Caffeine’s Sweet Spot for Gut Health May Curb Chronic Constipation

Moderate caffeine intake linked to better bowel function, but high levels may backfire except in older adults

A new study reveals a U-shaped relationship between caffeine intake and chronic constipation: consuming less than 204 mg per day may ease constipation, while higher doses increase the risk. Interestingly, in adults over 60, high caffeine consumption appears to reduce constipation risk, suggesting age-specific guidance for caffeine use may benefit bowel health.

Study Details

Caffeine is a widely consumed stimulant, often praised for its alertness-boosting properties, but its effects on the gastrointestinal system remain less understood. This recent study, conducted by researchers from the Xiyuan Hospital of the China Academy of Chinese Medical Sciences, analyzed U.S. national dietary and health data to investigate how caffeine consumption impacts bowel habits and the risk of inflammatory bowel disease (IBD).

Using data from the National Health and Nutrition Examination Survey (NHANES) between 2005 and 2010, researchers examined the association between caffeine intake sourced from coffee, tea, and energy drinks and chronic constipation, diarrhea, and IBD in a large adult population.

Methodology

The study included 12,759 adults, categorized by bowel function: 10,785 with normal bowel habits, 988 with chronic diarrhea, and 986 with chronic constipation. Dietary caffeine intake was assessed via two 24-hour dietary recall interviews. Bowel function was determined using the Bristol Stool Form Scale, and IBD status was self-reported based on physician diagnoses of ulcerative colitis or Crohn’s disease.

Key Findings

• Caffeine and Constipation:
  A U-shaped relationship was observed. Below 204 mg/day, every additional 100 mg of caffeine reduced constipation risk by 18%. Above that threshold, each 100 mg increase raised constipation risk by 6%.

• Age-Specific Effects:
  Among adults aged 60 and older, high caffeine intake consistently reduced the risk of chronic constipation, with no evidence of a U-shaped effect.

• Caffeine and Diarrhea:
  Among high-income participants, higher caffeine intake was linked to a 12% increased risk of chronic diarrhea for every 100 mg consumed.

• No Link to IBD:
  No significant association was found between caffeine intake and risk of inflammatory bowel disease.

Implications for Practice

For clinicians and patients managing bowel health, caffeine may offer a low-cost, accessible intervention when dosed carefully. This study supports moderate caffeine use under 204 mg/day, roughly equivalent to two 8-ounce cups of brewed coffee as beneficial for relieving constipation, particularly in younger adults.

In older populations, higher caffeine intake may be more favorable and less likely to produce adverse bowel effects. However, individual responses may vary, and factors such as income, diet, and underlying conditions should be considered when advising patients.

As the authors suggest, personalized caffeine strategies based on bowel symptoms and age may optimize benefits while minimizing gastrointestinal side effects.