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The Calcium-Bone Connection

Updated: Jun 29, 2020

I have a personal interest in how calcium relates to bones…not only because I treat broken bones as an Arm & Hand Occupational Therapist, but also because my mother was diagnosed with an early-onset of osteoporosis. She found this out after suffering a fall (while dancing) which broke her wrists. Both bones of both forearms (radius and ulna) were shattered. I will never forget the sight of her disfigured wrists with a bone sticking out of her forearm when I went to the ER. She had extensive surgery that required internal plating and external fixators (metal pins sticking up from the bones through the skin with rods connecting them, to provide traction and stability) on both arms! It’s a good thing she had daughters to help take care of her initially. If you look at the opening image of my webpage, you will see my hand holding my mother’s hand…and if you look closely you can see the surgical scar on the backside of her wrist.

My mother’s diagnosis of osteoporosis kick-started my journey of learning about what causes osteoporosis. More recently, while learning about Nutritional Therapy, I have delved more deeply into learning what nutrition and lifestyle practices can help to lessen it for my mother and hopefully prevent it from developing within myself and my sisters. There are loads of articles and books about this topic but I would like to start with the basics about the mineral of Calcium and its relationship with bone density.

Bone is like a calcium bank vault because it stores 99% of all calcium in the body. Deposits and withdrawals are made as needed to keep our blood pH within a narrow range. Blood pH is the number one priority of the body. When it comes to calcium, maintaining the right level in the blood is a matter of life and death! Too much calcium can cause the heart to stop, whereas too little calcium can cause breathing to cease. Calcium is required for blood clotting, most functions of nerve cells, and as a co-factor for many enzymes. The calcium stored in bone is the buffer back-up system for keeping calcium levels at just the right level within the bloodstream.

Bones are essentially hard, calcified connective tissue. They are composed primarily of mineral salts that make bone hard and collagen fibers that give bones strength. If minerals were not deposited into bone, the bony matrix would actually be flexible! Calcium is not the only mineral that contributes to bone formation and density. We also need phosphorus, magnesium, fluoride and manganese. But calcium wins the prize for being the key mineral involved in the regulation of blood pH.

Calcium could be called “the flexible relationship mineral” because it is constantly being moved between bone and blood. This calcium exchange is regulated by the parathyroid hormone (PTH) which is secreted by the parathyroid glands. I’ll spare you the nerdy details about how this hormone is stimulated and suffice to say that when calcium levels drop too low, more PTH is released into the blood.

An increase of PTH triggers three important results:

1) PTH boosts the number and activity of osteoclasts in the bone

2) PTH decreases the loss of calcium in the urine

3) PTH stimulates the kidneys to convert Vitamin D into a hormone called calcitriol, which promotes the absorption of calcium from the gastrointestinal tract.

Osteoclasts and osteoblasts are the worker-bees within bone, doing continuous bone remodeling. Osteoclasts are specialized “bone-Clearing” cells which can be remembered by the C letter in osteoClast. They release powerful enzymes and acids to breakdown the calcium stores and release calcium into the blood until the pH returns to normal. When blood pH become too high, a different hormone, produced by the thyroid gland, called calcitonin is released. Calcitonin inhibits the action of osteoclasts, which slows the breakdown of calcium. Instead of calcium being transported from bone to blood, the direction reverses and calcium is taken from the blood and deposited into bone through the action of osteoBlasts, aka the “bone-Building” cells. They synthesize and secrete collagen fibers and utilize organic minerals to build up the bone matrix.

Where do osteoblasts get these organic minerals? From the food we eat. Our bodies cannot produce minerals, which makes is important for us to eat a wide variety of organic whole-foods.

Top Calcium-Rich Foods: (1)

- Collard greens, Kale, Spinach Boy Choy

- Broccoli and Broccoli Rabe (note rabe has more calcium)

- Oranges, Apricots, Rhubarb and dried Figs

- Salmon, Sardines & Shrimp

- Beans & Lentils

- Almonds

- Seeds (poppy, sesame, celery, chia, amaranth)

- Tofu & Edamame

- Dairy products: yogurt, cheese, milk whey protein

Eating calcium-rich foods is beneficial but the problem is that many people have issues with absorption. I was surprised to learn that although most people get enough calcium in their diet, many people are missing the co-factors that allow the body to absorb and utilize it.

