Study analysis · Journal of Cachexia, Sarcopenia and Muscle · 2022
Eating more meat might help your bones—but protein supplements won't.
Older people who eat more animal protein have slightly stronger bones, but taking protein shakes for 6 months doesn't make bones denser.
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 looked at what older people ate and how strong their bones were, and found that people who ate more meat and dairy tended to have stronger bones, while those who ate more plants tended to have weaker bones. But it didn’t prove that eating more meat made bones stronger — maybe people with weaker bones just ate less meat because they didn’t feel like chewing.
What’s the bottom line?
This study looked at whether eating more protein, especially from meat and dairy, helps keep bones strong in people over 65.
How strong is this study?
The researchers did a good job combining data from four different studies to get a bigger sample, and they tried to fix for things like age and exercise. But since they didn’t randomly assign people to eat different foods, we can’t be sure the food caused the bone changes — it’s like noticing that people who wear hats have more hair, but that doesn’t mean hats grow hair.
40 / 100
- COI disclosure+40/40
- Data availabilitydata not shared
- Code availabilitycode not shared
56 / 100
- Randomizationrandomization unclear
- Blindingblinding unclear
- Control group+15/15
- Sample size (n=1570)+20.0/20
- 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 567 / 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. This study is observational and uses data from multiple cohorts without randomization. Although it adjusts for confounders like age, sex, and nutrient intake, it cannot rule out reverse causation or unmeasured confounding (e.g., lifestyle, overall diet quality, or health behaviors). The longitudinal component showed no significant effect of protein supplementation on BMD, further limiting causal inference.
No Conflicts
No conflicts of interest identified
No conflicts of interest were disclosed, and the study appears independently conducted with no evidence of industry control over design, analysis, or publication.
Funders
Independent Analysis Safeguards
- Data combined from four independently conducted trials with separate ethical approvals
- Dietary and BMD assessments conducted by trained professionals using standardized protocols
- Statistical analyses performed using adjusted linear mixed models without funder involvement described
The study integrates data from four publicly funded European trials with no indication of industry sponsorship or author industry employment. All trials obtained ethical approval from independent committees, and funding sources are academic or governmental.
Key takeaways
- 01
People who ate more total or animal protein had slightly denser bones (0.001–0.002 g/cm² higher per gram of protein).
- 02
Those who ate more plant protein had slightly less dense bones.
- 03
But giving extra protein supplements for up to 24 weeks didn’t make bones denser.
- 04
The bone density changes are very small—like a fraction of a penny’s weight spread over a whole bone.
- 05
It’s not enough to prevent fractures on its own.
Surprising findings
- Plant protein was linked to lower bone density, even after adjusting for calcium and vitamin D intake.Most people assume plant foods are bone-friendly due to alkaline properties, but this study found the opposite—even in people with adequate nutrients.
- The bone density changes from protein intake were tiny—like a fraction of a penny’s weight spread over a whole bone.Media often portrays protein as a miracle bone builder, but the actual effect size is clinically negligible on its own.
Practical takeaways
If you're over 65, aim for a higher ratio of animal to plant protein (e.g., more dairy, eggs, fish) to support bone density.
This is observational—correlation isn't causation. Also, increasing meat intake without balancing fiber and micronutrients may harm other health areas.
medium confidenceDon’t rely on protein shakes alone to strengthen bones—supplements for 3–6 months showed no measurable benefit.
Longer-term studies (18+ months) with resistance training show promise—so consistency and mechanical loading matter more than supplements.
high confidenceCombine protein intake with adequate calcium (>950 mg/day) and vitamin D (>50 nmol/L) for the strongest bone density association.
Only 23% of participants in this study had both adequate calcium and vitamin D—most are deficient.
high confidenceWhy this study matters
Animal Protein = Slightly Stronger Bones
Each extra gram of animal protein per day was linked to a 0.0011–0.0017 g/cm² increase in bone mineral density (BMD) at the spine and total body—equivalent to the weight of a fraction of a penny spread across an entire bone.
This challenges the idea that plant-based diets are automatically better for bones, suggesting animal protein may have a unique role in bone health for older adults.
Plant Protein Linked to Lower BMD
Higher plant protein intake was associated with a 0.0010–0.0019 g/cm² decrease in BMD—even after adjusting for calcium, vitamin D, and activity levels.
This flips the script on vegan and plant-based health narratives—suggesting that even healthy plant foods might not support bone density as well as expected.
Protein Supplements Don't Work (Short-Term)
Despite 12–24 weeks of protein supplementation (with or without resistance training), no significant improvement in bone density was found in 340 older adults.
