What Is Calcium?

The most abundant mineral in the body, calcium is vital to human health and bodily functions. Like several other vitamins and minerals, calcium is not easily absorbed on its own. Calcium needs vitamin D to be absorbed in the necessary amounts, which is why many supplements and dairy products are now fortified with vitamin D.

What are the Benefits of Calcium?

Calcium is most widely known for its beneficial effects on bone strength. Approximately 99% of calcium in our bodies is stored in our bones and teeth. Bones are continually growing, remodeling, or repairing themselves, and they use up enormous amounts of calcium to do so. The other 1% of calcium stored in your body is known as serum calcium.

Serum calcium is used by muscle tissues, nerves, vascular tissues, and in other critical metabolic functions such as intracellular communications and maintaining healthy hormone levels. Luckily, serum calcium levels are not affected by diet and stay consistent – drawing calcium from bones when needed. The amount of calcium available in your body for bone growth and repair is greatly impacted by age, sex, diet, and exercise. Calcium supplementation is best known for preventing and treating a condition called osteoporosis.

Osteoporosis is a bone disease that occurs when the body loses too much bone, makes too little bone, or both. A number of factors can increase the likelihood that you will develop osteoporosis, including your age, race, lifestyle choices, medical conditions, and medical treatments. Osteoporosis is much more common in women than men. Some of the most recent national data estimates that 16% of women and 4% of men 50 years of age and older have osteoporosis.

Research supports the role of calcium supplementation in improving bone mineral density at many historically weak joints in the body.  Supplementation with calcium has been shown to reduce bone density loss up to 43% in the lumbar spine, forearm and femur. For overweight or obese individuals there are several promising studies on the relationship between sufficient calcium intake and reducing hunger and food intake, particularly when calcium-rich foods or supplements are ingested at the first meal of the day.

Sources of Calcium

There are 3 ways to get calcium: proper nutrition through calcium-rich foods, calcium supplements, and prescription medication. Calcium is found naturally in a variety of foods, mostly dairy products.  

Common Food Sources

  1. Milk
  2. Yogurt
  3. Cheese
  4. Tofu
  5. Dark, Leafy Greens (kale, swiss chard, collard greens)

Calcium supplements are a good way to add calcium to your diet, especially for vegans that do not consume dairy products. Vitamin D is often added to calcium supplements as it is required for proper absorption, so it is important to find a supplement with both components. Prescription medication is used to prevent bone loss if you have a condition or medication known to deplete calcium levels in your system, or to treat bone loss if you are diagnosed with osteopenia or osteoporosis.

Do I Need to Take Calcium Supplements?

As mentioned above, there are a number of factors that affect calcium levels in the body. For bone growth and repair, your body will absorb the calcium needed and deposit it into new bone formations. Assuming average nutrition and good overall health, there are relatively predictable outcomes for calcium levels and the need for supplementation. For children and young adults, calcium absorption exceeds the amount needed to build and grow healthy bones. Proper nutrition is vital to the growth of healthy bones and teeth, and calcium supplements are rarely needed at this age. Further into adulthood, the processes of absorption and depositing for bone growth even out. With regular diet and nutrition, calcium supplements are usually not necessary but are also not harmful as long as you stay within the recommended daily amounts (detailed below).

One exception to the above rule is during pregnancy and breastfeeding, where calcium supplementation is highly recommended due to the unique demands placed on the mother’s body. In the aging population, the intake of calcium starts to slow and bone breakdown often exceeds calcium deposits. This imbalance leads to an increased risk of osteoporosis, especially in postmenopausal women.

How Much Calcium Do I Need?

The amount of calcium that is needed depends on a variety of health factors including genetics, lifestyle information, and medical history. The general RDA (recommended dietary allowances) of calcium for both men and women is approximately 1000 – 1300mg of calcium daily.  This is considered the adequate intake, or just enough, and does not necessarily apply to individuals who may benefit from calcium supplementation as described in the previous section.

Calcium Side Effects

Common side effects of consuming calcium are nausea, constipation, flatulence and gastrointestinal discomfort. These side effects are rare, and usually very mild.

Are There Any Medications or Supplements I Shouldn’t Take With Calcium?

