Not medical advice. I am a software engineer, not a physician. This page documents my own protocol and the research I read while building it. Talk to a qualified clinician before changing your supplementation, diet or any treatment. Lab reference ranges quoted here vary by laboratory and by individual.
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Bone Mineral Density (BMD) measures the amount of mineral matter (primarily calcium and phosphorus) per square centimeter of bone tissue. It is the primary diagnostic criterion for osteoporosis and a strong predictor of fracture risk. BMD is measured using DEXA (Dual-Energy X-Ray Absorptiometry) and reported as a T-score: the number of standard deviations your BMD falls above or below the mean for a healthy 30-year-old adult of the same sex.
| T-Score | Classification |
|---|---|
| -1.0 or above | Normal bone density |
| -1.0 to -2.5 | Osteopenia (low bone mass) |
| -2.5 or below | Osteoporosis |
| -2.5 or below + fracture | Severe osteoporosis |
Bone is living tissue that undergoes constant remodeling. Osteoclasts break down old bone (resorption) while osteoblasts form new bone. Before age 30, bone formation exceeds resorption, building peak bone mass. After 30, the balance shifts toward resorption, and without intervention, bone density gradually declines at approximately 0.5-1% per year.
Osteoporosis causes no symptoms until a fracture occurs — hence its designation as "the silent disease." The consequences are severe: hip fractures in people over 65 have a 20-30% one-year mortality rate (Haentjens et al., 2010, meta-analysis of 22 cohort studies with 858,978 participants). Globally, osteoporosis affects approximately 200 million people and causes more than 8.9 million fractures annually.
Risk factors include: age, female sex, low body weight, smoking, excessive alcohol, family history, low calcium/vitamin D intake, physical inactivity, prolonged corticosteroid use, and certain medical conditions (celiac disease, inflammatory bowel disease, rheumatoid arthritis).
Haentjens, P., et al. (2010). Meta-analysis: excess mortality after hip fracture among older women and men. Ann Intern Med, 152(6), 380-390. PubMed
Bone adapts to mechanical loading according to Wolff's Law: bone remodels in response to the forces placed upon it. Two types of exercise are particularly effective:
Running, jumping, stair climbing, and high-impact aerobics create ground reaction forces that stimulate bone formation. The impact creates strain on bone that triggers osteoblast activity. Martyn-St James and Carroll (2009), in a meta-analysis of 16 RCTs, found that high-impact exercise increased hip BMD by 1-2% per year in premenopausal women. Importantly, swimming and cycling, while excellent for cardiovascular health, do not significantly improve BMD because they are non-weight-bearing.
Resistance training is the most effective exercise modality for maintaining and increasing bone density. Muscles pull on bones during contractions, creating mechanical stress that stimulates bone formation at the attachment sites. A landmark meta-analysis by Howe et al. (2011), reviewing 43 RCTs with 4,320 participants, found that:
Howe, T. E., et al. (2011). Exercise for preventing and treating osteoporosis in postmenopausal women. Cochrane Database Syst Rev, 7, CD000333. PubMed
Calcium is the primary mineral in bone tissue. The RDA is 1,000 mg/day for adults aged 19-50, increasing to 1,200 mg/day for women over 50 and all adults over 70. Food sources are preferred over supplements: dairy products, fortified foods, sardines with bones, leafy greens (kale, broccoli). A meta-analysis by Tai et al. (2015) found that calcium supplementation increased BMD by only 0.7-1.8%, suggesting that while calcium is necessary, it alone is insufficient for meaningful bone protection.
Vitamin D is essential for calcium absorption. Without adequate vitamin D, only 10-15% of dietary calcium is absorbed; with adequate levels, absorption increases to 30-40%. The RDA is 600-800 IU/day, but many researchers argue this is insufficient. The Endocrine Society recommends maintaining serum 25(OH)D levels above 30 ng/mL (75 nmol/L). Supplementation with 1,000-2,000 IU/day is commonly recommended, especially in populations with limited sun exposure.
Vitamin K2 (menaquinone) activates osteocalcin, a protein that binds calcium to bone matrix, and activates matrix Gla protein, which prevents calcium deposition in arteries. A 3-year RCT by Knapen et al. (2013), with 244 postmenopausal women, found that 180 mcg/day of MK-7 (the most bioavailable form of K2) significantly improved bone strength and slowed age-related BMD decline at the lumbar spine and femoral neck.
Knapen, M. H., et al. (2013). Three-year low-dose menaquinone-7 supplementation helps decrease bone loss in healthy postmenopausal women. Osteoporos Int, 24(9), 2499-2507. PubMed
The bone health triad: Calcium (building material) + Vitamin D (enables absorption) + Vitamin K2 (directs calcium to bones, not arteries). All three work synergistically. Combine with resistance training for maximum benefit.
Women face significantly higher osteoporosis risk than men due to several factors:
Screening recommendation: The USPSTF recommends BMD screening for all women aged 65+ and for younger postmenopausal women with risk factors. Men should be screened starting at age 70 or earlier with risk factors.
A 2025 systematic review and meta-analysis published in PMC analyzing the effects of exercise on bone mineral density and bone turnover markers confirmed that combined aerobic and resistance training was the most effective exercise modality for improving femoral neck BMD in postmenopausal women. Impact exercise performed at least 2-3 times per week consistently improved BMD across studies. The 2025 USPSTF Recommendation Statement reaffirmed screening for osteoporosis in women aged 65 and older (Grade B recommendation) and in postmenopausal women younger than 65 at increased fracture risk, with DEXA remaining the standard screening tool.
Updated 2025 osteoporosis guidelines now recommend primary osteoanabolic treatment (rather than starting with antiresorptives) for individuals with a 3-year fracture risk exceeding 10%, representing a paradigm shift toward building bone before preventing loss. For lower-risk patients (3-year risk above 3%), antiresorptive therapy remains first-line. This "treat to target" approach parallels modern cardiovascular risk management strategies.
PMC (2025). Effects of exercise on bone mineral density and bone turnover markers in adults: a systematic review and meta-analysis. PubMed Central