Why is Calcium Important for Bone Health?

Calcium in Your Diet

Calcium in your Body

Calcium (Ca2+) is a mineral that must be consumed through diet and cannot be made inside the body. Over 99% of total bodily calcium is stored in your bones, which works as a mineral bank. Just like a regular bank, calcium is deposited and withdrawn from your bones on a regular basis and used to support vital bodily functions. The remaining 1% is distributed throughout the body in teeth, blood, muscle, and the fluid between cells [Naidu 2009].

Calcium is known to build strong bones, but it also performs several important functions in your body. Calcium is required for digestion, blood clotting, squeezing and relaxing muscles, releasing hormones, and proper nerve function. Calcium even helps you maintain a regular heartbeat. Furthermore, calcium is a highly bioactive mineral that works synergistically with co-factors to deliver its health benefits. Calcium and magnesium are primarily responsible for maintaining a healthy bone mineral balance and skeletal structure in your body. Vitamin D is an essential factor in the intestinal absorption of calcium in combination with magnesium.

Calcium Regulation PTH

Having proper balance of calcium is key for optimum health. Any imbalance in either deposition or withdrawals of calcium can lead to health problems. Too much calcium can cause a disease-state called hypercalcemia. On the other hand, not having enough calcium can lead to a condition called hypocalcemia.

High Calcium Level - Hypercalcemia

Too much calcium in the body (hypercalcemia) can be dangerous. Symptoms of hypercalcemia are usually seen when serum calcium levels are above 12 mg/dL. Individuals with a calcium level more than 15 mg/dL need to seek immediate medical treatment. While excessive dietary consumption of calcium can contribute to this clinical condition, the main cause of hypercalcemia is due to excess parathyroid hormone (PTH), which regulates the serum calcium levels in the body [Badireddy & Naganathan 2018]. High calcium levels can also indicate a serious underlying disease such as kidney failure, adrenal gland failure, and certain types of cancer. Symptoms of abnormally high calcium levels may show signs of illness such as weakness, restlessness, loss of appetite, increased drinking and urination. In some cases, prolonged hypercalcemia may contribute to formation of bladder or kidney stones.

Low Calcium Level - Hypocalcemia

Individuals that do not have enough calcium can suffer from hypocalcemia. The total serum pool of calcium is about 1200-1400 mg. This extra-cellular mineral pool maintains the plasma calcium level in tight control at a constant serum level (typically 8.4-9.5 mg/dL) using a complex combination of hormones and specific bioactive substances. The smallest drop in serum calcium below the normal level will trigger an immediate physiological response. As a result, calcium will be withdrawn from the bones to maintain normal serum calcium levels and prevent hypocalcemia [Beto 2015]. Hypocalcemia can be caused by a variety of factors, including inadequate vitamin D synthesis in the body, menopause, or poor diet. The thinning of bones and onset of osteoporosis are often the first signs of a calcium deficiency. Other symptoms include irregular heartbeat, joint problems, nervousness and insomnia [Naidu 2009].

Calcium from Foods

Foods with Calcium

Since calcium is a mineral; it cannot be produced (or synthesized) in your body. Therefore, calcium must be orally consumed, preferably through diet. Calcium is essential for your overall health. According to the U.S. National Institutes of Health (NIH) the recommended daily intake (RDI) of calcium is 1000 mg for most adults, though women over 50 and everyone over 70 should get 1200 mg/day, while children aged 4–18 are advised to consume 1300 mg daily [IOM 2010].


Dairy products, including milk, yogurt, cheese and ice creams are excellent sources of calcium. A single cup (8 oz.) of milk provides 25–35% (250-350 mg-Ca) of the RDI for calcium. Daily consumption of 2-4 servings of dairy products such as Yogurt (330 mg/cup), Parmesan or Ricotta cheese (330 mg/cup), Cottage cheese (250 mg/cup) or Ice cream (125 mg/cup) will help ensure enough calcium in your daily diet. While dairy products tend to pack the highest amounts of calcium, plenty of other good sources for this mineral exist – many of which are plant-based.

