Calcium Supplementation in Women

calcium supplementatonCalcium is a mineral that not only essential to the structural integrity of the bones and teeth but also plays an integral role in the functionality of the heart, nerves, and blood-clotting systems.

Calcium is used to replace calcium deficiency which can result in bone conditions such as osteoporosis (fragile bones due to low bone density), and osteomalacia ( painful bone softening). Calcium also plays a role in lessening the degree of premenstrual syndrome (PMS), leg cramps in pregnancy, high blood pressure in pregnancy (pre-eclampsia), and has also been shown to reduce the risk of colon and rectal cancers.

There are numerous calcium rich food sources to choose from including: milk and dairy products, kale and broccoli, as well as the calcium-enriched citrus juices, mineral water, canned fish with bones, and soy products processed with calcium.

calcium supplementaton

It is important to note that calcium can interact to affect the efficacy of many prescription medications, but sometimes the effects can be minimized by taking calcium at a different time. See the section titled “Are there any interactions with medications?”

So what beneficial role does calcium really play in our bodies?


  • Calcium has been proven to be effective in…
  • Raising calcium levels in people who have low calcium.
  • Preventing low calcium levels.
  • Reversing high potassium levels, when given intravenously (by IV).
  • Use as an antacid as calcium carbonate.
  • Reducing phosphate levels in people with kidney disease.

 

Calcium may also play an important role in…

  • calcium and osteoporosisTreatment and prevention of  osteoporosis (weak bones). Oral calcium has been shown to be effective in preventing and treating bone loss and osteoporosis. The optimal time for bone growth occurs in the teenage years, and then bone strength and integrity in women remains stable until age 30-40. After age 40, women have the potential to lose 0.5% to 1% of the bone integrity or strength per year. This rate of bone loss is enhanced if less than the daily recommended amount of calcium is obtained from the diet. Calcium and vitamin D deficiency is very common among American women, and can be managed very effectively in women over 40 by daily calcium and vitamin supplements (see website information on vitamin D). Many of the former studies and research suggest that taking calcium for up to 30 years after woman are menopausal may  result in a 10% improvement in bone strength and integrity, and the potential for a 50% overall reduction in bone fracture rates.
  • Reversing dietary calcium deficiency. This can reduce the risk of bone fracture.
  • calcium and pmsControlling or lessening the symptoms of premenstrual syndrome (PMS). Calcium deficiency has been associated with worsening symptoms of PMS. Appropriate daily calcium consumption has been shown to reduce mood swings, bloating, food cravings, and pain with the onset of menstrual cycles.. Women consuming average of 1200-1300 mg/day of calcium seem to have about a 25-30% less risk of developing PMS than women who consume half the amount of calcium per day. Unfortunately calcium supplementation,  does not seem to prevent PMS.
  • Reducing bone loss in patients taking medications which enhance bone loss ( e.g. coumadin, prednisone). This is especially beneficial when used in combination with vitamin D.

 

Calcium may also be effective for…

  • Reducing the risk of colorectal cancer. Much research has suggested  that those individuals with a higher daily intake of dietary or supplemental calcium seems to reduce the risk of colorectal cancer. The same research also shows that daily calcium supplementation also reduce the risk of recurrence of colorectal cancer.
  • high blood pressureHigh blood pressure. Evidence suggests that calcium supplementation may also slightly  reduce blood pressure (usually around 1-2 mmHg) in people with or without high blood pressure. Calcium seems to be more effective in people with higher daily intakes of salt or salt sensitive individuals and also people who are historically calcium deficient. Oral calcium intake also seems to be helpful for reducing blood pressure in people with serious kidney disease.
  • High cholesterol. A combination of  calcium supplements along with a low-fat or low-calorie diet can have a significant impact on reducing cholesterol. Taking calcium alone, without dietary control, doesn’t seem to lower cholesterol.
  • reducing bmiReducing body mass index (BMI) while dieting. Both adults and children with calcium deficiency are more likely to gain weight, have a higher body mass index (BMI), and be overweight or obese compared to those with normal to higher calcium intake. Research has shown that increasing daily calcium consumption from dairy products alone can enhance weight loss, lean body mass, and body fat loss in people on a low-calorie diet as well as people on a regular unrestricted-calorie diet.
  • Preventing stroke in women.
  • Reducing tooth loss in elderly people.

 

Calcium has been shown to essentially be ineffective for…

  • Preventing breast cancer postmenopausal women.

