an upright upper body. This study was released by Johns Hopkins University in the U.S. in August 2022. According to the researchers, reclining on your left side is the least favorable position, as it significantly retards absorption, potentially extending the process to around 100 minutes. This is approximately 10 times longer than the approximately 10 minutes it takes when lying on your right side. I should note that this study was conducted using a simulation model of the stomach rather than real individuals.

It is indeed true that the position of the body can influence the rate at which the stomach empties its contents into the intestines. A British study in 1980 provided experimental evidence of this phenomenon. When consuming water while lying down, it was observed that the passage of water into the intestines occurred more slowly when lying on the left side and more rapidly when lying on the right side. Lying on the right side can facilitate a slightly faster emptying of the stomach compared to sitting in an upright position. This phenomenon is attributed to both the structural configuration of the stomach and the effects of gravity. The passage from the stomach to the duodenum is typically oriented towards the right, so lying on the right side allows for a more efficient flow of stomach contents into the duodenum. Given that drug absorption primarily takes place in the duodenum, a faster entry of drugs into the intestines can lead to quicker absorption into the body.

However, It's important to note that the effect of posture on gastric emptying primarily applies to calorie-free liquids, like salt water. When consuming liquids with calories, such as sugar water, the intestines can detect them and regulate the rate of gastric emptying accordingly. In the case of solid foods, the posture has minimal impact. The body's priority is to efficiently absorb the nutrients from the food, regardless of posture, and the rate of elimination is adjusted based on the nutritional composition. Therefore, if you're taking a pill after a meal, there is no need to lie on your right side to accelerate absorption, as the body's natural processes will adapt to the meal's nutritional content.

For individuals with specific medical conditions that necessitate lying down, lying on the right side may be a preferable posture after taking medication. However, for most people, there is no need to lie on the right side to expedite the medication's onset. In general, it is safer to remain in an upright, standing, or seated position after swallowing a pill. Lying down immediately after taking a pill can potentially lead to the reflux of stomach contents into the esophagus, increasing the risk of the pill causing irritation or damage to the esophageal lining. Additionally, lying down right after taking a pill without consuming an adequate amount of water might result in the pill becoming lodged in the middle of the esophagus and adhering to the esophageal lining, potentially leading to inflammation or esophageal perforation.

Because of the stomach's anatomy, some individuals assert that reclining on the left side after eating is less likely to induce reflux symptoms. Others say the opposite is true: lying on the right side accelerates stomach emptying, reducing the risk of reflux. Irrespective of the side you choose to lie on, a more prudent approach is to refrain from lying down for two to three hours following a meal. Whether it's medication or food, avoid reclining immediately after consumption.

Jeong Jae-hoon is a food writer and pharmacist. He covers a variety of subjects, including trends in food, wellness and medications. This column was originally published in Korean in Joongang Ilbo on Sept. 28, 2023. – Ed.