Calcium: What You Should Know

Sources, Benefits, Forms, Dosage 

What is Calcium?

Calcium is an essential major mineral. Unlike trace minerals, major minerals, also known as macrominerals, need to be present in the diet in amounts larger than 100 mg (milligrams) because the body cannot make these nutrients on its own to sustain normal and healthy bodily functions.1

Benefits of Calcium – There are many

Calcium is most popularly known for its beneficial effect on the structure and function on skeletal and dental health. In fact 99% of calcium in the body is located in the teeth and bones.2,3 The calcium storage structures in bones, called hydroxyapatite crystals, are constantly remodeled by bone cells osteoclasts and osteoblasts.1,2 Osteoclasts break down old bone, and osteoblasts replace the old bone with new bone formation.1,3 It is important that children receive adequate levels of calcium during childhood as bone growth exceeds bone loss during this period of growth.3 Approximately, near age 30 is when peak bone mass is achieved, and bone loss will begin.2,3

In addition to benefiting the skeletal system, calcium also supports the circulatory system, vision, and muscle function.1,2 Other research shows it may even help to prevent certain diseases, including cardiovascular disease and certain cancers such as colon and prostate.1,2

The different forms of Calcium

The two major forms of calcium include calcium citrate and calcium carbonate. Calcium carbonate consists of 40% calcium, is less expensive, and it is recommended to be taken with meals, as stomach acid needs to be present for optimal absorption.2,3 Calcium citrate consists of 21% calcium, is more expensive, and is not dependent on stomach acid for absorption, therefore, it can be taken with or without meals.2,3 Other forms of calcium include calcium -phosphate, -lactate, -gluconate, and -citrate malate.2

Sources of Calcium – From food and nutrition supplements

Dietary sources with a high content of calcium include milk, yogurt, collard greens, spinach, tofu, and fortified foods.1,4 There are certain food sources, which include sources with large amounts of calcium, such as spinach, that can alter the needs of this micronutrient. Spinach, tea, cocoa, and other green vegetables decrease the levels of calcium that can be absorbed as these foods contain components called oxalates and phytates.1,2

Calcium is also available in nutrition supplements. When taking a supplement it is recommended to take calcium with a meal in split doses of 500 mg of less for optimal absorption.1 In addition to supplement, certain forms of calcium, such as calcium carbonate are found in antacid medications, such as Tums®.

Recommended daily dose of Calcium – What physicians advise

The recommended daily dose for nutrients is unique to a person’s age, gender, environment, and other personal factors. The Food and Nutrition Board (FNB) established a recommended dietary allowance (RDA) for calcium as a reference to meet the needs of healthy individuals. The RDA for calcium for healthy adults is 1,000 mg/day for men and between 1,000 – 1,200 mg/day for women. For infants the RDA has not been established, but an adequate intake (AI) level between 200 – 260 mg/day has been set as a guideline for nutritional adequacy.

Recommended Dietary Allowance
(RDA) Calcium
Infants (0 – 12 months) 200 – 260 mg/day AI
Children (1 – 8 years) 700 – 1,000 mg/day
Adolescents (9 – 18 years) 1,300 mg/day
Adults (19+ years) 1,000 – 1,200 mg/day
Pregnant and Lactating Women 1,000 – 1,300 mg/day

Table 1: Daily Calcium Recommended Dietary Allowance (RDA) for Healthy Individuals2

Certain populations may need to be more mindful when evaluating their calcium needs. Individuals frequently using certain medications such as antibiotics, bisphosphonates, levothyroxine, and anticonvulsants may experience inhibited medication absorption.2 Also, certain diuretics have the potential to interact with calcium causing an increased risk of hyperclacemia or hypercalciuria.2 Hypercalcemia occurs when there is too much calcium in the blood stream, and hypercalciuria occurs when there is too much calcium in urine, which can further result in kidney stones.5 With any particular medication or health condition it is always best to consult with your primary healthcare provider before taking the Healthycell® products or any nutrition supplement.

