Our bodies rely on many different minerals to function in a healthy way. Some minerals are classified as 'major' minerals, because they are needed by the body in large quantities. Other minerals are classified as trace minerals. These are still very important, but only needed in small amounts. Both major and trace minerals are essential for our body's metabolism, hormonal balance and general health.
The following recommended daily intakes (or 'RDI's') are based on the Australian National Health and Medical Research (NHMRC) guidelines. Other countries may have slightly different recommendations. We have also included information on minerals for conception, pregnancy and breastfeeding, as well as a list of some foods that contain these minerals. Most minerals are obtained through a well-balanced and varied diet, therefore supplementing is rarely required. It is important to be aware that it is possible to overdose on some minerals, to levels that are toxic to the body.
Conception, pregnancy and breastfeeding
Calcium is classified as a 'major' mineral. In fact, it is the most abundant mineral in the human body and an important part of our nutritional needs. About 99% of the body's calcium is stored in our bones and teeth. Here, calcium combines with the mineral 'phosphorus' to make our bones and teeth dense and hard. The remaining 1% of calcium circulates in our body fluids and is necessary for muscle contraction, blood clotting, nerve impulse conduction and the regulation of many hormones. Calcium also activates a protein called 'calmodulin' in the body, which relays messages to specific body cells to help maintain normal blood pressure.
Our bones constantly absorb and release calcium. They act like a 'calcium bank' for our body. During childhood and adolescence our bones absorb more calcium than they release (for storage). As adults the calcium levels remain relatively stable, while in old age we tend to lose more calcium from our bones than we absorb. However, the way our bones absorb, store and release calcium is also reliant on how much calcium we eat in our diets. If our diet is low in calcium, our bones will need to release more calcium into the blood stream, to keep calcium levels in our body normal, for healthy functioning.
Children who don't have enough calcium can experience stunted growth. Adults may stay healthy for years, even with consistently low calcium in their diet, but in later life they can become prone to weakened bones (a condition called 'osteoporosis'). There is also some evidence indicating that adequate calcium in the diet may help prevent high blood pressure, blood cholesterol, heart disease, diabetes and bowel cancer.
Recommended Daily Intake (RDI) of calcium for men and non-pregnant women is around 600 to 900mg (milligrams) per day. One serving of a dairy food typically contains about 300 milligrams of calcium. You can read more in about food servings of calcium in Class A.
Calcium supplements should only be taken under medical supervision. As a guide, supplements should not exceed 1000 to 1,500mg a day. If supplements are taken in combination with calcium rich foods, the total intake should not exceed 2,500mg per day. Excess calcium can lead to constipation, bloating and excess gas production by the bowel. It can also lead to the formation of kidney stones and interfere with the body's absorption of other minerals, such as iron. Very high doses of calcium can make levels in the blood abnormally high causing headaches, irritability, tiredness, and in extreme cases kidney failure.
You can read more in calcium supplements.
Conception, pregnancy and breastfeeding.
Calcium is essential for the development of your baby's bones. There is also some research indicating that adequate calcium may help prevent high blood pressure during pregnancy and possibly premature birth. Pregnant and breastfeeding women should aim and have at least 900 to 1200 milligrams of calcium each day (or 3 to 4 servings of calcium rich foods). Pregnant and breastfeeding women under the age of 20 need at least 1200 milligrams (or 4 servings) because their body is still building bone density for later life.
Women carrying twins need to have at least 1200 to 1500 mgs of calcium per day during pregnancy (or 4 to 5 servings of calcium rich foods). This is also recommended for women who breastfeed twins. Women carrying triplets need about 1500 to 1800 mgs per day (or 5 to 6 servings), eating similar amounts while breastfeeding. Your caregiver may prescribe calcium supplements to help you keep up with the calcium your body needs during this time. You can read more calcium supplements.
Dairy foods tend to contain the highest amounts of calcium. However, if you are vegan, dislike, or are allergic to dairy foods (or if your morning sickness makes them unpalatable for a while), you will need to look at eating alternative foods that contain calcium. This is particularly important during pregnancy, when your baby will draw on the calcium stores in your bones, for their own growth and development inside the womb. Some commercially prepared foods have added calcium. For example, there are now some brands of orange juices, cereals and tofu with added calcium. To read about how much calcium is in what foods you can go to calcium in foods.
Last revised: Tuesday, 15 January 2013
This article contains general information only and is not intended to replace advice from a qualified health professional.