Last week I reviewed the basics on bone composition and metabolism. Now I would like to review some basics about some factors that both positively and negatively influence bone mass.

Positive

Weightbearing activity and resistance training improve both the quantity and architecture of bone. Most female patients make the mistake of not incorporating strength training in their routine. Walking is good for many things but not sufficient for stimulating and maintaining bone mass.
Adequate intake of ALL bone building nutrients: complete protein (including animal protein which increases calcium uptake in the intestines): all minerals (calcium, magnesium, phosphorus, zinc and rare minerals like boron): Fat soluble vitamins like vitamin D, K2 and A.
Adequate balance of hormones: estrogen, progesterone, testosterone, DHEA, cortisol, and parathyroid
Close to optimal weight/BMI

Negative

Inadequate dietary intake or balance (more on that later)
Digestive malabsorption from various sources (very often missed!)
Insufficient physical activity and resistance training
Obesity/High BMI: although obese individuals tend to have a slightly higher bone mass, it is proportionately not enough for the extra weight the bone has to carry
Being significantly underweight
Many medications: steroids, estrogen blockers (for hormone positive breast cancer), anti-seizure medications, many anti-acid medications, progestin only birth control implants and injections (especially in teenage women).
Hormone Imbalance: estrogen deficiency, thyroid overmedication, hyperparathyroidism