16 Food Additives You Shouldn't Eat

UPDATE: Because of a convincing argument made by Chris Kresser, I've removed nitrates/nitrites from this list.

For thousands of years, humans have used spices to preserve and taste-enhance food. These spices were so important that wars were fought over them. Then, a couple hundred years ago, the newly created chemical industry started developing natural and synthetic preservatives, nutrients, and taste enhancers for the processed food industry. By the mid-20th century, thousands of chemicals were being developed for use in foods. These chemical additives improved the taste and appearance of overly-processed food, as well as allowed food to sit in storage and on store shelves for months without spoiling. (1,2)

While several of these chemical additives have never been shown to be harmful, and a few have recently been officially exonerated of any wrong doing (e.g., saccharin), the truth is that most of these chemicals have never been studied for their long-term safety in humans. Even fewer studies have been conducted on the negative synergistic effects of consuming several seemingly benign chemicals together (which is normal in most industrially-processed foods). This means that if you eat a lot of modern processed foods (e.g., microwavable meals, meal bars, bread), you are participating in a live chemical additive safety experiment (whether you want to or not). (2)

Of the hundreds of chemicals that are typically added to the foods you eat, I have listed 16 that you should completely avoid consuming. There isn't always absolute proof that some of these non-essential additives are harmful, but there is enough circumstantial or anecdotal evidence to warrant their avoidance.

1. Artificial Sweeteners
Synthetic chemicals that are designed to provide sweetness without any added calories. Includes:

• Acesulfame K. Also known as Ace K, Sunett, Sweet One. May cause cancer in animals; no sufficient evidence that this additive causes cancer in humans. (3)
• Aspartame. Also known as NutraSweet, Tropicana Slim, Equal. Comprised of highly toxic methanol, which breaks down into formaldehyde in the body. Users have reported headaches, hallucinations, seizures, insomnia, and dizziness (and this is just the short list). (4) Recently, researchers found that for diabetic mice, aspartame caused a rise in blood sugar. (5) And finally, aspartame has been linked to obesity. (6)
• Neotame. Similar to aspartame. About 7,000-13,000 times sweeter than sugar. There are no long-term studies available (that I'm aware of) that indicate that this new sweetener is safe or harmful to consume. (7)
• Saccharin. About 300 times sweeter than sugar. Can cause cancer in animals. While saccharin has not been shown to cause cancer in humans, (6) it can cause allergic reactions to those sensitive to sulfonamides. (8)
• Sucralose. Also known as Splenda. Although more than 100 short-term studies have shown this sweetener to be safe at a daily intake of less than 5 mg per kilogram, there have been no long-term studies showing it to be either safe or harmful in humans. Some studies have found that sacralose negatively affects the gut in mice (damages DNA and harms good bacteria). (9)

2. Artificial Colorings
Produced from coal tar and petroleum. (10) May cause hyperactivity and ADD in children. (11) Artificial colorings can also cause allergic reactions in sensitive individuals, as well as DNA damage. (12,13,14) Completely avoid the following artificial colors:

• FD&C Blue No. 1 (15)
• FD&C Blue No. 2 (16)
• FD&C Green No. 3 (17)
• FD&C Red No. 3 (18)
• FD&C Red No. 40 (19)
• FD&C Yellow No. 5 (20)
• FD&C Yellow No. 6 (21)
• Orange B (22)
• Citrus Red No.2 (23)

3. Artificial or Natural Flavors
Both are created by man; natural flavors are removed from natural sources, artificial flavors derive the same chemicals by rearranging molecules. Both natural and artificial flavors are used to make unappetizing, highly-processed foods taste good. (2)

4. Butylated Hydroxyanisole (BHA)
Antioxidant. May be an estrogen mimicker. (24,25) Causes cancer in animals; no sufficient evidence that this additive causes cancer in humans, although California has it listed as a known carcinogen. (26)

5. Butylated Hydroxytoluene (BHT)
Antioxidant. High levels have lead to kidney failure, enlarged livers, and damaged DNA in animals. (27,28)