Leafy Greens

Leafy greens are rich in calcium. The calcium content per one cup (190-g) of raw chopped kale (90 mg-Ca), collard greens (84 mg-Ca), broccoli (79 mg-Ca) and mustard greens (64 mg-Ca) could provide a sizable daily serving of this bone mineral. Vegans should aim to consume 2 or 3 servings of plant-based calcium per day. However, some leafy greens (i.e. spinach) contain oxalates, which may interfere with calcium absorption in the body.


Seeds such as poppy, sesame, celery and chia are high in calcium. For instance, two tablespoons (1 oz.) of poppy seeds pack 250 mg of calcium, or 25% of the RDI. Sesame seeds have 18% of the RDI for calcium/2 Tb, plus other bone minerals, including copper, iron and manganese. A single ounce of following seeds contains calcium as indicated in the parenthesis: chia (180 mg-Ca) also with boron that promotes healthy bones and muscles by helping the body to metabolize calcium, phosphorous and magnesium; sunflower kernels (110 mg-Ca) – also rich in magnesium that balances the effects of calcium in the body and regulates nerve and muscle health.


Protein works alongside calcium minerals to ensure strong muscles, tissues and bones, Meat, poultry, eggs, seafood, beans and peas, nuts, and seeds are all considered part of the protein diet. A serving (120-g) of red meat or chicken consists of 7 to 17 mg of elemental calcium to the body. A similar serving of egg provides about 10% RDI (85-90 mg-Ca) of this mineral. A single can (3.75 oz.) of sardines’ packs 35% of the RDI – just two sardines canned with bones contain about 90 mg of calcium. While these protein foods are good sources of calcium - consuming protein in excess (over the RDI) can cause adverse effects associated with long-term high protein/high meat intake, such as disorders of bone and calcium homeostasis [Delimaris 2013].

Calcium Supplementation

Should I take a Calcium Supplement?
Not necessarily. A calcium supplement is typically required only if you have a calcium deficiency. The ideal source of calcium, especially if you are seeking bone support, is whole foods rich in minerals, including calcium. Also, we recommend adding OsteoDenx® to your nutritional regimen to help maintain optimal bone and joint health.

How does OsteoDenx® support your bone and joint health?
OsteoDenx® is an exclusive bio-replenishment that supports multiple aspects of skeletal physiology. Unlike calcium-only products, which have limited absorption and bioavailability, OsteoDenx® helps maintain an optimal balance of bone and joint nutrients, including calcium. This formula, powered by patented Syno-PORTIN® Complex, is a novel target delivery system that is based on all natural ribonuclease-enriched lactoferrin (also known as R-ELF) and other bioactives [Bharadwaj et al 2009]. OsteoDenx® helps your body better absorb, transport and deliver essential nutrients to the bones and joints.

* These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent disease.

[1] Naidu AS (2009) Bio-replenishment for Bone Health. California: Bio-Rep Media. ISBN:978-0982445105
[2] Badireddy M, Naganathan S (2019) Hypercalcemia. In: StatPearls [Internet]. Treasure Island (FL): Stat Pearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK430714/
[3] 3. Beto JA (2015) The role of calcium in human aging. Clin Nutr Res 4(1):1-8. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4337919/
[4] Institute of Medicine (IOM): Food and Nutrition Board, Committee to Review Dietary Reference Intakes for Vitamin D and Calcium (2010) Dietary Reference Intakes for Calcium and Vitamin D. Washington, DC: National Academy Press, 2010.
[5] Delimaris I (2013) Adverse effects associated with protein intake above the recommended dietary allowance for Adults. ISRN Nutrition 2013:126929. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4045293/
[6] Bharadwaj S, Tezus Naidu AG, Betagiri GV, Prasadarao NV, Naidu AS (2009) Milk ribonuclease-enriched lactoferrin induces positive effects on bone turnover markers in postmenopausal women. Osteoporosis International 20(9):1603-1611.


Bevi Edlund brings over ten years of journalism experience to bioQuad. She graduated from California State University, Fullerton with a degree in Communications (where she majored in Journalism). Bevi is passionate about writing about nutrition, health and lifestyle. Prior to joining the bioQuad team, Bevi had experience writing for various newspapers throughout Southern California. Bevi loves to connect with people through her blogs posts and articles.

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