The Truth About 7 Common Food Additives

Reviewed by Kathleen M. Zelman, MPH, RD, LD on December 17, 2008
From the WebMD Archives

If, like many Americans, you stock your pantry with processed foods, you may worry about how safe food additives really are.

Over the years, the safety of many food additives, from food dyes to trans fats, has come into question. A scare over a food additive may linger in our minds long after researchers find that there's actually no cause for alarm. It can take years, or even decades, to find out the truth, and sometimes the case is never really closed.

To help you figure out what’s safe, WebMD took a look at the latest research on seven of the most controversial food additives. Here’s what we found:

1. Artificial coloring

What it is

Artificial food colors are chemical dyes used to color food and drinks.

Foods that have it

Many types of processed foods, beverages, and condiments have artificial coloring in them.

Why it's controversial

Artificial food color is suspected of causing increased hyperactivity in children. Also, the dye Yellow No. 5 has been thought to worsen asthma symptoms. (In the 1970s, the FDA famously banned Red Dye No. 2 after some studies found that large doses could cause cancer in rats.)

What the research shows

In 2007, a British study published in The Lancet concluded that consuming artificial coloring and preservatives in food can increase hyperactivity in kids. Scientists have been studying the link between food additives and hyperactivity in children for more than 30 years, with mixed results. But the results of the 2007 study compelled the European Food Standards Agency to urge companies to voluntarily remove artificial coloring from food products. The FDA, however, hasn't changed its opinion on the use of FDA-approved artificial food colors, which it considers safe when used properly.

Reports suggesting that the food color Yellow No. 5 might aggravate some people's asthma symptoms date back to the 1950s. But in most controlled studies, Yellow No. 5 has not been shown to have a significant impact on asthma, according to a review of all known studies, which is updated every year.

How you find it on the label

The following artificial colors are approved for use in food products and must be listed as ingredients on labels:

  • FD&C Blue No. 1 (brilliant blue FCF)
  • FD&C Blue No. 2 (indigotine)
  • FD&C Green No. 3 (fast green FCF)
  • FD&C Red No. 40 (allura red AC)
  • FD&C Red No. 3 (erythrosine)
  • FD&C Yellow No. 5 (tartrazine)
  • FD&C Yellow No. 6 (sunset yellow)
  • Orange B (restricted to use in hot dog and sausage casings)

2. High-fructose corn syrup

What it is

High-fructose corn syrup is a sweetener made from corn. It's sweeter and cheaper than sucrose, which is the form of sugar made from sugar cane.

Foods that have it

High-fructose corn syrup is a common additive in many kinds of processed foods, not just sweets. Most non-diet soft drinks are sweetened with high-fructose corn syrup.

Why it's controversial

Some experts have proposed that people metabolize high-fructose corn syrup in a way that raises the risk of obesity and type 2 diabetes more than sugar made from sugar cane. Much of the controversy stems from the observation that obesity in the United States and consumption of high-fructose corn syrup increased at the same time.

What the research shows

"It's just sugar," says Marion Nestle, PhD, a professor of nutrition and public health at New York University. "Biochemically, there's no difference."

The high-fructose corn syrups commonly used to sweeten foods and drinks are 55-58% fructose and 42-45% glucose. Sucrose (cane sugar) is a double sugar made of fructose and glucose. Digestion quickly breaks down cane sugar and high-fructose corn syrup into fructose and glucose.

"There's a little bit more fructose in high-fructose corn syrup, but not a lot," Nestle says. "It doesn't really make any difference. The body can't tell them apart."

The American Medical Association(AMA)  recently stated that there is scant evidence to support the idea that high-fructose corn syrup is any worse than cane sugar. The AMA days eating too much sugar of either kind is unhealthy.

How you find it on the label

High-fructose corn syrup can be found in the list of ingredients on a food label.

3. Aspartame

What it is

Aspartame is an artificial sweetener known by various brand names, including Equal and NutraSweet.

Foods that have it

Aspartame is a commonly used additive for sweetening diet soft drinks.

