In the 1800s, clinical trials administering cod liver oil (a source of Vitamin D) to tuberculosis patients provided early evidence of its clinical benefit. In 1859, sanatoriums used heliotherapy (exposure to sunlight) as a means to increase tuberculosis patient’s vitamin D intakes. And in case you’re wondering, Vitamin D exerts its effect by binding to and modulating key members of the immune system including T cells, B cells, macrophages and dendritic cells.
The more I learn about nutrition, the more and more confused I get when it comes to the recommended daily nutrient intake levels. The fact of the matter is, no one really knows exactly how much calcium, sodium, or iron we actually need on a daily basis. Part of this is due to the fact that we’re all different and the amount of Calcium that I need could be very different from the amount of Calcium that YOU need. Not to mention, the amount of Calcium that I require today may be different from the amount that I will need tomorrow. A large part of this is due to the fact that, beyond obvious factors like age and gender, there are many variables that can influence one’s calcium needs…
Consumption of foods/nutrients that aid Calcium absorption, such as Vitamin D…with that in mind, another factor influencing absorption is…
Exposure to sunlight. As you know, Vitamin D is produced when sunlight is absorbed through your skin, hence if you spend more time in the sun, you’ll probably absorb more Calcium.
Consumption of foods/nutrients that inhibit Calcium absorption. This includes chocolate, sugar, chocolate, alcohol and caffeine, giving you yet another reason to avoid these tempting, yet potentially harmful foods.
Genes! By now, it’s pretty obvious that genes affect everything. We’ve already discussed that Vitamin D aids Calcium absorption. However, even with adequate Vitamin D, your calcium absorption is dependent on which version of the vitamin D receptor gene you’ve inherited.
All things considered, you can imagine how hard it is to set Calcium recommendations for the entire population. In many ways, it’s an impossible task, any recommendation will only be an estimated average that may or may not be ideally suited to you.
For me, the large difference between the WHO’s recommendation (400-500mg) and the Institute of Medicine’s (IOM) recommendation (1000mg [for adults]) is reassuring. Personally, I’m not a huge fan of dairy products. Though I don’t necessarily advocate for veganism, I definitely think that there are some serious issues with consuming large amounts of milk (largely due to the hormone content). So if you’re like me, you can now rest assured that according to the WHO, approximately a cup and a half of milk (which contains around 500 mg of Calcium) could be enough to prevent you from developing osteoporosis.