Here are the 7 co-factors that impact Calcium absorption

(and tips for improving them)

1) Digestion: Calcium is only absorbed when stomach acid is strong enough. Many people have insufficient stomach acid, especially those who suffer “heart-burn”. This sounds paradoxical but it’s true (and worth a whole separate post). Also it is important to know that the quantity and quality of our stomach acid level goes down as we age, which results in older adults not absorbing as much calcium from the food they eat. As a Functional Nutritional Therapy Practitioner, I can teach you how to evaluate your stomach acid level with an “HCL challenge”.

2) Vitamin D: I cannot stress enough how important Vitamin D is for increasing the absorption of calcium through the gastrointestinal tract. Most people living in latitudes north of the 45th parallel (and vice versa in the southern hemisphere) are deficient in Vitamin D. 42% of the US population is deficient (2). The Vitamin D Council places the ideal level between 40 and 80 ng/mL (levels below 20 ng/mL are deficient). It is important to have your vitamin D levels checked once a year to ensure you are in the optimal range.

3) Other Minerals: Calcium must be in balance with Potassium and calcium needs the trace elements of Manganese, Boron, Copper and Zinc for proper usage. Eating a wide variety of organic vegetables (especially dark leafy greens) provides us with a variety of minerals. However, our soils have become depleted of many micronutrients over the past 100 years which has resulted in less nutrient-dense foods. I choose to supplement myself with Trace Minerals:

4) Hydration: Good hydration ensures blood is fluid enough to efficiently transport Calcium through the body to other tissues. Balanced electrolytes are necessary for the appropriate transfer of Calcium in and out of cells. Read more about how much water you need for your body size and how to boost your absorption of water with electrolytes in my first 2 blog posts.

5) Fatty Acids: Healthy fats are necessary for Calcium transport across the cell membrane into the cell. Coconut oil, avocado oil, organic butter and ghee are the best heat-tolerant oils for cooking. Olive oil is another healthy oil but should not be overheated. Uncooked seed oils (flax, walnut, hemp) are a great source of fatty acids (add small amounts to salad dressings). Cooking and eating vegetable oils like soybean, canola, sunflower/safflower, and corn oil should be avoided, especially since these are heavily overused in processed foods. I intend to write much more about healthy versus unhealthy fats in future posts.

6) Hormones: There is an interplay of many hormones that regulate the level of Calcium in the blood (parathyroid hormone, thyroid hormone, adrenal hormones, and sex hormones). This is a big topic on it's own so all I would like to write for now is that high-stress depletes adrenal hormones so please give yourself extra self-care during stressful times (gentle exercise, yoga/stretching, hot baths, warm soups, mugs of tea, mediation/prayer, laughter).

7) Systemic pH: When blood becomes too acidic, Calcium is pulled out of bones. When blood becomes too alkaline, Calcium is separated into solution and deposited into tissues. There is much that could be said about this topic as well, but for now, let’s focus on the simple way to help keep the blood from getting too acidic: eat green leafy vegetables every day!


Calcium supplementation is a controversial subject. I initially learned that Calcium Citrate is the best form for absorption for most people but I later learned that it is unwise to supplement with calcium alone because many other minerals are needed for proper calcium utilization. Excessive intake of supplemental calcium, along with low levels of phosphorus, can lead to soft tissue calcification. This happens when weakened areas of soft tissue take up some of the excess calcium. The buildup can lead to bone spurs in the heels and shoulders, even the tissue of the lens of the eye which can contribute to cataracts. So please be careful about taking high doses of straight calcium.

Here are some good supplement options that I recommend because they are a blend of supportive minerals. (Remember, it is important to talk with your primary doctor before adding new supplements.)

- OsteoForce by Designs for Health.

- Strontium Boost by Algae-Cal:

- Combo deal with 1 bottle Algae-Cal and 1 bottle Strontium Boost:

Algae-Cal products are expensive but they are backed by 3 human clinical studies with evidence to prove that they work to improve bone-density in people with osteopenia and osteoporosis. You can learn more at

I learned about Algae-Cal in an excellent book by Lara Pizzorno called “Your Bones: How You Can Prevent Osteoporosis & Have Strong Bones For Life – Naturally” (3)

I can provide you with further education and support for maximizing your calcium absorption as well as teach you bone-building exercises (which is another key component in building strong bones!) Reach out through my contact page if you’d like to learn more and we can set up a tele-health video call.


1) Jennings, K-A, July 27, 2018. “Top 15 Calcium-Rich Foods (Many Are Non-Dairy)”.

2) Brjarnadottir, A. June 4, 2017. “How Much Vitamin D Should You Take For Optimal Health?”.

3) Pizzorno, L. & Wright, J. “Your Bones”. 2013. Praktikos Books. pp 209-215.

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