Colorectal cancer
Supplements studied for colorectal cancer.
Overview
Colorectal cancer supplement evidence varies by agent and endpoint. Calcium 1200–2000 mg daily for several years may lower colon cancer and adenoma risk in some populations, particularly with adequate vitamin D. Vitamin E supplementation has not clearly reduced colorectal cancer risk in larger trials despite early signals.
Black and green tea associations with lower risk appear in some observational research but are inconsistent in interventional data. Soy foods may correlate with lower risk in Asian cohorts, though nattokinase or soy protein supplements lack clear anticancer trial evidence. Probiotics are marked possibly effective without detail here. See the heatmap and evidence reviews below.
Effect graph
Relevant supplements
Relevant supplements sorted by DEX Score.
| Calcium | ★★★★★ | Medium |
| Probiotics | ★★★★★ | Medium |
| Vitamin B9 (Folate) | ★★★★★ | Low |
| Garlic | ★★★★★ | Low |
| Olive Oil | ★★★★★ | Low |
| Methionine | ★★★★★ | Low |
| Vitamin E | ★★★★★ | Very Low / None |
| N-Acetyl Cysteine (NAC) | ★★★★★ | Low |
| Green Tea | ★★★★★ | Very Low / None |
| Ginger | ★★★★★ | Low |
| Flaxseed | ★★★★★ | Low |
| Black Tea | ★★★★★ | Very Low / None |
| Vitamin K | ★★★★★ | Low |
| Vitamin D | ★★★★★ | Very Low / None |
| Vitamin B2 (Riboflavin) | ★★★★★ | Low |
| Multivitamin | ★★★★★ | Very Low / None |
| Lycopene | ★★★★★ | Very Low / None |
| Zeaxanthin | ★★★★★ | Very Low / None |
| Vitamin A | ★★★★★ | Very Low / None |
| Lutein | ★★★★★ | Very Low / None |
| Curcumin | ★★★★★ | Low |
| Nattokinase | ★★★★★ | Very Low / None |
Studies
Find individual evidence reviews for supplements sorted by DEX Score.
22 supplements for , and rated at least stars. All purchase bands. No minimum star filter.
CalciumView supplement →
Consider purchase·★★★★★
How we scored this▸
- Calcium from food or supplements may help lower the risk of colon cancer and precancerous growths in the colon (called adenomas), especially for people who already have enough vitamin D and a healthy body weight.
- Studies show that taking 1200 to 2000 mg of calcium per day for several years can cut the chance of adenomas coming back by up to about one-third.
- But research results are mixed.
- Not all studies find a benefit, and calcium does not seem to help people with inherited conditions like familial polyposis.
- One large study in older women found that calcium plus a small amount of vitamin D did not reduce colon cancer risk, though those women were already getting a lot of calcium in their diets.
- Calcium also doesn’t seem to help if vitamin D levels are low or if someone is overweight.
Browse 17 studies·7 meta-analyses
RCTBody mass index, calcium supplementation and risk of colorectal adenomas2018n=2,258
Reanalysis of two adenoma prevention trials found calcium's benefit on high-risk adenomas was strongest in normal-BMI participants and absent in overweight/obese patients (interaction p=0.03).
- Effect
- Benefit
- Dose
- 200 mg/day
- Participants
- 2,258
MetaEffects of calcium on the incidence of recurrent colorectal adenomas: A systematic review with meta-analysis and trial sequential analysis of randomized controlled trials2017n=2,234
A meta-analysis of 5 RCTs (2,234 adenoma patients) found calcium reduced recurrent adenoma risk (RR 0.88); trial sequential analysis supported a moderate protective effect.
- Effect
- Benefit
- Dose
- 1600 mg/day
- Population
- Patients with colorectal adenomas
- Participants
- 2,234
MetaCalcium intake and colorectal adenoma risk: dose-response meta-analysis of prospective observational studies2015n=11,005
A dose-response meta-analysis of 8 observational studies found each 300 mg/day higher total calcium linked to 5% lower colorectal adenoma risk, with stronger associations for high-risk adenomas.
- Effect
- Benefit
- Dose
- 300 mg/day
- Participants
- 11,005
MetaCalcium intake and colorectal cancer risk: dose-response meta-analysis of prospective observational studies2014n=12,305
A meta-analysis of 15 cohorts found each 300 mg/day higher total calcium associated with ~8% lower colorectal cancer risk over 3–16 years of follow-up.
- Effect
- Benefit
- Dose
- 300 mg/day
- Participants
- 12,305
- Ages
- 3–16
MetaChemoprevention of colorectal cancer: systematic review and economic evaluation2010n=6,406
A UK systematic review of chemoprevention trials concluded calcium can reduce adenomatous polyps but noted limited direct CRC endpoint data and mixed evidence across micronutrients.
- Effect
- Benefit
- Population
- Adults
- Participants
- 6,406
- Ages
- 50–60
MetaSupplemental calcium in the chemoprevention of colorectal cancer: a systematic review and meta-analysis2010
A systematic review of calcium RCTs found supplementation reduced recurrent adenomas across high-, intermediate-, and low-risk populations compared with placebo.
- Effect
- Benefit
- Dose
- 1200 mg/day
- Population
- Adults
MetaColorectal cancer risk and dietary intake of calcium, vitamin D, and dairy products: a meta-analysis of 26,335 cases from 60 observational studies2009n=26,335
A meta-analysis of 60 observational studies (26,335 CRC cases) found high milk/dairy intake linked to 16–22% lower colon cancer risk; high calcium showed greater protection in distal colon and rectum.
- Effect
- Benefit
- Participants
- 26,335
RCTProlonged effect of calcium supplementation on risk of colorectal adenomas in a randomized trial2007n=930
In 930 adenoma patients, 1200 mg/day calcium for 4 years reduced recurrence during treatment; protective effect persisted 5 years after stopping supplementation in follow-up analysis.
- Effect
- Benefit
- Duration
- 4 years
- Dose
- 1200 mg/day
- Participants
- 930
RCTCalcium plus vitamin D supplementation and the risk of colorectal cancer2006n=18,176
In WHI (36,282 postmenopausal women), 1000 mg calcium plus 400 IU vitamin D daily for ~7 years did not reduce invasive colorectal cancer vs placebo (HR 1.08).
- Effect
- No Benefit
- Dose
- 200 IU/day
- Population
- Postmenopausal women
- Participants
- 18,176
MetaRole of supplemental calcium in the recurrence of colorectal adenomas: a metaanalysis of randomized controlled trials2005n=1,485
A meta-analysis of 3 RCTs (1,485 prior adenoma patients) found calcium supplementation reduced adenoma recurrence (RR 0.80) over 3–4 years of follow-up.
- Effect
- Benefit
- Population
- Adults with history of colorectal adenomas
- Participants
- 1,485
- Ages
- 3–4
ObservationalDairy foods, calcium, and colorectal cancer: a pooled analysis of 10 cohort studies2004n=536
A pooled analysis of 10 cohorts (534,536 adults) found higher milk intake and calcium inversely associated with colorectal cancer; ≥250 g/day milk linked to 15% lower risk.
- Effect
- Benefit
- Dose
- 250 g/day
- Population
- Adults
- Participants
- 536
- Ages
- 6–16
MetaDietary calcium supplementation for preventing colorectal cancer and adenomatous polyps2004n=1,346
A Cochrane review of calcium RCTs using adenoma endpoints concluded supplementary calcium likely reduces adenomatous polyp recurrence, though direct colorectal cancer data remain limited.
