What is the deal with Calcium? Do we need it, and how can we get it?
I’ve always sat firmly in the – calcium builds bones and prevents osteoporosis camp.
However recently I’ve heard whisperings that calcium is not actually beneficial for the prevention of bone related disease and fracture risk.
As a dairy free family (due to allergies, and environmental wellbeing reasons), I’d like to know if my quest to top up calcium is really necessary.
So what IS the deal with calcium?
Well calcium is found mainly in dairy produce, however you can also find it in smaller quantities in fruit, and vegetables.
The premise is that calcium is important for maintaining strong and healthy bones. Starting at about age 50 years, postmenopausal women lose about 0.7–2% of their bone mass each year, while men over age 50 years lose on average, 0.5–0.7% yearly. By the age of 75 years this would equate to around a 30% loss for women, and 15% loss for men.
According to government projections, around 50% of us are at risk of developing osteoporosis in our lifetime. Among adult women over age 45 years, osteoporosis accounts for more bed days in hospital than many other diseases such as diabetes, heart attack, respiratory diseases, and breast cancer. Fractures in elderly people are the primary cause of hospitalisation, admission to full time care, and death. (1)
It is hypothesized that dietary changes, such as low levels of calcium and high levels of phosphate (e.g white flour and meats - particularly processed), are associated with fracture risk.
So what does the evidence say?
Quite surprisingly for me, calcium does not have a linear relationship with bone deterioration.
I know, few things surprise me anymore, but this was one of them.
Several meta-analysis have looked at using calcium from food or supplements to increase bone density and decrease fracture risk. (2, 3) The outcomes have been pretty disappointing. On the whole any gains were so modest that it was barely significant, and would not have much if any impact on falls risk.
One of the theories behind this is that calcium is not the issue as much as Vitamin D, phosphorus, and protein. The last I highly doubt given the unusually high levels of protein in the populations diet in recent decades.
There evidence indeed supports my scepticism, showing little effect on bone health with increased protein. There was moderate increase in bone density with the lower spine in this study (4) – but no other sites showed a significant increase.
There is some suggestion that Vitamin D in combination with Calcium helps (5,6). This would support the idea that actually it is these vitamins and minerals working together which contributes to bone density. There has been substantial concern amongst public health officials over the last decade about the increase in vitamin D deficiency.
There are several hypothesis for this. Most likely it is a bit of all of them. They include;
- an increase in sedentary behaviour (more screen time, less outdoor time)
- the movement of darker skinned people away from the equator to areas with less sunshine hours (darker skin absorbs less Vit D meaning more exposure is needed, also cultures in hotter climates tend to where clothes covering them up more, which becomes problematic when you move somewhere with less intense sun)
- increased concerns around exposure to the sun and skin cancer
- and increased fear of letting kids play outside on their own
So should we be giving kids a heap of dairy products?
Cow's milk, rich in many nutrients, including calcium, has been long considered the golden goose of bone health. However with an estimated 65% of the world’s population being intolerant to it, and its link to long term disease such as prostate cancer and type 1 diabetes. It is a less than stellar option.
An alternative is fermented dairy foods, such as yogurt and cheese. This may be because most or all of d-galactose, the sugar in milk which may be responsible for inflammation causing disease, has been metabolised by bacteria in the fermentation process. (7)
Ok I’m confused – what should I be doing?
Well upon careful review of the evidence my recommendation would be to consume calcium-rich foods such as, fermented dairy (eg, unsweetened yogurt, kefir, cheese), leafy greens, almonds, and chia seeds, as these seem to provide the best bone health outcomes without sacrificing other areas of your health.
Additionally getting some sunlight hours - preferably early morning when the damaging rays of the sun are less problematic - will do you good. A walk around the block in your work breaks, or a decent stroll with the kids will work just fine.
Otherwise fatty fish is a good food alternative if the weather is not so great!
- Surgeons AAoO. The burden of musculoskeletal diseases in the United States: prevalence, societal and economic cost. Rosemont, IL: Amer Academy of Orthopaedic, 2008.
- Michaelsson K, Wolk A, Langenskiold S, et al. Milk intake and risk of mortality and fractures in women and men: cohort studies. BMJ 2014;349:g6015