The mouth is missing out too…
Nutrition guidelines for dental care vs. the evidence: Is there a disconnect?
Dental caries is the most common chronic childhood disease in New Zealand. The most recent data from the Ministry of Health (MOH) showed that 38% of five-year old children were diagnosed with dental caries in 2017, with a higher prevalence observed among Māori and Pacific children compared to children of other ethnicities. Some 7700 children aged five years old and under require extraction of decayed teeth under general anaesthesia; in addition, the cost of this operation for New Zealand taxpayers is some NZD $132,000 per working day. Concurrently, obesity and related chronic diseases including diabetes, cardiovascular disease and neurological disease are the most challenging public health problems. New Zealand is experiencing an obesity epidemic; New Zealanders are the third most overweight and obese population among countries included in the OECD. Approximately 67% of all New Zealanders over 15 years of age are overweight and the prevalence of obesity is 27%.
There is considerable evidence that a common dietary behaviour – high frequency consumption of ultra-processed, high carbohydrate foods – is the principal causal factor for both dental caries, and presentation of children and young people as overweight or obese. The relationship between high dietary intakes of sugar and dental caries is well established. In addition, high, and frequent consumption of processed foods containing sugars and starches are implicated in dental caries, and presentation of children and young people as overweight or obese.
Conversely, consumption of full-fat dairy products by children and young people is associated with reduced risks dental caries, body fatness, and hypertension. In addition, dairy product intake was associated with enhanced lipid profiles benefits for bone mineralisation. Recent systematic reviews found that intake of milk and other dairy products are consistently found to be either not associated, or inversely associated, with obesity and anthropometric indicators of adiposity in children,
Although government-endorsed dietary guidelines for young people correctly provide recommendations to decrease intake of high-sugar foods, recommendations are also provided to increase the amount, and frequency of consumption of high carbohydrate foods as children age.
This means that promoted foods include ultra-processed items that are associated with dental caries and other chronic disease.[5-9] Further, included in the MOH food suggestions are refined carbohydrates (such as cornflakes) and foods listed in the highest NOVA category of ultra-processed foods, such as plain sweet biscuits and tortillas. This advice for children contradicts evidence of the dietary causes of dental caries and contradicts the nutritional, metabolic and hormonal theory of metabolic health as the cause of obesity. Consumption of breads, cereals and other ultra-processed refined sugar-and starch-containing foods is associated with dental caries, is implicated in insulin resistance, and is associated with obesity in older children and adolescents.
Additional advice is provided in the dietary guidelines to choose low-fat options when consuming dairy produce. Although the anti-cariogenic properties of milk products are acknowledged in the guidelines, recommendations about dairy intake promote low-fat dairy products, in direct opposition to epidemiological evidence. Full-fat dairy products have not been associated with obesity in child and adolescent populations, and studies indicate that whole milk consumption is associated with favourable effects on body composition and lipid profiles of children. This advice directly contradicts evidence of the dietary causes of both dental caries and obesity and does not reflect the evidence regarding observed associations between the consumption of full-fat dairy produce and reduced dental caries, obesity and other indicators of health. Examples of the advice is provided in Table 1 below.
Table 1. Specific food and nutrition guidelines for healthy eating in children and young people pertaining to dietary factors and evidence for prevention of obesity and dental caries in young people.
|Dietary factor||Weight management||Optimal oral health|
|Carbohydrate intake||“Eat a variety of foods from each of the four major food groups each day…”
· … breads and cereals, increasing wholegrain products as children increase in age.
|“Eat a combination of foods at each meal, including whole grains…”
“Good oral hygiene and minimising intake of cariogenic foods and drinks are key behaviours in preventing dental caries”
|Recommendations for the “breads and cereals“ food group|
|Specific foods included||Recommendation (per day)||Serving size examples|
|All breads, cereals, rice and pasta (increasing wholegrain options as children age)||Pre-schoolers: at least 4 servings
Children: at least 5 servings
Young people: at least 6 servings
|1 medium slice of bread (26 g)
1 roll (50 g)
1 pita pocket or tortilla (50–80 g)
2 breakfast wheat biscuits (34 g)
½ cup muesli (55 g) ½ cup porridge (130g)
1 cup cornflakes (30 g)
1 cup cooked pasta or rice (150 g)
4 grainy crackers (40 g)
2 plain sweet biscuits (14 g)
1 cup plain popcorn
|Fat intake||Weight management||Optimal oral health|
|“Eat a variety of foods from each of the four major food groups each day…
· milk and milk products or suitable alternatives, preferably reduced or low-fat options
“Reduced or low- fat milk and milk products are the best choices because these foods include less saturated fat, and often more protein and calcium than high-fat alternatives.”
|“Eat a combination of foods at each meal, including whole grains, vegetables and fruit.”
“Anti-cariogenic foods and drinks are those that promote tooth remineralisation. They include foods high in calcium, phosphate and protein, such as milk and milk products”
|Recommendations for the “milk and milk products“ food group|
|Specific foods included||Recommendation (per day)||Serving size examples|
|Milk (includes calcium-fortified milk alternatives), cheese and yoghurt (choose low-fat options)||Pre-schoolers and children: at least 2–3 servings
Young people: at least 3 servings
|Glass of milk or calcium-fortified milk alternative (250 ml), one pot of yoghurt (150 g) 2 slices of cheese (40g)|
Given that the epidemics of dental caries the most common chronic disease of and metabolic disease are significant ongoing public health challenges in New Zealand and share common dietary causes, guidelines for healthy eating should focus on prevention of chronic disease through the lifespan by limit refined sugar-and starch-containing foods and encourage intake of whole foods, full-fat dairy items.
- Ministry of Health, Annual update of key results 2017/18 New Zealand Health Survey. 2019, Ministry of Health: Wellington.
- Beaglehole, R., Sugar sweetened beverages, obesity, diabetes and oral health: a preventable crisis. Pac Health Dialog, 2014. 20(1): p. 39-42.
- Dror, D.K. and L.H. Allen, Dairy product intake in children and adolescents in developed countries: trends, nutritional contribution, and a review of association with health outcomes. Nutr Rev, 2014. 72(2): p. 68-81.
- Dougkas, A., et al., A critical review of the role of milk and other dairy products in the development of obesity in children and adolescents. Nutr Res Rev, 2019. 32(1): p. 106-127.
- Monteiro, C.A., et al., Ultra-processed foods: what they are and how to identify them. Public Health Nutr, 2019. 22(5): p. 936-941.
- Campain, A.C., et al., Sugar-starch combinations in food and the relationship to dental caries in low-risk adolescents. Eur J Oral Sci, 2003. 111(4): p. 316-25.
- Fiolet, T., et al., Consumption of ultra-processed foods and cancer risk: results from NutriNet-Sante prospective cohort. Bmj, 2018. 360: p. k322.
- Srour, B., et al., Ultraprocessed Food Consumption and Risk of Type 2 Diabetes Among Participants of the NutriNet-Sante Prospective Cohort. JAMA Intern Med, 2019.
- Srour, B., et al., Ultra-processed food intake and risk of cardiovascular disease: prospective cohort study (NutriNet-Sante). Bmj, 2019. 365: p. l1451.
- Weiss, R., A.A. Bremer, and R.H. Lustig, What is metabolic syndrome, and why are children getting it? Ann N Y Acad Sci, 2013. 1281: p. 123-40.
- Hayden, C., et al., Obesity and dental caries in children: a systematic review and meta-analysis. Community Dent Oral Epidemiol, 2013. 41(4): p. 289-308.