The cereal market leader pulled the claim following an investigation by the Federal Trade Commission (FTC).

It has since agreed to refrain from pronouncing health benefits on packaging without the backing of scientific evidence.

FTC chairman Jon Leibowitz said: "We expect more from a great American company than making dubious claims - not once, but twice - that its cereals improve children's health.

"Next time, Kellogg needs to stop and think twice about the claims it's making before rolling out a new ad campaign, so parents can make the best choices for their children."

The embarrassment follows a similar incident last year.

In 2009 Kellogg claimed Frosties Mini-Wheats were ‘clinically shown to improve kids' attentiveness by nearly 20 per cent'.

Following an FTC probe the firm was told to remove the statement and refrain from unsubstantiated claims.

The FTC added that the Rice Krispies tagline was introduced around the same time as it agreed to pull the Frosties ad.