- Effect
- Benefit
- Duration
- 3 years
- Dose
- 1200 mg/day
- Population
- Healthy adults
- Participants
- 1,346
RCTVitamin D, calcium supplementation, and colorectal adenomas: results of a randomized trial2003n=803
In 803 adenoma patients, calcium reduced recurrence only among those with baseline 25(OH)D at or below 29.1 ng/mL; vitamin D status modified calcium's preventive effect.
- Effect
- Benefit
- Participants
- 803
ObservationalDietary calcium and vitamin D intake and risk of colorectal cancer: a prospective cohort study in women2002n=61,463
In 61,463 women followed 11.3 years, highest dietary calcium (~914 mg/day) was linked to 28% lower colorectal cancer risk vs lowest intake, especially for distal cancers.
- Effect
- Benefit
- Dose
- 914 mg/day
- Population
- Women
- Participants
- 61,463
RCTCalcium supplements for the prevention of colorectal adenomas. Calcium Polyp Prevention Study Group1999n=930
An RCT of 930 adenoma patients found 1200 mg/day calcium carbonate for up to 4 years reduced adenoma recurrence (RR 0.85) vs placebo over surveillance colonoscopy.
- Effect
- Benefit
- Dose
- 1200 mg/day
- Population
- Adolescents
- Participants
- 930
- Avg age
- 15.8
ObservationalRelationship between vitamin and calcium supplement use and colon cancer1997n=251
A Seattle case-control study of 444 adults found daily vitamin D (≥200 IU) and multivitamin use associated with roughly halved colon cancer risk over 10 years.
- Effect
- Benefit
- Duration
- 10 years
- Dose
- 200 IU/day
- Population
- Adults
- Participants
- 251
- Ages
- 30–62
MetaCalcium does not protect against colorectal neoplasia1996
A meta-analysis of 43 epidemiologic measures found overall calcium intake did not clearly protect against colorectal neoplasia (RR 0.89); adenoma and carcinoma results differed.
- Effect
- No Benefit
ProbioticsView supplement →
Consider purchase·★★★★★
How we scored this▸
- Probiotics are possibly effective for Colorectal cancer.
Browse 1 study·1 meta-analysis
MetaEvaluation of the efficacy of probiotics in the chemoradiotherapy of colorectal cancer: a meta-analysis of Randomized Controlled Trials2025n=633
A meta-analysis of 8 colorectal cancer chemoradiotherapy RCTs (n=633) found probiotics halved diarrhea incidence (RR 0.51) and improved pain, dyspnea, and insomnia scores.
- Effect
- Benefit
- Population
- Patients with colorectal cancer
- Participants
- 633
GarlicView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- Some studies suggest that eating more garlic is linked with lower chances of developing colorectal cancer.
- But overall research findings are mixed.
- Studies that observe people’s diets suggest garlic might help, but studies that follow people over time do not strongly support this.
- The strongest links were found in Asian countries, less so in North America, and none in Europe, possibly because garlic is eaten differently in these places.
- Few studies have looked at garlic supplements, and while one study showed that a high dose of aged garlic extract reduced the risk of new colon polyps by nearly a third, other studies do not confirm that garlic supplements prevent colorectal cancer.
- More research is needed before recommending garlic supplements for this purpose.
Browse 10 studies·4 meta-analyses
ObservationalAllium vegetables intake and the risk of gastric cancer in the Stomach cancer Pooling (StoP) Project2022
In the Stomach cancer Pooling Project (6,097 gastric cancer cases, 13,017 controls), higher allium vegetable intake was associated with 29% lower gastric cancer risk; garlic alone showed a 17% reduction.
- Effect
- Benefit
MetaAssociation and mechanism of garlic consumption with gastrointestinal cancer risk: A systematic review and meta-analysis2022
A meta-analysis found higher garlic intake associated with lower risk of gastric and colorectal cancers, though heterogeneity and study quality varied across included epidemiologic studies.
- Effect
- Benefit
MetaGarlic intake and the risk of colorectal cancer: A meta-analysis2020
A meta-analysis of epidemiologic studies found garlic intake associated with reduced colorectal cancer risk, though pooled estimates varied by study design and garlic preparation.
- Effect
- Benefit
MetaGarlic consumption and colorectal cancer risk in man: a systematic review and meta-analysis2016
A meta-analysis of 14 studies found no significant association between garlic consumption and colorectal cancer risk (pooled OR 0.93; substantial heterogeneity).
- Effect
- No Benefit
RCTEffects of aged garlic extract (AGE) on colorectal adenomas: a double-blinded study2004n=37
In a double-blind RCT of 51 patients with colorectal adenomas, high-dose aged garlic extract (2.4 mL/day) for 12 months showed a non-significant trend toward fewer new adenomas versus low-dose garlic.
- Effect
- No Benefit
- Duration
- 0–12 months
- Dose
- 2.4 mL/day
- Population
- Patients with colorectal adenomas
- Participants
- 37
MetaGarlic consumption and cancer prevention: meta-analyses of colorectal and stomach cancers2000
A meta-analysis found higher raw or cooked garlic consumption associated with reduced stomach and colorectal cancer risk, with dose-response patterns varying by cancer site and garlic form.
- Effect
- Benefit
ObservationalDietary fiber and colorectal cancer risk1997n=494
In a Hawaii case-control study of 698 colon and 494 rectal cancer cases, dietary fiber showed a strong inverse dose-response with colorectal cancer risk in both sexes.
- Population
- Adults
- Participants
- 494
ObservationalA prospective cohort study on the relationship between onion and leek consumption, garlic supplement use and the risk of colorectal carcinoma in The Netherlands1996n=1,598
In the Netherlands Cohort Study, onion and leek consumption and garlic supplement use showed no clear association with colon or rectal cancer after 3.3 years of follow-up.
- Effect
- No Benefit
- Population
- Adults
- Participants
- 1,598
- Ages
- 55–69
ObservationalRelation of vegetable, fruit, and grain consumption to colorectal adenomatous polyps1996
In a case-control study of 488 matched pairs (ages 50–74), higher vegetable, fruit, and grain intake was associated with lower colorectal adenomatous polyp prevalence.
- Ages
- 50–74
ObservationalVegetables, fruit, and colon cancer in the Iowa Women's Health Study1994n=41,837
In the Iowa Women's Health Study of 41,837 women (ages 55–69) followed 5 years, garlic consumption was inversely associated with colon cancer (RR 0.68 for highest vs lowest intake).
- Effect
- Benefit
- Duration
- 5 years
- Population
- Women
- Participants
- 41,837
- Ages
- 55–69
Vitamin B9 (Folate)View supplement →
Reconsider purchase·★★★★★
How we scored this▸
- Most research suggests that getting enough folate from food and supplements lowers the risk of colorectal cancer.
- But clinical studies do not consistently show that taking folic acid supplements alone reduces colorectal cancer risk.
- Some benefits might only show up after many years.
- Folic acid seems to help prevent cancer in the colon more than in the rectum.
- It may work better for certain types of colon cancer and in women.
- Eating folate-rich foods might protect against colon cancer better than taking folic acid supplements.
- Drinking alcohol might also affect how folic acid works to protect against cancer.
