* Vitamin K. This vitamin is now recognised to be an essential factor in bone metabolism. Vitamin K deficiency causes bone-density loss and bone fractures. After three years, patients taking both vitamins D and K had less bone loss than those taking a placebo or vitamin D alone (Calcif Tissue Int, 2003; 73: 21-6). Individuals taking antibiotics and those with compromised liver function may suffer from a vitamin K deficiency.

Leafy green vegetables and vegetable oils like soybean and canola oils are loaded with vitamin K1 (phylloquinone). Vitamin K2 (menaquinone) - the more potent form - is found in meat, cheese and fermented products like natto, made from soybeans. In a Japanese study, vitamin K2 improved bone mineral density and reduced spinal fractures in osteoporosis sufferers as effectively as etidronate (a bisphosphonate) (J Orthop Sci, 2001; 6: 487-92). The Nurses’ Heart Study showed that women with low vitamin-K intakes had a higher risk of hip fracture (Am J Clin Nutr, 1999; 69: 74-9) and, in the Framingham Heart Study, men and women in the highest quartile of vitamin K intake were significantly less likely to suffer hip fracture than those in the lowest quartile of intake (Am J Clin Nutr, 2000; 71: 1201-8).

As few, if any, adverse effects are seen with high-dose vitamin K, those with osteoporosis may take up to 1000 mcg/day of K1 or K2 (Am J Health Syst Pharm, 2005; 62: 1574-81). It can also work in synergy with bisphosphonate drugs (Altern Med Rev, 2005; 10: 24-35) but, because of its blood-coagulating properties, vitamin K should not be taken with warfarin.

* Vitamin D. This fat-soluble vitamin is essential for a healthy skeleton and calcium absorption. It is available from certain foods (fish oil, fortified milk, eggs and liver), but the best source is sunlight. About 15 minutes of sunlight on your skin every day should produce all the vitamin D you need. While the US recommended dietary allowance for vitamin D in adults is 5 mcg (200 IU)/day, with no sun exposure, this may be increased to at least 15 mcg (600 IU)/day (Am J Clin Nutr, 1994; 60: 619-30).

People who are older, who have limited sun exposure or heavily pigmented skin need extra vitamin D to prevent deficiency, as do osteoporosis sufferers. A higher dose of vitamin D than the currently recommended 600 IU/day - for example, 800-1000 IU/day - may be required for optimal bone health in people 65 and over. In fact, seniors taking 800 IU/day showed a 30 per cent decrease in non-spinal fractures (Ann Med, 2005; 37: 278-85). Studies also show that vitamin D supplementation reduces the number of falls that have the potential to cause broken bones (Am J Clin Nutr, 2005; 81: 1232S-9S).

* Strontium. This trace mineral is a component of human bone. Only 1-3 mg/day is needed to prevent osteoporosis. It is found in wholegrains, parsley, fish, Brazil nuts, lettuce and molasses. Even if you already have osteoporosis, consider adding strontium to your arsenal of supplements. When postmenopausal women with osteoporosis and a history of vertebral fracture were given 2 g/day of oral strontium ranelate for three years, their bone mineral density was increased, and their risk of fractures reduced by more than 40 per cent (N Engl J Med, 2004; 350: 459-68). However, little is known of the long-term effects of high-dose strontium supplementation (which caused bone defects in animals) (Townsend Lett Docs, 2005; 261: 67).