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Build Strong Bones And A healthy Body

Calcium is the most abundant mineral in the human body. Of the two to three pounds of calcium in the average body, 99 percent is stored in the bones and teeth. The remaining one percent plays a crucial role in muscle contraction, blood clotting, regulation of blood pressure, nerve transmission and other body processes.*

Building Strong Bones

Osteoporosis, a degenerative bone disease caused by long-term loss of calcium from the bones, affects approximately 28 million Americans. The most common symptoms of osteoporosis are brittle bones in the hip joint, or spine. Osteoporosis can affect anyone, but for every man who develops osteoporosis, eight women develop the bone disease.1  The risk of osteoporosis is higher in Caucasian and Asian women. Besides age, many lifestyle choices can lead to bone loss, such as smoking, drinking caffeinated beverages and lack of exercise.

The importance of calcium in building and maintaining strong bones and teeth is probably its most beneficial role.* A healthy skeleton is what allows us to stand upright and provides a strong foundation for the muscles that give us movement.

Bones are in a constant state of flux. In a process known as modeling, minerals contained in bones are reabsorbed into the body and a new supply of minerals then reforms the bones.* A constant supply of nutrients, including calcium, are needed for this modeling process of bones.* 2

Calcium is bound within the bone matrix, but can be moved in and out of the bones if blood levels of calcium drop. Conversely, if calcium blood levels get too high, the bones absorb a portion of the excess. This allows blood calcium levels to remain very stable.

Preventing or slowing bone loss is considered a crucial part of avoiding osteoporosis. Adequate calcium during childhood and the teenage years is important for building strong, dense bones.*3, 4  During the middle years of life, optimal calcium intake slows the natural loss of calcium from the bones.* 5, 6  And in later years, especially for women after menopause, calcium intake can inhibit the rapid bone loss common to this stage of life.* 7, 8, 9  Calcium is more effective in maintaining healthy bones when used with other minerals, such as magnesium, copper, manganese and zinc. These trace elements are essential in bone metabolism.*10 

Calcium and the Cardiovascular System

Calcium is a crutial element in the functioning of the cardiovascular system.*11, 12, 13 Optimal calcium intake helps maintain normal blood levels of total cholesterol and low-density lipoprotein (LDL-the “bad” cholesterol).* 11  Calcium also plays a role in blood pressure regulation.* 12, 13  When the calcium intakes of  adults are compared to their blood pressure, those with higher calcium intakes are more likely to have healthier blood pressure.*14 

Pregnancy: A Special Time for Calcium

Calcium requirements increase during pregnancy and lactation since the mother needs nutrients for herself, as well as for her baby. In response to this higher need, the gastrointestinal tract increases its absorption of calcium, but dietary intake should increase as well.

High blood pressure, fluid retention and other similar conditions occur in approximately one in ten pregnancies. The health of the mother and baby can be seriously compromised when these conditions continue unchecked. According to research, pregnant women with a high calcium diet (2 grams daily), compared to pregnant women with a lower calcium diet (640 mg daily), are more likely to maintain normal blood pressure during their pregnancy.* 15  However, supplemental calcium intake during pregnancy should be limited to 1,500 mg daily, since higher levels can increase the risk of kidney stones, (another condition of increasing incidence during pregnancy).16 

Other research suggests that pregnant women who take calcium supplements are more likely to have a full-term delivery.* 17  A preliminary study of pregnant teen-agers, a group at higher risk for pre-term deliveries, showed that a daily 1,500 mg calcium supplement helped normalize blood pressure and decreased the likelihood of premature birth, without leading to any adverse side effects.*18   Some women experience an increase of blood pressure during pregnancy, however, women taking calcium supplements during pregnancy are 36% less likely to experience abnormal blood pressure.* 19 

Calcium “Robbers”

The typical American diet contains several nutrients and compounds which adversely affect calcium levels in the body. Most Americans consume two to three times the necessary daily requirement for protein. Some researchers even speculate that excessive protein, rather than inadequate calcium, is a more significant contributor to loss of bone density.20  Weight-bearing exercise helps maintain strong bones and the lack of exercise leads to rapid calcium loss from bones.

The typical American diet is also high in phosphorus from soft drinks and other processed foods.21  A higher intake of calcium may be necessary to compensate for a high-protein or high-phosphorus diet. Phytonutrients called oxalates and phytates found in some grains and vegetables reduce the bioavailability of calcium. In addition, frequent use of aluminum-containing antacids can increase the loss of calcium.22 

Supplemental Calcium: Safety Considerations

Calcium is safe up to 2 grams per day, but toxic effects can develop when more than several grams are taken daily. Symptoms of excessive calcium intake include: nausea; deposition of calcium into the soft tissues, such as kidneys and heart, and; impaired absorption of other minerals, such as iron and zinc.23  These symptoms are temporary and are relieved simply by reducing calcium intake.

