If you are having a problem with not absorbing enough calcium, take a step back and look at your diet as a whole. It has long been known that calcium in some foods is absorbed better than others — the graph of milk versus spinach is a good example. You may be able to consume complementary foods or prepare your foods in strategic ways to increase your calcium absorption.
Vitamin D and Calcium Absorption
Adequate levels of vitamin D is critical in proper absorption of calcium because of the important role of the vitamin D hormone calcitriol in calcium absorption. Most fluid milk is actually fortified with vitamin D so that you can absorb more calcium from the milk itself. Eating fortified foods is one strategy to improve your calcium absorption, but you can get vitamin D in three other ways:
- Get more sunshine on your bare skin. Your body actually produces vitamin D when the sun hits your skin. Expose less delicate parts of your skin for twenty minutes a day during peak daylight hours to ensure that you are making enough vitamin D. This may be your best strategy because it is easy and free. Your body will only produce as much vitamin D as it needs and so there is no need to worry about toxicities.
- Eat more vitamin D foods. Saltwater fish and eggs tend to be in vitamin D. Incorporate more of these foods into your diet to improve your calcium absorption.
- Take a vitamin D supplement. A daily supplement of 600 IUs is typically recommended for the under-70 set; 800 IU daily for those over 70. (Your skin does not produce vitamin D as readily as you age.) Some people will take a large weekly dose of vitamin D.
Back Off on the Salt and Protein
Diets high in salt and protein may reduce our calcium absorption. This is one of the reason experts get concerned over strict diets like that in the Atkins Diet induction. It is extremely high in protein and can be high in salt as well. If you have a varied, mixed diet, these factors are less likely to be relevant to your calcium absorption.
If you are lactose intolerant and want to consume dairy products for calcium, lactase drops or lactase-fortified dairy foods may be in order. Some people make the lactase enzyme naturally, particularly those of northern European descent. Others may have a difficult time digesting dairy products and the calcium in them without the help of a lactase supplement.
As an aside, my raw milk friends tell me that raw milk contains lactase and is digestible to those with lactose intolerance. There was actually a study on this issue involving actual raw milk consumers at Stanford University. The researchers found no evidence for this claim.
Reduce Phytic Acid
For those who rely on grains, legumes, nuts, and seeds for calcium, consider strategies that reduce the calcium blocker phytic acid. Our resources on the phytic acid site on soaking beans and preparing grains will help you develop effective kitchen strategies.
Reduce Oxalic Acid
Some high calcium foods, notably spinach, are packed with calcium but also with a calcium inhibitor called oxalic acid. Read more about foods high in oxalic acid and your best kitchen preparation strategies.