The Keys to Calcium Absorption

Calcium is probably one of the most well known of the minerals that are necessary for the body to properly function. It is the most abundant mineral in the body, making up about 1.5-2% of the body by weight, and is a major part of the structure of our bones and teeth and is required for neurotransmitter activity and for proper contraction of the heart. It facilitates the movement of nutrients into our cells and helps to initiate the blood clotting process. Pretty darn important for something that we cannot make ourselves and have to get from our food.

We are taught at a young age to drink our milk in order to have strong bones. This is valuable advice, considering that 99% of our body’s calcium is stored in the bones and teeth, but it is not the whole story. Almost everyone gets enough calcium through diet, but that doesn’t mean our bodies are absorbing and using it.

There are certain states, known as co-factors, that must be present in the body for calcium to be properly absorbed and utilized. If they are not present or in balance, not as much calcium will be absorbed, no matter how much you are consuming.

  1. Stomach Acid - Sufficient levels of hydochloric acid in the stomach are necessary the entire chain of the digestive system to function properly. The ideal pH of the stomach for proper digestion and absorption of all nutrients, including calcium, should be somewhere between 1 and 3. Stomach acid pH is increased by over the counter acid blockers and proton pump inhibitors (PPIs). Long-term use of these medications will negatively impact proper digestion of food and absorption of nutrients, including calcium.

  2. Healthy Fats - Fatty acids make up part of the membrane surrounding every cell in our body and are necessary for the transport of calcium across the cell membrane and into the cell. They also help to increase calcium levels in tissues.

  3. Vitamin D - There is a reason that vitamin D is added to milk. It helps to increase the absorption of calcium through the gastrointestinal tract. It also works with parathyroid hormone to pull calcium from the bones when calcium levels in the blood fall and helps to decrease the loss of calcium through urine/feces.

  4. Other Minerals - Calcium levels must be in balance with other mineral levels in the body, including potassium, manganese, boron, copper, and zinc. High levels of phosphorus, which is common in people who drink a lot of soda, can also inhibit calcium absorption.

  5. Blood pH - Calcium stored in our bones plays a huge role in maintaining optimal pH levels in the blood that are required for our bodies to function properly. When our blood becomes too acidic, calcium (an alkaline substance) is pulled from the bones to bring blood pH back into balance. When blood becomes too alkaline, calcium is deposited into the bones from the blood to bring blood pH back down to normal levels. This process is called calcium homeostasis.

  6. Hydration - Making sure we drink enough water helps to ensure that our blood is fluid enough to transport calcium throughout the body to tissues that need it. Having sufficient electrolyte levels helps in the transfer of calcium into and out of our cells.

  7. Hormone Levels - As I mentioned in #3 above, parathyroid hormone is our primary hormone in the regulation of blood calcium levels. It raises calcium levels in the blood by causing the break down of bone (called resorption) to release calcium and increasing calcium absorption in the gut. A thyroid hormone called calcitonin decreases blood calcium levels by increasing calcium deposition in bone and decreasing calcium absorption. Estrogen also inhibits the breakdown of bone to release calcium while progesterone promotes bone growth activity.

Lack of calcium can lead to osteoporosis, which is a growing concern in our country, especially for women after menopause. Other symptoms of calcium deficiency include muscle cramps (including period cramps), periodontal disease, hyperactivity, anxiety, and insomnia. If tests have shown that you have low amounts of calcium, bringing these co-factors into balance will help to boost calcium absorption and naturally increase calcium levels.

Foods containing the highest amounts of calcium include dairy, leafy greens (collard greens, turnip greens, spinach, dandelion greens), yeast, lamb, sardines, rhubarb, oatmeal, nuts (almonds, and Brazil nuts), sesame seeds, and tofu.