Niki Bezzant: It's hip to care for your bones

A mother's diet will affect the future health of her child. Photo / iStock

I've just read something that's got me reaching for a milky smoothie. It's a report from the International Osteoporosis Foundation titled Healthy Nutrition, Healthy Bones. On the eve of World Osteoporosis Day on Tuesday it is worth thinking about the health of our skeletons. What we eat plays an important role in our bone health - and that in turn affects how healthy and mobile we are as we age.

As the baby-boomer generation gets older, the incidence of fractures caused by osteoporosis is going up. There are almost 100,000 fractures in New Zealand each year, mostly in the over-50s. Most don't see it coming; osteoporosis is an invisible disease. Even so, it's incredibly common. It is estimated that half of women and a third of men will suffer an osteoporotic fracture some time in their lives.

So how do we set ourselves up for strong healthy bones in old age?

As with many other things, nutrition throughout our lives is hugely important. This starts before we're born, with what expectant mums eat and drink. This can affect our bone strength as adults, and even our risk of fracture when we're in our 70s. That's why osteoporosis is sometimes called a "paediatric disease with geriatric consequences".

What we eat and do during childhood and adolescence determines whether we reach our "peak bone mass". As the report puts it: "We genuinely owe it to our children to ensure they have a well-balanced diet, rich in calcium, vitamin D and protein, and take adequate exercise, to set them up for a long, healthy and active life."

Those three nutrients are key at all ages, in fact.

Calcium is important for children and adolescents to help build strong bones. As adults, calcium helps us maintain our bone health and slow bone loss, which can start around the age of 40.

Calcium is in some green vegetables (such as broccoli, kale and bok choy); whole canned fish with soft, edible bones such as sardines; nuts (almonds and Brazil nuts); and tofu set with calcium (check the ingredients list).

But by far our biggest and best source of calcium is milk and other dairy foods. They also contain protein to build bone and help build and maintain muscle. This is essential as we get older to lower our risk of falls and fractures.

Vitamin D helps us absorb calcium, and helps our bones renew themselves. Although it's in some foods - fortified milks and cereals and oily fish - we get vitamin D mainly from the sun. It's a tricky balance to get enough sun to get our vitamin D without getting sunburned and risking skin cancer. To achieve that at this time of year the Cancer Society recommends we get outside daily in the early morning or late afternoon.

Other good things we can do for our bones: watch the alcohol and caffeine - too much of these adversely affects bone health. Being very underweight or very overweight is also not good. And moving our bodies at all ages is a great bone-boosting step.