Cystic fibrosis
Supplements studied for cystic fibrosis.
Overview
Most reviewed supplements show low trust and little benefit for cystic fibrosis. N-Acetyl Cysteine (NAC) (WA 52; low effect size, high evidence, medium trust) usually did not improve lung function, though one early high-dose study suggested possible airway inflammation reduction. Algal Oil rich in DHA (WA 36) did not improve lung function, infections, or flare-ups in children and young adults.
Taurine may reduce steatorrhea in some children but did not clearly improve growth or lung health. Vitamin K effects on clotting remain unclear despite low levels being common. Probiotics have insufficient evidence. The heatmap and evidence reviews below cover all eight supplements.
Effect graph
Relevant supplements
Relevant supplements sorted by DEX Score.
| Vitamin K | ★★★★★ | Low |
| Taurine | ★★★★★ | Low |
| N-Acetyl Cysteine (NAC) | ★★★★★ | Low |
| Vitamin D | ★★★★★ | Low |
| Inulin | ★★★★★ | Low |
| Probiotics | ★★★★★ | Very Low / None |
| Algal Oil | ★★★★★ | Very Low / None |
| Saccharomyces boulardii | ★★★★★ | Very Low / None |
Studies
Find individual evidence reviews for supplements sorted by DEX Score.
8 supplements for and rated at least stars. All purchase bands. No minimum star filter.
N-Acetyl Cysteine (NAC)View supplement →
Reconsider purchase·★★★★★
How we scored this▸
- Taking N-acetylcysteine by mouth or inhalation does not usually improve lung function in people with cystic fibrosis.
- One early study suggests that a high dose might reduce inflammation in the airways, but more research is needed.
Browse 5 studies·1 meta-analysis
MetaNebulized and oral thiol derivatives for pulmonary disease in cystic fibrosis2013n=255
A meta-analysis found nebulized and oral thiol agents including NAC improved pulmonary function in cystic fibrosis, with modest effect sizes.
- Effect
- Benefit
- Participants
- 255
Controlled trialHigh-dose oral N-acetylcysteine, a glutathione prodrug, modulates inflammation in cystic fibrosis2006
A 4-week controlled trial found high-dose oral NAC (1 g three times daily) modulated airway inflammation in cystic fibrosis patients.
- Effect
- Benefit
- Duration
- 4 weeks
- Dose
- 1.0 g 3×/day
- Population
- Cystic fibrosis patients
MetaSystematic review of N-acetylcysteine in cystic fibrosis1999n=181
A systematic review of 181 cystic fibrosis patients found NAC improved mucus clearance but did not consistently improve lung function.
- Effect
- Benefit
- Duration
- ≤3 months
- Population
- ALL patients
- Participants
- 181
Controlled trialThe clinical effect and the effect on the ciliary motility of oral N-acetylcysteine in patients with cystic fibrosis and primary ciliary dyskinesia1988
A controlled trial found oral NAC improved clinical symptoms and ciliary motility in cystic fibrosis patients versus control.
- Effect
- Benefit
- Dose
- 200 mg/day
- Population
- Cystic fibrosis patients
[Experiences with oral N-acetyl-cysteine treatment in children suffering from cystic fibrosis (author's transl)]1980
A clinical report found oral NAC treatment over 6 months improved respiratory status in children with cystic fibrosis.
- Effect
- Benefit
- Duration
- 6 months
- Population
- Children/adolescents
TaurineView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- Taurine supplements may help reduce fat in the stool (steatorrhea) in children with cystic fibrosis, but they do not seem to improve growth, lung health, or overall nutrition.
- Taking taurine along with usual liver medications does not appear to provide extra benefits for liver function or nutrient absorption in these patients.
Browse 7 studies
RCTUrsodeoxycholic acid for liver disease associated with cystic fibrosis: a double-blind multicenter trial. The Italian Group for the Study of Ursodeoxycholic Acid in Cystic Fibrosis1996n=39
In cystic fibrosis patients with liver disease, ursodeoxycholic acid improved liver enzymes and clinical liver status versus placebo in this double-blind multicenter trial.
- Effect
- Benefit
- Duration
- 1 year
- Dose
- 15 mg/kg
- Population
- Men
- Participants
- 39
- Avg age
- ~14
RCTEffect of a medium dose of ursodeoxycholic acid with or without taurine supplementation on the nutritional status of patients with cystic fibrosis: a randomized, placebo-controlled, crossover trial1994n=51
In young adults with cystic fibrosis and cholestasis, ursodeoxycholic acid with or without taurine improved liver tests and nutritional status versus baseline.
- Effect
- Benefit
- Duration
- 6 months
- Dose
- 10–12 mg/kg
- Population
- Young adults
- Participants
- 51
- Ages
- 8–32
RCTTaurine decreases fecal fatty acid and sterol excretion in cystic fibrosis. A randomized double-blind trial1991n=13
In 13 children with cystic fibrosis and steatorrhea, taurine 30 mg/kg/day for 8 weeks reduced fecal fat and sterol excretion versus placebo.
