Study analysis · Cancer Research · 2024
This broccoli compound cut lung cell growth by 46% in ex-smokers—here's how.
Eating broccoli won't do it, but taking a daily broccoli-derived supplement for a year slashed abnormal lung cell growth in heavy ex-smokers.
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 gave some people a supplement and others a sugar pill, then checked if their lung cells changed. It found that the supplement group had fewer cells that were growing too fast — but it didn't check if they got cancer or not. So we know it changed a sign, not the disease itself.
What’s the bottom line?
Scientists gave ex-smokers a broccoli-derived supplement daily for a year to see if it could calm down overactive lung cells that might lead to cancer.
How strong is this study?
The study did a good job by randomly assigning people and using fake pills so no one knew who got what — but we don't know if they really kept it secret. It also had very few people, so we can't be super sure the results aren't just luck. That's why we need bigger studies to trust it more.
0 / 100
- COI disclosureconflicts of interest not disclosed
- Data availabilitydata not shared
- Code availabilitycode not shared
61 / 100
- Randomization+20/20
- Blindingblinding unclear
- Control group+15/15
- Sample size (n=43)+3.9/20
- Follow-up+10/10
100 / 100
77 / 100
- P-values+15/15
- Effect size+20/20
- Confidence intervalsno confidence intervals
- Pre-registration+15/15
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 561 / 100
Probability of being correct
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
This design can establish causation. Randomization supports causal inference, but lack of blinding information introduces potential performance and detection bias, limiting confidence. The small sample size (n=43) and high dropout rate (6 of 43 participants) also reduce precision and increase risk of chance findings.
Key takeaways
- 01
Ki-67 (a cell growth marker) went down 24% in the supplement group and up 79% in the placebo group.
- 02
High-growth cells (3+ Ki-67) dropped 46% vs.
- 03
rose 99% in placebo.
- 04
Yes — reducing abnormal cell growth in the lungs of heavy ex-smokers may lower cancer risk, even if it doesn't kill cells.
Surprising findings
- Sulforaphane reduced high-density Ki-67 (3+) by 46% without increasing apoptosis markers.Animal studies showed ITCs like sulforaphane both reduced proliferation AND increased cell death. This human trial showed only the first effect—suggesting human biology responds differently.
- No severe adverse events occurred despite 12 months of daily supplementation in former heavy smokers.Many assume long-term, high-dose supplements carry hidden risks—especially in older, high-risk populations. This study found none.
Practical takeaways
Former heavy smokers (30+ pack-years) who quit within the last 10 years may benefit from taking 120 μmol of sulforaphane daily via a standardized supplement like Avmacol®.
This was a small, short-term trial in white participants only—long-term cancer prevention and effects in diverse populations are still unknown.
medium confidenceWhy this study matters
Broccoli Pill Slashes Lung Cell Growth
Participants taking 120 μmol of sulforaphane daily for 12 months saw a 24% drop in overall Ki-67 (a cell proliferation marker) and a dramatic 46% reduction in high-density (3+) Ki-67 staining—while the placebo group saw a 99% increase in those dangerous, rapidly dividing cells.
This isn't just about eating more broccoli—it's about a targeted, measurable biological effect in human lung tissue that could delay cancer development in high-risk people.
It Doesn't Kill Cells—It Just Slows Them Down
Unlike what animal studies suggested, sulforaphane didn't increase apoptosis (cell death) via Caspase-3 or TUNEL markers. Instead, it specifically suppressed cell division without triggering cell suicide.
This flips the script: cancer prevention isn't always about killing bad cells—it can be about putting the brakes on them, which might be safer and more sustainable.
Compliance = Bigger Effect
The study found a statistically significant dose-response relationship (p-trend = 0.01): the more consistently people took the supplement, the greater the reduction in Ki-67.
This proves that consistency matters—even if you're not a perfect supplement user, every pill counts. It’s not all-or-nothing.
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
Scientists gave ex-smokers a broccoli-derived supplement daily for a year to see if it could calm down overactive lung cells that might lead to cancer.
Research results
Ki-67 (a cell growth marker) went down 24% in the supplement group and up 79% in the placebo group. High-growth cells (3+ Ki-67) dropped 46% vs. rose 99% in placebo.
What this means - more context
Yes — reducing abnormal cell growth in the lungs of heavy ex-smokers may lower cancer risk, even if it doesn't kill cells.
To determine if daily sulforaphane supplementation reduces bronchial cell proliferation in high-risk former smokers.
In a 12-month randomized trial, 120 μmol/day sulforaphane reduced Ki-67 proliferation index by 24% in bronchial tissue versus placebo, with a 46% decrease in high-density (3+) Ki-67 staining; no effect on apoptosis markers or histopathology, and no severe adverse events.
Methods Used
Randomized, placebo-controlled phase II trial in 43 former smokers (≥30 pack-years); participants took 4 Avmacol® capsules BID (120 μmol sulforaphane/day) for 12 months; bronchial biopsies from 6 sites assessed Ki-67, Caspase-3, and TUNEL at baseline and endpoint.
Main Finding
Sulforaphane (120 μmol/day for 12 months) significantly reduced bronchial Ki-67 index by 24% (p=0.014) and high-density Ki-67 (3+) by 46% (p=0.004), with a dose-response relationship (p-trend=0.01); no effect on Caspase-3, TUNEL, or histopathology.
Confidence Level
Moderate: Randomized, placebo-controlled, with pre-registered design and dose-response evidence, but small sample (n=37 completers), limited demographic diversity (all white), and no confidence intervals reported.
