Food additives have played a key role in food preparation since humans learned that today's kill might make us sick after a few days if we don't take special measures.

Cooking meat, for instance, causes chemical reactions that allow the meat to be edible for a while. Curing it with salt extends its useful life even longer. Using salt-based brines allowed great-great-grandma to turn vegetables into pickles for her family to eat in the winter.

But — until relatively recently — most food additives were derived from natural sources, like parts of plants or minerals. Now many food additives are the result of chemical reactions.

According to Health Canada, a food additive is "any chemical substance that is added to food during preparation or storage and either becomes a part of the food or affects its characteristics for the purpose of achieving a particular technical effect."

They're usually used to increase shelf life, sweeten food without adding calories, keep powders free-running, or to enhance the colour of a product. They play a key role in Canada's food processing industry, estimated to be worth more than $43 billion US in 2001.

Who regulates what can and cannot be added to food in Canada?

The regulations are spelled out in Food and Drug Regulations. Anything that a food processor is allowed to add to a food product is listed in the tables under Division 16 of the regulations. A complete list is also available here.

If a food processor wants to add something that's not listed under the regulations, the processor must submit an application that is reviewed by scientists from Health Canada's food directorate, health products and food branch.

How do I know if something I buy includes food additives?

Read the label. If there are additives, they must be listed under ingredients.

Are substances added to food that are not considered additives?

Yes. Under the Food and Drug Regulations, the following are not considered to be additives:

• Food ingredients such as salt, sugar and starch.
• Vitamins, minerals and amino acids.
• Spices, seasonings and flavouring preparations.
• Agricultural chemicals.
• Veterinary drugs.
• Food packaging materials.

Are there health risks to food additives?

Depends who you ask. Health Canada says all food additives go through a rigorous process before they are approved. However, some additives that are permitted in Canada have been banned in other countries. And some additives have been linked to cancer and other conditions. For instance, Red Dye No. 3 — which is sometimes added to ice cream, jams, pickles, liqueurs, ketchup and smoked fish — was banned by the U.S. Food and Drug Administration in 1990 after studies linked it to cancer in animals. It is still permitted in Canada.

Are there any other concerns with food additives?

Some studies have linked some food additives to hyperactivity in children. A recent British study found that children without a history of any hyperactive disorder showed varying degrees of hyperactivity after consuming fruit drinks with various levels of additives. Those additives included:

• Sodium benzoate, a preservative used to extend the shelf life of food and drinks. It's common in pickles and sauces.
• Tartrazine, a yellow food dye used in ice cream, soft drinks and fish sticks. It is a sodium salt and contains more salt than the human body can handle. Besides hyperactivity, research has linked it to asthma, skin rashes, and migraines. This product is banned in Norway and Austria.
• Quinoline yellow, a yellow dye used in soft drinks, cosmetics and medications. This additive is banned in Australia, Japan, Norway and the United States.
• Sunset yellow, a dye used in yogurts and sweets. This product is banned in Norway and Finland.
• Carmoisine, a coal tar derivative used in sweets and yogurts. It has been banned by Canada, Japan, Norway, Sweden and the United States.
• Allura red, a dye used in soft drinks and bubble gum. This additive was introduced in the early 1980s to replace Amaranth, a dye that was banned by the U.S. Food and Drug Administration and is only allowed in France and Italy in the production of caviar. Allura red is banned in Denmark, Belgium, France, Germany, Switzerland, Sweden, Austria and Norway.

Why was melamine added to baby formula and pet food?

In September 2008, nearly 53,000 infants in China fell ill after melamine - a crystalline compound - was put in baby formula and milk products. Health authorities around the globe initiated a range of recalls for products ranging from coffee mix to candies to chocolates for fear that they too were contaminated with melamine. Authorities suggest melamine was used to mask low nutrient levels in watered-down milk.

The same compound was found in pet food sold in North America in 2007. U.S. Food and Drug Administration officials speculated melamine was added to Chinese wheat gluten and rice protein used for pet food because it falsely appeared to raise the protein content of the ingredients.

What are some of the other food additives that have raised concerns?

Some people report a sensitivity to monosodium glutamate. Some MSG-intolerant people can develop MSG symptom complex, which is characterized by one of more of the following:

• A burning sensation in the back of the neck, forearms and chest.
• A numbness in the back of the neck, radiating to the arms and back.
• A tingling, warmth and weakness in the face, temples, upper back, neck and arms.
• Facial pressure or tightness.
• Chest pain.
• Headache.
• Nausea.
• A rapid heartbeat.
• Bronchospasm (difficulty breathing) in MSG-intolerant people with asthma.
• Drowsiness.

(Source: U.S. Food and Drug Administration)

But for the vast majority of people, MSG has not been determined to be a risk.

Sulphites are also used to maintain food colour, prolong shelf life, prevent the growth of micro-organisms, and maintain the potency of certain medications. They are also one of the nine most common food products that cause severe allergic reactions.

U.S. doctors raised concerns in 2007 about the use of diacetyl, an additive used in some microwave popcorns. Doctors said a U.S. man developed life-threatening lymphocytic bronchiolitis, sometimes referred to as "popcorn lung," after eating several bags of microwave popcorn daily over the course of a number of years. ConAgra Foods, General Mills and Weaver Popcorn Company have all announced they no longer used diacetyl in their products.

High-fructose corn syrup has also come under scrutiny in recent months, spurring the Corn Refiners Association to launch a campaign defending the safety of the preservative. The sweetener, used in a wide rage of beverages and processed foods, has been linked in animal studies to diabetes and high cholesterol. At a 2007 American Chemical Society conference, U.S. researchers suggested soft drinks containing HFCS may be linked to the development of diabetes, especially in children.

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