People spend billions on protein powders for bone and muscle health—this study says short-term use won't help bones, even with exercise.
Animal-to-Plant Ratio Matters More Than Total Protein
Those with a higher ratio of animal to plant protein had higher BMD—even when total protein intake was identical to others with lower ratios.
It’s not just how much protein you eat—it’s where it comes from. This suggests the source matters more than the total amount.
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
This study looked at whether eating more protein, especially from meat and dairy, helps keep bones strong in people over 65.
Research results
People who ate more total or animal protein had slightly denser bones (0.001–0.002 g/cm² higher per gram of protein). Those who ate more plant protein had slightly less dense bones. But giving extra protein supplements for up to 24 weeks didn’t make bones denser.
What this means - more context
The bone density changes are very small—like a fraction of a penny’s weight spread over a whole bone. It’s not enough to prevent fractures on its own.
This study investigates the association between dietary protein intake (total, plant, animal) and bone mineral density (BMD) in older adults, as well as the effects of short-term protein supplementation with or without resistance exercise.
Cross-sectional analysis found higher total and animal protein intake associated with slightly higher BMD at spine and total body, while plant protein intake was associated with lower BMD. A higher animal-to-plant protein ratio correlated with higher BMD. However, 12–24 weeks of protein supplementation (with or without exercise) did not significantly improve BMD.
Methods Used
Combined individual data from four trials (NU-AGE, ProMO, ProMuscle, PiP) of older adults (≥65 years). Dietary protein intake assessed via 2–7 day food records; BMD measured by DXA. Cross-sectional associations analyzed using adjusted linear mixed models; longitudinal effects assessed over 12–24 weeks with protein supplementation ± resistance exercise.
Main Finding
Each additional gram per day of total protein was associated with a 0.0011–0.0015 g/cm² increase in BMD; animal protein with 0.0011–0.0017 g/cm² increase; plant protein with 0.0010–0.0019 g/cm² decrease. Protein supplementation for 12–24 weeks showed no significant BMD improvement.
Confidence Level
Moderate. Strong adjustment for confounders (age, sex, activity, smoking, alcohol, calcium, vitamin D, energy) and large sample size (n=1570) support cross-sectional findings. Longitudinal findings limited by short duration and small subsample (n=340).
Study Flags
Red Flags
- •Longitudinal intervention duration too short (12–24 weeks) to detect BMD changes
- •Cross-sectional design cannot prove causation
- •Plant protein association may be confounded by overall diet quality or nutrient gaps
No biological mechanisms were identified in this study. This may be an epidemiological, observational, or survey-based study that reports associations rather than proposing causal biological pathways.
Surprising Findings
Plant protein was linked to lower bone density, even after adjusting for calcium and vitamin D intake.
Most people assume plant foods are bone-friendly due to alkaline properties, but this study found the opposite—even in people with adequate nutrients.
Practical Takeaways
If you're over 65, aim for a higher ratio of animal to plant protein (e.g., more dairy, eggs, fish) to support bone density.
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 567 / 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 looked at what older people ate and how strong their bones were, and found that people who ate more meat and dairy tended to have stronger bones, while those who ate more plants tended to have weaker bones. But it didn’t prove that eating more meat made bones stronger — maybe people with weaker bones just ate less meat because they didn’t feel like chewing.
No conflicts of interest were detected in this study. No score impact.
Strengths
- Large combined sample size (n=1570) increases statistical power
- Use of standardized DXA for BMD measurement across sites
- Adjustment for multiple confounders (age, sex, physical activity, smoking, alcohol, calcium, vitamin D, energy intake)
Weaknesses
- No randomization — observational design limits causal inference
- Dietary intake assessed via short-term food records (2–7 days), which may not reflect long-term habits
- Unclear blinding and randomization in original studies — cannot classify as RCT
Methodology
Evidence Keywords
Statistical Reporting
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
This study looked at whether eating more protein, especially from meat and dairy, helps keep bones strong in people over 65.
Research results
People who ate more total or animal protein had slightly denser bones (0.001–0.002 g/cm² higher per gram of protein). Those who ate more plant protein had slightly less dense bones. But giving extra protein supplements for up to 24 weeks didn’t make bones denser.
What this means - more context
The bone density changes are very small—like a fraction of a penny’s weight spread over a whole bone. It’s not enough to prevent fractures on its own.
This study investigates the association between dietary protein intake (total, plant, animal) and bone mineral density (BMD) in older adults, as well as the effects of short-term protein supplementation with or without resistance exercise.