Why it's controversial

Various health concerns have been raised about aspartame since it was introduced in 1981. Most recently, it has been suspected of causing cancer. There have been reports of aspartame causing seizures, headaches, mood disturbances, and reduced mental performance. A study published in 2005 suggested that aspartame could cause leukemia and lymphoma in rats. Another study, published in 1996, argued that an increase in the rate of brain tumors in the United States could be related to consumption of aspartame.

What the research shows

Dozens of studies in people and animals have tested for effects possibly related to aspartame. The majority of these studies show that things such as headaches, seizures, and mental and emotional problems didn't occur with aspartame more often than with placebo, even at doses many times higher than anyone would likely ever consume. Large epidemiological studies haven't found a link between aspartame and cancer. A study of about 500,000 people, sponsored by the National Cancer Institute, compared those who drank beverages containing aspartame with those who didn't. It found that people who drank increasing amounts of beverages containing aspartame did not have a greater risk for lymphomas, leukemias, or brain cancer. Another study looked at data from a large survey done by the National Institutes of Health. The survey included detailed information on 1,888 cases of leukemia or lymphomas and 315 cases of brain cancer. The researchers found no link between aspartame consumption and those cancers.

"For more than three decades, research has found aspartame to be safe, and today it is approved for use in more than 100 countries," says Robert E. Brackett, PhD, spokesman for the Grocery Manufacturers Association, a lobbying organization in Washington, D.C. "In fact, the U.S. Food and Drug Administration has confirmed the safety of aspartame 26 times over a period of 23 years, with the most recent confirmation in April 2007."

How to find it on the label

Look for aspartame in the list of ingredients.

4. Monosodium glutamate (MSG)

MSG by itself looks like salt or sugar crystals. It is a form of the naturally occurring chemical glutamate. Glutamate doesn't have a flavor of its own, but it enhances other flavors and imparts a savory taste. Tomatoes, soybeans, and seaweed are examples of foods that have a lot of glutamate naturally. Some scientists say that glutamate, also known as "umami," is the fifth essential flavor that the human palate can detect, in addition to sweet, salty, bitter, and sour.

Foods that have it

MSG is an additive used in many foods.

Why it's controversial

Many people claim to have bad reactions when they eat food seasoned with MSG. In the late 1960s, people started talking about "Chinese restaurant syndrome," alleging that food prepared with MSG at Chinese restaurants made them sick.

What the research shows

Many studies over the past four decades have tested the idea that some people may be sensitive to MSG. Most scientists today agree that if there is such a thing as a sensitivity or allergy to MSG, it's extremely rare. Studies haven't found any regular pattern of symptoms that could be typical of a reaction to MSG. Also, people are more likely to have symptoms if they're given MSG crystals than if they eat the same amount of MSG mixed with food.

"It's very hard for me to believe that there's a problem with it," Nestle says. Nevertheless, some still swear that they have bad reactions to MSG. "People who think they have problems with it should avoid it," she says.

How you find it on the label

Some food labels come right out and say that a product contains added MSG. But there are other ingredients that may contain MSG such as "hydrolyzed soy protein" and "autolyzed yeast."

5. Sodium benzoate

What it is

Sodium benzoate is a food additive used as a preservative.

Foods that have it

Sodium benzoate is used in a variety of processed food products and drinks.

Why it's controversial

It's suspected that sodium benzoate, in addition to artificial food color, may increase hyperactivity in some children. Sodium benzoate in soft drinks may also react with added vitamin C to make benzene, a cancer-causing substance.

What the research shows

The 2007 Lancet study that linked additives with increased hyperactivity included the preservative sodium benzoate.

In 2006 and 2007, the FDA tested a sample of almost 200 beverages from stores in different states that contained sodium benzoate and vitamin C. Four of the beverages had benzene levels that were above federal safety standards. The drinks were then reformulated by manufacturers and later deemed safe by the FDA. The agency points out, however, that the tests were limited and that it's still not known how much benzene consumers could be exposed to from beverages.

How you find it on the label

Sodium benzoate is listed among the ingredients on a product label.

