Bone Health, Osteoporosis & Sarcopenia

Citation model. Claims grounded in AllNutrition's trust-scored library carry an inline bracketed reference [n] linking to the References section, which lists each source's evidence level and AllNutrition trust score (0–1). Where an AllNutrition query returned an overall evidence_strength and consensus_level, those labels are surfaced in the Evidence Review so readers can calibrate confidence. Only sources actually returned by the tool are cited; no trust scores are invented.

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1. Introduction

Bone and muscle are frequently taught as separate organ systems — one covered by endocrinology, the other by physiology or sports medicine — yet clinically they fail together. An older adult who loses muscle mass loses the mechanical loading that bone needs to maintain itself, falls more often because strength and balance decline, and then fractures a weakened hip because bone strength has also eroded. The resulting syndrome, osteosarcopenia, is not a coincidence of two age-related diseases occurring in the same body; it reflects a genuine biological "muscle-bone unit" connected by mechanical strain and by a shared vocabulary of signaling molecules — myokines and osteokines — that each tissue uses to instruct the other [1][2].

This module also serves as a case study in how nutrition science self-corrects. For decades, two influential but ultimately unsupported hypotheses shaped clinical practice: that dietary protein "leaches" calcium from bone via an acid load, and that calcium and vitamin D supplements are an almost unconditional good for skeletal health. Both narratives have been substantially revised by newer trial evidence — protein is now understood as bone-protective when calcium is adequate, and a landmark 2026 umbrella meta-analysis of 69 trials in over 150,000 participants found routine calcium/vitamin D supplementation offers little to no benefit for fracture or fall prevention in the general population [3][4]. Learners who master this module will be equipped to counsel patients accurately on both bone and muscle health, to recognize which supplement claims are supported and which are outdated, and to integrate nutrition with resistance exercise as the cornerstone of musculoskeletal aging.

2. Learning Objectives

By the end of this module, the learner will be able to:

1. Describe the mechanisms of bone remodeling (RANKL/RANK/OPG, Wnt/sclerostin, osteoblast-osteoclast coupling) and explain why peak bone mass, achieved by the third decade of life, determines lifelong osteoporosis risk [5].
2. Critically appraise the evidence for calcium and vitamin D supplementation in fracture prevention, including the community-versus-institutionalized distinction and the calcium-supplement cardiovascular controversy.
3. Explain why the "acid-ash"/net-acid-load hypothesis of protein-induced bone loss has been debunked, and describe the calcium-protein interaction that determines whether higher protein intake helps or harms bone [6][7].
4. Evaluate the roles of vitamin K, dairy, sodium, and caffeine in bone health, distinguishing established effects from overstated or mechanistic-only claims.
5. Define sarcopenia using consensus (EWGSOP2) criteria and explain the molecular mechanisms of anabolic resistance in aging muscle [8][9].
6. Apply evidence-based protein, leucine, vitamin D, HMB, and creatine strategies — combined with resistance exercise — to prevent and treat sarcopenia and osteosarcopenia in clinical practice [10][11][12].

3. Scientific Foundations

3.1 Bone remodeling and peak bone mass

Bone is continuously renewed by Basic Multicellular Units (BMUs), coordinated packets of resorption followed by formation. The central regulatory axis is RANKL/RANK/OPG: osteoblasts and osteocytes produce RANKL, which binds RANK on osteoclast precursors to drive their maturation into bone-resorbing osteoclasts; osteoprotegerin (OPG) acts as a decoy receptor that neutralizes RANKL. The RANKL/OPG ratio is the dominant determinant of net resorption, and a high ratio — as occurs after estrogen withdrawal at menopause — is the proximate cause of accelerated bone loss [5]. As osteoclasts resorb bone, they release matrix-bound growth factors (TGF-β, IGF-1, BMPs) that recruit osteoblasts to the site, coupling resorption to formation. Osteoblast differentiation is separately driven by Wnt/β-catenin signaling, which is restrained by sclerostin, an osteocyte-secreted inhibitor that is downregulated in response to mechanical loading — the cellular basis of Wolff's Law, whereby bone adapts its architecture to the strain placed on it by muscle contraction and weight-bearing activity [5].