- Effect
- Benefit
- Duration
- 8 weeks
- Dose
- 30 mg/kg
- Population
- Children/adolescents
- Participants
- 13
Controlled trialProtein metabolism in cystic fibrosis: responses to malnutrition and taurine supplementation1987n=13
In cystic fibrosis patients, taurine supplementation did not clearly normalize increased protein breakdown associated with malnutrition in this metabolic study.
- Effect
- No Benefit
- Population
- Children/adolescents
- Participants
- 13
RCTTaurine improves the absorption of a fat meal in patients with cystic fibrosis1987
In 5 cystic fibrosis patients, taurine 30 mg/kg/day for 1 week improved fat meal absorption versus placebo in this crossover study.
- Effect
- Benefit
- Duration
- 1 week
- Dose
- 30 mg/kg
- Population
- Patients with cystic fibrosis
- Avg age
- 12.1±2.6
Controlled trialTaurine supplementation, fat absorption, and growth in cystic fibrosis1987n=20
In 21 children with cystic fibrosis over 12 months, taurine 30–40 mg/kg/day did not significantly change coefficient of fat absorption versus placebo.
- Effect
- No Benefit
- Duration
- 12 months
- Dose
- 40 mg/kg
- Population
- Children/adolescents
- Participants
- 20
Controlled trialEffect of taurine supplements on fat absorption in cystic fibrosis1985n=19
In 22 CF children with steatorrhea, taurine 30 mg/kg/day for separate periods did not significantly improve fat absorption versus placebo.
- Effect
- No Benefit
- Duration
- 6 months
- Dose
- 30 mg/kg
- Population
- Children/adolescents
- Participants
- 19
Vitamin KView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- It is not clear if taking vitamin K by mouth helps with blood clotting problems in people with cystic fibrosis.
- Many people with cystic fibrosis, especially those with trouble digesting fat, have low vitamin K levels.
- Early studies show that taking 1 to 5 mg of vitamin K daily for one month might lower a marker linked to bone fracture risk.
- Another small study found that taking vitamins A, D, E, and K together for about 8.5 months reduced abnormal blood clotting markers in these patients.
Browse 4 studies
Systematic reviewVitamin K supplementation for cystic fibrosis2020n=38
In a systematic review of 38 participants, for 12 months, the trial did report that there did not appear to be any difference in serum undercarboxylated osteocalcin or vitamin K levels (very low-quality evidence).
- Effect
- Benefit
- Duration
- 12 months
- Dose
- 10 mg/day
- Population
- Cystic fibrosis patients
- Participants
- 38
- Ages
- 8–46
Suboptimal vitamin K status despite supplementation in children and young adults with cystic fibrosis2010n=60
In a study of 60 participants, these data suggest that higher doses of vitamin K are required.
- Population
- Healthy adults
- Participants
- 60
- Ages
- 8–25
Treatment of vitamin K deficiency in cystic fibrosis: Effectiveness of a daily fat-soluble vitamin combination2001n=72
In a study of 72 participants, 0.18 mg/day, an oral fat-soluble vitamin combination with a modest amount of vitamin K can, as a daily supplement, improve the PIVKA-II levels in patients with PI and CF.
- Effect
- Benefit
- Dose
- 0.18 mg/day
- Population
- Liver disease patients
- Participants
- 72
- Ages
- 0.6–46
Prevalence of vitamin K deficiency in cystic fibrosis1999n=62
In a study of 62 participants, vitamin K deficiency is common in unsupplemented patients with CF and pancreatic insufficiency and routine supplementation should be considered in all of these patients.
- Population
- Liver disease patients
- Participants
- 62
- Ages
- 1–45
InulinView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- Early research on cystic fibrosis is limited.
- A 12-week double-blind, placebo-controlled pilot trial in adults with cystic fibrosis showing that the combination of high-dose vitamin D3 and inulin was well tolerated and produced greater changes in both gut and airway microbiome diversity and composition than either intervention alone or placebo.
- More studies are needed before any benefit can be considered reliable.
Browse 1 study
RCTImpact of high-dose cholecalciferol (vitamin D3) and inulin prebiotic on intestinal and airway microbiota in adults with cystic fibrosis: A 2 × 2 randomized, placebo-controlled, double-blind pilot study2024n=10
In a 12-week pilot RCT of 10 adults with cystic fibrosis, high-dose vitamin D3 plus inulin (12 g/day) altered intestinal and airway microbiota versus placebo.
- Duration
- 12 weeks
- Dose
- 12 g/day
- Population
- Adults
- Participants
- 10
Vitamin DView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- People with cystic fibrosis (CF) often have weak bones due to ongoing inflammation and infection.
- During lung flare-ups, their bones break down more quickly.
- In a study, people with CF who received a large dose of vitamin D during a lung flare-up had a significant decrease in markers that show bone breakdown, while those who got a placebo had no improvement.
