This food group includes milk and milk products - cheese, yoghurt and fromage frais - but not butter, margarine or cream. They belong in the fat and sugar group of the Food Standards Agency's 'eatwell plate'.
Supermarkets now stock many different varieties of milk. The most common in the UK is still cow's milk, but others include sheep and goat's milk, as well as a number of plant-based substitutes - including soya, rice, oat and almond milk - for those with lactose intolerance.
Even whole milk is relatively low in fat and certainly semi-skimmed milk can be labelled as a low-fat food. Contrary to popular belief, lowering the fat content in milk does not affect the calcium content, so an adequate calcium intake can still be obtained from lower-fat dairy products. However, low fat milk contains less energy and lower amounts of fat soluble vitamins and isn't suitable for children under two years.
Some supermarkets have now started selling milk with a 1 per cent fat content which has almost half the fat of semi-skimmed milk but retains a more creamy flavour. This is a good option for those people who want to lower the amount of fat they're consuming but don't like the taste of skimmed milk.
Cheese contains the same beneficial nutrients as milk, but most cheeses contain much more saturated fat and high levels of added salt, so it's important to only eat full-fat cheese occasionally and in small portions.
Yoghurt is rich in protein and vitamin B2: essentially the same nutrients as in milk. Some varieties contain living bacteria that are healthy for your digestive system (probiotics). Yoghurt can be made from whole or low fat milk, but be careful. Fruit yoghurts often contain added sugar. Low fat doesn't necessarily mean low calories. If you're watching your weight, look for 'diet' versions, or make your own by mixing fruit with natural, low fat, unsweetened yoghurt. Check out the labels of packs for details.
Calcium is a mineral that helps build strong bones and teeth, regulates muscle contraction (including the heartbeat) and makes sure the blood is clotting normally. Milk and dairy products have long been held as an important source of calcium, although more recently the role and safety of dairy calcium sources have been questioned by some scientists and more research is needed to draw a firm conclusion.
More importantly, research also suggests that calcium in your diet is less important in developing healthy bones than vitamin D (from your daily diet or from the sun's effect on the skin). Similarly, sufficient exercise is now seen as another vital factor in maintaining healthy bone structure and density - concerns have been voiced that a lack of excercise in growing children will have a detrimental effect on their bones.
Calcium can continue strengthening your bones until the age of 20 to 25 when peak bone mass is reached. After this point, your bones can only maintain or lose their density and grow weaker as a natural part of the ageing process. Inadequate dietary calcium intake before this age can increase the risk of brittle bone disease and osteoporosis, as calcium is drawn from the bones as a reserve.
Each year in the UK, over £1.7 billion is spent on treating osteoporosis. Health professionals estimate that one in two women and one in five men over the age of 50 in the UK will break a bone, mainly because of osteoporosis. Women are more affected as they have less bone mass than men, and may lose it faster as they get older, especially after the menopause when falling oestrogen levels result in the loss of the protective effect of oestrogen on bone density.
If your diet excludes milk and dairy products, or if you can't tolerate milk sugar lactose, then you need to look for calcium alternatives. Other dietary sources of the mineral include: