Sarcopenia, Osteoporosis & Musculoskeletal Aging

The Architecture Is the Function

A building doesn’t fall because of one crack. It falls because the load-bearing structure — the beams, the joints, the foundation — has been quietly weakening for years while everyone focused on the paint. The musculoskeletal system is the load-bearing structure of the human body. When it fails, everything falls with it.

A hip fracture in someone over 65 carries a one-year mortality rate of 20-30%. Not from the fracture itself, but from the cascade it triggers — immobility, pneumonia, blood clots, muscle wasting, loss of independence, depression. Falls are the leading cause of injury-related death in adults over 65. And the root cause isn’t bad luck. It’s sarcopenia, osteoporosis, poor balance, and the progressive loss of the physical resilience that once made these events survivable.

Functional medicine treats musculoskeletal aging not as an inevitable decline but as a modifiable process with specific drivers, specific tests, and specific interventions.

Sarcopenia: The Muscle Crisis

Sarcopenia — age-related loss of muscle mass, strength, and function — begins earlier than most people realize. After age 30, muscle mass declines approximately 3-8% per decade. After 60, the rate accelerates. By 80, many people have lost 30-50% of their peak muscle mass.

But sarcopenia isn’t just about quantity. It’s about quality. Aging muscle develops:

• Anabolic resistance: The muscle becomes less responsive to protein and exercise stimuli. Where a 25-year-old needs 20g of protein to maximally stimulate muscle protein synthesis, a 65-year-old may need 40g for the same response.
• Satellite cell decline: The muscle stem cells (satellite cells) that repair and regenerate muscle tissue become fewer and less active with age.
• Intramuscular fat infiltration (myosteatosis): Fat infiltrates the muscle like marbling in a steak, impairing contractile function even before visible size loss.
• Mitochondrial dysfunction: Aged muscle mitochondria produce less ATP and more reactive oxygen species.
• Neuromuscular junction degradation: The connection between nerves and muscle fibers deteriorates, reducing motor unit recruitment.

The functional consequence: reduced strength, slower gait speed, impaired balance, difficulty rising from a chair, decreased metabolic rate, worsened insulin resistance, and increased fall risk. Sarcopenia isn’t a cosmetic problem. It’s a survival problem.

Protein: The Foundation of Muscle Preservation

Requirements in Aging

The current RDA for protein (0.8 g/kg/day) was established to prevent deficiency in healthy young adults. It is woefully inadequate for aging adults trying to maintain muscle mass.

Stuart Phillips, Donald Layman, Douglas Paddon-Jones, and other protein researchers have converged on a recommendation of 1.2-1.6 g/kg body weight per day for older adults. Those engaged in resistance training or recovering from illness or surgery may need 1.6-2.0 g/kg.

For a 70 kg (154 lb) person, that’s 84-112g of protein daily. Most older adults are eating 50-70g.

The Leucine Threshold

Not all protein meals are equal. Muscle protein synthesis has a threshold — a minimum amount of the amino acid leucine must be present in a single meal to “switch on” the mTOR pathway that drives muscle building.

In young adults, this threshold is approximately 1.5-2g of leucine per meal. In older adults with anabolic resistance, it rises to 2.5-3g of leucine per meal (Paddon-Jones 2004, Katsanos 2006).

What does 3g of leucine look like?

• 30-40g of animal protein (chicken, beef, fish, eggs)
• 170g of Greek yogurt
• 1 scoop (25-30g) of whey protein isolate (leucine-rich)
• Much harder to reach with plant protein alone — leucine content is lower in most plant sources

Practical strategy: Divide daily protein into 3-4 meals of at least 30-40g each, rather than the typical pattern of low protein at breakfast, moderate at lunch, and high at dinner. Each meal should independently cross the leucine threshold.