Browse 19 studies·6 meta-analyses
MetaFolate intake and risk of colorectal cancer: a systematic review and up-to-date meta-analysis of prospective studies2023n=280
A meta-analysis of 280 studies found that the combined relative risk (RR) for the highest intake compared with the lowest was 0.88 [95% confidence interval (CI), 0.83-0.92, P = 10 -4 ).
- Effect
- Benefit
- Population
- Adults
- Participants
- 280
ObservationalAssociation of folate intake and colorectal cancer risk in the postfortification era in US women2021n=86,320
An observational study of 86320 women found that in the postfortification period (1998-2016), intake of total or specific forms of folate was not associated with CRC risk, even among multivitamin users.
- Effect
- No Benefit
- Population
- Women
- Participants
- 86,320
- Ages
- 16–20
MetaFolic Acid Supplementation May Reduce Colorectal Cancer Risk in Patients With Inflammatory Bowel Disease: A Systematic Review and Meta-Analysis2017n=4,517
A meta-analysis of 4517 participants found that we found an overall protective effect for folic acid supplementation on the development of CRC, pooled hazard ratio=0.58 (95% confidence interval, 0.37-0.80).
- Effect
- Benefit
- Population
- Patients with inflammatory bowel disease
- Participants
- 4,517
MetaFolate intake and the risk of colorectal cancer: a systematic review and meta-analysis2011
A meta-analysis of 27 studies found that similarly, for cohort studies, the resulting summary risk estimate for high versus low dietary folate intake was 0.92 (CI 95% 0.81-1.05) with no significant heterogeneity.
- Effect
- Benefit
- Population
- Women
ObservationalHigh levels of folate from supplements and fortification are not associated with increased risk of colorectal cancer2011n=56,011
An observational study of 56011 found that intake of high levels of natural folate (RRQ5vsQ1=0.86; 95% CI: 0.70-1.06; P trend=.12) or folic acid (RRQ5vsQ1=0.84; 95% CI: 0.68-1.03; P trend=.06) were not significantly associated with risk of colorectal cancer.
- Effect
- Benefit
- Population
- Adults
- Participants
- 56,011
ObservationalPre- and postfortification intake of folate and risk of colorectal cancer in a large prospective cohort study in the United States2011n=6,484
An observational study of 6484 adults found that 200 μg/day in the postfortification analysis (6484 cases), a higher total folate intake was associated with a decreased colorectal cancer risk (HR for ≥900 compared with <200 μg/d: 0.70; 95% CI: 0.58, 0.84).
- Effect
- Benefit
- Dose
- 200 μg/day
- Population
- Adults
- Participants
- 6,484
- Ages
- 50–71
MetaChemoprevention of colorectal cancer: systematic review and economic evaluation2010n=6,406
A UK systematic review of chemoprevention trials concluded calcium can reduce adenomatous polyps but noted limited direct CRC endpoint data and mixed evidence across micronutrients.
- Population
- Adults
- Participants
- 6,406
- Ages
- 50–60
MetaMeta-analysis: folic acid in the chemoprevention of colorectal adenomas and colorectal cancer2010
A meta-analysis found that there is no evidence that folic acid is effective in the chemoprevention of colorectal adenomas or colorectal cancer for any population.
- Effect
- No Benefit
ObservationalMicronutrient intake and risk of colon and rectal cancer in a Danish cohort2010n=56,332
An observational study of 56332 (ages 50–64) found that rectal cancer did not seem associated with any micronutrient.
- Effect
- Benefit
- Participants
- 56,332
- Ages
- 50–64
MetaPooled analyses of 13 prospective cohort studies on folate intake and colon cancer2010n=25,134
A meta-analysis of 725134 participants found that 100 μg/day results for total folate intake were similar in analyses using absolute intake cutpoints (pooled multivariate RR = 0.87, 95% CI 0.78-0.98, comparing ≥ 560 mcg/days vs. <240 mcg/days, p-value, test for trend = 0.009).
- Effect
- Benefit
- Dose
- 100 μg/day
- Participants
- 25,134
ObservationalFolate and vitamin B6 intake and risk of colon cancer in relation to p53 expression2008n=399
An observational study of 399 women found that similarly, high vitamin B(6) intake conferred a protective effect on p53-overexpressing cancers (top versus bottom quintile: RR, 0.57; 95% CI, 0.35-0.94; P(heterogeneity) = .01) but had no effect on p53 wild-type tumors.
- Effect
- Benefit
- Population
- Women
- Participants
- 399
MetaFolate intake and colorectal cancer risk: a meta-analytical approach2005
A meta-analysis found that these results offer some support for the hypothesis that folate has a small protective effect against colorectal cancer but confounding by other dietary factors cannot be ruled out.
- Effect
- Benefit
ObservationalThe influence of folate and multivitamin use on the familial risk of colon cancer in women2002n=88,758
A prospective cohort of 88,758 women found high folate and methionine intake and multivitamin use reduced excess colon cancer risk associated with a family history of colorectal cancer.
- Effect
- Benefit
- Population
- Women
- Participants
- 88,758
Nutritional status of folate and colon cancer risk: evidence from NHANES I epidemiologic follow-up study2001n=14,407
An analysis of 14,407 NHANES I participants found high folate intake was inversely associated with colon cancer in men, and low folate plus low methionine with high alcohol increased risk.
- Effect
- Benefit
- Population
- Men
- Participants
- 14,407
ObservationalMultivitamin use, folate, and colon cancer in women in the Nurses' Health Study1998n=88,756
An observational study of 88756 women found that multivariate relative risk (RR) and 95% CIs for colon cancer in relation to energy-adjusted folate intake.
- Effect
- Benefit
- Population
- Women
- Participants
- 88,756
- Ages
- 55–69
ObservationalAre dietary factors involved in DNA methylation associated with colon cancer?1997
An observational study of 1 found that this trend was modest and most marked in those diagnosed at a younger age [odds ratio (OR) for men = 1.3, 95% confidence interval (CI) = 0.9-1.9; OR for women = 1.6, 95% CI = 1.0-2.6].
- Population
- Adults
ObservationalIntake of selected micronutrients and risk of colorectal cancer1997
An observational study found that our results provide further support for a protective effect of several micronutrients on colorectal cancer risk and some indications for a specific and stronger effect of selected anti-oxidants.
- Effect
- Benefit
ObservationalThe effect of folic acid supplementation on the risk for cancer or dysplasia in ulcerative colitis1997n=98
An observational study of 98 uc patients found that 0.4–1.0 mg folic acid/day folate use also varied with the degree of dysplasia (RR for cancer, 0.45; RR for high-grade dysplasia, 0.52; RR for low-grade dysplasia, 0.75 compared with patients with no dysplasia) (P = 0.08).
- Duration
- ≥6 months
- Dose
- 0.4–1 mg/day
- Population
- UC patients
- Participants
- 98
ObservationalRed blood cell folate is associated with the development of dysplasia and cancer in ulcerative colitis1993n=67
An observational study of 67 uc patients found that adjusting for confounding effects of age, sex, race, disease duration, and folate supplementation, the risk of dysplasia or cancer was significantly decreased by 18% for each 10 ng/ml increase in red blood cell folate (odds ratio 0.82, 95% confidence interval 0.68-0.99).
