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5. Population nutrient intake goals for preventing diet-related chronic diseases: Previous page | 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27

Table 13. Prevalence of edentulousness in older people throughout the world

Country or area

Prevalence of edentulousness (%)

Age group (years)

African Region

Gambia

6

65 +

Madagascar

25

65-74

Region of the Americas

Canada

58

65 +

United Sates

26

65-69

South-East Asian Region

India

19

65-74

Indonesia

24

65 +

Sri Lanka

37

65-74

Thailand

16

65 +

European Region

Albania

69

65 +

Austria

15

65-74

Bosnia and Herzegovina

78

65 +

Bulgaria

53

65 +

Denmark

27

65-74

Finland

41

65 +

Hungary

27

65-74

Iceland

15

65-74

Italy

19

65-74

Lithuania

14

65-74

Poland

25

65-74

Romania

26

65-74

Slovakia

44

65-74

Slovenia

16

65 +

United Kingdom

46

65 +

Eastern Mediterranean Region

Egypt

7

65 +

Lebanon

20

64-75

Saudi Arabia

31-46

65 +

Western Pacific Region

Cambodia

13

65-74

China

11

65-74

Malaysia

57

65 +

Singapore

21

65 +

Source: reference 7.

Dental caries occur because of demineralization of enamel and dentine by organic acids formed by bacteria in dental plaque through the anaerobic metabolism of sugars derived from the diet (24). Organic acids increase the solubility of calcium hydroxyapatite in the dental hard tissues and demineralization occurs. Saliva is super-saturated with calcium and phosphate at pH 7 which promotes remineralization. If the oral pH remains high enough for sufficient time then complete remineralization of enamel may occur. If the acid challenge is too great, however, demineralization dominates and the enamel becomes more porous until finally a carious lesion forms (25). The development of caries requires the presence of sugars and bacteria, but is influenced by the susceptibility of the tooth, the bacterial profile, and the quantity and quality of the saliva.

Dietary sugars and dental caries

There is a wealth of evidence from many different types of investigation, including human studies, animal experiments and experimental studies in vivo and in vitro to show the role of dietary sugars in the etiology of dental caries (21). Collectively, data from these studies provide an overall picture of the cariogenic potential of carbohydrates. Sugars are undoubtedly the most important dietary factor in the development of dental caries. Here, the term “sugars” refers to all monosaccharides and disaccharides, while the term “sugar” refers only to sucrose. The term “free sugars” refers to all monosaccharides and disaccharides added to foods by the manufacturer, cook or consumer, plus sugars naturally present in honey, fruit juices and syrups. The term “fermentable carbohydrate” refers to free sugars, glucose polymers, oligosaccharides and highly refined starches; it excludes non-starch polysaccharides and raw starches.

Worldwide epidemiological studies have compared sugar consumption and levels of dental caries at the between-country level. Sreebny (26, 27) correlated the dental caries experience (DMFT) of 12-year-olds with data on sugar supplies of 47 countries and found a significant correlation (+0.7); 52% of the variation in the level of caries was explained by the per capita availability of sugar. In countries with a consumption level of sugar <18 kg per person per year caries experience was consistently (28) did not find a similar association for developed countries. Sugar availability nevertheless accounted for 28% of the variation in levels of dental caries; 23 out of 26 countries with a per capita sugar availability <50g per day had a mean DMFT score for 12-year olds of <3, whereas only half of the countries with sugar availability above this level had achieved a DMFT score that was<3.

Miyazaki & Morimoto (29) reported a significant correlation (r = +0.91) between sugar availability in Japan and DMFT at age 12 years between 1957 and 1987. Populations that had experienced a reduced sugar availability during the Second World War showed a reduction in dental caries which subsequently increased again when the restriction was lifted (30-32). Although the data pre-date the widespread use of fluoride dentifrice, Weaver (33) observed a reduction in dental caries between 1943 and 1949 in areas of northern England with both high and low concentrations of fluoride in drinking-water.

Isolated communities with a traditional way of life and a consistently low intake of sugars have very low levels of dental caries. As economic levels in such societies rise, the amount of sugar and other fermentable carbohydrates in the diet increases and this is often associated with a marked increase in dental caries. Examples of this trend have been reported among the Inuit in Alaska, USA (34), as well as in populations in Ethiopia (35), Ghana (36), Nigeria (37), Sudan (38), and on the Island of Tristan da Cunha, St Helena (39).

There is evidence to show that many groups of people with high exposure to sugars have levels of caries higher than the population average. Examples include children with chronic diseases requiring long-term sugar-containing medicines (40), and confectionery workers (41-44). Likewise, experience of dental caries has seldom been reported in groups of people who have a habitually low intake of sugars, for example, children of dentists (45, 46) and children in institutions where strict dietary regimens are inflicted (47, 48). A weakness of population studies of this type is that changes in intake of sugars often occur concurrently with changes in the intake of refined starches, making it impossible to attribute changes in dental caries solely to changes in the intake of sugars. An exception to this are the data from studies of children with hereditary fructose intolerance (HFI). Studies have shown that people with HFI have a low intake of sugars and a higher than average intake of starch, but have a low dental caries experience (49).

Human intervention studies are rare, and those that have been reported are now decades old and were conducted in the pre-fluoride era before the strong link between sugars intake and dental caries levels was established. It would not be possible to repeat such studies today because of ethical constraints. The Vipeholm study, conducted in an adult mental institution in Sweden between 1945 and 1953 (50), investigated the effects of consuming sugary foods of varying stickiness and at different times throughout the day on the development of caries. It was found that sugar, even when consumed in large amounts, had little effect on caries increment if it was ingested up to a maximum of four times a day at mealtimes only. Increased frequency of consumption of sugar between meals was, however, associated with a marked increase in dental caries. It was also found that the increase in dental caries activity disappears on withdrawal of sugar-rich foods. Despite the complicated nature of the study the conclusions are valid, although they apply to the pre-fluoride era. The Turku study was a controlled dietary intervention study carried out on adults in Finland in the 1970s which showed that almost total substitution of sucrose in the diet with xylitol (a non-cariogenic sweetener) resulted in an 85% reduction in dental caries over a 2-year period (51).

5. Population nutrient intake goals for preventing diet-related chronic diseases: 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27 | Next page

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