- This suggests vitamin D taken during flare-ups might help protect bone health in people with cystic fibrosis.
Browse 1 study
RCTChanges in bone turnover after high-dose vitamin D supplementation during acute pulmonary exacerbation in cystic fibrosis2023n=45
In 45 cystic fibrosis patients given 250,000 IU vitamin D at pulmonary exacerbation, treated participants had significant decreases in bone turnover markers versus placebo.
- Effect
- Benefit
- Duration
- 1 year
- Dose
- 250000 IU/day
- Participants
- 45
Algal OilView supplement →
Do not purchase·★★★★★
How we scored this▸
- Most studies show that taking algal oil rich in DHA does not help improve symptoms of cystic fibrosis.
- Research in children and young adults found that daily DHA supplements for several months did not improve lung function, lower infections, or reduce lung flare-ups compared to not taking the supplements.
Browse 3 studies
RCTLong-term docosahexaenoic acid (DHA) supplementation in cystic fibrosis patients: a randomized, multi-center, double-blind, placebo-controlled trial2020n=96
A 48-week RCT in cystic fibrosis patients found long-term DHA supplementation did not significantly reduce pulmonary or systemic inflammation versus placebo.
- Effect
- No Benefit
- Duration
- 48 weeks
- Dose
- 50 mg/kg
- Population
- Patients with cystic fibrosis
- Participants
- 96
- Avg age
- ~15
RCTA randomized placebo-controlled study on high-dose oral algal docosahexaenoic acid supplementation in children with cystic fibrosis2013
A study of 41 CF patients aged 6-12 years found that high-dose DHA (100 mg/kg/day) for the first month and 1g/day for another 11 months (12-month supplementation) decreased plasma AA:DHA ratio, indicating reduced inflammation, but this change did not lead to any significant clinical benefits.
- Effect
- No Benefit
- Duration
- 12 months
- Dose
- 1 g/day
- Population
- Children/adolescents
- Ages
- 6–12
Clinical trialFatty acids in blood and intestine following docosahexaenoic acid supplementation in adults with cystic fibrosis2006
A small study in 5 adult cystic fibrosis patients found DHA supplementation raised plasma and intestinal DHA levels; effects on lung function were examined but sample size was very small.
- Effect
- No Benefit
- Dose
- 70 mg/kg
- Population
- Adults
- Ages
- 18–43
ProbioticsView supplement →
Do not purchase·★★★★★
How we scored this▸
- Probiotics have insufficient evidence for Cystic fibrosis.
Browse 2 studies·1 meta-analysis
MetaEffectiveness of Probiotics, Prebiotics, and Symbiotic Supplementation in Cystic Fibrosis Patients: A Systematic Review and Meta-Analysis of Clinical Trials2025n=552
A meta-analysis of 13 cystic fibrosis RCTs (n=552) found probiotics lowered fecal calprotectin and IL-6/IL-8 but did not reduce exacerbations or improve FEV1 significantly.
- Effect
- No Benefit
- Population
- Children/adolescents
- Participants
- 552
MetaProbiotics for people with cystic fibrosis2020n=464
A Cochrane review of 12 cystic fibrosis RCTs (n=464) found insufficient evidence that probiotics improve lung function or quality of life in CF.
- Effect
- No Benefit
- Dose
- 47.4 mcg/day
- Population
- Adults
- Participants
- 464
Saccharomyces boulardiiView supplement →
Do not purchase·★★★★★
How we scored this▸
- It is uncertain whether taking Saccharomyces boulardii helps people with cystic fibrosis.
- Taking 250 mg of this probiotic three times a day for 3 weeks did not seem to reduce yeast infections in the gut in people with cystic fibrosis.
Browse 1 study
Controlled trialMycoserological study of the treatment of paediatric cystic fibrosis patients with Saccharomyces boulardii (Saccharomyces cerevisiae Hansen CBS 5926)1995
In cystic fibrosis children on long-term antibiotics, S. boulardii did not significantly change intestinal Candida counts versus placebo.
- Effect
- No Benefit
- Duration
- 21 days
- Dose
- 750 mg/day
- Population
- Children/adolescents
Evidence visualised
Same ratings as above, aggregated so you can see coverage and imbalance.
| Supplement | DEX | Studies | Meta-analyses | Share |
|---|---|---|---|---|
| Taurine | ★★★★★52% | 7 | 0 | 29% |
| N-Acetyl Cysteine (NAC) | ★★★★★52% | 5 | 1 | 21% |
| Vitamin K | ★★★★★52% | 4 | 0 | 17% |
| Algal Oil | ★★★★★36% | 3 | 0 | 13% |
| Probiotics | ★★★★★36% | 2 | 1 | 8% |
| Inulin | ★★★★★44% | 1 | 0 | 4% |
| Saccharomyces boulardii | ★★★★★28% | 1 | 0 | 4% |
| Vitamin D | ★★★★★44% | 1 | 0 | 4% |