Function

Calcium has a number of important roles and is the most abundant of the minerals found in the human body. About 99% is used to form the rigid structure of our bones and teeth. The remaining amount plays a key role in blood clotting, muscle contraction, nerve signalling and enzyme functions.

Requirements

Requirements for calcium vary throughout life. They are highest during childhood and adolescence when new bone is formed as we grow. Requirements remain high throughout our adult life as we continually recycle and replenish our stores. It is recommended that females aged 15 to 18 achieve an intake 800mg per day of calcium and that females age 19 and over achieve an intake of 700mg per day.

Sources

Dairy foods such as milk, yogurt and cheese are a rich source of calcium and contain the mineral in a form that is easily absorbed by the body. Lower amounts are found in dairy foods such as cottage cheese and fromage frais.

Good non dairy sources include foods made with white or brown flour as this has calcium added by law, wholemeal flour which contains calcium naturally, fish with soft bones such as sardines or pilchards, tofu if made with calcium sulphate, soya milks and desserts if fortified with calcium, green leafy vegetables, pulses and nuts.

Here is a guide to the amounts of calcium found in the foods we eat:

Dairy

• A third of a pint of whole, semi-skimmed or skimmed milk = 230mg
• A standard 150g pot of low fat fruit or Greek yogurt = 225mg
• A small 40g match box sized piece of hard cheese = 288mg
• A small 150g carton of cottage cheese = 110mg
• A large 125g pot of fromage frais = 140mg
• 2 scoops of vanilla dairy ice cream = 120mg

Non Dairy

• 2 slices of white bread from a large loaf = 83mg
• 2 slices of wholemeal bread from a large loaf = 38mg
• 1 chapatti made with no fat (70g) = 42mg
• Half a naan bread (85g) = 137mg
• 35g slice of malt loaf = 36mg 50g
• Tofu made with calcium sulphate = 740mg
• A third of a pint of soya milk fortified with calcium = 273mg
• Half a tin of baked beans (200g) = 106mg
• 105g sardines in tomato sauce = 452mg

Combination foods

• 1 large slice of mixed vegetable deep pan pizza (150g) = 260mg
• 220g home made macaroni cheese = 374mg

As an approximate guide we should aim to eat at least 3 portions of dairy food each day to help us achieve the amount of calcium we need.

Below is a suggested meal plan for one day:

Breakfast

Fortified breakfast cereal or porridge made with 200ml semi-skimmed milk

250ml glass of pure orange juice

Mid morning snack

Banana or low fat fruit yogurt

Cup of tea made with semi skimmed milk

Lunch

Baked beans on toast with 30g grated cheese topping or cheese and salad sandwich with salad cream

Slice of malt loaf

Water

Evening meal

Grilled chicken breast, new potatoes carrots and broccoli

1 scoop of dairy ice cream with strawberries

Sugar free squash

Go to our recipe section and try some of the delicious calcium rich recipes.

Calcium supplements

For those who cannot, or choose not to eat dairy foods it is important to include a good range of alternative sources of calcium in your daily diet. Calcium supplementation can be a useful option for those who struggle to meet the recommended amount through diet alone. Calcium supplements are available on their own or as part of a multivitamin. There has been no adverse effects found if taken in daily doses up to 1500mg however there has been little benefit seen from excessively exceeding the recommended nutritional intake. Very high intakes of calcium have been found to reduce the absorption of iron and zinc for some individuals.

Nutrient interactions

Calcium requires vitamin D to be efficiently absorbed by the gut. Vitamin D is found in oily fish, meat, dairy products, eggs and fortified margarines and breakfast cereals. Individuals living in the UK obtain most of their vitamin D from exposure to sunlight during the summer months. The skin makes the vitamin when exposed to ultraviolet light and stores this for use throughout the year. As a result most of us have a sufficient supply however, some people who receive little or no exposure to sunlight, or whose ability to convert ultraviolet light is decreased, maybe at risk of vitamin D deficiency.

Absorption

Absorption of Calcium increases in the presence of lactose, a sugar found in dairy products. Calcium absorption decreases in the presence of oxalate, found in high concentrations in spinach, and phytates found in high fibre cereal grains such as wheat bran. For this reason these foods are not recommended sources of calcium.

Pregnancy functions and requirements

There is no increase in our requirements for calcium during pregnancy as the body adapts to improve absorption of calcium from the gut and decreases the amount of calcium excreted by the kidneys. However it is of particular importance that pregnant teenagers meet the recommended intake of 800mg calcium per day, as they continue to grow and develop. There is an increase in our requirements for calcium during lactation.