6. Sodium nitrite

Sodium nitrite is an additive used for curing meat.

Foods that have it

Sodium nitrite is usually found in preserved meat products, like sausages and canned meats.

Why it's controversial

There is a theory that eating a lot of sodium nitrite might cause gastric cancer.

What the research shows

There is evidence that sodium nitrite could have been to blame for a lot of the gastric cancers that people had in the past. Until the early 1930s, gastric cancer caused the most deaths of all cancers in the United States. After that, more Americans began to use modern refrigeration and ate less cured meat. Also, producers started to use much less sodium nitrite in the curing process around that time. As these changes took place, deaths from gastric cancer also dropped dramatically.

This theory has been debated for decades, and it is still an open question.

How you find it on the label

Sodium nitrite will be listed as an ingredient on the labels of food products.

7. Trans fat

What it is

Trans fats are created when manufacturers add hydrogen to vegetable oil. Trans fats are food additives in the sense that they're mainly added to the food supply by manufacturing processes, although small amounts of trans fats are present naturally in animal fat.

Foods that have it

These "partially hydrogenated oils" are used most often for deep-frying food, and in baked goods. Margarine and vegetable shortening may also be made with partially hydrogenated oil.

Why it's controversial

Trans fats are believed to increase the risk of heart disease and type 2 diabetes.

What the research shows

Most scientists now agree that eating trans fats can be very harmful to health. Trans fats have been found to lower people's HDL (good) cholesterol and raise LDL (bad) cholesterol. The American Heart Association recommends getting less than 1% of your daily calories from trans fats.

How you find it on the label

Product labels are now required to list the amount of trans fat in a serving. Partially hydrogenated oil may also be listed as an ingredient.

But many fried foods and baked goods that are laden with trans fats are served in restaurants, and they don't come with nutrition labels. To avoid trans fats, it's best to limit your overall daily fat intake.

"Usually, when you increase the total amount of fat you consume, you increase the amount of trans fat as well," says Benjamin Caballero, MD, a professor at the Center for Human Nutrition at the Johns Hopkins Bloomberg School of Public Health. If you reduce your total fat intake from 13% of your daily calories (which he says is typical for Americans) to less than 10% (which is recommended), you probably won't exceed the limit on trans fat.

"There are so many controversial studies about ingredients that are a little more emotionally mediated by one study showing it harmful and another study showing it not harmful, and then people say, ‘What am I to do?’”

"You're going to get more nutrient bang for your buck to eat less refined foods when you can," says Christine Gerbstadt, MD, RD, a spokeswoman for the American Dietetic Association.

Show Sources


Marion Nestle, PhD, MPH, Paulette Goddard Professor of Nutrition, Food Studies, and Public Health, New York University.

Robert E. Brackett, PhD, senior vice president, chief science and regulatory affairs officer, Grocery Manufacturers Association.

Benjamin Caballero, MD, PhD, professor, Center for Human Nutrition, Bloomberg School of Public Health, Johns Hopkins University.

McCann, D.,  Lancet, November 2007; vol 370: pp 1560-1567.

European Food Standards Agency.


Ram, F. Cochrane Database of Systematic Reviews, 2001, Issue 4.

Bray, G., American Journal of Clinical Nutrition, 2004; vol 79: pp 537-543.

National Cancer Institute.

Butchko, H. Regulatory Toxicology and Pharmacology, November 2001; vol 34: pp 221–233.

Magnuson, B. Critical Reviews in Toxicology, September 2007; vol 37: pp 629 - 727.

Chandrashekar, J. Nature, November 2006; vol 444: pp 288-294.

Wilson, B. Annals of Allergy, Asthma & Immunology, December 2005; vol 95: pp 499-507.

Paik, D. International Journal of Epidemiology, 2001; vol 30: pp 181-182.

American Heart Association.


Grocery Manufacturers Association.

Christine Gerbstadt, MD, RD, spokeswoman, American Dietetic Association.

© 2008 WebMD, LLC. All rights reserved. View privacy policy and trust info