Conditions

18 health conditions with evidence-based supplement research

Explore health conditions with evidence-graded supplement recommendations. Each condition page ranks ingredients by the strength of clinical research supporting them.

How We Grade Evidence

Each condition page ranks supplement ingredients by the strength of clinical evidence. Here is what each grade means:

Strong Evidence

Multiple randomized controlled trials (RCTs) or meta-analyses with consistent positive results and large sample sizes.

Good Evidence

At least one RCT with mostly consistent results across studies. Evidence suggests benefit but more research may be needed.

Some Evidence

Small studies or observational data with some positive signals. Promising but insufficient for strong recommendations.

Very Early Research

In vitro studies, case reports, or pilot studies only. Early-stage research that requires clinical validation.

Acute Diarrhea

1.7 billion cases of childhood diarrhea globally per year; 525,000 deaths

Loose/watery stools Abdominal cramps Nausea +4

Antibiotic-Associated Diarrhea (AAD)

5-39% of antibiotic users; varies by antibiotic class

Loose/watery stools Abdominal cramping Low-grade fever +1

Bloating and Intestinal Gas

15-30% of general population report regular bloating; more common in IBS patients (>75%)

Abdominal fullness/distension Excessive flatulence Belching +3

Chronic Constipation

15-20% of adults globally; increases with age; more common in women

Infrequent bowel movements Hard/lumpy stools Straining +3

Clostridioides difficile Infection (CDI)

500,000 infections/year in the US; 29,000 deaths

Watery diarrhea (>=3/day) Abdominal pain Fever +2

Crohn's Disease

~0.3% in Western countries; peak onset 15-35 years

Abdominal pain (right lower quadrant) Chronic diarrhea Weight loss +4

Functional Dyspepsia

10-20% of the general population

Postprandial fullness Early satiation Epigastric pain +3

Gastroesophageal Reflux Disease (GERD)

20-30% in Western populations; 5-10% in Asia

Heartburn Regurgitation Dysphagia +5

Gut Dysbiosis

Prevalence not precisely defined; associated with Western diet, antibiotic use, and numerous chronic diseases

Bloating Gas Irregular bowel habits +5

Helicobacter pylori Infection

~50% of global population infected; higher in developing countries

Often asymptomatic Epigastric pain Nausea +3

Increased Intestinal Permeability (Leaky Gut)

Prevalence uncertain; measurable by lactulose/mannitol ratio test. Common in IBD, celiac disease, alcoholism

Often subclinical Fatigue Food sensitivities +4

Inflammatory Bowel Disease (IBD) — General

~0.5% in Western countries; rising incidence in Asia and South America

Chronic diarrhea Abdominal pain Rectal bleeding +3

Irritable Bowel Syndrome (IBS)

10-15% of global population; more common in women (2:1 ratio)

Abdominal pain/cramping Bloating Gas +5

Lactose Intolerance

65-70% of global population (varies widely by ethnicity: 5% Northern European to 90% East Asian)

Bloating Gas Abdominal cramps +2

Peptic Ulcer Disease

5-10% lifetime prevalence; declining due to H. pylori treatment

Epigastric pain (burning, gnawing) Pain worse with empty stomach (duodenal) or after meals (gastric) Nausea +2

Small Intestinal Bacterial Overgrowth (SIBO)

Estimated 6-15% in healthy population; up to 80% in IBS patients

Bloating Gas Abdominal pain +6

Traveler's Diarrhea

30-70% of travelers to high-risk areas depending on destination

Watery diarrhea Abdominal cramps Nausea +4

Ulcerative Colitis (UC)

~0.3% in Western countries; peak onset 15-30 years

Bloody diarrhea Rectal bleeding Abdominal pain (left-sided) +4

FDA Disclaimer: These statements have not been evaluated by the Food and Drug Administration. The products and information on this website are not intended to diagnose, treat, cure, or prevent any disease. The evidence grades presented are based on our analysis of published peer-reviewed research and do not constitute medical advice. Always consult your healthcare provider before starting any supplement regimen.