To date there is insufficient evidence as to any significant impact on…

  • Preventing falls. Some studies have suggested that calcium plus vitamin D may help to prevent falls by decreasing stability balance and body sway while also helping to keep blood pressure stabilized. Calcium alone doesn’t seem to have the same fall prevention benefit. Of note is that, calcium plus vitamin D seems to effective in preventing falls in women, but not in men.
  • Cancer. Many research studies have suggested that healthy older women who take 1400-1500 mg/day of calcium plus 1100 IU/day of vitamin D3 (cholecalciferol) have a overall 60% reduction in developing cancer of any type.
  • Diabetes. There is evidence suggests that appropriate daily dietary consumption, either alone or in combination with vitamin D, might lower the risk of developing type 2 diabetes.
  • Lyme disease.
  • Seizures.

 

More evidence is needed to rate the effectiveness of calcium for these uses.

How does calcium work in our body?

Bones and teeth alone contain over 99% of the calcium in the human body. Calcium can also found in the blood, muscles, and other tissue. Bone calcium can be used as a reserve calcium source that can be released into the body as needed. The bodies concentration of calcium tends to steadily decrease as we age because it is released from the body through sweat, skin cells, and waste. It is important to note that in aging menopausal women, absorption of calcium tends to decline due to reduced estrogen levels. Calcium absorption can vary depending on race, gender, and age.

Bones are continually breaking down and rebuilding, and calcium is needed for this bone building process. Taking appropriate daily allowances of  calcium helps the bones rebuild properly and stay strong.

Is supplementing calcium safe overall?

Most experts will comment that appropriate daily calcium intake is LIKELY SAFE for most individuals. Calcium can cause some minor side effects to the gastrointestinal tract such as belching or gas.

While taking appropriate levels of calcium does merit benefit an individual should avoid too much daily calcium. The Institute of Medicine sets the limits for excessive or upper daily limits of calcium intake (UL) based on age to include: 19-50 years, 2500 mg; 51+ years, 2000 mg. Higher calcium doses increase the chance of having serious side effects. Significant research findings also suggests that doses over the recommended daily requirement of 1000-1300 mg daily for most adults might increase the chance of heart attack. While this research appears to be concerning it may be premature to say for certain that calcium at these levels truly provokes heart attack. Until more is known, calcium consumption should only meet daily recommended requirements, but not excessive amounts of calcium. One must be certain to consider the total calcium intake from both dietary and supplemental sources and not to exceed 1000-1300 mg of calcium per day. An easy rule of thumb calculation to figure out dietary calcium is to, count 300 mg/day from non-dairy foods plus 300 mg/cup of milk or fortified orange juice.

Precautions & warnings associated with calcium intake

Phosphate levels in the body. Caution must be taken with high levels of phosphate in the blood (hyperphosphatemia) or low levels of phosphate in the blood (hypophosphatemia). Calcium and phosphate work in synchrony within the body and have to be in balance to maintain proper function. High levels of calcium can throw this balance off and cause harm. Only take extra calcium under your health provider’s supervision.

Thyroid Conditions. Hypothyroidism(underactive thyroid) requires replacement of thyroid hormone for appropriate management. Calcium can interfere with thyroid hormone replacement dosing and management. It is important to separate calcium and thyroid medications by at least 4 hours.

Hypercalcemia (much calcium in the blood) This is a very common concern in condition such as parathyroid gland disorders and sarcoidosis: Calcium should be monitored extremely close and avoided with these conditions.

Calcium and medication interaction?
Major
Do not take this combination.
Ceftriaxone (Rocephin)
Administering intravenous ceftriaxone (Rocephin) and calcium can result in life-threatening damage to the lungs and kidneys. Calcium should not be administered intravenously within 48 hours of intravenous ceftriaxone (Rocephin).

Moderate
Be cautious with this combination.
Antibiotics (Quinolone antibiotics)
Calcium might decrease how much antibiotic your body absorbs. Taking calcium along with some antibiotics known as “quinolones” might decrease their effectiveness. To avoid this interaction, take these drugs at least 2 hours before, or 4 to 6 hours after calcium supplements.

Some quinolone antibiotics that might interact with calcium include ciprofloxacin (Cipro), levofloxacin (Levaquin), ofloxacin (Floxin), moxifloxacin (Avelox), gatifloxacin (Tequin), gemifloxacin (Factive), and others.

