Fruits and vegetables contain an array of vitamins, minerals, antioxidants and alkaline salts - some or all of which can have a beneficial effect on bone. Intakes lower than 5 servings per day of fruit and vegetable consumption are associated with higher fracture risk and lower bone density in elderly men and women [3]Lin, P.H., et al., The DASH diet and sodium reduction improve markers of bone turnover and calcium metabolism in adults. J Nutr, 2003. 133(10): p. 3130-6.

[4]Qiu, R., et al., Greater Intake of Fruit and Vegetables Is Associated with Greater Bone Mineral Density and Lower Osteoporosis Risk in Middle-Aged and Elderly Adults. PLoS One, 2017. 12(1): p. e0168906.

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When blood levels of vitamin B6, vitamin B12 and folic acid are low, homocysteine levels can rise and interfere with collagen synthesis. Accordingly, inadequacy of B vitamins could compromise bone health, a notion supported by observational studies which found an association between high homocysteine levels and lower BMD, and increased hip fracture risk in older people [5]McLean, R.R., et al., Homocysteine as a predictive factor for hip fracture in older persons. N Engl J Med, 2004. 350(20): p. 2042-9.

[6]Morris, M.S., P.F. Jacques, and J. Selhub, Relation between homocysteine and B-vitamin status indicators and bone mineral density in older Americans. Bone, 2005. 37(2): p. 234-42.
 

. However, a 2014 review concluded that inconsistencies within the current evidence base necessitate definitive studies to be conducted to evaluate the role of B vitamins in prevention of osteoporosis [7]Dai, Z. and W.P. Koh, B-vitamins and bone health--a review of the current evidence. Nutrients, 2015. 7(5): p. 3322-46.

[8]Kuroda, T., et al., Multiple vitamin deficiencies additively increase the risk of incident fractures in Japanese postmenopausal women. Osteoporos Int, 2018.

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Approximately half of total body magnesium is stored in the skeleton. Magnesium plays an important role in bone formation through stimulating proliferation of osteoblasts. Magnesium deficiency is rare in well-nourished populations, but magnesium absorption decreases with age and the elderly can be at risk of mild magnesium deficiency, particularly in response to diuretics or laxatives therapies. Good sources of magnesium include green vegetables, legumes, nuts, seeds, unrefined grains, fish and dried fruit (apricots, prunes, raisins) [9]de Baaij, J.H., J.G. Hoenderop, and R.J. Bindels, Magnesium in man: implications for health and disease. Physiol Rev, 2015. 95(1): p. 1-46.

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Vitamin K is required to make osteocalcin, which is the second most abundant protein in bone after collagen. Some studies have suggested that diets high in vitamin K are associated with a lower risk of hip fractures in older people [10]Feskanich, D., et al., Vitamin K intake and hip fractures in women: a prospective study. Am J Clin Nutr, 1999. 69(1): p. 74-9.

. Food sources of vitamin K include leafy green vegetables such as spinach, cabbage, kale, liver, dried fruit (e.g. prunes), and fermented foods such as fermented cheeses and natto (fermented soybeans). Randomized controlled trials of vitamin K1 or K2 supplementation did not increase BMD at major sites [11]Hamidi, M.S., O. Gajic-Veljanoski, and A.M. Cheung, Vitamin K and bone health. J Clin Densitom, 2013. 16(4): p. 409-13.

. Accordingly, further studies are needed to determine the role of vitamin K supplements for the prevention and treatment of osteoporosis.

Zinc is required for bone tissue renewal and mineralization. Severe deficiency is usually associated with calorie and protein malnutrition and has been reported to be common in community-dwelling older people. Milder degrees of zinc deficiency have been reported in the elderly and could potentially contribute to poor bone status [12]Kvamme, J.M., et al., Risk of malnutrition and zinc deficiency in community-living elderly men and women: the Tromso Study. Public Health Nutr, 2015. 18(11): p. 1907-13.

. Sources of zinc include lean red meat, poultry, whole grain cereals, pulses, legumes and dried fruit. 

The role of vitamin A in osteoporosis is controversial. Consumption of vitamin A in amounts well above the recommended daily intake may have adverse effects on bone [13]Tanumihardjo, S.A., Vitamin A and bone health: the balancing act. J Clin Densitom, 2013. 16(4): p. 414-9.

. Such high levels of vitamin A intake are probably only achieved through over-use of supplements, and intakes from food sources are not likely to pose a problem. Further research is needed into the role of vitamin A in bone health, although many countries at present caution against taking a fish liver oil supplement and a multivitamin supplement concurrently.

For both men and women, more than two units per day of alcohol can increase the risk of a fragility fracture, while more than four units per day can double fracture risk [14]Kanis, J.A., et al., Alcohol intake as a risk factor for fracture. Osteoporos Int, 2005. 16(7): p. 737-42.

. Up to two 120 mL glasses of wine per day do not negatively impact on bone health.

Caffeine increases urinary and faecal calcium losses and so, in combination with a diet low in calcium, has the potential to adversely affect bone health. A Swedish study suggests that caffeine intake at 330 mg per day (i.e. four cups /600 mL) could be associated with a 20% increase in risk of osteoporotic fractures as compared to caffeine intake of less than 200 mg per day [15]Hallstrom, H., et al., Coffee, tea and caffeine consumption in relation to osteoporotic fracture risk in a cohort of Swedish women. Osteoporos Int, 2006. 17(7): p. 1055-64.

. However, increasing calcium intake by 40 mg for every cup of caffeine containing coffee consumed counter balances the potential for loss [16]Barrett-Connor, E., J.C. Chang, and S.L. Edelstein, Coffee-associated osteoporosis offset by daily milk consumption. The Rancho Bernardo Study. JAMA, 1994. 271(4): p. 280-3.

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A Body Mass Index (BMI) below 19 is considered underweight and is a risk factor for osteoporosis. Emerging data also suggests that the belief that obesity is protective against osteoporosis may be flawed, with a UK study reporting a surprisingly high prevalence of obesity in postmenopausal women presenting with fragility fractures. Furthermore, the Global Longitudinal Study of Osteoporosis in Women (GLOW) has reported that obese women with fracture undergo a longer period of hospitalization for treatment and have poorer functional status and health-related quality of life than non-obese women [17]Compston, J.E., et al., Obesity, health-care utilization, and health-related quality of life after fracture in postmenopausal women: Global Longitudinal Study of Osteoporosis in Women (GLOW). Calcif Tissue Int, 2014. 94(2): p. 223-31.

[18]Premaor, M.O., et al., Obesity and fractures in postmenopausal women. J Bone Miner Res, 2010. 25(2): p. 292-7.

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