Because calcium is so widely studied and so important to the body, there are a number of medications and supplements known to either deplete calcium levels or cause an increase in calcium absorption.  Most interactions are mild, and may have no definitive impact according to clinical studies. The Vitality DNA test can tell you whether taking calcium is right for your body, especially if you are on any of the medications or supplements detailed below.

Medication Interactions

  • Anticonvulsants
    • Anticonvulsant medications are known to negatively affect vitamin D levels, which in turn leads to a decrease in calcium absorption.  Hypocalcemia and osteomalacia are known to occur, especially with prolonged therapy and use of more than one of these drugs concurrently. Calcium and vitamin D supplements are recommended for those taking these medications for six months or more: Phenytoin (Dilantin), fosphenytoin (Cerebyx), phenobarbital, and carbamazepine (Tegretol). Other anticonvulsants such as gabapentin (Neurontin), felbamate (Felbatol), lamotrigine (Lamictal), levetiracetam (Keppra), tiagabine (Gabitril), and topiramate (Topamax) do not have these effects
  • Corticosteroids
    • Corticosteroids, in daily doses equivalent to 7.5 mg of prednisone or more, may cause significant bone loss, osteoporosis, and increased risk of fractures. The severity increases with duration of therapy. Adults taking prednisone 7.5 mg/day (or equivalent doses of other corticosteroids) for six months or longer may require a higher calcium intake and a vitamin D supplement.
  • Ceftriaxone (Rocephin)
    • The interaction between Rocephin and calcium supplementation has only been seen in some case reports of newborn babies. In these cases, life-threatening cardiopulmonary events were noted. Interactions have not been reported in adult patients at this time. Intravenous (IV) ceftriaxone should not be administered within 48 hours of any form of IV calcium.
  • Bisphosphinates (ie: Fosamax, Boniva)
    • Calcium supplements decrease absorption of bisphosphonates in humans. This interaction can be avoided by taking bisphosphonates at least 30 minutes before calcium supplements, but preferably at a different time of day. Bisphosphonates include alendronate (Fosamax), etidronate (Didronel), ibandronate (Boniva), risedronate (Actonel), and tiludronate (Skelid).
  • Calcipotriene (Dovonex)
    • The comination of calcipotriene with calcium supplements might increase the risk of hypercalcemia, as this medication mimics vitamin D.
  • Digoxin
    • Taking digoxin with calcium in IV form may cause hypercalcemia and increase the risk of cardiac arrhythmias.
  • Diltiazem
    • Calcium supplementation in high doses may reduce the effectiveness of verapamil, a medication very similar in mechanism to Diltiazem.
  • Estrogens
    • Estrogen increases supplemental calcium absorption in postmenopausal women. While this may benefit osteoporotic patients, it could cause hypercalcemia in others.
  • Levothyroxine
    • Calcium reduces absorption and efficacy of levothyroxine in humans. People who take levothyroxine should consider taking calcium supplements at least 4 hours apart from this medication.
  • Lithium
    • Clinical evidence suggests that long-term use of lithium may cause hypercalcemia in 10% to 60% of patients. Theoretically, concomitant use of lithium and calcium supplements may further increase this risk.
  • Loop Diuretics
    • Loop diuretics increase urinary calcium excretion and may reduce serum calcium levels in humans, especially at higher doses. Loop diuretics include furosemide (Lasix), bumetanide (Bumex), ethacrynic acid (Edecrin), and torsemide (Demadex).
  • Quinolone Antibiotics
    • Taking calcium at the same time as quinolones reduces quinolone absorption in humans. People who take these drugs should consider taking calcium supplements at least 2 hours before, or 4-6 hours after taking these medications. Quinolones include ciprofloxacin (Cipro), levofloxacin (Levaquin), ofloxacin (Floxin), moxifloxacin (Avelox), gatifloxacin (Tequin), gemifloxacin (Factive), and others.
  • Sotalol
    • Calcium appears to reduce the absorption of sotalol in humans.  
  • Stimulant Laxatives
    • Prolonged use of stimulant laxatives may reduce dietary calcium and vitamin D absorption, and possibly lead to osteomalacia (anecdotal evidence). Some stimulant laxatives include cascara (CitraMax Plus), senna (Senokot), bisacodyl (Dulcolax), and others.
  • Tetracycline Antibiotics
    • Calcium decreases the absorption of tetracyclines in humans.Tetracyclines include demeclocycline (Declomycin), doxycycline (Vibramycin), and minocycline (Minocin).
  • Thiazide Diuretics
    • Thiazides reduce calcium excretion by the kidneys in humans. Combining thiazides with moderately large amounts of calcium carbonate increases the risk of milk-alkali syndrome (hypercalcemia, metabolic alkalosis, renal failure). These diuretics include chlorothiazide (Diuril), hydrochlorothiazide (HydroDIURIL, Esidrix), indapamide (Lozol), metolazone (Zaroxolyn), chlorthalidone (Hygroton), etc.
  • Verapamil
    • Calcium supplements in high doses may lead to hypercalcemia, which could reduce the effectiveness of verapamil in atrial fibrillation.
  • Alcohol (Ethanol) (with Calcium D-Glucarate)
    • Theoretically, consuming alcohol with calcium D-glucarate may reduce the effectiveness of the calcium supplement. It may also increase the urinary excretion of D-glucarate.
  • Glucuronidated Drugs (with Calcium D-Glucarate)
    • Taking calcium D-glucarate could cause medications that undergo a process called glucuronidation to exit the human body faster than usual, thereby decreasing the duration of their effectiveness. Some of these drugs include acetaminophen, atorvastatin (Lipitor), diazepam (Valium), digoxin, entacapone (Comtan), estrogen, irinotecan (Camptosar), lamotrigine (Lamictal), lorazepam (Ativan), lovastatin (Mevacor), meprobamate, morphine, oxazepam (Serax), and others.

