Study analysis · International journal of cancer · 2020
Eating more branched-chain amino acids after colorectal cancer was linked to a 30% higher relative risk of death from any cause, but not from cancer itself.
In a study of 1,674 colorectal cancer patients, those who ate the most BCAAs had a 30% higher relative risk of dying from any cause compared to those who ate the least, but the study couldn't prove cause and effect and didn't say how many extra deaths that means.
Overview
What the study found
The study in plain English — the bottom line, every takeaway we extracted, and what to do with them.
In simple terms
This study followed people after they were diagnosed with colon or rectal cancer and checked whether those who ate more BCAAs (nutrients found in meat and milk) died sooner. It can show a link between eating more BCAAs and dying from any cause, but it cannot prove that BCAAs caused the deaths. To prove cause, scientists would need a randomized experiment, which this was not.
What’s the bottom line?
Researchers followed 1,674 people who had nonmetastatic colorectal cancer and asked what they ate. They focused on branched-chain amino acids (BCAAs), nutrients found in meat, milk, and fish.
How strong is this study?
The study is fairly strong because it followed a large group of patients for many years and used careful diet questionnaires. But people choose what they eat, so other differences between high and low BCAA eaters could explain the results. That means we should treat the findings as a clue, not a final answer.
0 / 100
- COI disclosureconflicts of interest not disclosed
- Data availabilitydata not shared
- Code availabilitycode not shared
37 / 100
- Randomizationnot randomized
- Blindingblinding unclear
- Control groupno control group
- Sample size (n=1674)+20/20
- Follow-up+10/10
100 / 100
77 / 100
- P-values+15/15
- Effect size+20/20
- Confidence intervals+15/15
- Pre-registrationnot pre-registered
Each component is scored out of 100 and then capped by the study design — a case series cannot reach the ceiling a randomised trial can, however well it is reported.
Where it sits
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 552 / 100
Probability of being correct
Groups of people are followed over time to see who develops an outcome. Strong for identifying risk factors and associations, but cannot prove causation as firmly as RCTs.
This design cannot establish causation — the findings describe an association, not a cause. Observational prospective cohort study without randomization or a control group. It can show associations but cannot control for unmeasured confounding, reverse causation, or selection effects. Dietary exposure is self-reported, and the study cannot prove that branched-chain amino acid intake causes mortality differences.
COI Unknown
Could not determine conflict of interest status
No conflicts of interest or funding information were included in the provided text; the manuscript appears truncated before disclosure sections.
The provided text is truncated and lacks an author list, affiliations, funding statement, and conflict-of-interest disclosures. No industry funding or author COI can be confirmed from the available text.
Key takeaways
- 01
People who ate the most total BCAAs had a 30% higher relative risk of dying from any cause compared with those who ate the least (HR 1.30).
- 02
For death from colorectal cancer itself, the relative risk was 18% higher, but this was not statistically significant (HR 1.18).
- 03
Valine alone showed a 33% higher relative risk of all-cause death (HR 1.33).
- 04
The study did not report the absolute risk increase.
- 05
The study did not report how many people died in the lowest-intake group, so we cannot say exactly how many extra deaths are linked to higher BCAA intake.
- 06
Overall, 991 of 1,674 patients died during about 10.6 years, but the absolute risk difference between high and low BCAA intake remains unknown.
Surprising findings
- Higher BCAA intake was linked to all-cause mortality but not cancer-specific mortality.It challenges the assumption that BCAAs directly fuel cancer growth; instead, the effect might be through other health conditions like heart disease.
- Valine showed a stronger association than leucine or isoleucine.All three BCAAs are often considered together, but this study suggests valine might be particularly important.
- BCAA intake was almost perfectly correlated with animal protein intake (r=0.92).It's hard to separate the effect of BCAAs from the effect of animal protein, which is known to be associated with worse outcomes.
Practical takeaways
If you are a colorectal cancer survivor, consider moderating your intake of BCAAs, especially from animal sources, and emphasize plant protein instead.
This is based on an observational study that cannot prove cause and effect. The absolute risk increase is unknown. Consult your oncologist or dietitian before making significant dietary changes.
low to medium confidenceIf you take BCAA supplements for muscle building, be aware that this study raises questions about their safety after a cancer diagnosis. Discuss with your doctor.
The study did not examine supplements, only dietary intake. The findings may not apply to supplements.
low confidenceFocus on overall diet quality: previous research in the same cohort found that higher animal protein intake was linked to worse survival, while vegetable protein was linked to better survival.