Antibiotics (Tetracycline antibiotics)

Calcium can attach to some antibiotics called tetracyclines in the stomach. This decreases the amount of tetracyclines that can be absorbed. Taking calcium with tetracyclines might decrease the effectiveness of tetracyclines. To avoid this interaction, take calcium at least 2 hours before or 4 to 6 hours after taking tetracyclines.

Some tetracyclines include demeclocycline (Declomycin), minocycline (Minocin), and tetracycline (Achromycin, and others).

Bisphosphonates

Calcium can decrease how much bisphosphate your body absorbs. Taking calcium along with bisphosphates can decrease the effectiveness of bisphosphate. To avoid this interaction, take bisphosphonate at least 30 minutes before calcium or, preferably, at a different time of day.

Some bisphosphonates include alendronate (Fosamax), etidronate (Didronel), ibandronate (Boniva), risedronate (Actonel), tiludronate (Skelid), and others.

Calcipotriene (Dovonex)

Calcipotriene (Dovonex) is a drug that is similar to vitamin D. Vitamin D helps your body absorb calcium. Taking calcium supplements along with calcipotriene (Dovonex) might cause the body to have too much calcium.

Digoxin (Lanoxin)

Calcium can affect your heart. Digoxin (Lanoxin) is used to help your heart beat stronger. Taking calcium along with digoxin (Lanoxin) might increase the effects of digoxin (Lanoxin) and lead to an irregular heartbeat. If you are taking digoxin (Lanoxin), talk to your doctor before taking calcium supplements.

Diltiazem (Cardizem, Dilacor, Tiazac)

Calcium can affect your heart. Diltiazem (Cardizem, Dilacor, Tiazac) can also affect your heart. Taking large amounts of calcium along with diltiazem (Cardizem, Dilacor, Tiazac) might decrease the effectiveness of diltiazem (Cardizem, Dilacor, Tiazac).

Levothyroxine

Levothyroxine is used for low thyroid function. Calcium can decrease how much levothyroxine your body absorbs. Taking calcium along with levothyroxine might decrease the effectiveness of levothyroxine. Levothyroxine and calcium should be taken at least 4 hours apart.

Some brands that contain levothyroxine include Armour Thyroid, Eltroxin, Estre, Euthyrox, Levo-T, Levothroid, Levoxyl, Synthroid, Unithroid, and others.

Sotalol (Betapace)

Taking calcium with sotalol (Betapace) can decrease how much sotalol (Betapace) your body absorbs. Taking calcium along with sotalol (Betapace) might decrease the effectiveness of sotalol (Betapace). To avoid this interaction, take calcium at least 2 hours before or 4 hours after taking sotalol (Betapace).

Verapamil (Calan, Covera, Isoptin, Verelan)
Calcium can affect your heart. Verapamil (Calan, Covera, Isoptin, Verelan) can also affect your heart. Do not take large amounts of calcium if you are taking verapamil (Calan, Covera, Isoptin, Verelan).

Water pills (Thiazide diuretics)
Some “water pills” increase the amount of calcium in your body. Taking large amounts of calcium with some “water pills” might cause there to be too much calcium in the body. This could cause serious side effects, including kidney problems.

Some of these “water pills” include chlorothiazide (Diuril), hydrochlorothiazide (HydroDIURIL, Esidrix), indapamide (Lozol), metolazone (Zaroxolyn), and chlorthalidone (Hygroton).

Minor
Be watchful with this combination.
Estrogens
Estrogen helps your body absorb calcium. Taking estrogen pills along with large amounts of calcium might increase calcium in the body too much.

Estrogen pills include conjugated equine estrogens (Premarin), ethinyl estradiol, estradiol, and others.

Medications for high blood pressure (Calcium channel blockers)

Some medications for high blood pressure can affect calcium in your body. These medications are called calcium channel blockers. Getting calcium injections might decrease the effectiveness of these medications for high blood pressure.

Some medications for high blood pressure include nifedipine (Adalat, Procardia), verapamil (Calan, Isoptin, Verelan), diltiazem (Cardizem), isradipine (DynaCirc), felodipine (Plendil), amlodipine (Norvasc), and others.

Are there interactions with herbs and supplements?

Magnesium
Calcium supplements can decrease the absorption of dietary magnesium, but only at very high doses (2600 mg per day). However, in people who have enough magnesium stored in their bodies, taking calcium doesn’t cause a problem over the long term. People at high risk for magnesium deficiency, however, should take calcium supplements at bedtime, instead of with meals, to avoid reducing dietary magnesium absorption.