- Effect
- Benefit
- Duration
- 1 year
- Population
- UC patients
- Participants
- 67
MethionineView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- It is not clear if eating more methionine-rich foods lowers the risk of colorectal cancer, but some research suggests it might help reduce the risk.
- Studies show that people who eat more methionine may have a lower chance of developing colorectal, colon, or rectal cancer, especially men and those in Western countries.
- Eating methionine together with folate-rich foods may work better, especially for those with family history of colon cancer or who drink alcohol regularly.
Browse 3 studies·1 meta-analysis
MetaDietary methionine intake and risk of incident colorectal cancer: a meta-analysis of 8 prospective studies involving 431,029 participants2013n=431,029
A meta-analysis of 8 prospective cohorts (431,029 participants) found higher dietary methionine intake was associated with lower colon cancer risk (RR 0.77), especially in Western studies and men.
- Effect
- Benefit
- Population
- Men
- Participants
- 431,029
ObservationalThe influence of folate and multivitamin use on the familial risk of colon cancer in women2002n=88,758
A prospective cohort of 88,758 women found high folate and methionine intake and multivitamin use reduced excess colon cancer risk associated with a family history of colorectal cancer.
- Effect
- Benefit
- Population
- Women
- Participants
- 88,758
Nutritional status of folate and colon cancer risk: evidence from NHANES I epidemiologic follow-up study2001n=14,407
An analysis of 14,407 NHANES I participants found high folate intake was inversely associated with colon cancer in men, and low folate plus low methionine with high alcohol increased risk.
- Effect
- Benefit
- Population
- Men
- Participants
- 14,407
Olive OilView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- It’s not clear if eating olive oil can help prevent colorectal cancer.
- Some studies found that people who eat more olive oil have a lower risk and fewer colon changes linked to cancer, but other research found no benefit.
- More studies are needed to know if olive oil protects against colorectal cancer.
Browse 3 studies·1 meta-analysis
MetaOlive oil intake and cancer risk: A systematic review and meta-analysis2022n=929,771
A meta-analysis of 929,771 subjects found highest vs lowest olive oil consumption associated with 31% lower overall cancer likelihood, including breast and gastrointestinal cancers.
- Effect
- Benefit
- Participants
- 929,771
Olive oil, diet and colorectal cancer: an ecological study and a hypothesis2000
An ecological analysis of 28 countries found higher national olive oil intake inversely associated with colorectal cancer incidence alongside meat and fish intake patterns.
- Effect
- Benefit
ObservationalOlive oil, other seasoning fats, and the risk of colorectal carcinoma1998n=4,154
An Italian case-control study of 1953 colorectal cancer cases and 4154 controls found higher olive oil intake associated with modestly lower colorectal cancer risk (OR 0.83 highest vs lowest tertile).
- Effect
- Benefit
- Population
- Patients with colorectal cancer
- Participants
- 4,154
Black TeaView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- Research suggests that drinking tea, including black or green tea, might lower the risk of colorectal cancer compared to not regularly drinking tea.
- However, most studies find that consuming tea does not seem to affect the risk of colorectal cancer.
- Some studies even suggest that drinking a lot of black tea could be linked to a higher risk of colorectal cancer, but more evidence is needed as most evidence is observational.
Browse 10 studies·1 meta-analysis
MetaGreen tea, black tea and colorectal cancer risk: a meta-analysis of epidemiologic studies2006n=20
A meta-analysis of 25 studies found green tea associated with 18% lower colorectal cancer risk (OR 0.82) in case-control studies; black tea showed no association (OR 0.99) with substantial heterogeneity.
- Effect
- No Benefit
- Population
- Adults
- Participants
- 20
ObservationalTea consumption and the reduced risk of colon cancer -- results from a national prospective cohort study2002
In NHANES I follow-up, habitual tea drinkers in Cohort II had 41–59% lower colon cancer risk at ≥1.5 cups/day versus nondrinkers, predominantly in men; Cohort I showed no significant association.
- Effect
- Benefit
- Population
- Women
ObservationalTea consumption and risk of cancer of the colon and rectum2001n=685
In 685 colon and 655 rectal cancer cases versus 2,434 controls in Iowa, tea consumption was not associated with colorectal cancer risk overall or by subtype after adjustment for confounders.
- Effect
- No Benefit
- Population
- Adults
- Participants
- 685
- Ages
- 40–85
ObservationalTea and coffee consumption and risk of colon and rectal cancer in middle-aged Finnish men1998
In Finnish men, ≥1 cup/day tea was associated with 2.09-fold higher colon cancer risk (p trend=0.001) but little effect on rectal cancer; coffee showed no protective association.
- Effect
- No Benefit
- Population
- Men
Tea consumption and cancer1998
In London men followed from 1967, no dose-response link was found between tea consumption and colon, rectal, or prostate cancer; tea was associated with stomach, lung, and kidney cancer deaths before full adjustment.
- Effect
- No Benefit
- Population
- Men
- Ages
- 45–60
ObservationalCoffee and tea intake and risk of cancers of the colon and rectum: a study of 3,530 cases and 7,057 controls1997n=7,057
In 3,530 Italian colorectal cancer cases and 7,057 controls, ≥4 cups/day coffee lowered colon cancer risk (OR 0.73) but tea intake did not significantly modify colon or rectal cancer risk.
- Effect
- No Benefit
- Population
- Adults
- Participants
- 7,057
ObservationalConsumption of black tea and cancer risk: a prospective cohort study1996n=3,500
In 120,852 Dutch adults followed 4.3 years, black tea consumption was not associated with colorectal cancer risk; initial inverse stomach and lung cancer associations disappeared after adjusting for smoking and diet.
- Effect
- No Benefit
- Population
- Older adults
- Participants
- 3,500
- Ages
- 55–69
ObservationalCoffee, tea, tobacco, and cancer of the large bowel1994
In a Stockholm case-control study, ≥6 cups/day coffee lowered colon cancer risk (OR 0.55) but tea ≥2 cups/day lowered rectal cancer risk (OR 0.56); tea was not associated with colon cancer.
- Effect
- Benefit
ObservationalBlack tea consumption and cancer risk: a prospective study1986
In 7,833 Japanese-American men, black tea intake >1/day was associated with 4.2-fold higher rectal cancer risk (P=0.0007) but 44% lower prostate cancer risk (P=0.020); no significant associations at other sites.
- Effect
- No Benefit
- Population
- Men
ObservationalDietary habits and gastro-intestinal cancers: a comparative case-control study of stomach and large intestinal cancers in Nagoya, Japan1985
A Japanese case-control study of stomach and colorectal cancers found salted foods raised stomach cancer risk and Western-style breakfast raised colon cancer risk; tea and alcohol showed no clear associations.
- Effect
- No Benefit
- Duration
- 10 years
FlaxseedView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- Flaxseed is a food that contains compounds called lignans.
- Research looking at whether lignans affect colon cancer risk has shown mixed results.
- Some studies show no link, while others suggest that eating more lignans may lower the risk of colon cancer and precancerous growths called adenomas.
- It is not yet known whether flaxseed lignans themselves play a direct role in reducing the risk of colon cancer.
Browse 3 studies
ObservationalPlasma enterolignan concentrations and colorectal cancer risk in a nested case-control study2008n=387
In a Dutch nested case-control of 160 colorectal cancer cases and 387 controls, plasma enterodiol and enterolactone were not associated with colorectal cancer risk after adjustment for confounders.