This is not from the current study but from the same cohort and is also observational.
medium confidenceWhy this study matters
BCAAs Linked to Higher All-Cause Mortality, But Not Cancer-Specific Mortality
The study found that higher postdiagnostic total BCAA intake was associated with a 30% higher relative risk of all-cause mortality (HR 1.30, 95% CI 1.01-1.69) when comparing highest to lowest quartile. However, there was no significant association with colorectal cancer-specific mortality (HR 1.18, 95% CI 0.75-1.85). The absolute risk difference was not reported.
This suggests that BCAAs might affect overall health through non-cancer pathways, such as cardiovascular disease, rather than directly promoting cancer growth.
Valine Stands Out Among BCAAs
Among individual BCAAs, valine intake showed the strongest association: a 33% higher relative risk of all-cause mortality (HR 1.33, 95% CI 1.03-1.73, P trend=0.02). Leucine and isoleucine had non-significant trends (HR 1.28 and 1.25, respectively).
If you're going to single out one amino acid, valine seems to be the one most linked to mortality, which could guide future research.
The Animal Protein Confounder: BCAAs Are Highly Correlated with Meat Intake
Dietary BCAA intake was highly correlated with animal protein intake (r=0.92) but only weakly with vegetable protein (r=0.24). Animal protein itself was associated with a 64% higher relative risk of CRC-specific mortality and a 47% higher relative risk of all-cause mortality, while vegetable protein was linked to lower risk.
This raises the question: are BCAAs harmful, or is it the animal protein (and other compounds in meat) that's driving the association?
Sex Differences: Association Primarily in Men, But Not Statistically Significant
The positive association between BCAA intake and all-cause mortality appeared mainly in men, with no significant association in women. However, tests for heterogeneity by sex were not statistically significant, so this difference could be due to chance.
It hints at potential biological differences, but we can't be sure yet.
No Absolute Risk Reported: We Don't Know How Many Extra Deaths
The study did not report the absolute risk difference. Overall, 991 of 1,674 patients died during a median follow-up of 10.6 years, but deaths were not broken down by BCAA quartile. So we can't say how many extra deaths are linked to high BCAA intake.
Without absolute risk, it's hard to gauge the real-world impact. A 30% relative increase could mean a small or large absolute increase depending on baseline risk.
Want the whole report?
Detailed mode opens the full scientific breakdown — every score component, the methodology, conflicts of interest, the evidence analysis behind each claim, and the raw study data.
Overview
What the study found
The study in plain English — the bottom line, every takeaway we extracted, and what to do with them.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Researchers followed 1,674 people who had nonmetastatic colorectal cancer and asked what they ate. They focused on branched-chain amino acids (BCAAs), nutrients found in meat, milk, and fish.
Research results
People who ate the most total BCAAs had a 30% higher relative risk of dying from any cause compared with those who ate the least (HR 1.30). For death from colorectal cancer itself, the relative risk was 18% higher, but this was not statistically significant (HR 1.18). Valine alone showed a 33% higher relative risk of all-cause death (HR 1.33). The study did not report the absolute risk increase.
What this means - more context
The study did not report how many people died in the lowest-intake group, so we cannot say exactly how many extra deaths are linked to higher BCAA intake. Overall, 991 of 1,674 patients died during about 10.6 years, but the absolute risk difference between high and low BCAA intake remains unknown.
To evaluate whether higher postdiagnostic dietary intake of branched-chain amino acids (BCAAs) is associated with colorectal cancer-specific and all-cause mortality among patients with nonmetastatic colorectal cancer.
In 1,674 patients with nonmetastatic colorectal cancer from the Nurses' Health Study and Health Professionals Follow-up Study, higher postdiagnostic total BCAA intake was associated with a 30% higher relative risk of all-cause mortality (HR 1.30, 95% CI 1.01–1.69, P for trend=0.04) comparing highest with lowest quartile, but not with colorectal cancer-specific mortality (HR 1.18, 95% CI 0.75–1.85, P for trend=0.46). Valine intake showed a 33% higher relative risk of all-cause mortality (HR 1.33, 95% CI 1.03–1.73, P for trend=0.02); leucine and isoleucine had non-significant trends. Absolute risk difference was not reported in the study.
