Calcium Benefits and Side Effects

Calcium Benefits and Side Effects

Calcium is an important mineral stored mostly in our bones and teeth. Aside from strengthening bones, calcium is also involved in many body functions such as muscle contraction, blood circulation, and nervous system relay activities.

Calcium is found abundantly in various foods such as dairy products, green vegetables, fish, and grains. Many food products such as fruit juice, cereals, and tofu are fortified with calcium. In addition to these, people who are at risk for calcium deficiency can take calcium supplements.

Calcium supplements are usually prescribed for people with increased need for the mineral, like postmenopausal, pregnant and lactating women, girls aged 9-18, vegans, elderly individuals and people with lactose intolerance.
In addition, people whose regular diets may lack calcium or who are on a restrictive diet that limits calcium-rich foods may take calcium supplements.

Calcium is usually taken in doses ranging from 500 to 1500 mg per day, depending on individual need.

Benefits of Calcium

A growing body of evidence indicates that dietary calcium offers many benefits. These include:

Bone Health

A combination of adequate calcium, vitamin D, and regular exercise are essential to maintain healthy bones throughout life. A lack of calcium over many years is related to weaker bones, a condition known as osteoporosis or rickets (in children) and related complications. Children may fail to reach their potential adult height while adults may be at risk for bone fractures. Increasing calcium intake helps prevent bone weakness in all ages.

Calcium supplements help raise calcium levels and prevent bone loss in women over 40 and results in a 10% improvement in bone strength and 50% overall reduction in bone fracture rates. They also reduce bone loss in people taking drugs like corticosteroids, when used in combination with vitamin D.

Calcium supplementation can also increase fetal bone density when taken by pregnant women with low calcium intake.

Cardiovascular Health

Studies have found that adequate intake of calcium can reduce the risk of developing hypertension (high blood pressure). Taking calcium supplements also appears to exert beneficial effects in people who already have high blood pressure, in people with serious kidney disease, and in pregnant women with high blood pressure (pre-eclampsia).

Cancer Prevention

Research suggests that consumption of dietary or supplemental calcium may reduce the risk of colorectal cancer. The American Cancer Society’s Cancer Prevention Study II Nutrition Cohort which included more than 120,000 men and women found that those who had the highest intakes of calcium had a lower risk of colorectal cancer compared with participants who had the lowest calcium intakes.

A stronger association between calcium intake and colorectal cancer risk was demonstrated in the Nurses’ Health Study and the Health Professionals Follow-up Study which included more than 135,000 men and women. Participants who took more than 700 mg of calcium per day had a 35 to 45% reduced risk of colon cancer than those who had a lower calcium intake.

Calcium Side Effects

According to the National Institutes of Health the safe upper limits of calcium intake are as follows:

Life Stage Upper Safe Limit
Birth to 6 months 1,000 mg
Infants 7–12 months 1,500 mg
Children 1–8 years 2,500 mg
Children 9–18 years 3,000 mg
Adults 19–50 years 2,500 mg
Adults 51 years and older 2,000 mg
Pregnant and breastfeeding teens 3,000 mg
Pregnant and breastfeeding adults 2,500 mg

Taking doses higher than these safe upper limits may lead to side effects such as:

  • Constipation, gas, and bloating
  • Impaired absorption of zinc and iron
  • Prostate cancer
  • Kidney stones
  • Increased risk for heart attacks


The best way to obtain calcium for good health is to consume a healthy balanced diet that includes a variety of foods rich in vitamins and minerals. However, for those who need calcium supplements to meet their daily requirements, it is best to find out how much you need to take on a regular basis.

Consult your physician, especially for special cases like pregnancy, menopause, and other health conditions where many factors should be considered, such as intake of other medications.

Experts recommend taking calcium supplements in increments of 500 mg, preferably with meals, for better absorption. You may take these in the form of tablets, capsules, chews, liquids, and fortified foods. Avoid taking more than recommended dosages.


  1. Find a Vitamin or Supplement: Calcium. WebMD.
  2. Calcium and calcium supplements: Achieving the right balance. Mayo Clinic.
  3. Dietary Supplement Fact Sheet: Calcium. NIH.
  4. Calcium and Cancer Prevention: Strengths and Limits of the Evidence. National Cancer Institute.