Calcium is an essential mineral and 99 per cent of your body’s calcium is stored in your bones and teeth. It is present mainly as hydroxyapatite in our bones, which gives bones strength and rigidity. The remaining one per cent is found in blood, muscle and extracellular fluid.
Besides bone and teeth health, calcium is essential for nerve transmission, muscle contraction, cell membrane and capillary permeability, cell division, regulating heartbeat, respiration, maintenance of electrolytes, normal blood clotting, neurotransmitter and hormone secretion and blood acid-base balance.
Why you may need calcium
Osteoporosis prevention – calcium (along with vitamin D) is effective in the prevention and treatment of osteoporosis. Adequate intake of calcium is important throughout life but especially during our growing years and development of peak bone mass (the late 20s and into the early 30s). Low dietary intake of calcium during adolescence and young adulthood may reduce peak bone mass and bone mineral content and increase the risk of osteoporosis in later life.
Bone loss starts to occur in women over 40 at the rate of 0.5 to 1 per cent per year and this can be reduced with calcium intake. The rate of bone loss in postmenopausal women is two per cent per year and can be decreased to 0.25 to 1 per cent with higher calcium intake. Men are also susceptible to osteoporosis and adequate calcium intake is important throughout life.
High blood pressure (hypertension) – calcium helps decrease high blood pressure.
Premenstrual syndrome – calcium reduces premenstrual symptoms such as fluid retention, depression and pain.
Pre-eclampsia during pregnancy – women who get adequate calcium throughout pregnancy are 70 per cent less likely to suffer from hypertension in pregnancy.
Bone fractures – studies indicate that calcium can decrease risk of fractures. Lack of calcium can lead to brittle bones that are more susceptible to fractures.
How much to use
Recommended Daily Intake:
Adults 19-50 years: 1,000mg daily
Adults 51-70 years: 1,300mg (women), 1,000mg (men) daily
Adults over 71 years: 1,300mg daily
Pregnancy: 1,000mg daily
Breastfeeding: 1,000mg daily
Children 9-11 years: 1,000mg daily
Children 12-18 years: 1,300mg daily
Symptoms of deficiency
Deficiency symptoms of calcium include stunted growth in children, bone loss, brittle fingernails, heart palpitations, hypertension, muscular cramps, menstrual cramps, irritability and insomnia.
The best dietary sources include – dairy products, salmon and sardines with bones, soybeans (soymilk – choose those that are fortified with calcium), oysters, parsley, broccoli, almonds, sesame seeds and leafy green vegetables.
Other reasons why you may need more
Factors that may increase your demand for calcium include low stomach acidity and malabsorption conditions, thyroid and parathyroid abnormalities, children, adolescents, pre- and postmenopausal women, pregnant and breastfeeding women , vegans, lactose intolerance (due to avoidance of dairy products/ low calcium diet), vitamin C deficiency, excessive intake of caffeine, alcohol, sodium, phosphate, fibre, oxalate, protein or sugar, bone fractures, cigarette smoking, lack of exercise and being bed-ridden.
- Calcium is generally well tolerated. Side effects that have been reported include mild nausea, constipation and flatulence.
- If you have hypercalcuria, (high calcium in the urine), hyperparathyroidism (overactive parathyroid), hyper or hypo phosphatemia, (high of low phosphate in the blood) kidney disease, kidney stones, sarcoidosis or hypertension, consult your healthcare professional before supplementing with calcium.
- Many supplements contain calcium hydroxyapatite, which is derived from bovine (cow) bones. Although it is a very good source of calcium, it may not be appropriate for vegetarians.