AdvertisementsIn rare cases, taking calcium supplements may cause some minor side effects such as stomach and intestinal irritation, belching, bloating, flatulence and constipation. These minor side effects may be nullified by taking the calcium supplements with food. The absorption of the supplement is directly related to the vitamin D status of an individual. However doses over and above the UL can increase the risk of renal calculus (kidney stone), prostate cancer and cardiovascular disease.
Dietary calcium supplementsCalcium supplements are prescribed and used to prevent and treat deficiency. Recommended dietary allowance (RDA) by the Office of Dietary Supplements, National Institutes of Health, United States, for adults ranges from 1000 mg to 1300 mg. It is recommended to spread the doses over the day, ideally every 6 to 8 hours. It is also advised not to take more than 600 mg at a time as with the increase in the intake, the absorption of the mineral decreases.
It is the most common and the least expensive supplement. It better absorbed when taken along with the food. Acidic conditions in the intestine help in better absorption. Some individuals may develop mild side effects like stomach and intestinal discomfort and flatulence when the carbonate form is consumed. Carbonate form contains 40% of the element. Coral calcium is predominantly a carbonate salt and has traces of other minerals. Several brands of antacids also contain the carbonate salt.
Calcium phosphate supplement is available in the form of dicalcium phosphate and Microcrystalline Hydroxyapatite (MH). Hydroxyapatite is about 40% of the element. It is expensive when compared to carbonate supplements. In some persons mild side effects have been noted.
Unlike carbonate salt, lactate compound can be absorbed at various PHs and can be taken separately with no side effects. It is used as a supplement as well as an antacid. The available element in the compound is less and it is expensive.
This compound is used intravenously to treat hypocalcemia. Side effects include nausea, constipation, upset stomach.
The tolerable upper intake levels (ULs)
In order not to have side effects ULS for calcium should never be exceeded. The Tolerable Upper Intake Levels (ULs) established by the Food and Nutrition Board to avoid side effects are:
- ULs for infants
0-6 months of age is 1,000 mg/day
6-12 months of age is 1,500 mg/day
- ULs for children
1-8 years of age is 2,500 mg/day
9-13 years of age is 3,000 mg/day
- ULs for adolescents
- 14-18 years of age is 3,000 mg/day
- ULs for adults
19-50 years of age is 2,500 mg/day
above 51 years of age is 2,000 mg/day
- ULs for pregnant or lactating women
14-18 years of age is 3,000 mg/day
19-50 years of age is 2,500 mg/day
Calcium side effectsThe major side effect of excessively high intake of calcium is hypercalcemia. Hypercalcemia, high levels of calcium in the blood, is primarily associated with primary hyperparathyroidism and cancers. Some of the side effects of excessive intake of calcium supplements are:
- Some of the symptoms and side effects of severe hypercalcemia include, loss of appetite, nausea, vomiting, abdominal pain, indigestion, constipation, excessive thirst, frequent urination, muscle pain, joint pain, weakness, lethargy, formation of kidney stones, high levels of calcium in the urine, prostate cancer, calcification of soft tissues, heart arrhythmia and confusion.
- Hypercalciuria is a side effect of high intake of supplements. Hypercalciuria is considered to be present when urinary excretion of calcium exceeds 250 mg/day in women or 275-300 mg/day in men. It is the outcome of kidney's inability to reabsorb calcium. The presence of hypercalcemia and the related renal insufficiency leads to hypercalciuria. Hypercalciuria may also occur due to hyperabsorption of calcium in the intestines or enhanced excretion of the mineral.
- Decreased renal efficiency
- Decreased renal efficiency can either be the cause of hypercalcemia or arise as the side effect of hypercalcemia. Excessive blood levels of calcium damages kidney function affecting the renal efficiency. In persons with compromised renal health slightly higher levels of the mineral in the diet can bring about many of the side effects. In aged people there is decrease in renal efficiency and slightly higher levels of calcium may become problematic.
- Metastatic calcification (soft tissue calcification)
- Metastatic calcification is deposition of calcium salts in the normal tissues. The cause is high blood levels of the mineral. Interstitial tissues of the blood vessels, kidneys, lungs, and gastric mucosa may get affected. Nephrocalcinosis, deposition of calcium salts in the renal parenchyma, may occur as a side effect of excess consumption of the supplements. Hypercalciuria and hypercalciuria are the basic causes for nephrocalcinosis.
- Calcification of vascular tissues and cardiovascular risks
- Decrease in the renal function increases the risks of cardiovascular disease. Deposition of the mineral inside the blood vessels leads to side effects like their calcinosis.
- Nephrolithiasis (formation of kidney stones)
- Hypercalciuria is the primary contributing factor for the formation of kidney stones. Various dietary and non-dietary factors are involved in the formation of kidney stones. About 80% of the kidney stones involve calcium.
- Burnett's syndrome (milk-alkali syndrome)
- Milk-alkali syndrome is characterized by hypercalcemia. Milk-alkali syndrome is caused in persons taking excessive amounts of milk and antacids in order to control dyspepsia (indigestion). High alkaline condition along with the side effects of excessive calcium inhibits parathyroid hormone secretion by the parathyroid gland leading to high blood levels. Milk-alkali syndrome when not properly treated can lead to deposition of the mineral salts in otherwise normal tissue and renal failure.
Calcium and nutrient interactionsAbsorption of iron in the intestines is affected in the presence of calcium. The interaction can be minimized by taking the supplement a few hours after the food. When anemia is being treated, milk, yogurt and antacids should not be taken at the same time as iron as they will interfere with iron absorption.
Calcium and zinc compete in their absorption by the body. Calcium at higher doses affects the absorption zinc whereas zinc at high doses affects absorption of the other mineral. It is advisable to take these supplements at different times to avoid the side effects.
Calcium supplements interactions with medicationsDietary supplements are known to interact with several types of medications. Individuals under any type of medication may take the advice of their health provider before starting on any supplement, as there is always a possibility of interaction or side effect.
- Calcium supplements can give side effects and decrease the absorption of antibiotics like fluoroquinolone, ciprofloxacin, norfloxacin and tetracyclines. At least one hour gap may be given between the antibiotic and the supplement.
- The absorption of bisphosphonates given for the treatment of osteoporosis is decreased. The absorption of phenytoin (antiepileptic drug) and levothyroxine (hormone) is affected.
- Thiazide-type diuretics can increase the risk of side effects when taken along with the supplements.
- Antacids containing aluminum or magnesium increase the urinary excretion of the element.
- Laxatives decrease the absorption of the mineral.
- Prolonged use of glucocorticoids has serious side effects and can deplete the mineral in the body.
- Estrogen pills apart from their side effects can increase the blood levels of the mineral in the body.
- Intravenous ceftriaxone and calcium can give rise life-threatening side effects and there should be at least 48 hours gap in administration.
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Dietary Supplement Fact Sheet. National Institutes of Health.
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