A small Japanese study suggests that drinking a diluted vinegar beverage daily may help people with mild constipation have more frequent bowel movements, though researchers and outside experts caution the findings are preliminary and shouldn’t be mistaken for a green light on apple cider vinegar shots.
Constipation is generally defined as having fewer than three bowel movements a week, according to the National Institutes of Health, often with stools that are hard, dry or difficult to pass. The NIH recommends adults get between 22 and 34 grams of fiber daily, but federal dietary guidelines show fewer than 10% of women and about 3% of men actually hit that target. Left untreated, chronic constipation can lead to hemorrhoids, anal fissures and, in severe cases, fecal impaction requiring emergency care.
The usual first-line advice is to boost fiber through legumes, whole grains, fruits, vegetables, nuts and seeds, along with over-the-counter medications if needed. The new study, published in the journal Scientific Reports, looked at whether vinegar itself might offer additional benefit.
What the study tested
Researchers noted that eating vinegar-based dishes had previously been linked to better bowel habits, but it wasn’t clear how much vinegar, or its active ingredient acetic acid, was actually needed. To find out, they ran a randomized controlled trial with 44 healthy Japanese adults ages 20 to 69 who reported having three to five bowel movements a week — classified as mild constipation.
Participants were randomly assigned to drink either a vinegar beverage or a placebo at breakfast for four weeks. The vinegar drink combined brewed vinegar with water to deliver 750 milligrams of acetic acid per 200-milliliter serving. The placebo used citric acid to mimic the tart taste, and both drinks were sweetened with sucralose and flavored with apple so participants couldn’t tell them apart.
What the researchers found
In the first week, the vinegar group showed trends toward improvement in bowel-movement frequency, number of defecation days and stool volume compared with the placebo group. By week four, the vinegar group’s defecation frequency was significantly higher than the placebo group’s — about 1.2 more bowel movements per week.
