This has been in the news recently. Scientists have noticed a problem with the caramel colouring agents used in Coca-Cola, Pepsi and other drinks. This stuff is made of sugar combined with certain chemicals, and contains an ingredient called methylimidazole-4. This is a carcinogen, and the levels may be high enough to cause harm although this hasn't been confirmed yet. But some bodies in the US are asking the Food and Drug Administration to look again at the status of caramel colouring, which is now classed as safe, or at least to be more specific about it when labelling drinks.

But even if this carcinogen does not turn out to be at dangerous levels, any health professional would tell you not to drink Coke and Pepsi, or only in very small quantities. The sugar content alone makes them very unhealthy and fattening drinks.

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