Calcium toxicity – Uncommon

Calcium toxicity is uncommon from food sources, and is only typically seen when consuming dangerously high doses from nutrition supplements or with certain pre-existing health conditions. Toxic amounts of calcium can cause calcification of body organs, development of kidney stones and other kidney issues, constipation, and it can interfere with the absorption of other micronutrients such as zinc and iron.1,2 For this reason, a maximum level that may cause an adverse event, also known as a tolerable upper intake level (UL) has been established to avoid toxic side effects.

Tolerable Upper Intake Level (UL) of Calcium
Infants (0 – 12 months) 1,000 – 1,500 mg/day
Children (1 – 8 years) 2,500 mg/day
Adolescents (9 – 18 years) 3,000 mg/day
Adults (19 – 50 years) 2,500 mg/day
Adults (50 + years) 2,000 mg/day
Pregnant and Lactating Women 2,500 – 3,000 mg/day

Table 2: Daily Calcium Tolerable Upper Intake Level (UL)2

Minerals such as calcium, are closely regulated by the body, making toxicities uncommon.1 When blood calcium is high, calcium absorption is impaired to keep a stable level in the body.1

Calcium deficiency, symptoms, and people at risk

Calcium deficiency is thought to be uncommon, as levels are highly regulated. When blood calcium is low calcium absorption will increase.1 However, there are negative health effects when consuming inadequate levels below the recommended intakes.2 The body will borrow calcium deposited in the bones as a homeostasis mechanism to keep stable and adequate blood calcium levels.4 

Calcium deficiency symptoms include muscle spasms and pain, numbness of extremities, tetany, and most notably osteoporosis and osteopenia.1 At a certain age the body does not optimally absorb calcium anymore, making older populations at a higher risk to develop deficiency, the bone disease osteoporosis, and bone fractures.1

Populations at risk for developing a calcium deficiency are the elderly and postmenopausal women due to impaired calcium absorption, those who are lactose intolerant as many calcium rich foods are eliminated from lactose free diets, and vegetarians who consume high amounts of oxalates and phytates inhibiting calcium absorption.2

Calcium in Healthycell® Pro 

The source of calcium in Healthycell® Pro is a combination of calcium citrate and carbonate. The dosage of calcium in Healthycell® Pro is 75 mg in the morning formula and 75 mg in the evening formula, for a daily dose of 150 mg, satisfying 16% of the Daily Value (%DV).

The source of calcium in Healthycell® is also a mixture calcium citrate & carbonate. The dosage of calcium in Healthycell® is 100 mg in the morning formula and 100 mg in the evening formula, for a daily dose of 200 mg, satisfying 20% of the Daily Value (%DV). Nutrition supplement labeling and food labeling guidelines use Reference Daily Intake (RDI) as the standard for dosage.


1.  McGuire, Michelle, PhD, and Kathy Beerman A., PhD. “Chapter 12 The Major Minerals.”

Nutritional Sciences: From Fundamentals to Food. 2nd ed. Australia: Thomson/Wadsworth,

2007. 533-540. Print.

2. “Office of Dietary Supplements – Calcium.” NIH Office of Dietary Supplements, U.S.

Department of Health and Human Services,

3. Sherman, Adria. “Major Minerals.” Nutrition and Health. Nutrition and Health, 2012,

New Brunswick, Rutgers University.

4. Wolfram, Taylor. “What Is Calcium?”, Academy of Nutrition and Dietetics, 9 Sept.


5. Wisse, Brent, MD, David Zieve, MD, MHA, and Isla Ogilvie, PhD. “Hypercalcemia: MedlinePlus Medical

Encyclopedia.” Hypercalcemia: MedlinePlus Medical Encyclopedia. US National Library of Medicine, 03 Feb.

2016. Web. 15 Sept. 2016.