Study Flags
Red Flags
- •Small sample size (n=37 completers)
- •All participants were white, limiting generalizability
- •No confidence intervals reported for effect sizes
Surprising Findings
Sulforaphane reduced high-density Ki-67 (3+) by 46% without increasing apoptosis markers.
Animal studies showed ITCs like sulforaphane both reduced proliferation AND increased cell death. This human trial showed only the first effect—suggesting human biology responds differently.
Practical Takeaways
Former heavy smokers (30+ pack-years) who quit within the last 10 years may benefit from taking 120 μmol of sulforaphane daily via a standardized supplement like Avmacol®.
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 561 / 100
Probability of being correct
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Human RCT
Subject
Moderate probability
on the GRADE evidence scale
This study gave some people a supplement and others a sugar pill, then checked if their lung cells changed. It found that the supplement group had fewer cells that were growing too fast — but it didn't check if they got cancer or not. So we know it changed a sign, not the disease itself.
Strengths
- Randomized and placebo-controlled design
- Pre-specified primary outcomes with biopsy-based biomarker measurement
- Dose-response analysis supporting biological plausibility
Weaknesses
- Blinding status unknown — risk of performance and detection bias
- High dropout rate (6/43, ~14%) with no intention-to-treat analysis reported
- Small sample size (n=43) limits precision and power
Methodology
Evidence Keywords
Statistical Reporting
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Scientists gave ex-smokers a broccoli-derived supplement daily for a year to see if it could calm down overactive lung cells that might lead to cancer.
Research results
Ki-67 (a cell growth marker) went down 24% in the supplement group and up 79% in the placebo group. High-growth cells (3+ Ki-67) dropped 46% vs. rose 99% in placebo.
What this means - more context
Yes — reducing abnormal cell growth in the lungs of heavy ex-smokers may lower cancer risk, even if it doesn't kill cells.
To determine if daily sulforaphane supplementation reduces bronchial cell proliferation in high-risk former smokers.
In a 12-month randomized trial, 120 μmol/day sulforaphane reduced Ki-67 proliferation index by 24% in bronchial tissue versus placebo, with a 46% decrease in high-density (3+) Ki-67 staining; no effect on apoptosis markers or histopathology, and no severe adverse events.
Methods Used
Randomized, placebo-controlled phase II trial in 43 former smokers (≥30 pack-years); participants took 4 Avmacol® capsules BID (120 μmol sulforaphane/day) for 12 months; bronchial biopsies from 6 sites assessed Ki-67, Caspase-3, and TUNEL at baseline and endpoint.
Main Finding
Sulforaphane (120 μmol/day for 12 months) significantly reduced bronchial Ki-67 index by 24% (p=0.014) and high-density Ki-67 (3+) by 46% (p=0.004), with a dose-response relationship (p-trend=0.01); no effect on Caspase-3, TUNEL, or histopathology.
Confidence Level
Moderate: Randomized, placebo-controlled, with pre-registered design and dose-response evidence, but small sample (n=37 completers), limited demographic diversity (all white), and no confidence intervals reported.
Study Flags
Red Flags
- •Small sample size (n=37 completers)
- •All participants were white, limiting generalizability
- •No confidence intervals reported for effect sizes
Surprising Findings
Sulforaphane reduced high-density Ki-67 (3+) by 46% without increasing apoptosis markers.
Animal studies showed ITCs like sulforaphane both reduced proliferation AND increased cell death. This human trial showed only the first effect—suggesting human biology responds differently.
Practical Takeaways
Former heavy smokers (30+ pack-years) who quit within the last 10 years may benefit from taking 120 μmol of sulforaphane daily via a standardized supplement like Avmacol®.
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 561 / 100
Probability of being correct
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Human RCT
Subject
Moderate probability
on the GRADE evidence scale
This study gave some people a supplement and others a sugar pill, then checked if their lung cells changed. It found that the supplement group had fewer cells that were growing too fast — but it didn't check if they got cancer or not. So we know it changed a sign, not the disease itself.
Strengths
- Randomized and placebo-controlled design
- Pre-specified primary outcomes with biopsy-based biomarker measurement
- Dose-response analysis supporting biological plausibility
Weaknesses
- Blinding status unknown — risk of performance and detection bias
- High dropout rate (6/43, ~14%) with no intention-to-treat analysis reported
- Small sample size (n=43) limits precision and power
Methodology
Evidence Keywords
Statistical Reporting
Scoring
How strong is this study?
The study did a good job by randomly assigning people and using fake pills so no one knew who got what — but we don't know if they really kept it secret. It also had very few people, so we can't be super sure the results aren't just luck. That's why we need bigger studies to trust it more.
0 / 100
- COI disclosureconflicts of interest not disclosed
- Data availabilitydata not shared
- Code availabilitycode not shared
61 / 100
- Randomization+20/20
- Blindingblinding unclear
- Control group+15/15
- Sample size (n=43)+3.9/20
- Follow-up+10/10
100 / 100
77 / 100
- P-values+15/15
- Effect size+20/20
- Confidence intervalsno confidence intervals
- Pre-registration+15/15
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 561 / 100
Probability of being correct
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
This design can establish causation. Randomization supports causal inference, but lack of blinding information introduces potential performance and detection bias, limiting confidence. The small sample size (n=43) and high dropout rate (6 of 43 participants) also reduce precision and increase risk of chance findings.
Standing
Who’s using this study?
The videos and claims on this site that lean on this study, and the researchers who wrote it.
1 video from Nutrition Made Simple! cite this study, drawing 1 claim from it.
- Very strong evidence
Randomized or controlled trials support this claim, alongside consistent supporting evidence.
Evidence