Three days in hospital, two weeks on crutches, pain-free walking and full mobility after four weeks at the latest, then off to Italy on holiday. That was the original plan. In the end, however, things turned out differently. An unforeseen complication has meant that I will probably have to walk on crutches for 12 weeks and will not be able to put much weight on the leg in the first few weeks either. My dream of sun, beach and la dolce vita has been shattered, and I will be spending the next few weeks more or less within my own four walls. I have found that reading, Netflix and co. is good for two or three days, but after that it gets a bit boring. I have no excuses and more than enough time, so I'm taking the opportunity to finally devote myself to my long-neglected blog again. When you have a broken leg, the topic is quickly found:

How does alcohol consumption affect the bones?

Alcohol is a cell toxin that can damage almost every organ in the body. So yes, our skeletal system is also affected. But what exactly are the mechanisms involved? Does it only affect fracture healing or does it also affect healthy bone? And what effect does alcohol have during the growth phase? Is moderate consumption okay or does even a small amount do harm? I wanted to get to the bottom of these questions and searched medical databases.

To understand how alcohol damages the bones, it is important to know what bones are made of, how they are formed and what they need for healthy growth. When you think of the fossilised skeletons of dinosaurs, which were unearthed millions of years after their death, you don't necessarily think that bones are a very vital tissue in which lifelong growth and remodelling processes take place. Bones are quite important for our body. They support and move us, protect important organs such as the brain, heart and lungs, are involved in blood formation and serve as a calcium store. Bones consist of cells surrounded by a hard matrix of calcium crystals and protein fibres. Blood vessels ensure that the bones are supplied with nutrients and oxygen. There are two types of bone tissue. The outer layer consists of particularly dense and thick cortical bone, also known as the cortex. These form the shafts of the long bones in the arms and legs. Inside, we have the spongiosa, a porous network of thin bone trabeculae, known as trabeculae. This is found mainly at the ends of the long bones and in the spine.

Physical activity and an adequate supply of nutrients, especially calcium, vitamin D and protein, ensure that our bones remain strong and resilient.

From birth to the end of puberty, our bones grow quickly. After the final growth spurt, the bone mass continues to increase. We reach our maximum bone mass between the ages of 9 and 18.

Even in adulthood, the bones are constantly being remodelled and replaced so that they remain strong and resilient and can adapt to changing loads. Between the ages of 20 and 40, bone density decreases, leading to a 30–40% decrease in skeletal mass by the age of 70. After menopause, women lose bone mass faster. With increasing age, bones become weaker and can break even under low loads. This applies particularly to osteoporosis, also known as bone loss. In this disease, too much bone mass is lost in a short time. Sufferers have a greater risk of bone fractures, especially in the area of the spine, thighs and arms.

Hormones play an important role in our bone metabolism. That is why women who reach the menopause are particularly susceptible to osteoporosis. This is because the body then produces fewer oestrogens, which protect the bones from premature breakdown by inhibiting the bone-degrading cells (osteoclasts). But men can also get osteoporosis. The biggest risk factors here testosterone deficiency, which can be caused by medication or alcohol consumption, among other things.

Alcohol and calcium metabolism

It's getting a bit complicated now, but I'll try to explain it as simply as possible. Bones are an important store for calcium and other minerals. Calcium has many important functions in our body. We need it not only for strong bones and strong teeth. Calcium controls muscle function and heart rhythm, and is important for blood clotting and the function of many enzymes. The small intestine absorbs calcium from food and the kidneys excrete excess calcium. The body needs vitamin D to absorb calcium. Calcium levels in the blood must be correct for nerves and muscles to function properly. By producing various hormones (e.g. parathyroid hormone, calcitonin), growth factors and vitamin D, the body ensures that the concentration of calcium in the blood is always exactly right, thus regulating the flow of calcium between blood and bones. Alcohol affects these hormones and thus disrupts calcium metabolism. This results in less calcium being absorbed through the intestines and more being excreted by the kidneys. To keep blood calcium levels constant, the body has to tap into our calcium stores in the bones, which in turn weakens the bones.

Alcohol during the growth phase

Drinking a lot of alcohol on a regular basis damages your bones at any age. However, alcohol is particularly harmful to young, growing bones. It reduces peak bone density and leads to relatively weak bones in adults, who are then more prone to fractures.

Effects on bone healing

As in my case with the broken leg, it is also advisable to avoid alcohol here. This is because there are indications that alcohol can delay callus formation. Callus is a bony growth that forms where the broken bone fuses. The callus ossifies through the storage of calcium and new bone tissue forms over time. In addition to disrupting vitamin D and calcium metabolism, alcohol probably directly inhibits the activity of bone-building cells (osteoblasts). Without proper callus formation, fracture healing is delayed or does not occur at all.

How much is too much?

It is undisputed that high and regular consumption damages the bones. But what about the occasional drink? Is that harmful too? Opinions differ on this, and even the scientific community provides varying results. There are actually a few studies that show that people with a low alcohol intake have better bone mineralisation than people who don't drink at all. But I would be careful about this. Most adults in the world drink alcohol or have done so at some point in their lives. It's not that easy to find enough lifelong teetotallers for a study who have never drunk alcohol in their lives. This means that the sober comparison group often includes people who used to drink a lot of alcohol and may have already suffered damage from it. A study from 2022 also showed that even if the bone mineral density does not change, alcohol consumption reduces the proportion of collagen and the thickness of the bone trabeculae and increases bone fragility.

For me, this means: I make sure I get enough calcium and vitamin D, exercise patience and when it comes to wine, I say no, thank you!