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Building and Maintaining Strong Bones
The strength of your bones depends on many different things. Bone strength is related to bone mass - the accumulation or build-up of bone. Other factors that determine bone strength are bone turnover (replacing old bone), bone size and area, and the combination of minerals within the bone.
Throughout your life your bones are constantly changing in both shape and size. The changes are very small and slow, so you don't notice them.
So How Do Bones Grow?
There are two important types of cells that are responsible for bone growth and maintenance. These are called osteoclasts and osteoblasts. They sound like something from outer space, don't they? Although their names are very similar they have two distinct jobs in helping bones to grow. Osteoclasts renew old or damaged bone by dissolving or resorbing it, leaving an empty space. The osteoblasts then fill this empty space with new bone.
Bones go through two stages of development:
- The growth stage is what you are in right now. Babies, toddlers and teens are also at this stage, which is called the acquisition or bone gaining phase.
- Adults and the elderly aren't growing any more, just making the best of the bones they already have, so their stage is called the optimisation phase.
The next time an adult tells you that you are just going through a phase you can answer, "Yes, you are quite right. I am going through a bone acquisition phase, and you are going through an optimisation phase!" That will be sure to get them thinking!
1. Growth - Acquisition or Bone Gaining Phase
During the acquisition phase it is extremely important to eat and drink enough calcium-rich foods, like dairy foods, to ensure that you are building a strong and healthy bone mass. This is the time when you are growing the most, and is probably the most important time of bone growth. Your bones are growing in both length and size. Bone density does not always keep up with bone growth, so young children and teenagers may be at a greater risk of broken bones than adults.
Your bone strength is determined by the time you reach your mid- twenties and your bones will not get much stronger from then on. Your bones grow and are modelled (sculpted into the right shape and size) from the moment you are born to about your 25th birthday. This may seem a long way off at the moment but every day counts when it comes to building unbeatable bones.
It is extremely important to do everything you can to build up that strength now. The easiest way to grow unbeatable bones is to eat and drink three serves of dairy every day. And dairy is so yummy too - a bone-us!
2. Adulthood - Optimisation Phase
This phase is entered around your mid-twenties and continues afterwards. The remodelling of your bones involves repeated cycles of bone removal (resorption) and replacement. Osteoclasts break down old bone and osteoblasts then repair the bone. In healthy bones this process is able to happen without any loss of bone because the osteoblasts can reabsorb the calcium from your blood. However, all the ingredients for healthy, unbeatable bones need to be deposited in your skeleton when you're young, because no extra bone mass is created when you're older.
Peak Bone Mass
Bone strength is measured as bone mineral density, which you might see written as BMD. Peak bone mass describes maximum bone size and mineral density - it is when your bones are at their strongest. Do you remember learning that your skeleton acts as a storage tank for calcium? The higher the peak bone mass you can achieve by your mid-twenties the fuller your bones (or tanks) are. This means that your bones will have plenty of back-up supplies to rely on to replace natural bone mineral loss and repair any damage.