Individuals prone to developing calcium deposits in the kidneys have, in the past, been advised to limit their calcium intake, but new research suggests that the timing of calcium intake may be the real issue. According to the Nurses’ Health Study, a diet containing plenty of high-calcium foods actually decreases the risk of calcium deposits in the kidneys. However, the women in this study with a high calcium intake resulting from calcium supplements increased their risk.24 

The difference between dietary and supplemental calcium intake may be related to oxalates (a phytonutrient that is a common constituent of calcium deposits in the kidneys). When calcium is consumed at the same time as a meal rich in oxalates, the  calcium inhibits the absorption of the oxalates.*24  Calcium supplements are not always taken at the same time as a meal containing oxalates, which may account for why supplemental calcium did not protect against formation of calcium deposits in kidneys. Rather than forego calcium supplements, the researchers suggest that it is probably prudent to take calcium supplements with a meal, particularly lunch or dinner—meals which tend to have high oxalate contents.*24

Lead In Calcium-Making It Safe: Minute amounts of lead are naturally present throughout the environment, including all foods and calcium supplements. Excess lead exposure, however, is a concern since large amounts of this naturally occurring mineral contribute to several health problems, especially in young children.

The Good Manufacturing Practices (GMPs) at Nature’s Life ensure that all of the calcium found in Nature’s Life supplements have very low, and very safe, levels of lead (less than 1 ppm of lead or 1mcg/g; far less than the Federal standard). The low levels of lead in our products is demonstrated by the fact that the maximum amount of lead present in any Nature’s Life calcium supplement is only 5% of the safe daily intake level for pregnant women, who are the most sensitive and at-risk individuals for lead exposure. Additionally, calcium actually inhibits the absorption of lead.* As calcium intake increases, blood levels of lead have been reported to decrease.*25 

Calcium’s Changing RDAs

Calcium requirements change throughout life. Calcium needs are greatest during the times of rapid growth and development: childhood, adolescence, pregnancy, and lactation, as well as in later adult life to prevent excessive calcium losses.*26  For adolescents the Recommended Dietary Allowance (RDA) for calcium ranges from 400 mg to 1,500 mg per day.  According to the National Institutes of Health Consensus Conference, optimal calcium intake varies throughout life.27 

Age Optimal Calcium Intake


  • birth - 6 months ..... 400 mg

  • 6 months - 1 year ..... 600 mg


  • 1 - 5 years ..... 800 mg

  • 6 - 10 years ..... 800 - 1,200 mg

Adolescents/Young Adults

  • 11 - 24 years ..... 1,200 - 1,500 mg

Adult Men

  • 25 - 65 years ..... 1,000 mg

  • 65+ years ..... 1,500 mg

Adult Women

  • Pregnant and Nursing ..... 1,200 - 1,500 mg

  • 25 - 50 years ..... 1,000 mg

  • 50+ years ..... 1,000 - 1,500 mg

  • 65+ years ..... 1,500 mg        

Different Forms of Calcium

Like all minerals, calcium is inorganic (not bound to carbon) and is usually bound to a carbon-containing compound to ensure its absorption into the body. Dietary supplements may contain several different forms of calcium. One of the main differences found between various calcium forms is the percentage of elemental calcium they provide. For instance, in the popular carbonate form, calcium accounts for 40% of the compound calcium carbonate.

The following examples show common forms of calcium compounds and the percentage of elemental calcium in each. The greater the percentage of elemental calcium, the smaller the amount needed to obtain the desired amount of calcium.28 

Form of Calcium % Elemental Calcium

  • Calcium (carbonate-purified)........ 40%

  • Calcium (carbonate from oyster shell).......40%

  • Calcium (bone meal)...... 32%

  • Calcium (hydroxyapatite-veal bone meal)...... 32%

  • Calcium (citrate).......24%

  • Calcium (citrate/malate)......22%

  • Calcium (dolomite)..... 21%

  • Calcium (aspartate) 13% - 20%

  • Calcium (ascorbate)... 10%

  • Calcium (gluconate)..... 9%

Absorption of Calcium

The percentage of elemental calcium is not the only difference between various forms of calcium; the absorption of calcium from foods or supplement sources is another factor to consider. Substantial research shows that supplemental calcium carbonate is at least as bioavailable as the calcium in milk.29  Milk and other dairy products are preferred sources of well-absorbed calcium. Research also shows that calcium citrate/malate has better calcium absorption than calcium carbonate.30 

Other studies indicate that calcium absorption from several different supplement forms, including carbonate, acetate, lactate, gluconate, and citrate forms, are not significantly different from one another.31, 32  Although the best absorbed form of calcium continues to be debated by researchers, it is widely accepted that the best time to take calcium supplements is with food.


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