Methods Used
Prospective cohort study using validated food frequency questionnaires to assess postdiagnostic dietary BCAA intake, with multivariable Cox proportional hazards regression adjusted for tumor characteristics and potential confounders. Median follow-up was 10.6 years.
Main Finding
Higher postdiagnostic total BCAA intake was associated with a 30% higher relative risk of all-cause mortality (highest vs lowest quartile HR 1.30, 95% CI 1.01–1.69, P for trend=0.04), but no statistically significant association was found for colorectal cancer-specific mortality (HR 1.18, 95% CI 0.75–1.85). Valine showed a 33% higher relative risk of all-cause mortality (HR 1.33, 95% CI 1.03–1.73). The absolute risk increase was not reported; overall 991 of 1,674 patients died during median 10.6 years, but deaths were not reported by BCAA quartile.
Confidence Level
Observational design cannot establish causation; residual confounding is possible. The study adjusted for many confounders but lacked data on treatment and recurrence, and participants were mostly white US health professionals, limiting generalizability. Findings are suggestive and require confirmation.
Study Flags
Red Flags
- •Observational design cannot prove causation; residual confounding possible
- •Absolute risk difference not reported; only relative risks are available
- •Limited generalizability (mostly white US health professionals) and no data on treatment or recurrence
Surprising Findings
Higher BCAA intake was linked to all-cause mortality but not cancer-specific mortality.
It challenges the assumption that BCAAs directly fuel cancer growth; instead, the effect might be through other health conditions like heart disease.
Practical Takeaways
If you are a colorectal cancer survivor, consider moderating your intake of BCAAs, especially from animal sources, and emphasize plant protein instead.
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 552 / 100
Probability of being correct
Groups of people are followed over time to see who develops an outcome. Strong for identifying risk factors and associations, but cannot prove causation as firmly as RCTs.
Human Cohort Study
Subject
Moderate probability
on the GRADE evidence scale
This study followed people after they were diagnosed with colon or rectal cancer and checked whether those who ate more BCAAs (nutrients found in meat and milk) died sooner. It can show a link between eating more BCAAs and dying from any cause, but it cannot prove that BCAAs caused the deaths. To prove cause, scientists would need a randomized experiment, which this was not.
Strengths
- Prospective cohort design with long follow-up (median 10.6 years).
- Large sample of 1,674 colorectal cancer patients from two well-established cohorts (NHS and HPFS).
- Validated food frequency questionnaires used to assess dietary intake.
Weaknesses
- Observational design cannot establish causation.
- Residual confounding cannot be excluded despite extensive adjustment.
- Dietary exposure measured by self-report FFQ, prone to measurement error and misclassification.
Methodology
Evidence Keywords
Statistical Reporting
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Researchers followed 1,674 people who had nonmetastatic colorectal cancer and asked what they ate. They focused on branched-chain amino acids (BCAAs), nutrients found in meat, milk, and fish.
Research results
People who ate the most total BCAAs had a 30% higher relative risk of dying from any cause compared with those who ate the least (HR 1.30). For death from colorectal cancer itself, the relative risk was 18% higher, but this was not statistically significant (HR 1.18). Valine alone showed a 33% higher relative risk of all-cause death (HR 1.33). The study did not report the absolute risk increase.
What this means - more context
The study did not report how many people died in the lowest-intake group, so we cannot say exactly how many extra deaths are linked to higher BCAA intake. Overall, 991 of 1,674 patients died during about 10.6 years, but the absolute risk difference between high and low BCAA intake remains unknown.
To evaluate whether higher postdiagnostic dietary intake of branched-chain amino acids (BCAAs) is associated with colorectal cancer-specific and all-cause mortality among patients with nonmetastatic colorectal cancer.
In 1,674 patients with nonmetastatic colorectal cancer from the Nurses' Health Study and Health Professionals Follow-up Study, higher postdiagnostic total BCAA intake was associated with a 30% higher relative risk of all-cause mortality (HR 1.30, 95% CI 1.01–1.69, P for trend=0.04) comparing highest with lowest quartile, but not with colorectal cancer-specific mortality (HR 1.18, 95% CI 0.75–1.85, P for trend=0.46). Valine intake showed a 33% higher relative risk of all-cause mortality (HR 1.33, 95% CI 1.03–1.73, P for trend=0.02); leucine and isoleucine had non-significant trends. Absolute risk difference was not reported in the study.