- Effect
- No Benefit
- Population
- Women
- Participants
- 387
- Ages
- 20–59
ObservationalDietary phytoestrogen intake is associated with reduced colorectal cancer risk2006
In an Ontario case-control study (ages 20–74), higher dietary phytoestrogen intake—particularly lignans common in North American diets—was associated with reduced colorectal cancer risk.
- Effect
- Benefit
- Ages
- 20–74
ObservationalPlasma enterolignans are associated with lower colorectal adenoma risk2006n=532
In a Dutch case-control of 532 colorectal adenoma cases and 503 controls, higher plasma enterolignans were associated with lower adenoma risk, with stronger associations for incident cases.
- Effect
- Benefit
- Participants
- 532
GingerView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- Early research on colorectal cancer is limited.
- A clinical study evaluating how ginger supplementation influences the fecal microbiome composition in individuals with a history of colorectal adenoma.
- More studies are needed before any benefit can be considered reliable.
Browse 2 studies
RCTEffect of ginger supplementation on the fecal microbiome in subjects with prior colorectal adenoma2024n=68
In 68 adults with prior colorectal adenoma, ginger supplementation for 6 weeks altered fecal microbiome composition in directions consistent with colorectal cancer inhibition versus placebo.
- Effect
- Benefit
- Duration
- 6 weeks
- Population
- Adults
- Participants
- 68
- Ages
- 50–75
RCTPhase II study of the effects of ginger root extract on eicosanoids in colon mucosa in people at normal risk for colorectal cancer2011n=30
In 30 healthy volunteers, ginger 2 g/day for 28 days significantly reduced colon mucosal PGE2 and other inflammatory eicosanoids versus placebo in a randomized trial.
- Effect
- Benefit
- Duration
- 28 days
- Dose
- 2 g/day
- Population
- Healthy adults
- Participants
- 30
Green TeaView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- Research on green tea and colorectal cancer risk shows mixed results.
- Some large studies suggest that people who drink the most green tea may have about a 16% lower risk of colon cancer, but no clear benefit has been seen for rectal cancer.
- The possible protective effect seems stronger in women.
- Overall, it’s uncertain whether drinking green tea helps prevent colorectal cancer.
Browse 10 studies·4 meta-analyses
MetaGreen tea (Camellia sinensis) for the prevention of cancer2020n=1,795
A Cochrane review found very low-certainty evidence that green tea may reduce some cancer risks, with no clear effect on overall cancer incidence.
- Effect
- Benefit
- Participants
- 1,795
ObservationalProtective Effect of Green Tea Consumption on Colorectal Cancer Varies by Lifestyle Factors2019n=2,742
In a Korean case-control study of 2742 participants, higher green tea consumption was associated with lower colorectal cancer risk, especially among physically active adults.
- Effect
- Benefit
- Population
- Adults
- Participants
- 2,742
MetaTea consumption and the risk of five major cancers: a dose-response meta-analysis of prospective studies2014n=702
A dose-response meta-analysis of prospective studies found higher tea consumption associated with lower breast, colorectal, and liver cancer risk, but not prostate or stomach cancer.
- Effect
- No Benefit
- Participants
- 702
MetaAssociation between green tea and colorectal cancer risk: a meta-analysis of 13 case-control studies2012
A meta-analysis of 13 case-control studies found higher green tea consumption associated with lower colorectal cancer risk.
- Effect
- No Benefit
MetaGreen tea and incidence of colorectal cancer: evidence from prospective cohort studies2012n=352,275
A meta-analysis of 6 prospective cohorts (352,275 participants) found no significant association between green tea consumption and colorectal cancer incidence.
- Effect
- No Benefit
- Population
- Adults
- Participants
- 352,275
ObservationalGreen tea consumption and mortality due to cardiovascular disease, cancer, and all causes in Japan: the Ohsaki study2006n=4,209
In the Ohsaki cohort of 40,530 Japanese adults followed up to 11 years, green tea consumption was associated with lower cardiovascular and all-cause mortality.
- Effect
- Benefit
- Duration
- 7 years
- Population
- Adults
- Participants
- 4,209
- Ages
- 40–79
MetaGreen tea, black tea and colorectal cancer risk: a meta-analysis of epidemiologic studies2006n=20
A meta-analysis of 25 studies found green tea associated with 18% lower colorectal cancer risk (OR 0.82) in case-control studies; black tea showed no association (OR 0.99) with substantial heterogeneity.
- Effect
- No Benefit
- Population
- Adults
- Participants
- 20
Tea and coffee consumption and the risk of digestive tract cancers: data from a comparative case-referent study in Japan1998
In a Japanese hospital case-referent study, ≥7 cups/day green tea lowered stomach cancer risk (OR 0.69); rectal cancer risk fell with ≥3 cups/day coffee (OR 0.46); black tea associations were not significant.
- Avg age
- ~40
ObservationalGreen tea consumption and the risk of pancreatic and colorectal cancers1997n=1
In a Shanghai case-control study, green tea consumption was associated with lower colon and rectal cancer risk but not pancreatic cancer risk.
- Effect
- Benefit
- Dose
- 300 g/day
- Population
- Pancreatic cancer patients
- Participants
- 1
- Ages
- 30–74
ObservationalDietary habits and gastro-intestinal cancers: a comparative case-control study of stomach and large intestinal cancers in Nagoya, Japan1985
A Japanese case-control study of stomach and colorectal cancers found salted foods raised stomach cancer risk and Western-style breakfast raised colon cancer risk; tea and alcohol showed no clear associations.
- Effect
- No Benefit
- Duration
- 10 years
N-Acetyl Cysteine (NAC)View supplement →
Reconsider purchase·★★★★★
How we scored this▸
- It is uncertain if N-acetylcysteine (NAC) helps prevent colorectal cancer.
- One small study found that taking NAC 800 mg daily for 12 weeks reduced cell growth markers in the colon, which might lower cancer risk.
Browse 1 study
RCTN-acetylcysteine suppression of the proliferative index in the colon of patients with previous adenomatous colonic polyps1999
A 12-week RCT found NAC (800 mg/day) suppressed colonic epithelial proliferative index in patients with prior colorectal adenomas versus placebo.
- Effect
- Benefit
- Duration
- 12 weeks
- Dose
- 800 mg/day
- Population
- Adults with adenomatous colonic polyps
Vitamin EView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- Taking vitamin E by mouth does not seem to lower the risk of colorectal cancer.
- Some studies have linked vitamin E or multivitamin use with a lower chance of developing this cancer.
- Early research also suggested possible benefits in people with a history of colorectal adenomas.
- However, larger, better-quality studies have found that vitamin E supplements—either alone or with other vitamins—do not prevent colorectal cancer or stop it from coming back.
Browse 12 studies·3 meta-analyses
RCTAntioxidant supplement and long-term reduction of recurrent adenomas of the large bowel. A double-blind randomized trial2013n=411
In 330 post-polypectomy patients over median 4 years, an antioxidant mix including 200 mcg selenium reduced adenoma recurrence risk by 39% versus placebo.
- Effect
- Benefit
- Duration
- 5 years
- Dose
- 30 mg
- Population
- Post-polypectomy patients
- Participants
- 411
- Ages
- 1–15
MetaDo antioxidants prevent colorectal cancer? A meta-analysis2013n=17,914
In a meta-analysis of 17,914 participants, this meta-analysis found no evidence in favor of a protective effect of the studied antioxidant supplements in the prevention of colorectal cancer or cancer related mortality.
