Bone is an amazing material — weight for weight, it’s actually as strong as steel. Well, healthy bone is, but weakened bone can break with the force of a simple sneeze.
Yet few people think about their bone health until they have a fracture or a scan which identifies a weakness.
However, it really is something we should all pay more attention to, as weak bones can ultimately rob you of your independence, and in many cases there are really simple diet and lifestyle adjustments (including eating onions!) that can help prevent future problems. And these are things I think everyone should be doing from a young age, even in your 20s.
Bone is a living thing: old bone is constantly being broken down and replaced with new bone (our skeleton is completely replaced over a decade).
But from quite a young age — after the age of 30 — we lose more than we make, meaning we experience a progressive loss of bone mass, a process which in women accelerates after the menopause.
For those with osteoporosis the process is accelerated even more, and their bones can become so weakened that even a minimal knock, a sudden move or sneeze can lead to a fracture.
This is still incredibly common — according to the Royal Osteoporosis Society, more than three million people in the UK have osteoporosis (and it’s more common in women).
The risk of osteoporosis hinges on multiple factors, including genetics and taking certain medications such as steroids, which can slow the production of new bone.
But diet can play a part, too, and many people with osteopenia, the precursor to osteoporosis when the bone is starting to weaken, may prevent the progression to full-blown osteoporosis by switching to a more bone-friendly diet.
The one thing we can all do for our bones is to have calcium-rich food in two meals a day.
For those with osteoporosis the process is accelerated even more, and their bones can become so weakened that even a minimal knock, a sudden move or sneeze can lead to a fracture
Around 99 percent of bone is formed of calcium — it helps mould the strength and structure. If your diet doesn’t provide enough calcium for your body’s needs (it’s also required, for example, to help your heart contract, digestive enzymes to work, your blood to clot and your nervous system to function), then it will be leached from your bones, weakening them.
But the pathways through which calcium is absorbed can become saturated, like a bottleneck on a busy road. So if you have a single, calcium-rich meal containing more than 500 mg (the amount in a large glass of milk), your body will absorb much less of it than if you consume small quantities across the day.
So what are the best sources? Milk, yoghurt, good-quality cheese and sardines are fantastic. The sardine bones are especially rich in calcium. We also eat the ends of chicken wings: we crisp them up in the oven for a delicious and calcium-rich snack, with two providing 400 mg or so of the 700mg of calcium we need daily.
Those on a plant-only diet need to be more savvy. Spinach and rhubarb provide calcium but they also contain oxalates, compounds that bind to the calcium, meaning it isn’t so easily absorbed. The same mechanism is why foods such as nuts, seeds and wholegrains containing phytates are also not considered good calcium sources. However, tofu set in calcium (it will say on the packet), broccoli, kale and spring greens are decent sources. But if your diet is plant-based, I’d recommend having calcium-enriched, plant-based milks, too.
Bone health isn’t all about calcium. You also need adequate vitamin D, as several of the transporters that carry calcium across our gut lining rely on vitamin D to work; having sufficient vitamin D increases the absorption of calcium by around 50 percent.
Now to explain about onions. These are a type of prebiotic — like garlic, legumes, artichokes, dates and barley — which act as fertiliser, feeding the gut bacteria which make the gut slightly more acidic, an environment that makes calcium more absorbable.
Prebiotics may also help bone health in other ways. Gut bacteria break them down to produce short-chain fatty acids, which in animal studies have been shown to help regulate the osteoclasts (the cells responsible for breaking down bone) and bone mass.
Onions specifically contain the flavonoids quercetin and kaempferol, thought to stimulate osteoblasts (the cells that generate new bone).
A 2009 study published in the journal Menopause found that women over the age of 50 who consumed onions once or more a day had better bone density than those who consumed onions once a month or less.
-Daily Mail.uk