Vitamin D
Taking vitamin D along with calcium increases absorption of calcium

Are there interactions with foods?

Caffeine
calcium and caffeineHigh caffeine intake from foods and beverages causes the body to remove calcium. Taking more than 300 mg of caffeine per day (three to four cups of coffee, or six 12-oz. cola drinks) is linked to increased bone loss and breaks in elderly women, especially when calcium intake is low. Be sure to get the amount of calcium from food and supplements that is recommended for your age and gender.

Fiber
Dietary fiber from certain sources can interfere with calcium absorption. These sources include wheat bran, spinach, rhubarb, and others. It’s best not to eat fibrous foods within two hours of taking calcium supplements.

Iron
Calcium supplements may decrease the absorption of dietary iron. However, in people who have enough iron stored in their body, taking calcium doesn’t cause a problem over the long term. People who are at high risk for iron deficiency should take calcium supplements at bedtime, instead of with meals, to avoid reducing the absorption of iron.

Magnesium
Calcium supplements may decrease the absorption of dietary magnesium. However, in people who have enough magnesium stored in their body, taking calcium doesn’t cause a problem over the long term. People who are at high risk for magnesium deficiency should take calcium supplements at bedtime, instead of with meals, to avoid reducing the absorption of magnesium.

Sodium
Eating foods that contain a lot of sodium causes the body to remove calcium. A calcium intake of 1000 mg/day is needed to prevent bone loss in postmenopausal women ingesting 2000 mg sodium chloride daily. About 1500 mg/day calcium is needed if sodium chloride intake is 3000 mg/day.

Zinc
Calcium supplements may decrease the absorption of dietary zinc. However, in people who have enough zinc stored in their body, taking calcium doesn’t cause a problem over the long term. People who are at high risk for zinc deficiency should take calcium supplements at bedtime, instead of with meals, to avoid reducing the absorption of zinc.

What dose is used?
The following doses have been studied in scientific research:

BY MOUTH:

  • For preventing low calcium levels: 1 gram elemental calcium daily is typically used.
  • For heartburn: Calcium carbonate as an antacid is usually 0.5-1.5 grams as needed.
  • calcium and osteoporosisFor prevention of weak bones (osteoporosis): Doses of 1-1.6 grams elemental calcium daily from foods and supplements. Osteoporosis treatment guidelines in North America currently recommend 1200 mg daily of calcium.
  • For prevention of bone loss in premenopausal women over 40: A dose of 1 gram.
  • Calcium and PMSFor premenstrual syndrome (PMS): 1-1.2 grams calcium per day as calcium carbonate.
  • For reducing thyroid hormone levels in people with chronic renal failure: 2-21 grams calcium carbonate.
  • To prevent bone loss in people taking corticosteroid drugs: Divided daily doses of 1 gram of elemental calcium daily.
  • For high blood pressure: 1-1.5 grams calcium daily.
  • For preventing colorectal cancer and recurrent colorectal benign tumors (adenomas): Calcium 1200-1600 mg/day.
  • For high cholesterol: 1200 mg daily with or without vitamin D 400 IU daily has been used in conjunction with a low-fat or calorie-restricted diet.
  • For weight loss, increasing calcium consumption from dairy products to total intake of 500-2400 mg/day in combination with a calorie-restricted diet has been used.

Calcium carbonate and calcium citrate are the two most commonly used forms of calcium.

Calcium supplements are usually divided into two doses daily in order to increase absorption. It’s best to take calcium with food in doses of 500 mg or less.



The Institute of Medicine publishes a recommended daily allowance (RDA) for calcium which is an estimate of the intake level necessary to meet the requirements of nearly all healthy individuals in the population. The current RDA was set in 2010.

The RDA varies based on age as follows:

  • Women 51-70 years, 1200 mg
  • 70+ years, 1200 mg;

Doses over the recommended daily intake level of 1000-1300 mg/day for most adults have been associated with an increased risk of heart attack. Until more is known, continue consuming adequate amounts of calcium to meet daily requirements, but not excessive amounts of calcium. Be sure to consider total calcium intake from both dietary and supplemental sources and try not to exceed 1000-1300 mg of calcium per day. To figure out dietary calcium, count 300 mg/day from non-dairy foods plus 300 mg/cup of milk or fortified orange juice.