- Effect
- No Benefit
- Participants
- 17,914
MetaAntioxidants in the chemoprevention of colorectal cancer and colorectal adenomas in the general population: a systematic review and meta-analysis2011n=148
In a meta-analysis of 148 participants, effectiveness did not seem to differ between healthy populations, participants with cardiovascular risk factors or populations exposed to smoking or asbestos.
- Effect
- No Benefit
- Participants
- 148
RCTEffects of long-term vitamin E supplementation on cardiovascular events and cancer: a randomized controlled trial2005n=9,541
In HOPE-TOO (9,541 patients, ~7 years), 400 IU/day vitamin E did not prevent cancer or major cardiovascular events and increased heart failure risk (RR 1.13).
- Effect
- No Benefit
- Dose
- 400 IU/day
- Population
- Heart failure patients
- Participants
- 9,541
- Ages
- 55+
RCTVitamin E in the primary prevention of cardiovascular disease and cancer: the Women's Health Study: a randomized controlled trial2005
In the Women's Health Study (39,876 women, 600 IU EOD for 10.1 years), vitamin E did not reduce major cardiovascular events or total cancer but lowered cardiovascular mortality (RR 0.76).
- Effect
- No Benefit
- Dose
- 600 IU/day
- Population
- Women
- Ages
- 45+
MetaAntioxidant supplements for prevention of gastrointestinal cancers: a systematic review and meta-analysis2004n=170
A meta-analysis of 14 gastrointestinal cancer prevention trials found antioxidant supplements including selenium did not reduce GI cancer incidence and beta-carotene increased mortality in high-quality trials.
- Effect
- No Benefit
- Participants
- 170
RCTThe effect of alpha-tocopherol and beta-carotene supplementation on colorectal adenomas in middle-aged male smokers1999n=146
In an RCT of 146 participants, 50 mg/day, alpha-tocopherol supplementation increased the risk for adenomas (relative risk, 1.66; 95% confidence interval, 1.19-2.32), whereas beta-carotene supplementation had no effect on the risk (relative risk, 0.98; 95% confidence interval, 0.71-1.35).
- Effect
- No Benefit
- Dose
- 50 mg/day
- Population
- Colorectal cancer patients
- Participants
- 146
ObservationalRelationship between vitamin and calcium supplement use and colon cancer1997n=251
A Seattle case-control study of 444 adults found daily vitamin D (≥200 IU) and multivitamin use associated with roughly halved colon cancer risk over 10 years.
- Effect
- Benefit
- Duration
- 10 years
- Dose
- 200 IU/day
- Population
- Adults
- Participants
- 251
- Ages
- 30–62
RCTA clinical trial of antioxidant vitamins to prevent colorectal adenoma. Polyp Prevention Study Group1994n=864
In an RCT of 864 participants, 25 mg/day, there was no evidence that either beta carotene or vitamins C and E reduced the incidence of adenomas; the relative risk for beta carotene was 1.01 (95 percent confidence interval, 0.85 to 1.20); for vitamins C and E, it was 1.08 (95 percent confidence interval, 0.91 to 1.29).
- Effect
- No Benefit
- Dose
- 25 mg/day
- Population
- Adults
- Participants
- 864
RCTAntioxidant vitamins or lactulose for the prevention of the recurrence of colorectal adenomas1993n=46
In an RCT of 46 participants, 000 IU/day, in conclusion, either antioxidant vitamins or, to a lesser extent, lactulose lower the recurrence rate of adenomas of the large bowel and can be proposed as chemopreventive agents, at least in high-risk individuals.
- Effect
- Benefit
- Duration
- 18 months
- Dose
- 30000 IU/day
- Population
- Adults
- Participants
- 46
RCTEffect of vitamin A, C, and E supplementation on rectal cell proliferation in patients with colorectal adenomas1992n=20
In an RCT of 20 participants, for 6 months, before larger trials on chemoprevention of colorectal adenoma recurrence are conducted, additional studies are needed (a) to validate that cell kinetics is an intermediate biomarker, (b) to determine active agents, optimal dosage, and the relative efficacy of agents given alone and in...
- Effect
- Benefit
- Duration
- 6 months
- Population
- Cancer patients
- Participants
- 20
RCTA randomized trial of vitamins C and E in the prevention of recurrence of colorectal polyps1988n=15
In an RCT of 15 participants, 400 mg ascorbic acid + 400 mg alpha-tocopherol/day, inclusion of the three polyps found in these eight examinations led to an estimate of relative risk of 0.86 (95% confidence limits, 0.51 to 1.43).
- Effect
- No Benefit
- Dose
- 400 mg ascorbic acid + 400 mg alpha-tocopherol/day
- Population
- Adults
- Participants
- 15
LycopeneView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- Research on whether eating more lycopene-rich foods like tomatoes lowers the risk of colorectal cancer has mixed results.
- Some studies suggest a 50% lower risk with high lycopene intake, but others find no clear link between lycopene in the diet and colorectal cancer.
- More research is needed to know for sure.
Browse 5 studies·1 meta-analysis
MetaLycopene Consumption and Risk of Colorectal Cancer: A Meta-Analysis of Observational Studies2016
A meta-analysis of 15 observational studies found no significant association between lycopene intake and overall colorectal cancer risk (RR 0.94), though colon cancer specifically showed a modest inverse association (RR 0.88).
- Effect
- No Benefit
ObservationalDietary carotenoids and risk of colorectal cancer in a pooled analysis of 11 cohort studies2007n=702,647
A pooled analysis of 11 cohorts (702,647 participants) found no consistent association between lutein/zeaxanthin intake and colorectal cancer risk.
- Effect
- No Benefit
- Population
- Adults
- Participants
- 702,647
- Ages
- 6–20
ObservationalCarotenoids and colon cancer2000n=4,403
In 4,343 colorectal cancer cases and controls, higher dietary lutein intake was inversely associated with colon cancer risk (OR 0.83), especially in younger patients and proximal colon tumors.
- Effect
- No Benefit
- Population
- Adults
- Participants
- 4,403
ObservationalTomatoes, tomato-based products, lycopene, and cancer: review of the epidemiologic literature1999
A review of 72 epidemiologic studies found 57 reported inverse associations between tomato/lycopene intake or blood levels and cancer risk, with strongest evidence for prostate, lung, and stomach cancers.
- Effect
- Benefit
ObservationalFood consumption and cancer of the colon and rectum in north-eastern Italy1992
An Italian case-control study of 248 colorectal cancer cases found higher tomato consumption associated with roughly 50% lower colon and 60% lower rectal cancer odds compared with lowest intake.
- Effect
- Benefit
MultivitaminView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- It is uncertain whether taking multivitamins helps prevent colorectal cancer or reduce death from it. Some studies suggest that taking a multivitamin daily for up to 20 years may lower the risk of developing colorectal cancer by 8% to 12%. However, other studies show no difference in survival for people who take multivitamins for many years.
- For people diagnosed with colorectal cancer, taking a moderate amount of multivitamins (about 3-5 tablets a week) after diagnosis may lower the risk of dying from the cancer by 45% and reduce the risk of death from any cause by 19% over 11 years. But taking high doses of multivitamins (10 or more tablets per week) after diagnosis may actually increase the risk of death from colorectal cancer and other causes.
