After the last series, we received hundreds of emails from people telling us about things they were worried about, and food additives were top of the list. People wanted to know what additives are and what they could be doing to us.
What are additives?
All kinds of things can be legally added to our food. Most of them are given E numbers. These include things like preservatives and colourings. Flavourings are not given E numbers, but are still approved by the Food Standards Agency.
Richard Hammond, the presenter of Should I Worry About...?, tried to avoid all additives and found it extremely difficult. Additives are used in nearly all processed foods. Preservatives keep things from going off, while emulsifiers and stabilisers are used to stop dressings and sauces from separating out. Colourings and flavourings tend to be used to replace colours and flavours that can be lost when food is processed.
Many additives are things that occur naturally anyway. For example vitamin C has an E number. So does citric acid, which is found in lemon juice and is used as a preservative.
Anything which has been given an E number will have been tested for things like toxicity and links to cancer. If potential problems are found, the additive will be given a figure for Acceptable Daily Intake (ADI). This is the amount you could have every day over a lifetime without any ill effects.
But although food labels have to list additives, they donít have to say exactly how much is in the product. So itís very difficult to calculate if you are exceeding the ADI. We have to rely on the Food Standards Agency, who say they monitor the average diet, to ensure we donít regularly exceed the ADI for any additive.
Additives are not regularly tested for effects on behaviour. Some, such as sodium benzoate and tartrazine, have been associated with hyperactivity in children. However, the scientific evidence is inconclusive.
A new study, which will take two years to complete, is being launched by the FSA to try and determine if there could be behavioural effects from various colourings and the preservative sodium benzoate.
FSA information about food additives research projects
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An additive-free diet
We asked one family to go completely additive-free for six weeks to see if there were any noticable changes. The results were dramatic.
At the beginning of the six weeks, everyone in the family had levels of vitamin C in their blood well below the recommended levels. Most of them had zinc levels right at the bottom of what is considered healthy.
At the end of the six weeks, their levels of zinc and vitamin C had all risen, some by as much as four times. The whole familyís nutritional status had improved, and six-year-old Adam seemed to be suffering from fewer colds and sleeping better.
But was it the additives in their diet that affected the familyís nutritional status? Probably not. The key lies in what they ate instead. Nutritionist Amanda Hamilton thinks itís quite simple. Before they started the diet they were snacking on biscuits and chocolates Ė all of which contained additives. On the diet, they replaced all of this junk food with fresh fruit and vegetables. Itís no surprise that their nutritional status improved.
Homemade vs ready-made
Richard decided to compare the nutrients in his homemade cottage pie with the ready-made equivalent. We sent average ready-made cottage pies from each of Britainís four biggest supermarkets and Richardís homemade pie to a lab for testing.
The results were clear. The homemade version came top, with the highest levels of protein, iron and zinc.
Many ready-made meals contain additives such as modified maize starch. This is not bad for you but it is essentially used to bulk out food and has little nutritional value. Ready-made products also tend to contain different proportions of key ingredients than homemade products. For example, Richard was shown a chicken, chorizo and potato bake that contained only about 20% chicken and nearly 50% potato. If you made the same dish at home, you would almost certainly include more chicken.
The key is to know how to read labels. If you think a ready meal doesnít contain enough of the key healthy ingredients, and instead has lots of ingredients you wouldnít normally find in your kitchen, then why not make your own instead?
Be a sceptical sleuth
If youíre looking for advice on additives on the web, be extra careful of whose advice you take. Lots of sites donít contain any indication of where they got their information from, and lots of sites are very alarmist. Wild rumours are everywhere, so think about the source of the reports and how reliable you think they are.
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