There have been lots of studies investigating a possible link between colours and childhood hyperactivity or attention deficit syndrome.

The results have not given a clear-cut answer. Behaviour in children is a very complex area and many different factors could be responsible for any problems.

Evidence suggests that a person’s whole diet can have an effect but it has not been narrowed down to particular foods or additives.

There is a vast amount of information about food additives and hyperactivity on the internet. Much of it is unregulated and can be biased. Always look at the information closely to see how reliable it is.

• Is the number of people in any test large enough to give reliable results?
• Do the people being tested know if they are in the trial group or the control group?
  • Good tests should be ‘double-blind’. In this way neither the researchers nor the people in the trial know if they are being tested or are in the control group.
• Are the observations reliable and consistent?
• Is it personal opinions or scientific tests?
• Measurements and tests need to be consistent throughout the whole group and not rely on personal judgments.
  • For example, saying something is hot is very personal but stating that it is at 60°C is clear.
• Are the results analysed statistically to see if there are significant effects?