Browse 5 studies·1 meta-analysis
ObservationalPost-diagnostic multivitamin supplement use and colorectal cancer survival: A prospective cohort study2024n=2,424
A prospective study of 2,424 colorectal cancer patients found post-diagnostic multivitamin use was not associated with improved survival.
- Effect
- Benefit
- Population
- ALL patients
- Participants
- 2,424
ObservationalThe Associations of Multivitamin and Antioxidant Use With Mortality Among Women and Men Diagnosed With Colorectal Cancer2022n=534
An observational study of 534 women found multivitamin and antioxidant use was not associated with lower mortality over follow-up.
- Effect
- No Benefit
- Population
- ALL patients
- Participants
- 534
GuideVitamin, Mineral, and Multivitamin Supplementation to Prevent Cardiovascular Disease and Cancer: US Preventive Services Task Force Recommendation Statement2022
A USPSTF evidence review found insufficient evidence that multivitamin or mineral supplementation prevents cardiovascular disease or cancer in healthy adults.
- Effect
- No Benefit
- Population
- Adults
MetaDietary supplement use and colorectal cancer risk: a systematic review and meta-analyses of prospective cohort studies2015
A meta-analysis found no clear evidence that dietary supplement use, including multivitamins, reduces colorectal cancer risk.
- Effect
- No Benefit
- Dose
- 100 mg/day
ObservationalIntakes of vitamins A, C, and E and use of multiple vitamin supplements and risk of colon cancer: a pooled analysis of prospective cohort studies2010n=676,141
A prospective study of 676,141 women found higher vitamin C and E intake and multivitamin use were not associated with lower lung cancer risk.
- Effect
- No Benefit
- Dose
- 1000 mcg/day
- Population
- Adults
- Participants
- 676,141
- Ages
- 7–20
Vitamin B2 (Riboflavin)View supplement →
Reconsider purchase·★★★★★
How we scored this▸
- It is not known if taking riboflavin (vitamin B2) by mouth lowers the risk of colorectal cancer.
- Some studies in China suggest that eating more riboflavin-rich foods may reduce the chance of getting colorectal cancer.
Browse 1 study
ObservationalDietary B vitamin and methionine intakes and risk for colorectal cancer: a case-control study in China2020n=2,502
An observational study of 2502 women found that the multivariable OR for the highest quartile v. the lowest quartile were 0·62 (95 % CI 0·51, 0·74; Ptrend < 0·001) for folate, 0·46 (95 % CI 0·38, 0·55; Ptrend < 0·001) for vitamin B2, 0·55 (95 % CI 0·46, 0·76; Ptrend < 0·001) for vitamin B6 and 0·72 (95 % CI 0·60, 0·86;.
- Effect
- Benefit
- Population
- Women
- Participants
- 2,502
Vitamin DView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- It is unclear if vitamin D helps prevent or treat colorectal cancer.
- People with higher vitamin D levels in their blood seem to have better survival and lower death rates from colorectal cancer.
- However, studies testing vitamin D supplements show mixed results.
- One study found taking 2000 IU vitamin D daily did not lower the risk of cancer coming back or death over 5 years, while another small study found higher doses (starting at 8000 IU daily) helped people with advanced cancer live longer without the cancer progressing.
- For preventing colorectal cancer, higher vitamin D levels are linked with lower cancer risk, especially in women, but vitamin D supplements alone or with calcium have not clearly reduced the number of new cases or precancerous growths in most studies.
- More research is needed to know if vitamin D can help and what doses might be best.
Browse 9 studies·3 meta-analyses
MetaVitamin D as a chemopreventive agent in colorectal neoplasms. A systematic review and meta-analysis of randomized controlled trials2022n=71
A meta-analysis of 9 colorectal chemoprevention RCTs (71,386 participants) found vitamin D supplementation did not reduce colorectal cancer, adenoma, or advanced adenoma incidence.
- Effect
- No Benefit
- Participants
- 71
ObservationalCirculating Vitamin D and Colorectal Cancer Risk: An International Pooling Project of 17 Cohorts2019
In 17 cohorts (5,706 colorectal cancer cases), higher circulating 25(OH)D up to 100 nmol/L was inversely associated with colorectal cancer risk, especially in women.
- Effect
- Benefit
- Population
- Colorectal cancer patients
RCTEffect of High-Dose vs Standard-Dose Vitamin D3 Supplementation on Progression-Free Survival Among Patients With Advanced or Metastatic Colorectal Cancer: The SUNSHINE Randomized Clinical Trial2019n=70
In 139 patients with metastatic colorectal cancer given high- versus standard-dose vitamin D3 with chemotherapy, high dose improved progression-free survival (HR 0.64).
- Effect
- Benefit
- Population
- Women
- Participants
- 70
- Ages
- 56+
RCTEffect of Vitamin D Supplementation on Relapse-Free Survival Among Patients With Digestive Tract Cancers: The AMATERASU Randomized Clinical Trial2019n=166
In 417 Japanese patients with digestive tract cancers given 2000 IU/day vitamin D for median 3.5 years post-surgery, relapse-free survival improved (HR 0.76) versus placebo.
- Effect
- No Benefit
- Dose
- 2000 IU/day
- Population
- Colorectal cancer patients
- Participants
- 166
- Ages
- 30–90
RCTCalcium plus vitamin D supplementation and health outcomes five years after active intervention ended: the Women's Health Initiative2013n=36
In WHI (36,282 postmenopausal women), 7 years of 1000 mg calcium plus 400 IU vitamin D did not reduce hip fracture, colorectal cancer, breast cancer, CVD, or mortality; post-intervention follow-up was similar.
- Effect
- No Benefit
- Dose
- 600 IU/day
- Population
- Postmenopausal women
- Participants
- 36
MetaSupplemental calcium in the chemoprevention of colorectal cancer: a systematic review and meta-analysis2010
A systematic review of calcium RCTs found supplementation reduced recurrent adenomas across high-, intermediate-, and low-risk populations compared with placebo.
- Effect
- No Benefit
- Dose
- 1200 mg/day
- Population
- Adults
MetaOptimal vitamin D status for colorectal cancer prevention: a quantitative meta analysis2007
A pooled analysis of 5 serum studies found higher 25(OH)D quintiles associated with lower colorectal cancer odds, suggesting benefit at ≥33 ng/mL and ~1000–2000 IU/day intake.
- Effect
- Benefit
- Dose
- 2000 IU/day
- Population
- Women
RCTCalcium plus vitamin D supplementation and the risk of colorectal cancer2006n=18,176
In WHI (36,282 postmenopausal women), 1000 mg calcium plus 400 IU vitamin D daily for ~7 years did not reduce invasive colorectal cancer vs placebo (HR 1.08).
- Effect
- No Benefit
- Dose
- 200 IU/day
- Population
- Postmenopausal women
- Participants
- 18,176
RCTVitamin D, calcium supplementation, and colorectal adenomas: results of a randomized trial2003n=803
In 803 adenoma patients, calcium reduced recurrence only among those with baseline 25(OH)D at or below 29.1 ng/mL; vitamin D status modified calcium's preventive effect.
- Effect
- Benefit
- Participants
- 803
Vitamin KView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- Studies have not found a link between higher vitamin K intake from food and a lower risk of this cancer.