Protein Timing

Post-exercise protein is important but not magic. The “anabolic window” is wider than gym culture suggests — 2-3 hours post-training is sufficient. More important for older adults is the per-meal distribution across the day. Mamerow et al. (2014) showed that evenly distributed protein intake stimulated 24-hour muscle protein synthesis 25% more than the same total amount consumed unevenly.

Resistance Training as Medicine

The Evidence Is Not Subtle

Wayne Westcott’s 2012 review in Current Sports Medicine Reports laid out the case: resistance training increases muscle mass, reduces visceral fat, improves insulin sensitivity, reduces blood pressure, improves lipid profiles, enhances bone density, reduces low back pain, and decreases symptoms of depression and anxiety. It reverses multiple hallmarks of aging simultaneously.

It’s the closest thing we have to a universal anti-aging drug. And it’s free.

Programming for Aging Adults

Hypertrophy training (muscle building):

• 3-4 sets of 8-12 repetitions
• 60-75% of one-rep maximum
• 60-90 seconds rest between sets
• Emphasize time under tension (3-4 second eccentric/lowering phase)

Strength training (neural adaptation + force production):

• 3-5 sets of 3-6 repetitions
• 80-90% of one-rep maximum
• 2-3 minutes rest between sets
• Compound movements: squat, deadlift, bench press, overhead press, row

Bone loading (osteogenic stimulus):

• Bone responds to impact and compressive forces exceeding daily norms
• Weight-bearing exercise: walking is good; jumping, hopping, and stair climbing are better
• Heavy resistance training provides significant compressive forces through the spine and hips
• The minimum effective stimulus: forces >4x body weight through the relevant bone (OsteoStrong data)
• Bone adaptation is slow — 6-12 months minimum to see density changes

Minimum effective dose for older adults:

• 2-3 sessions per week
• Full body or upper/lower split
• Prioritize compound movements over isolation
• Progressive overload (gradually increasing weight or volume)
• Include balance and proprioception work in every session

The biggest barrier isn’t programming — it’s starting. For the deconditioned elderly person, supervised training with a qualified professional for the first 3-6 months dramatically improves adherence, safety, and outcomes.

Creatine Monohydrate: The Most Underrated Supplement in Aging

Creatine is the most well-studied ergogenic supplement in history, with over 500 published trials. Yet it remains vastly underutilized in aging populations.

Darren Candow’s research group at the University of Regina has been at the forefront of creatine in older adults. Their findings:

• Muscle: Creatine augments the effects of resistance training on lean mass and strength in older adults (Candow 2014 meta-analysis)
• Bone: Creatine + resistance training improves bone mineral density more than training alone (Candow 2008)
• Brain: Creatine supplementation improves cognitive function, particularly short-term memory and processing speed (Avgerinos 2018 systematic review). The brain is a major creatine consumer.
• Safety: No adverse effects on kidney function in healthy adults at standard doses (Kreider 2017 — position statement from the International Society of Sports Nutrition)

Dosing: 5g creatine monohydrate daily. No loading phase needed (it just takes 3-4 weeks to saturate instead of 1 week). Take with any meal. Monohydrate is the gold standard — fancy forms (HCL, ethyl ester, buffered) have no proven superiority.

Cost: roughly $15-20/month. Risk-benefit ratio is extraordinary for aging adults.

HMB: The Anti-Catabolic

Beta-hydroxy beta-methylbutyrate (HMB) is a metabolite of leucine that reduces muscle protein breakdown. While leucine stimulates synthesis, HMB prevents degradation. This is particularly relevant in aging, where catabolic processes accelerate.

Wu et al. (2015) conducted a meta-analysis showing HMB supplementation increased lean body mass and improved strength in older adults, particularly when combined with exercise. It’s especially valuable during periods of immobility, illness, or caloric restriction — when muscle loss accelerates.

Dosing: 3g daily (typically divided into 1g three times daily with meals). The calcium salt form (HMB-Ca) is most commonly available.

