​Calcium: Strengths, Forms, and What to Take With It

Calcium is an important nutrient our body needs for many of its most basic functions like healthy blood circulation, muscle movement, and hormone release. Calcium also helps carry messages from the brain to other parts of the body and plays a major role in maintaining healthy bones and teeth. Our bones are our body's calcium reserve. If we don't receive an adequate amount of calcium through our diet, our body will take the calcium it needs from our bones.
We depend on the foods we eat to get the calcium we need. Foods that are high in calcium include: dairy products such as milk, cheese, and yogurt; dark green vegetables such as a kale, spinach, and broccoli; sardines; and calcium-fortified breads, cereals, soy products, and orange juices. Not everyone gets the calcium they need from diet alone due to being lactose intolerant or vegan, or just not consuming enough dairy products. For this reason, a supplement can be a great option. 
Calcium supplements can fill the nutritional gaps in our diet. The two most recommended supplemental calcium forms include calcium carbonate and calcium citrate. Calcium carbonate needs to be taken with food for maximum absorption and function. Calcium citrate doesn’t need to be taken with food and may be better absorbed by people with lower levels of stomach acid, or by those who take antacid medications that block stomach acid.
Calcium works synergistically with other nutrients such as magnesium and vitamins D3 and K2, so it is important we eat a healthy, well-balanced diet and supplement as needed. Calcium supports healthy muscle contraction, while magnesium helps our muscles relax. And our body requires vitamin D3 in order to absorb calcium, so we won't fully benefit from a calcium-rich diet if our body is low on vitamin D3. Vitamin D promotes healthy calcium absorption by activating calcium-binding proteins in our intestinal cells and regulating the vitamin K2-dependant proteins osteocalcin and Matrix GLA. These are both essential for directing calcium into our bones. 
How do we know if we’re getting enough calcium? The National Institutes of Health (NIH) recommends that adults get 1,000 mg every day. For women over the age of 50 and during pregnancy and breastfeeding, the NIH recommends 1,200 mg daily. These recommendations for a higher dose of calcium likely reflect that as a culture, our magnesium and vitamins D3 and K2 intake are typically not adequate. In those who have more ideal vitamin D3 levels, calcium intake should be lower. 
Recent studies suggest that calcium absorption is enhanced with higher 25(OH)D status. Depending on the size of this effect, calcium intake recommendations may be excessive among individuals with higher 25(OH)D concentrations. Illustrating this point, an Icelandic study suggested that, to maintain calcium metabolism, calcium intakes beyond 800 mg daily may only be needed in individuals who have vitamin D deficiencies. (We can test our vitamin D levels with an at-home Vitamin D Test Kit.)
Always look for balance when considering nutritional supplements. Our calcium needs the support of teammates magnesium and vitamins D3 and K2 to function at its best.