Peak bone mass, reached around the third decade of life, functions as a "bone bank": individuals who accrue a higher peak have a longer runway before age-related resorption reaches the fracture threshold. Peak accrual depends on mechanical loading (physical activity), adequate calcium and protein for matrix formation, sufficient vitamin D for calcium absorption, and pubertal sex-hormone exposure, which supports osteoblast survival and restrains osteoclast activity [5]. Bone loss accelerates sharply around age 65, independent of but additive to the estrogen-driven losses of the menopausal transition, and osteocyte apoptosis and increased resorption can compromise bone strength before bone mineral density (BMD) measurably declines — one reason BMD and fracture risk are imperfectly correlated, particularly in glucocorticoid-induced osteoporosis [5].

3.2 Muscle protein turnover and anabolic resistance in aging

Skeletal muscle mass is governed by the balance between muscle protein synthesis (MPS) and breakdown. In young adults, a protein-containing meal robustly stimulates MPS via activation of the mTORC1/PI3K-Akt pathway, triggered primarily by the amino acid leucine. With aging, this response becomes blunted — a phenomenon termed anabolic resistance — such that a given dose of protein or bout of exercise produces a smaller MPS response than in a younger person [9]. Older adults show roughly a 30% decline in muscle protein synthesis capacity relative to younger adults [9].

Mechanistically, anabolic resistance arises from multiple converging processes: blunted mTORC1/PI3K-Akt signaling; inflammaging — chronic low-grade inflammation driven by TNF-α and IL-6 that both promotes proteolysis and interferes with anabolic signaling; a 30–35% age-related decline in myocytic insulin sensitivity that impairs amino acid as well as glucose uptake; attenuation of the GH/IGF-1 axis and declining sex hormones (testosterone, estrogen), reducing systemic anabolic drive; mitochondrial dysfunction and oxidative stress with ectopic lipid accumulation (ceramides, diacylglycerols) in muscle; and depletion of satellite cells (muscle stem cells), particularly in type II (fast-twitch) fibers, limiting regenerative capacity [8][9]. Disuse — including bed rest and prolonged inactivity — sharply amplifies anabolic resistance, which is one reason hospitalization is so catabolic for older patients.

3.3 The muscle-bone unit

Bone and muscle communicate bidirectionally. Myokines released by contracting muscle — notably irisin, which promotes osteoblast activity and inhibits osteoclasts, along with IGF-1 and FGF2 — favor bone formation, while myostatin negatively regulates both muscle growth and bone health. Conversely, osteokines from bone act on muscle: osteocalcin enhances muscle protein synthesis and myocyte proliferation, while sclerostin may impair muscle differentiation in addition to its role restraining osteoblasts [1][2]. This crosstalk, together with the shared mechanostat response to loading, explains why muscle and bone senesce in parallel and why interventions that build muscle (resistance exercise, adequate protein) tend to also support bone, and vice versa.

4. Clinical Relevance

Osteoporotic fractures and sarcopenia are among the most consequential — and most nutritionally modifiable — conditions of aging. A hip fracture in an older adult carries substantial mortality and permanently reduces independence; sarcopenia independently predicts falls, disability, prolonged hospitalization, and death, and the two conditions compound each other in osteosarcopenia, which carries worse outcomes than either alone, including roughly double the risk of fracture nonunion [13][14]. Because both muscle and bone respond to modifiable nutritional and exercise exposures across the lifespan — not only in old age — this module has direct relevance to preventive counseling for adults of all ages, to perioperative and hospital nutrition (malnutrition dramatically worsens both bone and muscle outcomes), and to the routine primary-care conversation about "should my patient take a calcium/vitamin D pill," where the evidence has shifted substantially from earlier dogma. Cross-reference Module 6 (macronutrients/protein), Module 7 (micronutrients, including the calcium/vitamin D cardiovascular signal), and Module 21 (life-stage nutrition, for pediatric/peak bone mass and pregnancy considerations).

5. Evidence Review

Established (high confidence):

