Omeprazole and body weight changes
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Omeprazole and Body Weight Changes: Animal Studies
Suppression of Body Weight Gain in Rats and Chickens
Multiple studies in animal models show that long-term omeprazole treatment can suppress body weight gain. In young male rats, extended omeprazole administration led to reduced body weight gain without altering body composition (fat and lean mass) or the lengths of the spine and femur. This treatment also resulted in reduced bone mineral content and density, suggesting an impact on overall growth and bone health, likely linked to changes in gastric hormones such as gastrin and histamine1. Similarly, in chickens, omeprazole treatment reduced body weight gain and bone density, while increasing the size and activity of the parathyroid glands. These effects occurred without changes in blood calcium levels, indicating a specific impact on growth and bone metabolism rather than general nutritional status23.
Mechanisms: Hormonal and Endocrine Changes
The suppression of weight gain in these animal studies is associated with omeprazole-induced hypergastrinemia, which leads to changes in the stomach’s endocrine cell populations and increased parathyroid hormone gene expression. These hormonal shifts may disrupt normal growth signals and bone mineralization, contributing to the observed reductions in body weight and bone mass123. Additionally, omeprazole-induced changes in inflammatory markers, such as increased IL-1β, may also play a role in reduced weight gain, as seen in mice7.
Genetic and Sex Differences in Mice
The effect of omeprazole on body weight can vary depending on genetic background and sex. In mice fed a high-calorie diet, omeprazole’s impact on weight gain was influenced by both factors. Some male mice on a high-energy diet with omeprazole gained significantly more weight than females, while other strains showed no difference. These findings suggest that the response to omeprazole is not uniform and may depend on individual genetic and biological factors5.
Omeprazole and Body Weight in Humans: Indirect Evidence
Obesity, Bariatric Surgery, and Omeprazole Pharmacokinetics
While direct evidence of omeprazole causing weight changes in humans is limited, several studies have examined how body weight and obesity affect omeprazole’s pharmacokinetics. Obese individuals have altered omeprazole metabolism, with lower drug clearance compared to normal-weight individuals, potentially leading to higher drug exposure over time69. After weight loss surgery (such as Roux-en-Y gastric bypass), omeprazole bioavailability and metabolism tend to return to levels similar to those in non-obese individuals49. These pharmacokinetic changes do not directly address weight gain or loss but highlight that body weight can influence how the body processes omeprazole.
Summary of Findings
- In animal studies, long-term omeprazole use suppresses body weight gain and bone mineralization, likely through hormonal and endocrine changes1237.
- The effect of omeprazole on weight gain in mice depends on genetic background and sex, with some groups experiencing increased weight gain on high-calorie diets with omeprazole5.
- In humans, there is no strong evidence that omeprazole directly causes weight changes, but obesity alters omeprazole metabolism, and these changes normalize after significant weight loss469.
Conclusion
Current research in animals suggests that omeprazole can suppress body weight gain and affect bone health, mainly through hormonal changes. In humans, while omeprazole’s metabolism is influenced by body weight, there is no clear evidence that it directly causes weight gain or loss. More research is needed to determine if these animal findings translate to significant effects on body weight in people.
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