Calcium Absorption Makes All the Difference

Calcium Absorption Makes All the Difference

Bone growth is a gradual process that peaks around age 30. The process of bone loss will take longer if there is a good, strong bone foundation.This is why it is important to build and maintain strong bones while we are in our youth and young adult life. One of the most important minerals necessary to achieve this goal is calcium. And calcium absorption in particular impacts how well our bones respond.

To Get Enough Calcium in Your Bones

The easiest way to ensure that you have adequate calcium stores is two-fold: dietary calcium and weight-bearing exercise. Weight-bearing exercise-like walking, for example-stimulates the mineralization of bone tissue. Moreover, the added benefit of eating a well-balanced diet will help combat bone demineralization in the future.

For some, however, exercise and diet are not sufficient insurance of long-term bone health. Calcium supplementation may be required for maximum calcium absorption.

Calcium, as well as other minerals, is stored in bone tissue. A low level of circulating blood calcium triggers bone to release the stored calcium, so that calcium can be utilized in critical areas:

  • the heart
  • nerve conduction
  • muscle contraction of internal organs

Calcium leaching leaves the bone in a precarious position. As long as the body has enough circulating calcium, the bone can have its precious mineral.

Read Magnesium: The Most Magnificent Mineral

Calcium Supplements

Calcium preparations come in a variety of compounds, strengths, and doses. Because of this, it is often confusing to determine which supplement is better. Additionally, since the body can only absorb calcium in small doses (500 mg), taking higher doses at one time is wasteful.

To determine the actual amount of calcium in a product, look on the label for elemental calcium. Different forms of calcium contain different amounts of elemental calcium. The following are some examples of different forms or compounds:

  • Calcium Carbonate
  • Calcium Citrate
  • Calcium Gluconate
  • Calcium Lactate

Calcium Carbonate

Calcium carbonate has the highest level of elemental calcium (40%) and is commonly used as an antacid to treat heartburn, acid indigestion, peptic ulcers, and reflux. For many the high level of elemental calcium makes it a good source of supplementation for the treatment of bone-mass-related issues, like osteoporosis.

To optimize absorption of calcium carbonate, it must be taken with an acidic beverage like orange juice or with a meal (because the meal will stimulate acid production in the stomach). Potential side effects are bloating, gas, and constipation.

Some advise against the use of calcium carbonate because of its ability to lower stomach acid, something that is normally reduced (and needed) during aging.

Read more about the causes of heartburn

Calcium Citrate

Calcium citrate has the second highest level of elemental calcium (20%) and is the most absorbable supplement. However, it is more expensive than carbonate.

Calcium citrate is commonly used post-surgically for gastric bypass patients due to its effortless absorbability. Because of its propensity to bind to heavy metals, it is often used in water softeners. It is found in food as a preservative. As a supplement, it must be taken on an empty stomach to ensure adequate absorption.

Calcium Gluconate

Calcium gluconate contains 9% of elemental calcium. In the hospital setting, it is used intravenously to treat hypocalcemia. It is the antidote for magnesium sulfate overdose is and often administered to women who are in preterm labor. Lastly, due to its unique cardiac protective properties, it is used during episodes of hyperkalemia.

Read more about the link between soda and preterm delivery

Calcium Lactate

Calcium lactate contains 13% of elemental calcium and is used in food preparation in the form of baking soda. Added to fresh fruit, it prolongs shelf life; added to sugar-free products, it prevents tooth decay. Because pH levels have little to no impact on its absorbability, it can be taken with or without food.

Forms of Calcium to Avoid

Finally, there is a small group of calcium supplements that have been found to contain lead and other heavy metals and therefore not recommended for ingestion:

  • oyster shell
  • dolomite
  • bone meal


In conclusion, the best way to achieve strong bones is through dietary calcium and exercise. Realistically, these options may not be enough for some individuals. The use of calcium supplementation is appropriate and achievable in a variety of ways. Because individual needs and contraindications vary, it is best to consult a health care professional before embarking on a calcium supplement program.

Image: Mike Baird

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Linda Mundorff, MPH, MSN, ND, RN, CNC, CTN has worked in health care for over 25 years as a registered nurse, health educator, associate professor, and a naturopathic doctor. She holds several degrees in health education, public health, nursing, and naturopathy. She is a certified nutritional consultant and a board certified traditional naturopath. Dr. Mundorff is the author of several books, including Memories Of My Sister: Dealing with Sudden Death, Medical Terminology: A Student Workbook. Her latest, Take Control: A Guide to Holistic Living, is an innovative health guide, which helps the reader learn how to regain control of their health by discovering the practical effectiveness of combining alternative and modern medicine.