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Alternative sugars: Lactose (milk sugar)

Elaine Gardner, British Dietetic Association (BDA) Spokesperson, discusses the sugar content in lactose and provides related oral health advice.

Lactose (milk sugar)

What is it? The sugar found in animal milks and dairy products. It has 20% the sweetness of table sugar.

Found in? As a powder, it is available from health food stores and online. In the pharmaceutical industry, lactose is a filler when forming tablets. It is also used widely by the food manufacturing industry and in home brewing. Lactose is most commonly consumed within milk and dairy products.

The quantity of lactose in animal milks remains similar at about 4.7% lactose, whether the milk is from a cow, goat or sheep and whether it is semi-skimmed or skimmed. Flavoured milks (such as strawberry, chocolate) can have sugary additions.

Effect on general health: If you are lactose intolerant, you cannot digest milk sugars because the body cannot produce the enzymes needed to digest lactose. There are now a number of lactose-free milks available.

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Oral health impact: Lactose is a non-fermentable sugar so is not cariogenic and is not harmful to teeth. Milk and the associated dairy foods also tend to be high in protein, calcium and phosphates which help neutralise the effects of acid production which is beneficial to oral health.

Dairy products without added sugar or a small piece of cheese can be advised as snacks or as after-meal desserts for positive oral health. It is noted, however, that eating a piece of cheese may not be a practical solution and that this may have a detrimental impact on overall dietary intakes, especially if eaten frequently.

Dairy-based foods such as fruit yoghurts may also have free sugars added to sweeten them. On average, three teaspoons of free sugars can be added to a small pot (125 g) of yoghurt. Likewise flavoured milks can contain over 5% sucrose and as such have cariogenic potential.

Advice for patients: Plain milk and dairy based choices with no added sugars, such as natural yoghurt, are the best options to choose. While lactose is not harmful to teeth, patients are often unaware of the additional sugars added to dairy products that can impact on oral health. Oral hygiene should always be maintained.

Find out more about the British Dietetic Association at:

Coming up in our final instalment: Sucralose


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Alternative sugars: Lactose (milk sugar). Br Dent J 223, 801 (2017).

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