Body Composition Biomarkers

Why Body Composition Matters

Weight alone fails to capture health status comprehensively. Two individuals with identical weight can have vastly different health outcomes depending on their underlying tissue composition. The distribution and type of tissue significantly influence disease risk.

Excess adiposity — particularly visceral fat — is strongly associated with type 2 diabetes, cardiovascular disease, and certain cancers. Conversely, low skeletal muscle mass predicts frailty, disability, and premature mortality, affecting approximately 10–27% of older adults globally.

Body Composition as a Systems Biomarker

Body tissues function as active metabolic and endocrine organs, not passive structural components.

• Adipose tissue releases adipokines; excess visceral fat produces pro-inflammatory molecules promoting insulin resistance
• Skeletal muscle generates myokines during contraction, regulating glucose metabolism and energy balance
• Bone acts as an endocrine organ, influencing insulin sensitivity
• Muscle-bone interaction creates osteosarcopenia when both decline simultaneously

Core Biomarkers

Lean Body Mass

Primarily driven by skeletal muscle, adequate lean mass maintains physical performance and metabolic stability. Higher lean mass correlates with improved glucose disposal and resting energy expenditure.

Fat Mass Percentage

Healthy ranges typically fall around 10–25% for men and 20–35% for women. Higher values increase cardiometabolic risks including insulin resistance and hypertension.

Visceral Adipose Tissue (VAT)

This intra-abdominal fat is metabolically active and releases free fatty acids directly into portal circulation. Higher VAT is highly predictive of type 2 diabetes, cardiovascular disease, and all-cause mortality — even among individuals with normal BMI.

Skeletal Muscle Index (SMI)

Standardized as kg/m², thresholds indicating sarcopenia are < 7.0 kg/m² in men and < 5.5 kg/m² in women, correlating with falls, disability, and reduced survival.

Waist-to-Hip Ratio (WHR)

An accessible anthropometric measure. Values above 0.9 in men and 0.85 in women suggest central obesity and increased health risk.

Bone Mineral Density (BMD)

Measured via DXA scanning, BMD predicts fracture risk. Osteoporosis is defined as T-score ≤ -2.5, while osteopenia ranges from -1.0 to -2.5.

Links Between Body Composition and Aging

• Inflammaging — visceral fat promotes chronic low-grade inflammation that accelerates aging
• Mitochondrial health — skeletal muscle supports mitochondrial density and cellular energy production
• Oxidative stress — adipose-driven damage versus muscle-mediated antioxidant protection
• Bone-muscle decline — simultaneous loss accelerates frailty and disability risk

Evidence-Based Optimization

• Resistance training — increases muscle mass and functional outcomes across all age groups
• Aerobic exercise — reduces visceral fat with synergistic effects when combined with resistance work
• Protein intake — 1.0–1.2 g/kg/day for older adults; 1.2–1.6 g/kg/day for sarcopenia prevention
• Vitamin D and calcium — support bone health alongside weight-bearing exercise
• Sleep and stress management — poor sleep and chronic stress link to adverse body composition changes

Testing Methods

Testing proves especially valuable for older adults at sarcopenia risk, individuals with obesity or metabolic syndrome, and chronic illness patients experiencing muscle loss.