Many factors contribute to your overall bone health.
Your bones are dynamic – continually being broken down and rebuilt. Certain lifestyle habits can disrupt this process, wreaking havoc on your skeletal health.
In this blog we explore the effects of three of the most common vices – caffeine, alcohol and smoking.
Ninety percent of people on the planet consume at least one caffeinated beverage per day.¹ But can too much java put you in hot lava when it comes to bone health?
The general consensus is that anything less than 400mg of caffeine a day poses no significant risk to your bones, or the rest of your health.²
That is the equivalent to about four cups of coffee, or ten cans of caffeine-containing fizzy drinks.
When drank in large amounts, caffeine can interfere with the way your body interacts with calcium. Calcium is essential for healthy bones, and can only provide this support when absorbed properly.
Research states that consuming any more than 400mg of caffeine a day can prevent calcium absorption, so that it is flushed out by the kidneys when you urinate instead. A recent study found that 800mg of caffeine over a nine hour period increased the amount of calcium in participants’ urine by 77%.³ High consumption of carbonated drinks is often linked to increased fracture risk.⁴
Because calcium plays a critical role in bone growth and maintenance, high levels of caffeine can increase your risk of osteoporosis.
Partial to a beer garden on the weekend? Or a glass of wine with dinner? Even short-term alcohol intoxication can bring along some unwelcome effects for your bones.
Whatever your tipple, even a few glasses can cause something called transitory hypoparathyroidism.⁵ In other words, temporary underactivity of the parathyroid glands – small pea-sized glands located in your neck, behind the thyroid.
These glands produce a hormone called parathyroid hormone (PTH), which is critical for regulating levels of calcium in the blood.
Calcium and PTH are tightly linked – if calcium levels are low, PTH levels rise, and if calcium levels are high, PTH secretion declines.
However, when levels of PTH are compromised, such as when you are drunk, the body loses this regulatory function, causing increased excretion of calcium in urine and a lower concentration of calcium in the blood, also known as hypocalcaemia.⁶
Excessive alcohol consumption or chronic alcoholism causes hypocalcaemia to occur more often. If calcium deficiency persists, it can cause loss of bone which can result in fracture, loss of mobility and more.
Chronic consumption can also lead to low levels of vitamin D in the body – another key player in bone health. Without vitamin D, calcium absorption is decreased and ultimately calcium is released from bones, causing them to weaken.⁷ This reduces bone density and increases fracture risk, leading to the development of osteoporosis over time.
In all cases – whether of short duration, social, heavy or chronic – alcohol consumption inhibits the function of osteoblasts.⁸ These are the cells responsible for rebuilding and maintaining bone.
Under the influence of alcohol you are at more risk of fractures as a result of falls. And because alcohol suppresses the function of osteoblasts, continuing to drink post-fracture will greatly slow bone reformation.⁹
Although smoking is on the decline in the UK, there are still around 6 million regular cigarette smokers. Conversely to this, vaping and use of e-cigarettes is on the rise, with about 8.7% of adults and 15.5% of 16 to 24 year olds opting to vape at least occasionally, with the majority of people doing so daily.¹⁰
While the risks of cancer and heart disease from smoking are well known, there is less awareness of the impact on bone health.
Even so, smoking has a more clear cut effect on bone density than caffeine and alcohol. Research is consistent in showing that smokers have markedly lower bone density scores when compared to non-smokers.¹¹
There are several ways smoking can lead to low bone density. Firstly, smoking can limit the supply of blood and oxygen to the bones. This can lead to something called osteonecrosis, also known as avascular necrosis, a disease resulting in the death of bone tissue. If this occurs around a joint, which it often does, it can cause the joint to collapse.¹² If a fracture happens, healing is dramatically impaired due to the lack of blood supply.
The nicotine in cigarettes and vapes can impair the function of osteoblasts so much that bone resorption occurs at a faster rate than bone building. Flavouring chemicals often added to vapes also negatively impact osteoblast function by preventing their ability to form bone.¹³
Nicotine also has an indirect effect on bone by suppressing appetite.¹⁴ This can lead to lower body weight and lack of proper nutrition, both of which can decrease bone density. Find out more about the effect of low body weight and malnutrition on bone health by reading Anorexia and osteoporosis – what’s the link?.
Smoking can also disrupt your hormones. Oestrogen plays a protective role in bone health, promoting osteoblast activity and suppressing osteoclast activity. Smoking makes less oestrogen available in the blood, particularly in women. ¹⁵
Women who smoke tend to reach the menopause two years earlier than non-smokers.¹⁶ The menopause, which causes oestrogen levels to drop rapidly, is the number one risk factor for osteoporosis. Read more about the link between the menopause and osteoporosis here.
Smoking can cause a high concentration of free radicals to accumulate in the body.¹⁷ Free radicals are unstable atoms that are highly reactive, causing oxidative stress and damage to cells. In terms of bone health, they cause an imbalance of osteoblast and osteoclast activity, leading to increased turnover of bone and therefore increased bone loss.¹⁸
Smoking results in less efficient calcium absorption, through altering the function of PTH in the same way alcohol does.¹⁹ Plus, cortisol levels are often elevated in long-term smokers. Cortisol can interrupt osteoblast formation and accelerate action of osteoclasts to decrease bone density.
Calling it a day on the cigarettes or retiring the vapes is the number one thing you can do to protect your bones and slow the loss of bone density.
Life-time fracture risk remains higher in ex-smokers when compared to people who have never smoked, but is lower than that of current smokers.²⁰
The heavier the smoker, the longer it will take to recover, but quitting can help weakened bones regenerate cells. Various literature shows that within months of cessation, smokers can see a significant increase in levels of osteoblasts.²¹ Quitting smoking is therefore highly recommended in osteoporosis guidelines.
As for alcohol, it has been shown that eight weeks of teetotalism may be enough for previous alcoholics to initiate a healthier balance between osteoblasts and osteoclasts (the cells that break down bone), causing an increase in bone mass, when paired with moderate physical activity.
A few weeks of abstinence shows slow improvement to bone metabolism, but full recovery of bone health for chronic alcoholics may take years.²²
If you are a regular social drinker, it pays to reduce your alcohol consumption to low risk levels, as recommended by the NHS. They advise you to limit yourself to 14 units of alcohol per week, spread across 3 days or more. That’s equivalent to around 6 medium (175ml) glasses of wine, or 6 pints of beer.
There is no entirely harm-free level of drinking, but sticking to these guidelines can lower your risk of damaging your bone health long-term.
To reduce the risk of caffeine on your bones, the obvious thing to do is to stay below the recommended 400mg a day. If you are a habitual coffee drinker, try swapping every other cup for a decaf option.
As we previously mentioned, bone health is dynamic and influenced by many factors. Cutting back on the caffeine and alcohol and surrendering the cigarettes needs to be combined with other healthy lifestyle choices, such as a balanced diet and regular physical activity, in order to maintain healthy bones.
For more information on how to look after your bones and prevent osteoporosis, read our blog, Osteoporosis Prevention: What Can You Do?.