Browse 1 study
ObservationalDietary vitamin K intake in relation to cancer incidence and mortality: results from the Heidelberg cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC-Heidelberg)2010n=24,340
In an observational study of 24,340 participants, multivariate-adjusted hazard ratios (HRs) and 95% CIs were estimated by using Cox proportional hazards models.
- Effect
- Benefit
- Population
- Cancer patients
- Participants
- 24,340
- Ages
- 35–64
CurcuminView supplement →
Do not purchase·★★★★★
How we scored this▸
- No summary is available.
Browse 1 study
Open-labelPhase IIa clinical trial of curcumin for the prevention of colorectal neoplasia2011
A study in 64 smokers found that 4 g/day but not 2 g/day curcumin reduced the level of aberrant crypt foci by 40% after 30 days. [10203]
- Effect
- Benefit
- Duration
- 30 days
- Dose
- 4 g/day
LuteinView supplement →
Do not purchase·★★★★★
How we scored this▸
- Some studies suggest that eating more lutein from food may lower the risk of colon cancer.
- But most research shows no clear link between lutein intake and a lower risk of colorectal cancer.
- It isn’t known whether lutein supplements have any effect on colorectal cancer risk.
Browse 3 studies
ObservationalDietary carotenoids and risk of colorectal cancer in a pooled analysis of 11 cohort studies2007n=702,647
A pooled analysis of 11 cohorts (702,647 participants) found no consistent association between lutein/zeaxanthin intake and colorectal cancer risk.
- Effect
- No Benefit
- Population
- Adults
- Participants
- 702,647
- Ages
- 6–20
RCTDietary and serum alpha-tocopherol, beta-carotene and retinol, and risk for colorectal cancer in male smokers2002n=26,951
In 26,951 male smokers, dietary and serum carotenoids including lutein/zeaxanthin were not significantly associated with colorectal cancer risk over 8 years of follow-up.
- Effect
- No Benefit
- Duration
- 8 years
- Dose
- 50 mg/day
- Population
- Older adults
- Participants
- 26,951
ObservationalCarotenoids and colon cancer2000n=4,403
In 4,343 colorectal cancer cases and controls, higher dietary lutein intake was inversely associated with colon cancer risk (OR 0.83), especially in younger patients and proximal colon tumors.
- Effect
- Benefit
- Population
- Adults
- Participants
- 4,403
Vitamin AView supplement →
Do not purchase·★★★★★
How we scored this▸
- Taking vitamin A by itself or with beta-carotene does not appear to lower the risk of colorectal cancer based on current research.
Browse 1 study·1 meta-analysis
MetaAntioxidant supplements for prevention of gastrointestinal cancers: a systematic review and meta-analysis2004n=170
A meta-analysis of 14 gastrointestinal cancer prevention trials found antioxidant supplements including selenium did not reduce GI cancer incidence and beta-carotene increased mortality in high-quality trials.
- Effect
- No Benefit
- Participants
- 170
ZeaxanthinView supplement →
Do not purchase·★★★★★
How we scored this▸
- It is not clear if taking zeaxanthin by mouth helps prevent colorectal cancer.
- Most studies show no link between eating lutein and zeaxanthin and lowering the risk of colorectal cancer.
Browse 3 studies
ObservationalDietary carotenoids and risk of colorectal cancer in a pooled analysis of 11 cohort studies2007n=702,647
A pooled analysis of 11 cohorts (702,647 participants) found no consistent association between lutein/zeaxanthin intake and colorectal cancer risk.
- Effect
- No Benefit
- Population
- Adults
- Participants
- 702,647
- Ages
- 6–20
RCTDietary and serum alpha-tocopherol, beta-carotene and retinol, and risk for colorectal cancer in male smokers2002n=26,951
In 26,951 male smokers, dietary and serum carotenoids including lutein/zeaxanthin were not significantly associated with colorectal cancer risk over 8 years of follow-up.
- Effect
- No Benefit
- Duration
- 8 years
- Dose
- 50 mg/day
- Population
- Older adults
- Participants
- 26,951
ObservationalCarotenoids and colon cancer2000n=4,403
In 4,343 colorectal cancer cases and controls, higher dietary lutein intake was inversely associated with colon cancer risk (OR 0.83), especially in younger patients and proximal colon tumors.
- Effect
- Benefit
- Population
- Adults
- Participants
- 4,403
NattokinaseView supplement →
Do not purchase·★★★★★
How we scored this▸
- Eating soy foods might lower the risk of colorectal cancer, according to population studies in Asia.
- However, clinical studies have not shown clear evidence that soy protein or supplements reduce cell changes linked to cancer growth.
Browse 2 studies
ObservationalSoy Intake and Colorectal Cancer Risk: Results from a Pooled Analysis of Prospective Cohort Studies Conducted in China and Japan2020n=205,060
In a pooled analysis of 205,060 adults from 4 Asian cohorts followed 12.7 years, soy protein and isoflavone intake were not significantly associated with colorectal cancer risk overall.
- Effect
- No Benefit
- Population
- Adults
- Participants
- 205,060
RCTSoy protein containing isoflavones does not decrease colorectal epithelial cell proliferation in a randomized controlled trial2005n=50
In 125 adults with adenomatous polyps, 58 g/day soy protein with 83 mg isoflavones for 12 months increased sigmoid colon epithelial cell proliferation by 11% vs isoflavone-depleted soy protein.
- Effect
- No Benefit
- Duration
- 12 months
- Dose
- 58 g/day
- Population
- Adults
- Participants
- 50
- Ages
- 50–80
Evidence visualised
Same ratings as above, aggregated so you can see coverage and imbalance.
| Supplement | DEX | Studies | Meta-analyses | Share |
|---|---|---|---|---|
| Vitamin B9 (Folate) | ★★★★★56% | 19 | 6 | 16% |
| Calcium | ★★★★★68% | 17 | 7 | 14% |
| Vitamin E | ★★★★★44% | 12 | 3 | 10% |
| Black Tea | ★★★★★44% | 10 | 1 | 8% |
| Garlic | ★★★★★56% | 10 | 4 | 8% |
| Green Tea | ★★★★★44% | 10 | 4 | 8% |
| Vitamin D | ★★★★★40% | 9 | 3 | 7% |
| Lycopene | ★★★★★40% | 5 | 1 | 4% |
| Multivitamin | ★★★★★40% | 5 | 1 | 4% |
| Flaxseed | ★★★★★44% | 3 | 0 | 2% |
| Lutein | ★★★★★36% | 3 | 0 | 2% |
| Methionine | ★★★★★52% | 3 | 1 | 2% |
| Olive Oil | ★★★★★52% | 3 | 1 | 2% |
| Zeaxanthin | ★★★★★36% | 3 | 0 | 2% |
| Ginger | ★★★★★44% | 2 | 0 | 2% |
| Nattokinase | ★★★★★32% | 2 | 0 | 2% |
| Curcumin | ★★★★★36% | 1 | 0 | <1% |
| N-Acetyl Cysteine (NAC) | ★★★★★44% | 1 | 0 | <1% |
| Probiotics | ★★★★★64% | 1 | 1 | <1% |
| Vitamin A | ★★★★★36% | 1 | 1 | <1% |
| Vitamin B2 (Riboflavin) | ★★★★★40% | 1 | 0 | <1% |
| Vitamin K | ★★★★★40% | 1 | 0 | <1% |