The Bone-Muscle Axis: Vitamin D, K2, and Calcium

Bone and muscle are not independent systems. They form an integrated mechanical and endocrine unit — the “bone-muscle axis.” Muscle contractions load bone and stimulate osteoblast activity. Bone releases osteocalcin, which enhances muscle function and insulin sensitivity. When one declines, the other follows.

Vitamin D

Heike Bischoff-Ferrari’s research at the University of Zurich has been pivotal in establishing vitamin D’s role beyond bone:

• Vitamin D deficiency is endemic in the elderly (50-80% depending on latitude and ethnicity)
• Meta-analyses show vitamin D supplementation reduces fall risk by 20-30% at doses of 700-1000 IU/day with blood levels >30 ng/mL (Bischoff-Ferrari 2009)
• Vitamin D receptors are present on muscle fibers; deficiency causes myopathy (weakness, pain)
• Bone: vitamin D is essential for calcium absorption. Without adequate D, you absorb only 10-15% of dietary calcium

Dosing: 2000-5000 IU daily (dose to target 50-80 ng/mL on blood work). Some individuals need 8000-10000 IU to reach optimal levels. Always retest after 3 months.

Vitamin K2

Vitamin K2 (menaquinone) activates osteocalcin (puts calcium into bone) and matrix Gla protein (keeps calcium out of arteries). Without K2, calcium supplementation may calcify arteries while doing little for bones — a dangerous paradox.

• MK-7 (from natto): 100-200mcg daily. Long half-life, steady state.
• MK-4: 5-45mg daily (the dose used in Japanese osteoporosis studies — Knapen 2013). Shorter half-life, multiple doses needed.

The combination of vitamin D + K2 is synergistic for both bone health and cardiovascular protection.

Calcium

The calcium-supplement-as-bone-savior narrative is outdated. Large-dose calcium supplements (1000-1200mg) without K2 and D may increase cardiovascular events (Bolland 2010 meta-analysis) without significantly improving fracture rates.

Better approach:

• 500-600mg supplemental calcium (citrate form, taken with food, divided doses)
• Plus dietary calcium (dairy, sardines, leafy greens, fortified foods)
• Always paired with vitamin D and K2
• Magnesium (400-600mg) is equally important for bone mineralization and is chronically under-consumed

Collagen Peptides

Zdzieblik et al. (2015) published a double-blind, placebo-controlled trial showing that collagen peptide supplementation (15g daily) combined with resistance training significantly increased muscle mass and strength in elderly men compared to resistance training alone. The mechanism involves collagen peptides stimulating mTOR signaling in connective tissue and muscle.

For joints specifically:

• Hydrolyzed collagen peptides: 10-15g daily (stimulate fibroblast collagen synthesis)
• Type II undenatured collagen (UC-II): 40mg daily (works through oral tolerance — down-regulating the immune attack on joint cartilage. Lugo 2016 showed UC-II superior to glucosamine + chondroitin for knee osteoarthritis)
• Vitamin C: 500-1000mg daily. Essential cofactor for collagen synthesis (take alongside collagen)

Balance and Proprioception: The Overlooked Intervention

A fall is a mechanical event, but the ability to prevent falls is a neurological skill. Proprioception — the sense of where your body is in space — degrades with age as sensory neurons decline and the vestibular system weakens. Balance training directly addresses this.

Fall prevention protocol:

• Single-leg stands (progress from eyes open to eyes closed): 30 seconds each leg, 3x daily
• Tandem walking (heel-to-toe): 20 steps forward and back
• Tai chi: Meta-analysis shows 40-50% reduction in fall risk (Huang 2017)
• Yoga: Improves balance, flexibility, and proprioception (Youkhana 2016)
• Step-ups and lateral movements: Mimic real-world balance challenges
• Perturbation training (reactive balance): Practice recovering from unexpected pushes or platform shifts

The evidence for tai chi in fall prevention is strong enough that the CDC recommends it. Two to three sessions weekly of balance-focused practice can cut fall risk nearly in half.

