Preservatives
Related Terms
Antioxidant, coloring, dye, emulsifier, flavor, flavoring agent, food allergy, food intolerance, preservative, stabilizer, taste enhancer.
Background
Food additives are substances that preserve flavor or improve the taste of a product. These additives are classified as: dye or coloring agents, antioxidants, emulsifiers or stabilizers, flavoring or taste enhancers, or preservatives.
Food additives and preservatives have been used for thousands of years. For instance, it is believed that spices in curry seasonings were initially created to preserve the freshness of foods and conceal the taste of slightly spoiled foods. In industrialized nations, the last 50 years have seen a significant increase in the number of preservatives and additives introduced to foods before they go to market.
Today, there are over 14,000 man-made preservatives and additives added to consumables. In the United States, the U.S. Food and Drug Administration (FDA) must recognize these additives as GRAS, Generally Recognized as Safe, before any such agent is added to food products. These are listed under both their Chemical Abstract Services number and under the U.S. Code of Federal Regulations. Nearly every product in grocery stores contains some sort of additive or preservative. However, recent years have seen an increasing market demand for natural and organic products that include fewer or no additives.
It is believed by some that food additives or preservatives may cause symptoms of physical illness. While a few of these intolerances, such as monosodium glutamate (MSG) sensitivity, have a more well-known genetic or physiological basis, a majority are not acknowledged by the medical community.
Considerable controversy exists as to the cause and effect relationship between most food additives or preservatives and undesired medical symptoms. Though much information on intolerance for food additives and preservatives is anecdotal, many consumers believe that a correlation exists, and scientific evidence for adverse effects after the ingestion of some additives, such as MSG, exists.
Additional clinical research is needed in this area to help determine the potential correlation between food additives and preservatives and symptoms of illness.
Theory / Evidence
Most of the evidence supporting the existence of intolerance to most commonly used food additives is anecdotal. Food additive opponents suggest that chemicals on the FDA's GRAS list should be further evaluated for potential safety problems.
Large scale clinical trials have not been conducted to evaluate the validity of claims for most types of food intolerances.
A 2005 article by Wilson et al. summarized the literature of reported adverse reactions to food additives. The authors claimed that intolerance or allergy to food additives may be under reported because doctors do not usually suspect these agents as the possible cause of symptoms. A trial period of eliminating an additive from a patient's diet is recommended if such an agent is suspected of causing adverse reactions.
Author information
This information has been edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).
Bibliography
Bush RK, Taylor SL, Hefle SL. Adverse Reactions to Food and Drug Additives. In: Adkinson NF, Yunginger JW, Busse WW. Middleton's Allergy Principles and Practice. 6th edition. Philadelphia: Mosby Publishing; 2003:1645-1663.
U.S. Food and Drug Administration.
Wilson BG, Bahna SL. Adverse Reactions of Food Additives. Ann Allergy Asthma Immunol. 2005; 95:499-507.
Food additive allergy/intolerance
Generally, an intolerance to a food additive or preservative is suspected if a person consistently experiences symptoms of illness after eating certain foods, such as pre-packaged (prepared) foods or those found at a restaurant. The symptoms reported by individuals claiming to experience this type of intolerance vary significantly. However, the most common symptoms include abdominal pain, vomiting, diarrhea, headaches, facial flushing, weakness, breathing problems, and changes in heart rate.
While some of these reactions have been classified as allergic, a majority of them may actually be intolerances. That is, the body's immune system does not usually attack the offending additive or preservative as if it were a virus or bacteria that could cause illness. These symptoms are usually restricted to those that are similar to getting sick or having allergies to pollen or animal dander. Food intolerances are more difficult to classify because the way that they may cause feelings of illness and discomfort in the body is not well understood.
A diagnosis of allergy to food additives is suspected when a person experiences various reactions to prepared foods or when eating at restaurants, but not from foods prepared at home. Symptoms of intolerance to additives or preservatives may occur with seemingly unrelated foods, as they may contain the same additive, such as food colorings or preservatives. Once a food or food additive is suspected of causing physical symptoms, allergy testing may be possible.
In cases where a patient has a food allergy, a doctor may provide allergy testing to formally diagnose the patient. However, this testing is not available for food intolerances.
Testing for allergy to many types of synthetic allergies is not available. In addition, many people have additive intolerances, which differ from an allergy in that the immune system is not causing the symptoms to occur.
If a patient suspects that they are having a reaction to a food additive or preservative, they may eliminate that agent from the diet to see if symptoms resolve. Healthcare professionals may recommend this process of food exclusion in order to investigate the cause of symptoms.
Detecting food additives and preservatives requires the careful reading of food labels. Food additive opponents claim that eating organic food and cooking at home whenever possible will reduce a person's exposure to these agents.
There is a common misconception that all processed foods contain food additives. Some popular processed foods, such as long-life milk, canned foods, and frozen foods may not require additives. Patients who are eliminating a food additive from their diet usually learn about these products because they are acceptable during the period of elimination.
Some products may not list food additives on their packaging, even if additives are present. For instance, margarine might be a listed ingredient, and margarine usually contains food additives.
Individuals who eliminate food additives from their diet are encouraged to keep a food diary to record everything eaten and time and duration of symptoms. This log assists in identifying substances that may be causing physical symptoms.
If a food additive intolerance or allergy is identified, an individual may take steps to eliminate that agent from their diet.
Common food additives
Antioxidants:
Sodium metabisulphite: Sodium metabisulphite is used to preserve the freshness of foods. Anecdotal evidence has linked this substance to asthma and anaphylaxis.