• Bone remodeling is governed by the RANKL/RANK/OPG axis and Wnt/sclerostin signaling; peak bone mass (third decade) and subsequent loss rate jointly determine osteoporosis risk. AllNutrition evidence_strength: limited, consensus_level: moderate (mechanistic consensus is strong even though the query's overall rating reflects the mixed-quality source mix) [5].
• Sarcopenia is defined by EWGSOP2 as low muscle strength (probable), confirmed by low muscle quantity/quality, and staged as severe when low physical performance is also present; anabolic resistance is multifactorial (mTOR blunting, inflammaging, insulin resistance, hormonal decline, satellite cell loss). evidence_strength: limited, consensus_level: moderate [8][9].
• The acid-ash/net-acid-load hypothesis of protein-induced bone loss is not supported; higher protein intake is neutral-to-beneficial for BMD and fracture risk when calcium intake is adequate. evidence_strength: strong, consensus_level: moderate [6][7].
• Malnutrition and sarcopenia interact bidirectionally and synergistically worsen fracture healing, falls, and mortality (Malnutrition-Sarcopenia Syndrome). evidence_strength: strong, consensus_level: moderate [13][14].
• Combining protein/nutritional supplementation with resistance exercise produces greater gains in muscle mass and, in some analyses, strength than either alone; direct head-to-head comparisons of exercise-alone versus supplement-alone are often not significantly different, underscoring exercise as the primary driver [11][15][16].

Probable:

• Vitamin D supplementation (800–1000 IU/day) improves muscle strength and reduces falls specifically in individuals who are vitamin D deficient (<30 nmol/L); in vitamin-D-replete, healthy community-dwelling adults, large trials (VITAL) show no benefit, and high-dose bolus regimens may increase fall risk. evidence_strength: strong, consensus_level: moderate [10][17].
• Protein intake of 1.0–1.2 g/kg/day (versus the 0.8 g/kg RDA) better preserves lean mass in older adults, with an even greater benefit when at least one meal provides 30–40 g of high-quality, leucine-rich protein. evidence_strength: moderate, consensus_level: moderate [9][18].
• Creatine monohydrate (≥5 g/day) combined with resistance training modestly increases lean mass and strength in older adults, including postmenopausal women, without increasing adverse events. evidence_strength: strong, consensus_level: moderate [19].
• Vitamin K2 (menaquinone) supplementation, particularly combined with calcium and vitamin D3, may reduce vertebral and hip fracture risk and support lumbar BMD in osteoporotic populations, though effect sizes vary widely across trials. evidence_strength: strong, consensus_level: mixed [20].
• Fermented dairy (yogurt, cheese) is associated with reduced hip fracture risk in large cohorts, and a nursing-home RCT combining higher dairy-derived calcium (~1,142 mg/day) and protein (~1.1 g/kg) reduced all fractures by 33% and hip fractures by 46% — a considerably larger effect than seen with calcium/vitamin D pills alone, suggesting food-matrix or population (frail/institutionalized) effects. evidence_strength: strong, consensus_level: moderate [21].

Emerging:

• The gut-muscle-bone axis (microbiota effects on inflammation, nutrient absorption, and both myokine/osteokine signaling) as a therapeutic target for osteosarcopenia. evidence_strength: moderate, consensus_level: moderate [1][22].
• HMB (β-hydroxy-β-methylbutyrate), alone or combined with creatine, for preserving functional strength in older adults — benefits appear most consistent when paired with exercise and may occur independently of measurable muscle mass change. evidence_strength: strong, consensus_level: moderate [12].
• Precision/targeted vitamin D supplementation strategies (2024 Endocrine Society guidance) that restrict routine supplementation in healthy adults under 75 while targeting older adults, pregnant individuals, and those with prediabetes. evidence_strength: moderate, consensus_level: moderate [23].

Controversial:

• Whether calcium (with or without vitamin D) supplementation meaningfully prevents fracture in the general, community-dwelling, non-deficient population. A 2026 BMJ umbrella systematic review/meta-analysis of 69 trials (>150,000 participants) found little-to-no net benefit for fracture or fall prevention, in tension with older meta-analyses reporting a themed 11% reduction in total fracture risk and 14% in vertebral fracture risk (but not hip or forearm). The benefit appears concentrated in deficient, frail, or institutionalized subgroups rather than the general population. evidence_strength: moderate, consensus_level: mixed [4][17][24].
• The calcium-supplement cardiovascular safety question: several reviews report that isolated calcium supplementation (without food-matrix co-factors) may be associated with increased coronary/cardiovascular risk even at doses within the "normal" range, while other interventional-outcome reviews find vitamin D supplementation cardiovascularly neutral; overall RCT evidence does not show that calcium/vitamin D supplementation improves cardiovascular outcomes. evidence_strength: moderate, consensus_level: mixed [3][25]. (Cross-reference Module 7.)
• Whether an alkaline diet or alkaline mineral water meaningfully prevents osteoporosis beyond the nutrient density (potassium, magnesium, polyphenols) of the foods involved. evidence_strength: moderate, consensus_level: moderate [7].

