Calcium Supplementation

Calcium is important in bone and teeth formation, muscle contractility, blood clotting and preventing osteoporosis.  99% of calcium is stored in your bones and teeth.  The remaining 1% is in your blood and soft tissue.  Without this 1% of calcium your muscles would not contract correctly, your blood would not clot and your nerves would not carry messages.  Calcium that is found in dairy products (milk, cheese, ice cream) contains the highest levels of calcium.  Although many people tend to avoid milk because of its fat content, low-fat dairy products such as skim and 1% milk contain high levels of calcium.  Non-dairy food sources of calcium generally contain much lower levels but significant amounts occur in canned salmon and sardines when the bones are also eaten.  Some green vegetables (such as kale, broccoli, spinach) as well as legumes (such as soybeans and common beans) either contain much less calcium than dairy products or the calcium is poorly absorbed by the body or both.  

The recommended nutrient intake (RNI) varies within different age groups. These calcium requirements also apply to vegetarians and people who eat a low protein diet.

Adults who are 50+ years require high amounts of calcium due to the reduction in absorption and menopause.  Calcium requirements in the management of osteoporosis range between 1000-1500mg per day. 

Calcium supplementation is required when not enough is ingested in the diet. Constipation is the most common side of effect of calcium. Symptoms of calcium deficiency include muscle cramps and soft bones.  Supplements range in size of pill, type of preparation (tablets, chewable forms, dissolvable tablets or liquid preparations) and price.  Preparations in chewable or dissolvable tablets and liquids are easily absorbed, as they do not need to be broken down.  These products are good for patients who have low acidity in their stomach.  The most expensive are not necessarily the best. 

·        Calcium carbonate is inexpensive and contains the most elemental calcium but it is the least soluble (do not dissolve easily in water).  Therefore, it requires acid to be absorbed.  Generally if calcium carbonate is taken with a meal the amount of acid increases in the stomach, which will help with absorption.

·        Calcium citrate is more soluble than calcium carbonate.  It does not require acid to be easily absorbed.  This product is recommended for patients who have low stomach acidity (such as the elderly or those taking acid blocking drugs) 

·        Calcium lactate and gluconate are also soluble but provide less elemental calcium per tablet. 

·        Calcium dolomite, bone meal, and oyster-shell are not recommended as they may be contaminated with lead.

The human body cannot absorb more than 500 mg at on time; therefore, calcium tablets must be taken in divided doses.  For example: three tablets should not be taken at the same time, one tablet should be taken at each meal. 

          The calcium absorption in the small intestine is lower from calcium carbonate than from calcium citrate, lactate or gluconate. 

          Vitamin D increases calcium absorption and is important in the maturation of bone.  Vitamin D is found in fish liver oils, fish, fortified milk and margarine, liver, egg yolk and UV radiation from the sun.  Unless 15 minutes a day is spent in the sun, which is unlikely in a cold winter, or ingesting plenty of fish, liver and milk, Vitamin D supplementation is required.  Elderly people and those who wear heavy sunscreens should have an intake of 400-800 IU of Vitamin D per day.  Vitamin D requirements in the management of osteoporosis range between 400-1000 IU per day. Excessive intake (> 1000 IU per day) can lead to too much calcium absorption.

Anyone who is unable to meet the recommended nutrient intake (RNI) due to inadequate intake or increased requirements may need supplementation.  For most patients, calcium carbonate (333mg, elemental) containing Vitamin D (133IU) and Magnesium (167mg, elemental) is the best choice.  A high calcium intake and a high intake of dairy foods fortified with Vitamin D result in decreased magnesium absorption.  Therefore, the ratio of calcium to magnesium should be either 1:1 or 2:1.  The ratio of 3:1 has high amounts of calcium, which leads to decreased magnesium absorption.  For patients with low gastric acidity, calcium citrate is the best choice.  Generally, brands such as Jamieson, Sisu and Wampole are better quality than products bought in bulk, which are very cheap. 

Recommended dosage is to take one tablet orally three times a day with a meal aiming for 1000-1500 mg per day of elemental calcium, 400-600 IU of Vitamin D and 300 mg of magnesium.

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