Stannous chloride (tin): Stannous chloride (tin) is an antioxidant and color-retention agent used in canned and bottled foods and fruit juices. Acute poisoning has been reported from the ingestion of fruit juices containing concentrations of tin greater than 250 milligrams per liter.
Color-retention agents:
Stannous chloride (tin): Stannous chloride (tin) is an antioxidant and color-retention agent used in canned and bottled foods and fruit juices. Acute poisoning has been reported from the ingestion of fruit juices containing concentrations of tin greater than 250 milligrams per liter.
Flavorings:
Spices: Spices are the aromatic part of various weeds, flowers, roots, barks, and trees. Because they are derived from plants, spices have the ability to cause allergic reactions similar to pollens, fruits, and vegetables. Common spices include chili peppers, celery, caraway, cinnamon, coriander, garlic, mace, onion, paprika, parsley, and pepper.
Flavor enhancers:
Monosodium glutamate (MSG): MSG is a flavor enhancer that is naturally occurring in some foods, such as cheese. It is also added to many foods. Symptoms attributed to MSG include pressure on the head, seizures, chest pains, headache, nausea, burning sensations, and tightness of the face.
Food colorings:
Artificial colorings: Artificial colorings used in processed food products may not always be individually labeled. These agents are used to make food look more appealing. Those opposed to food additives claim that many food colorings may be toxic or carcinogenic.
Ponceau 4R, Conchineal Red A: People who suffer from asthma, rhinitis, or hives may find that their symptoms become worse following consumption of foods containing this coloring.
Saffron: This yellow food coloring, obtained from the flower of the Crocus sativa plant, has been reported as a potential cause of anaphylaxis. Many other food colorings are less common, but possible causes of adverse reactions. These include sunset yellow (yellow #6), amaranth (red #2), erythrosine (red #3), and quinoline yellow.
Preservatives:
Benzoates: Benzoates are preservatives in many foods including meat products, drinks, cereals, and low sugar products. The anecdotal symptoms associated with intolerance include hives and a runny, congested nose. More serious health problems associated with benzoates may include depleted levels of glycine and a decrease number of the enzymes necessary for digestion.
BHA & BHT: BHA and BHT prevent spoilage of fats and oils in packaged products. Some people claim that ingesting these chemicals results in hives and swelling under the skin. More seriously, some opponents of this preservative claim that it causes cancer.
Nitrite and nitrate: Sodium nitrite and sodium nitrate are two closely related chemicals used for centuries to preserve meat. These are thought to produce cancer-causing chemicals when heated and eaten. Less serious symptoms may include hives and itching.
Potassium nitrate: Potassium nitrate is a preservative used in cured meats and canned meat products. Potassium nitrate can lower the oxygen-carrying capacity of the blood; it may combine with other substances to form nitrosamines, which are known to be carcinogenic; and it may have an atrophying effect on the adrenal gland.
Propyl p-hydroxybenozoate, propylparaben, and paraben: Propyl p-hydroxybenozoate, propylparaben, and paraben are preservatives used in cereals, snacks, pate, meat products, and confectioneries. Anecdotal evidence suggests that parabens are the cause of chronic dermatitis in numerous cases.
Sodium metabisulphite: Sodium metabisulphite is used to preserve the freshness of foods. Anecdotal evidence has linked this substance to asthma and anaphylaxis.
Sodium sulphite: Sodium sulphite is a preservative used in wine and other processed foods. Sulphites have been associated with triggering asthma attacks. Most asthmatics are sensitive to sulphites in food.
Spices: Spices are derived from the aromatic parts of various weeds, flowers, seeds, roots, barks, and trees. Because they are derived from plants, spices have the ability to cause allergic reactions, similar to pollens, fruits, and vegetables. Common spices include chili peppers, celery, caraway, cinnamon, coriander, garlic, mace, onion, paprika, parsley, and pepper.
Sulphur dioxide: Sulphur dioxide reacts with a wide range of substances found in food, including various essential vitamins, minerals, enzymes, and essential fatty acids. Adverse reactions attributed to sulphur dioxide include bronchial problems particularly in those prone to asthma, hypotension (low blood pressure), flushing, tingling sensations, or anaphylactic shock.
Stabilizers:
Potassium bromate: Potassium bromate has long been used to increase the volume of bread and to produce bread with a fine crumb (the non-crust part of bread) structure. Most bromate rapidly breaks down to form innocuous bromide. However, bromate itself causes cancer in animals. The tiny amounts of bromate that may remain in bread may pose a small risk to consumers. Bromate has been banned in many countries, although it is still legal in Japan and the United States. It is rarely used in California because a cancer warning is required on product labels.
Sweeteners:
Aspartame: Aspartame is a sugar substitute that is present in many diet sodas and drinks. Some individuals with PKU (phenylketonuria) report that aspartame makes their symptoms worse. Some patients without PKU claim that the agent may cause seizures. Anecdotal reports indicate that there is a possibility of headaches, blindness, seizures, and mental retardation with high use for long periods of time. Shorter term effects noted by opponents of this sweetener include headaches, hives, and menstrual problems.
Saccharin & its Na, K and Ca salts: Saccharin is a sweetener used in diet and no-sugar products. Saccharin has shown carcinogenicity in laboratory animals. The International Agency for Research on Cancer has concluded that saccharin is possibly carcinogenic to humans. However, other major health organizations, such as the U.S. Food and Drug Administration (FDA), disagree with these claims.