- The most abundant mineral found in the body.
- Predominantly stored in bones.
- Absorbed throughout the small intestine, specifically in the duodenum and the proximal jejunum.
- Plays an important role in natural blood clotting, cardiovascular health, nervous system function, hormone secretion, muscle contraction, and maintaining strong bones and teeth.
- Calcium cannot be produced by the body on its own and needs to be obtained from the food and/or supplements we consume.
- The best sources of calcium with a high absorption rate (high bioavailability) include dairy products such as milk, yoghurt and cheese as well as tinned salmon and sardines with edible bones.
- Calcium sources with a lower absorption rate (low bioavailability) include green leafy vegetables such as spinach, Chinese cabbage, kale and broccoli, fortified cereals, firm tofu and almonds. This is due to the presence of oxalates and phytates which are compounds that bind to minerals in the gut, preventing the body from absorbing them.
- Caffeine, iron and alcohol also reduce the amount of calcium available to your bones.
Iron and calcium compete for absorption in the body. As a result, taking your iron and calcium tablet simultaneously may result is a deficiency of either iron and/or calcium in the long-term.
- The absorption of calcium is enhanced by the presence of vitamin D and magnesium.
- Calcium deficiency is very common after bariatric surgery due to reduced intake of calcium rich foods as well as malabsorption in the gut.
- Symptoms of calcium deficiency include muscle cramps, numbness and tingling of extremities and increased risk of fracture. Without adequate calcium, your body withdraws calcium from your bones, resulting in weak and brittle bones. This can lead to osteoporosis.
- A DEXA scan is used to evaluate the status of bone health.
- According to published bariatric nutrition guidelines, calcium requirements after a sleeve gastrectomy and gastric bypass is 1,200-1,500 mg each day.
- Calcium supplements come in different forms, two of which include calcium carbonate and calcium citrate. Calcium citrate is in the acidic form and is better absorbed by the body, thus can be taken with or without food. Calcium carbonate is cheaper and will need to be taken with food to allow for better absorption.
- It is better to spread out your calcium intake throughout the day. Ideally, doses of 500 mg at a time are recommended for optimal calcium absorption.
There are many varieties of calcium supplements in the market to suit everyone’s needs. For any questions about your specific calcium requirements, please get in contact with your healthcare provider or Dietitian.