After that, we begin to lose bone density as we age. There are also around 500 million people worldwide with osteoporosis, a condition that weakens our bones, causing them to become thinner and more brittle. Conditions like osteopenia and osteoporosis are often silent diseases that show no symptoms until a potentially life-altering fracture occurs, explains Julie Thompson from the Royal Osteoporosis Society in the UK.

This is especially the case for hip fractures, of which more than 10 million occur globally per year in those aged over 55. The consequences of this can be dire, with fractures leading to complications such as pneumonia or heart attacks. In all, about 30% of patients over the age of 60 die within one year of a hip fracture – though other factors such as age and pre-existing conditions may also be involved.

As women age, they are particularly vulnerable to loss of bone density, especially during menopause – and they have a higher prevalence of osteoporosis. But men are affected too.

"Historically osteoporosis was considered a disease of women and that is because [more] men were dying in their 60s due to heart disease. They now live long enough to express osteoporosis," says Bess Dawson-Hughes a professor of medicine at Tufts University who specialises in bone and muscle function.

So, what can we eat to ensure our bones stay strong?