Supplement Interactions

  • Aluminum Salts
    • Calcium citrate can increase the absorption of aluminum when taken with aluminum hydroxide (human research). The increase in aluminum levels may become toxic in individuals with kidney disease.
  • Mineral Oil
    • Mineral oil may interfere with how well calcium is used and retained by the human body by reducing the absorption of both calcium and vitamin D.
  • Iron
    • Iron absorption is greatly decreased when combined with calcium supplements or calcium-rich dairy products.
  • Magnesium
    • For those supplementing with magnesium at very high levels, calcium supplements may decrease magnesium absorption.
  • Prebiotics or probiotics
    • Evidence from clinical studies indicate that prebiotics or probiotics can increase calcium absorption.
  • Vitamin D
    • Taking vitamin D in conjunction with calcium will increase the absorption of calcium. Calcium supplements are often combined with vitamin D for this very reason.
  • Caffeine
    • Intake of more than 300mg of caffeine daily is known to increase calcium loss through the urine. High caffeine intake is linked to increased bone loss, increased fracture rates in elderly women, especially when dietary calcium intake is low.
  • Fiber
    • Some types of fiber (listed below) are known to decrease calcium absorption or serum calcium levels.
  • Protein
    • High protein diets may increase the loss of calcium through urinary output. On the contrary, low-protein diets may increase calcium absorption, which may lead to hypercalcemia.
  • Sodium
    • High sodium intake increases urinary excretion of calcium. To prevent loss of too much calcium, postmenopausal women are advised to intake at least 1000 mg of calcium with a dietary intake of 2000 mg of sodium, and 1500 mg of calcium for 3000 mg of sodium daily.
  • Zinc
    • Calcium supplements may decrease the absorption of dietary zinc. However, in people with adequate zinc stores, this does not have any clinically significant effect on the long-term status of iron, zinc, or magnesium in the body.

There are a few health conditions that can cause decreased calcium levels, and others that will benefit from calcium supplementation. These include, but are not limited to:

  1. Indigestion
  2. Kidney (renal) failure
  3. Hyperparathyroidism
  4. High cholesterol (hypercholesterolemia)
  5. High blood pressure (hypertension)
  6. Weight loss in overweight/obese individuals.

Interested in learning whether calcium supplementation is right for you? Take the Vitality DNA test today to find out exactly which nutrients your body needs.


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