Unsupported / overstated:

• The acid-ash hypothesis as a primary driver of osteoporosis — dietary protein-induced urinary calcium loss is offset by increased intestinal calcium absorption and does not translate into net BMD loss or higher fracture risk in adequately calcium-fed populations [6][7].
• Treating "alkalinity" of a food or beverage per se (as opposed to its nutrient content) as bone-protective [7].
• Assuming calcium/vitamin D supplementation is a low-risk, universally beneficial intervention for all older adults regardless of baseline status or care setting [4][24].

6. Practical Clinical Applications

Bone health targets:

• Calcium: 1,000–1,200 mg/day for most adults, preferentially from food (dairy, fortified plant milks, leafy greens); supplementation reserved for those unable to meet intake through diet, particularly institutionalized or frail elders, rather than prescribed routinely to healthy community-dwelling adults [4][23].
• Vitamin D: 400–1,000 IU/day for general adults; 2,000–4,000 IU/day considered for adults ≥75; target serum 25(OH)D ≥30 ng/mL (75 nmol/L) in those being treated for deficiency or osteoporosis. The 2024 Endocrine Society guidance explicitly does not recommend routine supplementation for healthy adults <75 with adequate dietary/sun exposure [23].
• Protein: ≥0.8 g/kg is a floor, not a target, for older adults; aim for 1.0–1.2 g/kg/day (up to 1.2–1.5 g/kg/day with illness, frailty, or during intentional weight loss), paired with ≥800 mg/day calcium to preserve the favorable calcium-protein interaction [6][18].
• Vitamin K: Dietary sufficiency (K1 from leafy greens; K2 from fermented foods, aged cheese) is reasonable; supplemental doses used in trials (e.g., 45 mcg–45 mg/day of MK-4/MK-7) require caution and are contraindicated or require close monitoring in patients on warfarin [20].

When to use calcium/vitamin D supplements — and when not to:

• Favor supplementation in: documented vitamin D deficiency, institutionalized/frail elders, those with very low dietary calcium intake, patients initiating antiresorptive therapy (bisphosphonates require adequate calcium/vitamin D to avoid hypocalcemia and to achieve efficacy), and patients on chronic glucocorticoids [23][26].
• Avoid routine, indiscriminate supplementation in healthy, vitamin-D-replete, community-dwelling adults, given the 2026 umbrella meta-analysis showing minimal fracture/fall benefit at the population level and signals of possible cardiovascular and renal-stone risk with isolated calcium supplements [4][25].

Sarcopenia and muscle health:

• Protein distribution: aim for ≥25–30 g of high-quality, leucine-rich (≥2.5–3 g leucine) protein per meal rather than back-loading intake at dinner; whey protein is a practical leucine-dense source, with plant-protein strategies (mixing sources, higher total intake) as alternatives [9][18][20].
• Resistance training (2×/week, 8–10 exercises, 8–12 repetitions) is the single most effective intervention for both muscle and bone and should be prescribed alongside — not instead of — nutritional optimization [14][15].
• Creatine (≥5 g/day) and/or HMB (3 g/day) may be added for patients already engaged in resistance training who need additional support for strength/function; neither is a substitute for exercise [12][19].
• Vitamin D repletion (target ≥30 ng/mL) before or alongside sarcopenia-directed protein/exercise interventions, particularly in deficient or institutionalized patients [10].

Drug-nutrient interactions:

• Bisphosphonates: take on an empty stomach with plain water; avoid calcium-containing food or supplements for 30–60 minutes afterward, as co-administered calcium markedly impairs absorption [26].
• Proton pump inhibitors: long-term use is linked to secondary osteoporosis via gut microbiota alteration and impaired calcium carbonate dissolution (an acidic environment is needed); consider calcium citrate and periodic BMD monitoring in long-term PPI users [26].
• Glucocorticoids: induce bone loss via decreased osteoblastogenesis and increased osteoclastogenesis; monitor serum calcium and 25(OH)D and supplement proactively in patients on chronic steroid therapy [26].
• Antiepileptics and certain antidepressants are also associated with secondary osteoporosis via vitamin D metabolism disturbance [26].

