caused by effective saliva stimulation,together with the effect of its milk compo-nents. The consensus of opinion is thatmilk and milk products, if unsweetened byadded sugars, are safe and possibly benefi-cial for teeth.1

Sugar-sweetened milk and milkproductsThe increasing consumption of sugar-sweetened milk products raises the ques-tion of their cariogenicity, however mostavailable evidence comes from laboratoryresearch. A study on rats showed anincrease in cariogenicity with only 2%sucrose added to milk4 and an intra-oralplaque study found an increase in plaqueacid production with 5% sucrose in milk.5

However another intra-oral study assessingdemineralisation of bovine enamel slabsshowed no effect from 5% sucrose in milk,but pronounced demineralisation with 5%sucrose in water.6 In a human study, rinsingwith 10% sucrose in milk produced similarplaque acidity to 10% sucrose in water andsignificantly more than with plain milk.7 Inthe only relevant clinical trial, institution-alised young people received a daily supple-ment of 0.45L of chocolate milk (5%sucrose) for 2 years, producing a small butnon-significant increase in caries compared

with a plain milk supplement.8 Flavouredmilks, milkshakes and sugar-sweetenedyoghurts typically contain 5% or more ofadded sugars. The low intrinsic pH foundin many yoghurts may interfere with plaqueglycolysis of sugars and one study foundyoghurt with 5% sucrose to have low cario-genic potential.9

There are few reports on the cariogenicityof specific sweetened milk products andsince testing procedures vary, generalisa-tions must be guarded. However, it wouldappear from the available evidence thatproducts containing about 5% added sugarshave a negligible or low cariogenic potentialwhich is likely to be less than that of aqueoussugar-sweetened beverages, of which thetotal UK consumption in 1999 was 11,000million litres, under 16-year-olds consum-ing 60%.10 The practice of adding sugar tomilk should be discouraged. More researchon the cariogenic potential of milk-basedproducts is needed as they form an impor-tant part of our diet.

ConclusionBecause sweetened milk products have anutritional value and may not be consumedby children as frequently as other sugar-sweetened beverages, the cariogenic loadproduced in most individuals is likely to below and their occasional consumptionshould be accepted.

1 Rugg-Gunn A J. Nutrition and dental health.Chapter 9. Oxford: Oxford University Press,1993.

2 National Dairy Council, London, 2000.3 Jenkins G N, Ferguson D B. Milk and dental

caries. Br Dent J 1966; 120: 472-477.4 Bowen W H, Pearson S K. Effect of milk on

cariogenesis. Caries Res 1993; 27: 461-466.5 Thompson M E, Dever J G, Pearce E I F. Intra-

oral testing of flavoured sweetened milk. NZDent J 1984; 86: 44-46.

6 Mor B M, McDougall W A. Effects of milk onpH of plaque and salivary sediment and theoral clearance of milk. Caries Res 1977; 11: 223-230.

7 Moynihan P J et al. Effect of glucose polymersin water, milk and a milk substitute on plaquepH in vitro. Int J Pediatr Dent 1996; 6: 19-24.

8 Dunning J M, Hodge A T. Influence of cocoa inmilk on dental caries incidence. J Dent Res1971; 50: 854-859.

9 Mundorff S A et al. Cariogenic potential offoods 1. Caries in the rat model. Caries Res1990; 24: 344-355.

10 UK market review. Reading: Tate & LyleSpeciality Sweeteners, 2000.

20 BRITISH DENTAL JOURNAL VOLUME 191 NO. 1 JULY 14 2001

PRACTICEbriefing paper

Milk is of major nutritional value, espe-cially for children, being their main

source of calcium.1 The consumption ofmilk products such as flavoured milks,milkshakes and yoghurts has increased, theannual consumption of flavoured milksgrowing from 56 to 84 million litresbetween 1992 and 19992 and the question ofthe cariogenicity of such products, whilecomplex, must be addressed. This paperaims only to give a brief overview.

MilkCow’s milk contains about 4–5% of the dis-accharide lactose which in aqueous solutionis metabolised by plaque organisms toorganic acids with a consequent fall inplaque pH, although to a lesser extent thanwith sucrose. However cow’s milk producesa negligible fall in plaque pH in the mouthand the balance of evidence from animaland human studies suggests that cow’s milkis non-cariogenic.3

The explanation for milk’s apparent lackof cariogenicity appears to lie with its highbuffering capacity and other components,including a high calcium and phosphatecontent. Milk proteins are adsorbed ontothe enamel surface and may impedeenamel demineralisation; the phospho-protein casein is implicated in this effect.Milk fat adsorbs to the enamel surface andmay have a protective role. Finally, milkenzymes may have a role in reducing thegrowth of acidogenic plaque bacteria.Cheese has been shown to help restoreplaque pH after a sugar intake, probably

Milk, flavoured milk products and cariesR. S. Levine,1

The consumption of flavoured milk increased by 50% between 1992and 1999 and dental health educators need to know if these and othersugar and fruit juice sweetened milk products, such as fruit yoghurts,are acceptable as snack items. Available evidence suggests that theircariogenicity is negligible to low and consumed in moderation they area preferable alternative to similarly sweetened soft drinks.

1*Independent Scientific Adviser and General DentalPractitioner, 370 Alwoodley Lane, Leeds LS17 7DN*Correspondence to: Ronnie Levineemail: ronnielevine@onetel.net.ukREFEREED PAPER

Received 22.02.99; Accepted 23.11.00© British Dental Journal 2001; 191: 20

In brief• Unsweetened milk and milk-based

products are safe for teeth, as areartificially sweetened products.

• Sugar and fruit juice sweetened milkproducts consumed in moderation area preferable alternative to similarlysweetened soft drinks.

• The practice of adding sugar to milkshould be discouraged.