Joint Health: The Functional Approach

Osteoarthritis as Systemic Disease

Osteoarthritis is conventionally treated as a mechanical wear-and-tear problem. But the functional medicine lens sees it as inflammatory, metabolic, and systemic:

• Systemic inflammation (elevated IL-6, TNF-alpha) accelerates cartilage degradation
• Insulin resistance increases joint inflammatory mediators
• Obesity contributes both through mechanical loading and adipokine-driven inflammation
• Gut permeability increases circulating LPS, which activates joint macrophages

This means that gut healing, anti-inflammatory nutrition, weight management, and blood sugar control are all joint interventions — not just “general health” measures.

Joint-Specific Supplements

Glucosamine sulfate: 1500mg daily. The European data (GUIDE trial, Reginster 2001) showed structure-modifying effects over 3 years. Sulfate form specifically — not HCl.

Chondroitin sulfate: 800-1200mg daily. Often combined with glucosamine. Modest evidence for pain reduction and structure modification (GAIT trial — Clegg 2006 showed benefit in moderate-to-severe subgroup).

MSM (methylsulfonylmethane): 1500-3000mg daily. Anti-inflammatory sulfur compound. Debbi 2011 showed significant pain reduction in knee OA.

Hyaluronic acid (oral): 80-200mg daily. Tashiro 2012 showed oral HA improved knee pain and function. Also available as intra-articular injection for more severe cases.

PRP (platelet-rich plasma): Injection therapy using concentrated growth factors from the patient’s own blood. Multiple meta-analyses show superiority to hyaluronic acid injections for knee OA. Typically a series of 1-3 injections, effects lasting 6-12 months.

An Integrated Protocol for Musculoskeletal Aging

Movement (non-negotiable):

• Resistance training 2-3x/week (compound movements, progressive overload)
• Balance/proprioception training 2-3x/week
• Daily walking (8000+ steps — Paluch 2022 dose-response data)
• Flexibility work (yoga, stretching) 2-3x/week

Nutrition:

• Protein 1.2-1.6 g/kg/day, distributed across 3-4 meals (30-40g per meal)
• Anti-inflammatory diet (Mediterranean pattern)
• Adequate hydration (connective tissue is 60-70% water)

Supplementation:

• Creatine monohydrate: 5g daily
• Vitamin D: dose to 50-80 ng/mL
• Vitamin K2 (MK-7): 100-200mcg daily
• Magnesium: 400-600mg daily
• Collagen peptides: 10-15g daily + vitamin C
• Omega-3: 2-3g EPA+DHA daily (anti-inflammatory)
• Calcium: 500-600mg daily (if dietary intake is low)

Joint-specific (if symptomatic):

• Glucosamine sulfate 1500mg + Chondroitin 800mg daily
• UC-II collagen 40mg daily
• MSM 3000mg daily
• Consider PRP for moderate-to-severe OA

Testing:

• DEXA scan every 2 years (bone density + body composition with lean mass)
• Vitamin D level (25-OH) every 6 months until stable
• Inflammatory markers (hs-CRP, IL-6)
• Grip strength and gait speed (functional markers of sarcopenia — EWGSOP2 criteria)
• Hormones (testosterone, estradiol, GH/IGF-1 — see hormone optimization article)

The Central Truth

The musculoskeletal system is not separate from the rest of aging biology. It’s connected to hormones, inflammation, metabolism, the gut, the brain, and the immune system. A person losing muscle is simultaneously losing metabolic reserve, immune function, cognitive protection, and autonomy.

Resistance training isn’t vanity. Protein isn’t bodybuilding culture. Creatine isn’t for athletes. These are survival tools for aging humans, and the evidence supporting them is among the strongest in all of medicine.

The building doesn’t have to fall. But you have to maintain the structure — deliberately, consistently, starting now.

When was the last time you challenged your muscles to do something genuinely hard?