18. Eating Your Way To Good Dental Health AssociateContributed by:
Professor Dr. Nasruddin Jaafar
Department of Community Dentistry, University of Malaya, Kuala Lumpur
Your dietary habit is one of the most important influences on dental health. But it is impossible to look at dental health alone in total isolation from your general health. While this article will suggest ways how yon can maintain good oral health through tooth-friendly dietary habits, you must remember that you must balance it with moderation. For example if you are trying to reduce or give up sugar totally, you must ensure that you are not eating more fatty and salty snacks as replacement.
The general guideline suggested by nutrition experts should be observed. Among them is to ensure a daily balanced diet consisting of roughly 60% carbohydrates (whole wheat bread, rice, cereals, potatoes), 20% proteins (milk, meats, soya bean, nuts, legumes) and 20% fats. The food pyramid suggested by the Ministry of Health in the healthy lifestyle campaign should be the reference point for most Malaysians.
As far as dental health is concerned, sugar has been identified as one of the main problems. Although all sugars, whether natural or "artificially refined", are capable of being turned into acids by plaque bacteria, the evidence suggest that sugars in fresh fruits (intrinsic sugars) are not of dental concern. Similarly, although lactose (milk sugar) can produce pH drops is lab-experiments, the milk fat offers some protective effect against caries so it is not a dental public health problem. The main culprit causing rampant caries has been narrowed down to non-milk extrinsic (NME) sugars. These NME sugars include sucrose, fructose, glucose and maltose.
The recommended daily dietary allowance for NME sugar by respected nutritional authorities, including the WHO and COMA of the UK, is quite specific. The policy is directed at decreasing dietary sugars to improve not only dental but general health as well. Of the 60% daily carbohydrate intake, it is recommended only 10% should come from free sugars or non-milk extrinsic (NME) sugar. The rest should come from complex carbohydrates and fresh food products especially fruits and vegetables.
Practically, the NME sugar allowance can be translated into a daily intake of 10 -12 teaspoonfuls of free sugars per day or around 20 kg per person per year so ensure good general and dental health. Unfortunately, most canned foods and drinks contain very high sugar preparations. For example a can of fizzy soft drinks typically contain 7-9 teaspoonfuls of NME sugars - almost reaching your daily recommended health allowance of 10 -12 teaspoonfuls per day.
The lower limit is zero NME sugar intake. But most Malaysians would find this difficult. Since the Malaysian per capita sugar intake is currently around 38 kg per person per year, you should perhaps start to have your current NME sugar intake to reach the 20 kg per person per year target. Eventually, your personal target should be towards zero NME sugar intake.
For dental health, the local effect of diet is much more important after the tooth has erupted in the mouth than the systemic effect before it erupts. The only important dietary trace element with proves pre- and post-eruptive caries preventive effect, shown in a large number of studies, is fluoride. Present evidence show that among the total dietary factors, NME sugar exerts the most significant effect.
What this imply is that eating lots of calcium-rich foods, vitamin D and phosphorus when your teeth are still forming (in the womb, infants, toddlers and early childhood) will help your teeth to be well formed before it erupts. But it does not make much difference in preventing dental caries when most teeth have already erupted if you are a teenager or adult. Controlling NME sugar is much more effective to prevent dental decay than increasing your vitamins, minerals or calcium intake, once all your teeth have erupted.
There are a number of ways how dietary sugars can influence dental decay. Studies have shown that not all people eating the same amount of sugar will get the same amount of caries. You can in fact modify your eating habit to reduce the risk of getting caries, especially if you really cannot avoid sweet foods.
First, foods differ in their ability to stimulate salivary flow. Generally, a lot of salivary flow is good for teeth. That is why some studies show that eating sugary foods at-meal times (when salivary flow is maximum) is less damaging to teeth, than in-between meals or before going to bed. A four-year study investigating the role of sugar is dental decay found that very high sugar consumption did not cause much caries if it is takes up to four times a day at-meal times and none between-meals. But of course we know now that a high sugar intake is not good for general health. Chewing gums has been advocated as good-for- teeth because of their ability to stimulate salivary flow. Of course, sugar-free gums should be your preferred choice.
Second, the frequency of sugar challenge (how often) per day is generally more damaging to teeth than the quantity (amount) of sugar taken. This is because the pH drop in plaque occurs within 3-7 minutes of a sugar challenge and only rises to the normal safe level around 40 minutes later. That means each time you take a sugary food (of drink) the micro-damage to your teeth (called de-mineralization) starts almost immediately. If the sugary snack is continuous such as taking regular sips of a sugared drink over a long period of time while watching your favourite TV programme, the damage is worst than if you had finished the drink in 2 or 3 big gulps. The acidic pH stays as the dangerous level for hours on end before being neutralized by your saliva.
A few studies have shows that there is another way to encourage the pH level to rise faster after a sugary challenge. As stated earlier, chewing gum after taking a sugary food will stimulate saliva, which will neutralize the acids. Other foods which have the same effect are savoury ones like cheese, nuts, crisps and our local keropok. Thus you could order your food intake to start off with sweet sugary ones and finish off with savoury ones so that the risk of damage is reduced. If you like your tea of coffee to be sweet, you can still do so by using alternative sweeteners which are non-cariogenic. But plain water is still best for health.
If you are looking after young children - stop giving them sugar-containing sweets. There are alternative sugar-free sweets, which are safe for teeth and taste just as rice. Never put sugared drinks or fruit juices in bottle reservoir feeders. Remember the longer the time of continuous contact between sugar, plaque and tooth - the more severe the damage. Saliva is greatly reduced just as your child is dosing off to sleep.
Increasing the consumption of fresh fruits will indirectly decrease the need for NME sugars as snacks. Furthermore, the fibre, vitamins and overall nutritional content of fresh fruits is much, much better. Thus you end up with much healthier diet. So in conclusion, you have to view your eating habits not just from the dental perspective but from your overall health. While you can reduce the risk of getting caries by modifying your sugar eating habits as suggested, for the sake of your health, it is always better to cut down the calories- laden, nutrient-deficient NME sugars. Moderation is the key to health. So keep trying.