7. Clinical Pearls

• "Calcium and vitamin D for bone" is not a universal prescription — the strongest evidence for benefit is in deficient, frail, or institutionalized patients, not in the general well-nourished population.
• Protein is not the enemy of bone. The acid-ash hypothesis has been debunked; the real risk factor is inadequate calcium paired with high protein, not high protein itself.
• Anabolic resistance means older adults need more protein per meal, not less, to achieve the same muscle-building signal as a younger adult — reflexively restricting protein in aging patients (absent renal contraindication) is a disservice.
• Exercise is the load-bearing intervention (literally): nutrition amplifies what resistance training builds, but rarely substitutes for it.
• Bone density (BMD/DXA) and fracture risk are not the same thing — bone strength can decline before BMD does, particularly in glucocorticoid-treated patients.
• Always check for osteosarcopenia together: a frail patient with low muscle strength should prompt a bone-health assessment, and vice versa.

8. Common Misconceptions

• "High-protein diets leach calcium from bone and cause osteoporosis." Refuted by clinical trial evidence; the calcium-protein interaction, not protein per se, determines the outcome [6][7].
• "Everyone over 50 should take a calcium and vitamin D supplement for their bones." Large modern meta-analyses do not support population-wide benefit and note possible harms (GI effects, kidney stones, a debated cardiovascular signal) [3][4][25].
• "An alkaline diet neutralizes bone-damaging acid from food." The acid-ash framework itself lacks support; benefits attributed to "alkaline" foods trace to their potassium, magnesium, and polyphenol content, not pH [7].
• "Sarcopenia is just normal, unavoidable aging." It is a diagnosable, staged condition (EWGSOP2) that is substantially modifiable with protein and resistance exercise, even in frail and institutionalized elders [8][15].
• "Protein or HMB/creatine supplements alone will rebuild lost muscle." Supplementation without resistance exercise produces minimal-to-no gains in most trials; exercise is necessary, not optional [11][12][19].

9. Summary

Bone and muscle age together because they are mechanically and biochemically coupled through the muscle-bone unit. Peak bone mass, achieved by the third decade, together with the postmenopausal acceleration of RANKL-driven resorption, sets an individual's lifelong fracture trajectory, while anabolic resistance — driven by blunted mTOR signaling, inflammaging, insulin resistance, hormonal decline, and satellite cell loss — progressively impairs the muscle's ability to respond to protein and exercise. The evidence base has meaningfully shifted: the acid-ash hypothesis of protein-induced bone loss is not supported, and routine calcium/vitamin D supplementation for fracture prevention in the general population is now contested by large modern meta-analyses, even as targeted supplementation remains clearly beneficial in deficient, frail, or institutionalized patients. For sarcopenia and osteosarcopenia, the strongest, most consistent evidence favors combining adequate, well-distributed, leucine-rich protein (1.0–1.2+ g/kg/day) with resistance exercise, with creatine, HMB, and vitamin D repletion as second-line adjuncts. Clinicians should individualize supplementation to risk and setting rather than applying blanket recommendations, and should treat bone and muscle as a single system to assess and manage together.

10. References

Ordered by evidence strength / relevance. Evidence level and AllNutrition trust score (0–1) as returned by the tool.