Methods Used
Prospective cohort study using validated food frequency questionnaires to assess postdiagnostic dietary BCAA intake, with multivariable Cox proportional hazards regression adjusted for tumor characteristics and potential confounders. Median follow-up was 10.6 years.
Main Finding
Higher postdiagnostic total BCAA intake was associated with a 30% higher relative risk of all-cause mortality (highest vs lowest quartile HR 1.30, 95% CI 1.01–1.69, P for trend=0.04), but no statistically significant association was found for colorectal cancer-specific mortality (HR 1.18, 95% CI 0.75–1.85). Valine showed a 33% higher relative risk of all-cause mortality (HR 1.33, 95% CI 1.03–1.73). The absolute risk increase was not reported; overall 991 of 1,674 patients died during median 10.6 years, but deaths were not reported by BCAA quartile.
Confidence Level
Observational design cannot establish causation; residual confounding is possible. The study adjusted for many confounders but lacked data on treatment and recurrence, and participants were mostly white US health professionals, limiting generalizability. Findings are suggestive and require confirmation.
Study Flags
Red Flags
- •Observational design cannot prove causation; residual confounding possible
- •Absolute risk difference not reported; only relative risks are available
- •Limited generalizability (mostly white US health professionals) and no data on treatment or recurrence
Surprising Findings
Higher BCAA intake was linked to all-cause mortality but not cancer-specific mortality.
It challenges the assumption that BCAAs directly fuel cancer growth; instead, the effect might be through other health conditions like heart disease.
Practical Takeaways
If you are a colorectal cancer survivor, consider moderating your intake of BCAAs, especially from animal sources, and emphasize plant protein instead.
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 552 / 100
Probability of being correct
Groups of people are followed over time to see who develops an outcome. Strong for identifying risk factors and associations, but cannot prove causation as firmly as RCTs.
Human Cohort Study
Subject
Moderate probability
on the GRADE evidence scale
This study followed people after they were diagnosed with colon or rectal cancer and checked whether those who ate more BCAAs (nutrients found in meat and milk) died sooner. It can show a link between eating more BCAAs and dying from any cause, but it cannot prove that BCAAs caused the deaths. To prove cause, scientists would need a randomized experiment, which this was not.
Strengths
- Prospective cohort design with long follow-up (median 10.6 years).
- Large sample of 1,674 colorectal cancer patients from two well-established cohorts (NHS and HPFS).
- Validated food frequency questionnaires used to assess dietary intake.
Weaknesses
- Observational design cannot establish causation.
- Residual confounding cannot be excluded despite extensive adjustment.
- Dietary exposure measured by self-report FFQ, prone to measurement error and misclassification.
Methodology
Evidence Keywords
Statistical Reporting
Scoring
How strong is this study?
The study is fairly strong because it followed a large group of patients for many years and used careful diet questionnaires. But people choose what they eat, so other differences between high and low BCAA eaters could explain the results. That means we should treat the findings as a clue, not a final answer.
0 / 100
- COI disclosureconflicts of interest not disclosed
- Data availabilitydata not shared
- Code availabilitycode not shared
37 / 100
- Randomizationnot randomized
- Blindingblinding unclear
- Control groupno control group
- Sample size (n=1674)+20/20
- Follow-up+10/10
100 / 100
77 / 100
- P-values+15/15
- Effect size+20/20
- Confidence intervals+15/15
- Pre-registrationnot pre-registered
Each component is scored out of 100 and then capped by the study design — a case series cannot reach the ceiling a randomised trial can, however well it is reported.
Where it sits
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 552 / 100
Probability of being correct
Groups of people are followed over time to see who develops an outcome. Strong for identifying risk factors and associations, but cannot prove causation as firmly as RCTs.
This design cannot establish causation — the findings describe an association, not a cause. Observational prospective cohort study without randomization or a control group. It can show associations but cannot control for unmeasured confounding, reverse causation, or selection effects. Dietary exposure is self-reported, and the study cannot prove that branched-chain amino acid intake causes mortality differences.
COI Unknown
Could not determine conflict of interest status
No conflicts of interest or funding information were included in the provided text; the manuscript appears truncated before disclosure sections.
The provided text is truncated and lacks an author list, affiliations, funding statement, and conflict-of-interest disclosures. No industry funding or author COI can be confirmed from the available text.
Standing
The people behind it
The researchers who wrote the study this analysis is built on.
Authored by
15 researchersIf this is your work, this is how we attribute it on Fit Body Science. Lü Long is listed as the lead author.