If we were to talk of prevention, we find ourselves making invalid assumptions. For instance, we start with 'washing hands with soap regularly prevents disease'. But the problem is, say a huge proportion of children and the community, 'there is not enough water even to drink, how do we wash hands with soap?' Next we say, 'you must eat green leafy vegetables'. However, the response: 'hey, there isn't enough food to eat in the first place, let alone leafy vegetables'. The list is endless. The bottom-line: poverty is at least as important a health issue as lack of health education.
On the other hand, emphasizing prevention has its own limitations. For example, when discussing scabies it is common to find the use of neem being advocated. Though neem is commonly available, it is not exactly always useful in all cases of scabies. Medical advice should be sought rather than relying only on such suggestions. As they say, it can be dangerous to be armed with half-baked information.
So what do we do? Not talk about health at all?
No, we do need to educate our children on health. But the emphasis has to be on educate rather than merely plying them with information. In concrete terms this implies helping children perceive the causal links between different factors in their immediate environment and their health. How the body works, what it is affected by and how it responds to different factors, and how our own actions (individually and collectively) impact upon it -- these are some of the components of what contemporary health education should be like.
This would naturally require scope for exploration, projects and activities. The pedagogy involved should help children arrive at their own conclusions, especially in terms of actions they could take. Here's an example of what might be a good health education activity (for grade 3 students, assisted by their teacher):
Take two small plates -- put a little dal water in one, and a little sweet tea in the other. Set these plates in the sun and let the fluids dry. After a while, touch both of them with your fingers - one of them feels sticky and the other doesn't. Why do you think this is so?
Next, take a knife (let your teacher do this!). Cut a cucumber and feel the knife edge carefully. Now cut a piece of jaggery and feel the edge again (carefully!). Which item left a more sticky knife edge? Why?
So when we eat, which items are more likely to continue sticking to our teeth? And what will happen if they remain there (discuss with your teacher)? So what do we need to do?
That's it. There's no need really to give a long lecture of oral hygiene, full of facts and figures and information on exactly how to hold the brush etc. etc. All that sounds so platitudinous that children instinctively 'switch off' (as do adults when lectured!). The intention is that by helping children arrive at their own conclusions, we increase their stake in taking appropriate health-related action. And hence the increased chance that the understanding will actually translate into behavior!