1. Why Osteosarcopenia Matters: Clinical and Investigative Implications. European Journal of Clinical Investigation (2026). Review — trust 0.748.
2. Body composition in male hypogonadism: practical considerations to the use of dual-energy x-ray absorptiometry. Reviews in Endocrine and Metabolic Disorders (2026). Review — trust 0.887.
3. Effects of calcium and vitamin D supplementation on cardiovascular disease outcomes: A review of interventional studies. Trends in Cardiovascular Medicine (2025). Review — trust 0.69.
4. Calcium, vitamin D, or combined supplementation to prevent fractures and falls: systematic review and meta-analysis. The BMJ (2026). Systematic review — trust 0.892.
5. Prevention of Hip Fractures in the Elderly. A Public Health Problem. I. Basic Science. Revista Española de Cirugía Ortopédica y Traumatología (2026). Review — trust 0.887.
6. Impact of Dietary Protein on Osteoporosis Development. Nutrients (2023). Review — trust 0.825.
7. Nutrition and Osteoporosis Prevention. Current Osteoporosis Reports (2024). Review — trust 0.705.
8. Inflammaging and Sarcopenia as Interconnected Hallmarks of Aging: Integrative Roles of Bioactive Compounds and Lifestyle Interventions. Nutrients (2026). Review — trust 0.688.
9. MALNUTRITION-SARCOPENIA SYNDROME IN OLDER ADULTS: CAUSES, CONSEQUENCES, AND COUNTERMEASURES. e-Journal of Clinical Nutrition and Metabolism (2026). Review — trust 0.70.
10. Vitamin D Status and Supplementation and the Functional Outcomes of Human Musculoskeletal Tissues: A Stratified Systematic Review. Health Science Reports (2026). Systematic review — trust 0.79.
11. Systematic review and meta-analysis of the effects of exercise in older adults with sarcopenia. Scientific Reports (2026). Systematic review — trust 0.863.
12. Combined creatine and HMB co-supplementation improves functional strength independent of muscle mass in physically active older adults: a randomized crossover trial. GeroScience (2025). RCT — trust 0.817.
13. Mapping the evidence: Effects of malnutrition and sarcopenia on fracture healing. Bone (2026). Systematic review — trust 0.845.
14. Prognostic and Associative Significance of Malnutrition in Sarcopenia: A Systematic Review and Meta-Analysis. Advances in Nutrition (2025). Systematic review — trust 0.835.
15. Nutrition in the prevention and treatment of skeletal muscle ageing and sarcopenia. Proceedings of the Nutrition Society (2025). Review — trust 0.69.
16. Effect of exercise interventions on hand grip and TUG in older adults: A network meta-analysis of randomized controlled trials. Archives of Gerontology and Geriatrics (2026). Systematic review — trust 0.762.
17. Impact of Vitamin D and Calcium on Falls and Fractures in Older Adults. Endocrine Practice (2025). Review — trust 0.742.
18. An Update on Protein, Leucine, Omega-3 Fatty Acids, and Vitamin D in the Prevention and Treatment of Sarcopenia and Functional Decline. Nutrients (2018). Review — trust 0.812.
19. Creatine monohydrate for lean mass, strength, and bone density in postmenopausal women: a systematic review and meta-analysis. Journal of the International Society of Sports Nutrition (2026). Systematic review — trust 0.857.
20. Calcium, vitamin D, vitamin K2, and magnesium supplementation and skeletal health. Maturitas (2020). Review — trust 0.627.
21. Nutrition and Osteoporosis Prevention. Current Osteoporosis Reports (2024) [dairy/fracture data]. Review — trust 0.705.
22. Exploring osteosarcopenia from the gut microbiota perspective: mechanistic insights and therapeutic potentials based on the gut-muscle-bone Axis. Frontiers in Microbiology (2026). Review — trust 0.698.
23. Rethinking Vitamin D Deficiency: Controversies and Practical Guidance for Clinical Management. Nutrients (2025). Review — trust 0.73.
24. Vitamin D and calcium supplementation in women undergoing pharmacological management for postmenopausal osteoporosis: a level I of evidence systematic review. European Journal of Medical Research (2025). Systematic review — trust 0.817.
25. Editorial commentary: Calcium/Vitamin D supplements and the heart. Trends in Cardiovascular Medicine (2025). Review — trust 0.705.
26. Linking the relationship between drug-induced osteoporosis and the gut microbiota. Frontiers in Endocrinology (2026). Review — trust 0.85.

Supporting sources also surfaced: Impact of Dietary Patterns on Skeletal Health (Nutrients 2025, systematic review, trust 0.807); Effect of protein supplementation on hip bone mineral density during weight-loss RCT (Osteoporosis International 2026, RCT, trust 0.835); BHOD bone-health optimized dietary pattern (npj Science of Food 2026, observational, trust 0.738); Effect of a protein intervention during resistance training in frail older adults RCT (JNHA 2026, RCT, trust 0.75); Effects of Combined Exercise and Calcium/Vitamin D Supplementation on BMD in Postmenopausal Women (Nutrients 2025, systematic review, trust 0.807); Revisiting the Role of Vitamin D in Fracture Prevention in the Era of Mega-Trials (Endocrinology and Metabolism 2026, review, trust 0.733).

Note on gaps: Several AllNutrition queries on this topic (direct RCT-level detail on calcium+vitamin D combined vs. alone, and community- vs. institutionalized-setting comparisons) returned tool timeouts or mismatched cached responses after retry; equivalent evidence was recovered via search_references and is reflected above, but readers should treat the community/institutionalized subgroup distinction as inferred from the cited nursing-home RCT and umbrella review rather than from a dedicated head-to-head AllNutrition synthesis.