Nutrition is the study of the relationship between diet and states of health and disease. It is defined as the study of food. Absence of adequate nutrients can cause certain diseases to take hold that can potentially result in death.

Between the extremes of optimal health and death from starvation or malnutrition, there is an array of disease states that can be caused or alleviated by changes in diet. Deficiencies, excesses and imbalances in the diet can produce negative impacts on health, which may result in diseases such as scurvy, obesity or osteoporosis. Also, excess ingestion of elements that have no apparent role in health (e.g. lead, mercury, PCBs, dioxins) may have toxic and potentially lethal effects depending on dose.

The science of nutrition attempts to understand how and why specific aspects of diet have specific influences on health.

Nutrition seems to be a complicated subject. This is strangely a result of our attempts to simplify it. Governments have introduced nutritional directives ranging from food pyramids, to recommended daily intakes to food groups. Yet where do we stand at this time when nutrition information is forced upon us on food packets and nutrition is simplified in our schools?

It would be fair to say that while our nutrition knowledge has increased, the actual nutrition of a majority of people has decreased. This reduced nutrition is a result of processed foods and mass market agricultural practices among other things.

Our food used to come from small market farmers, who rotated crops to ensure soil nutrition productivity. Now it is often mass produced with nutrition deprived soils. Fertilisers are added to ensure a good crop, but the resulting nutrition of the food is poor. Where possible try to buy organic produce that is both better for nutrition and supports small farmers. Quite often the organic produce has twice the nutrition of mass produced food. So you technically would only need to eat half as much to get the same nutrition anyway.

The nutrition of processed food is usually poor. Adding vitamins and minerals is not the best way to get nutrition, so give things like breakfast cereals with a dozen added vitamins and minerals a skip. It is not possible to supplement nutrition for every known and unknown vitamin. There are many as yet undiscovered nutrients, so a supplement cannot cover these. An example is folate, which until only recently was unknown but essential for nutrition.