Question explored with the scientific record
What causes bloated belly in 64 year old men and what are the most effective treatments ?
The short version: bloating in a 64-year-old man is usually gut or prostate related, and the best treatments target the cause, not the symptom.
The retrieved evidence splits into two camps. One is prostate: an enlarged prostate can press on the bowel and cause a swollen feeling, and it is common at this age [2]. The other is gut: irritable bowel syndrome, constipation, and slow bowel transit all cause bloating directly [5][6][8][11]. A third cause, worth naming even though these records do not cover it, is medication side effects; metformin, for example, causes bloating in about 35 in 100 people who take it [10].
For gut-related bloating, the strongest evidence points to diet and probiotics. A low FODMAP diet improved bloating in about 82 in 100 people in one trial, versus 49 in 100 on standard advice [8]. Probiotics also help: one strain, Lactobacillus plantarum 299v, cut bloating significantly versus placebo [6], and a 2025 multi-strain study found bloating scores dropped from about 7 to 3.4 out of 10 over a year [7]. The SSRI citalopram improved bloating in IBS patients in a randomized crossover trial, though the effect may partly be carryover [5]. The antibiotic rifaximin helped bloating at 12 weeks, but the improvement was not statistically significant and side effects were more common [9].
For prostate-related bloating, the evidence is thinner. Alpha-blockers like tamsulosin improve urinary symptoms [3], but no retrieved study measured whether they relieve belly bloating. Saw palmetto added to tamsulosin made no difference [1]. Pumpkin seed improved urinary symptoms modestly in one trial [4].
The evidence does not include a head-to-head comparison of gut versus prostate treatments for bloating, and no long-term safety data on the drug options here. Start with the low FODMAP diet and a probiotic; if urinary symptoms dominate, get the prostate checked.
My call: treat the gut first with diet and probiotics, and see a doctor to rule out prostate and medication causes. Confidence: moderate.
Sources used 11
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Does the addition of Serenoa repens to tamsulosin improve its therapeutical efficacy in benign prostatic hyperplasia?
This study investigates the efficacy and tolerability of a combination therapy of tamsulosin and Serenoa repens compared to each treatment alone in patients with benign prostatic hyperplasia, finding no significant differences in outcomes among the groups.
DOI: 10.2298/vsp110620029a -
Association between prostatic resistive index and cardiovascular risk factors in patients with benign prostatic hyperplasia
This study investigates the relationship between prostatic resistive index and cardiovascular risk factors in patients with benign prostatic hyperplasia, finding significant associations with metabolic syndrome and smoking.
DOI: 10.1016/j.kjms.2014.12.008 -
Comparison of prazosin, terazosin and tamsulosin in the treatment of symptomatic benign prostatic hyperplasia: A short‐term open, randomized multicenter study
This study compares the short-term efficacy and safety of prazosin, terazosin, and tamsulosin in treating lower urinary tract symptoms associated with benign prostatic hyperplasia, finding that terazosin is significantly more effective in improving symptoms compared to tamsulosi…
DOI: 10.1046/j.1442-2042.2000.00175.x -
Effects of Pumpkin Seed in Men with Lower Urinary Tract Symptoms due to Benign Prostatic Hyperplasia in the One-Year, Randomized, Placebo-Controlled GRANU Study
The GRANU study demonstrated that treatment with pumpkin seed significantly improved lower urinary tract symptoms in men with benign prostatic hyperplasia over a one-year period compared to placebo.
DOI: 10.1159/000362903 -
A controlled crossover study of the selective serotonin reuptake inhibitor citalopram in irritable bowel syndrome
A randomized, double-blind, placebo-controlled crossover trial found that the SSRI citalopram significantly improves several irritable bowel syndrome (IBS) symptoms—abdominal pain, bloating, and impact on daily life—over six weeks compared with placebo, with effects largely inde…
DOI: 10.1136/gut.2005.077503 -
Clinical trial: Lactobacillus plantarum 299v (DSM 9843) improves symptoms of irritable bowel syndrome
This clinical trial demonstrates that Lactobacillus plantarum 299v (DSM 9843) significantly improves symptoms of irritable bowel syndrome, particularly abdominal pain and bloating, in patients meeting the Rome III criteria.
DOI: 10.3748/wjg.v18.i30.4012 -
Impact of Probiotics on Gut Microbiota and Symptoms in Patients with Irritable Bowel Syndrome
Long-term use of multi-strain probiotics in adults with IBS significantly improved global symptoms, abdominal pain, bloating, and IBS-related quality of life, while positively reshaping gut microbiota over 12 months in a real-world, single-center cohort.
DOI: 10.61919/jhrr.v5i10.1886 -
Does a low FODMAP diet help IBS?
Short-term, small trials suggest a low FODMAP diet can improve IBS symptoms, but long-term efficacy and safety remain uncertain.
DOI: 10.1136/dtb.2015.8.0346 -
Efficacy of Rifaximin in Diarrhoea Predominant Irritable Bowel Syndrome: A Placebo Controlled Clinical Trial
In patients with irritable bowel syndrome, rifaximin was more effective than placebo for abdominal pain, bloating, and dissatisfaction with bowel movement at 12 weeks, although the 12-week improvement was not statistically significant and adverse events were more common.
DOI: 10.3329/medtoday.v35i1.64940 -
Impact of Metformin-Induced Gastrointestinal Symptoms on Quality of Life and Adherence in Patients with Type 2 Diabetes
This study investigates the impact of metformin-induced gastrointestinal symptoms on health-related quality of life and medication adherence in patients with type 2 diabetes, revealing that such symptoms significantly lower quality of life and may lead to reduced adherence to tr…
DOI: 10.3810/pgm.2010.03.2128 -
Slow transit syndrome and mechanisms of constipation (lazy bowel syndrome): current understanding of causes, diagnosis, and consequences
This narrative review summarizes slow transit syndrome and functional constipation (lazy bowel syndrome) as a multifactorial motility disorder, outlining Rome IV criteria, radiopaque marker diagnosis, and stepwise therapy from diet and lifestyle to osmotic laxatives and prucalop…
DOI: 10.51793/os.2025.28.12.007