Cross-sectional analysis found higher total and animal protein intake associated with slightly higher BMD at spine and total body, while plant protein intake was associated with lower BMD. A higher animal-to-plant protein ratio correlated with higher BMD. However, 12–24 weeks of protein supplementation (with or without exercise) did not significantly improve BMD.
Methods Used
Combined individual data from four trials (NU-AGE, ProMO, ProMuscle, PiP) of older adults (≥65 years). Dietary protein intake assessed via 2–7 day food records; BMD measured by DXA. Cross-sectional associations analyzed using adjusted linear mixed models; longitudinal effects assessed over 12–24 weeks with protein supplementation ± resistance exercise.
Main Finding
Each additional gram per day of total protein was associated with a 0.0011–0.0015 g/cm² increase in BMD; animal protein with 0.0011–0.0017 g/cm² increase; plant protein with 0.0010–0.0019 g/cm² decrease. Protein supplementation for 12–24 weeks showed no significant BMD improvement.
Confidence Level
Moderate. Strong adjustment for confounders (age, sex, activity, smoking, alcohol, calcium, vitamin D, energy) and large sample size (n=1570) support cross-sectional findings. Longitudinal findings limited by short duration and small subsample (n=340).
Study Flags
Red Flags
- •Longitudinal intervention duration too short (12–24 weeks) to detect BMD changes
- •Cross-sectional design cannot prove causation
- •Plant protein association may be confounded by overall diet quality or nutrient gaps
No biological mechanisms were identified in this study. This may be an epidemiological, observational, or survey-based study that reports associations rather than proposing causal biological pathways.
Surprising Findings
Plant protein was linked to lower bone density, even after adjusting for calcium and vitamin D intake.
Most people assume plant foods are bone-friendly due to alkaline properties, but this study found the opposite—even in people with adequate nutrients.
Practical Takeaways
If you're over 65, aim for a higher ratio of animal to plant protein (e.g., more dairy, eggs, fish) to support bone density.
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 567 / 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 looked at what older people ate and how strong their bones were, and found that people who ate more meat and dairy tended to have stronger bones, while those who ate more plants tended to have weaker bones. But it didn’t prove that eating more meat made bones stronger — maybe people with weaker bones just ate less meat because they didn’t feel like chewing.
No conflicts of interest were detected in this study. No score impact.
Strengths
- Large combined sample size (n=1570) increases statistical power
- Use of standardized DXA for BMD measurement across sites
- Adjustment for multiple confounders (age, sex, physical activity, smoking, alcohol, calcium, vitamin D, energy intake)
Weaknesses
- No randomization — observational design limits causal inference
- Dietary intake assessed via short-term food records (2–7 days), which may not reflect long-term habits
- Unclear blinding and randomization in original studies — cannot classify as RCT
Methodology
Evidence Keywords
Statistical Reporting
Scoring
How strong is this study?
The researchers did a good job combining data from four different studies to get a bigger sample, and they tried to fix for things like age and exercise. But since they didn’t randomly assign people to eat different foods, we can’t be sure the food caused the bone changes — it’s like noticing that people who wear hats have more hair, but that doesn’t mean hats grow hair.
40 / 100
- COI disclosure+40/40
- Data availabilitydata not shared
- Code availabilitycode not shared
56 / 100
- Randomizationrandomization unclear
- Blindingblinding unclear
- Control group+15/15
- Sample size (n=1570)+20.0/20
- 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 567 / 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. This study is observational and uses data from multiple cohorts without randomization. Although it adjusts for confounders like age, sex, and nutrient intake, it cannot rule out reverse causation or unmeasured confounding (e.g., lifestyle, overall diet quality, or health behaviors). The longitudinal component showed no significant effect of protein supplementation on BMD, further limiting causal inference.
No Conflicts
No conflicts of interest identified
No conflicts of interest were disclosed, and the study appears independently conducted with no evidence of industry control over design, analysis, or publication.
Funders
Independent Analysis Safeguards
- Data combined from four independently conducted trials with separate ethical approvals
- Dietary and BMD assessments conducted by trained professionals using standardized protocols
- Statistical analyses performed using adjusted linear mixed models without funder involvement described
The study integrates data from four publicly funded European trials with no indication of industry sponsorship or author industry employment. All trials obtained ethical approval from independent committees, and funding sources are academic or governmental.
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 Shawn Baker MD cite this study, drawing 1 claim from it.
- Very strong evidence
Randomized or controlled trials support this claim, alongside consistent supporting evidence.
Evidence
Authored by
13 researchersIf this is your work, this is how we attribute it on Fit Body Science. Inge Groenendijk is listed as the lead author.
- N. I. Lobachevsky State University of Nizhny Novgorod
Cited in 1 claim