Last night I went for a CT scan on my left wrist. A fractured scaphoid still hasn’t healed some 4 months after coming off my bike. Last week, I walked into a workbench carrying some boxes and, I strongly suspect, cracked my lower ribs. These are my first broken bones in all my 50 years, but it does lead me to wonder – “how does anorexia affect bones?”
Our bones are in a state of constant flux – new bone is made and old bone is broken down and reabsorbed. During childhood and early adolescence, new bone is laid down faster than it is being broken down, which means that we reach peak bone mass in our younger years – usually by our early 20s and definitely by the age of 30. Bone mass shrinks about 1% annually thereafter, and can be accelerated by such factors as smoking, a sedentary lifestyle, overly strenuous exercising, inadequate nutrition, hormonal changes and some medications. Reduced bone mass can lead to weaker bones that have a tendency to break or fracture easily. We also reach our full height when long bones stop growing – usually in our mid teens.
Bones affected by anorexia
Females with anorexia often have absence of menstrual periods due to low oestrogen levels, and low oestrogen levels lead to significant losses in bone density. Anorexia can also increase the production of the hormone cortisol, which is also responsible for bone loss. In males with anorexia, low testosterone levels can also lead to low bone density, and calcium deficiency and malnutrition generally will affect growth and bone density.
Given that puberty is an important time for developing bones, and that anorexia often occurs around puberty, the consequences for bones cannot be ignored. If peak bone mass is never achieved the individual will be at increased risk for osteoporosis in later life. The longer the duration of the illness, the greater the bone loss, and the less likely bone density and growth will return to normal.
It is difficult to think about things that might happen to you later in life as a result of what you are doing in the present time, but try to think of your bones as a bank account. The more bone tissue you deposit in your youth, the more you will be able to withdraw in your later years without getting into trouble. Weak and brittle bones will put you at risk of fractures, affect your ability to exercise, to perform everyday tasks, and may even affect your appearance and / or lead to disability. Look after your bones.
Looking after your bones
Weight restoration: Reaching a healthy weight and the return of menstruation may reverse some of the negative effects of anorexia in terms of bone density and growth.
Nutrition: Eating a diet rich in calcium and vitamin D is essential for bone health. Calcium can be found in dairy products, dark green leafy vegetables, and fortified foods, such as breakfast cereal and bread. Vitamin D is essential for calcium absorption and is synthesised in the skin through exposure to sunlight. Many of us do not have adequate exposure to sunlight, and supplementation is advised.
Exercise: Bones become stronger with weight bearing exercise that works against gravity – e.g. walking, running, lifting weights, dancing, climbing stairs etc. The benefits of exercise of any nature, however, need to be balanced against the potential negative effects of exercising whilst underweight and / or while trying to reach a healthy weight in sufferers of anorexia, so it is recommended that you are guided by the person medically responsible for your care.
Healthy Lifestyle: Smoking and drinking can negatively affect calcium absorption, as can some medications such as corticosteroids and SSRI antidepressant medicines.