What is food?  
  What happens to the food we eat?  
Our nutrient needs
  Energy balance  
  Nutritional status  
  Laws & labels  
  Additives & colours  
  Toxicity in food  
  Processing food  
  Stability of food nutrients  
  Storage life of foods  
  Food- associated health problems  

- How our nutrient needs are assessed -

How do we know the amounts of different nutrients we should eat to keep us healthy?
In many countries, committees of nutrition experts have assessed the available evidence regarding safe and adequate intakes of nutrients, and have formulated recommended dietary intakes (RDIs) for some of the nutrients. The vitamin A overdose aria (hair falling out scene, from the Merry Widow.These recommendations are based on fairly clear evidence, and relate to the average daily amounts that are considered adequate to meet the known nutritional needs of most healthy people. They do not indicate the needs of any specific individual, but should allow for normal requirements under most circumstances. They do not allow for factors such as illness or interactions with certain drugs, which may have special needs (see Figure 19 and Figure 20).

Where an RDI for a nutrient has not yet been formulated, a 'safe and adequate' range can generally be advised. In fact, some nutritionists think that a range rather than a specific amount should be stated for all RDIs.

It is difficult to apply RDIs to an individual because what really needs to be known is that individual's particular requirements for the nutrients in question. However, if your average daily intake of any nutrient is less than two-thirds of the RDI, or is below the lower end of the 'safe and adequate' range, then you may not be getting enough of an essential nutrient.

Act 5- The 'Low nutrient intake' overture.Sometimes this may be due to not eating enough food or alternatively it may be due to poor food choice.

In these few pages, you will find tables listing the general recommended dietary intakes. Differences in recommendations between countries are, by and large, of no real consequence and reflect slightly different views of scientific evidence or local differences in food supply and nutritional needs. In the latter part of this book RDIs for individual nutrients are also shown in the Food Charts.

Food Facts
- Our nutrient needs
How our nutrient needs are assessed
- Recommended dietary intakes
5: How the human diet has changed
6: Our nutrient needs change with age
7: Recommended dietary intakes for different groups
8: Recommended daily dietary intakes in some developed countries
9: Estimated safe and adequate range of daily dietary intakes
10: How to check your intake of a particular nutrient