6. Gluten
Dough conditioner, stabilizer, texturizer, thickener. Can be deadly to those who are sensitive to gluten (e.g., celiac disease, gluten intolerance). (29,30)

7. Hydrolyzed Vegetable Protein
Flavor enhancer. Also known as hydrolyzed wheat protein. Source of monosodium glutamate (MSG). May cause reactions to those who are sensitive to gluten, wheat, soy, or milk. May also cause brain damage (via the excitotoxin MSG). (31,32)

8. Monosodium Glutamate (MSG)
Flavor enhancer. Imparts meat or savory flavor (also known as umami). Known excitotoxin. Those sensitive to MSG can experience headaches, moodiness, and nausea. May also cause brain damage. (33)

9. Refined Fructose Sweeteners
Refined fructose sweeteners contain some percentage of the sugar fructose. While fructose is not harmful when consumed in its natural environment (fruit), it can become toxic when refined fructose sweeteners are consumed in excess of 50 grams per day. Once refined, the fructose portion of the sweetener is sent to the liver to be converted into glycogen or fat. If too much fructose moves into the liver at one time, it can cause a stress response. Fructose is also highly reactive with proteins and lipids, causing AGE formation, and may stimulate overeating. (34,35)

• Agave Nectar. Produced from cactus. 50-90% fructose (depending on source) as a disaccharide. (36)
• High-Fructose Corn Syrup (also corn syrup). Chemically produced from corn. 55% fructose as a monosaccharide. (37)
• Table sugar. Produced from sugar cane or sugar beets. 50% fructose as a disaccharide. (38)

10. Partially Hydrogenated Oils
Fat ingredient, preservative. The hydrogenation process normally used to transform liquid fats (polyunsaturated) into solid fats. Produces unnaturally straight man-made trans fats. Hydrogenated oils have been linked to an increased rate of heart disease, cancer, infertility, and unwanted weight gain. (39)

11. Potassium Bromate
Dough conditioner. Also known as bromated flour. Studies have shown that potassium bromate causes cancer in animals and humans. (40)

12. Sodium Benzoate
Preservative. Also known as benzoic acid. Linked to cancer and hyperactivity in children. Many other side effects also reported. (41,42)

13. Sodium Silicoaluminate
Anti-caking agent. Also known as sodium aluminosilicate, aluminum sodium salt, aluminosilicic acid, aluminum sodium silicate. This compound contains aluminum. Aluminum consumption has been linked to Alzheimer's Disease. (43)

14. Vitamin and Mineral Enrichment
Nutrient. Essential nutrients--that are often synthetic--used to "enrich" a highly-processed food that has lost many of its natural nutrients due to aggressive or careless processing. Can cause health problems not associated with naturally-occurring essential nutrients. Synthetic vitamins are also not as biologically active as natural ones. Avoid consuming foods that have been enriched with these nutrients:

• Synthetic Vitamin D. Known as vitamin D2 or ergocalciferol. Not an effective form of vitamin D (vitamin D3 is activated 500 times faster in the human body than D2). (44)
• Synthetic Vitamin E . Known as alpha tocopheral acetate, tocopheryl acetate, dl-alpha tocopheral, succinate. Has higher toxicity than natural vitamin E. Excess intake associated with health risks. (45)
• Folic Acid. Known as pteroylglutamic acid. Has higher toxicity than natural vitamin (niacin). Excess intake associated with health risks. (46)
• Calcium. While calcium found naturally in food is not toxic to humans, calcium supplementation (either taken as a supplement or added to processed foods) is associated with increased risk of developing heart disease and cancer. Intake must be balanced with sufficient daily intake of vitamins D3 and K2. (47)
• Iron. Iron supplements may be helpful for those suffering from anemia, but can be toxic to those with normal or high blood levels of iron (causes excess oxidative stress). Excess blood iron levels associated with increased heart disease risk. (48,49) 
• Omega-3 Fatty Acid. Delicate essential polyunsaturated fatty acid. Can become rancid when exposed to aggressive or careless processing. Excessive omega-3 intake can become toxic to the liver when combined with excessive sugar or alcohol intake. Small amounts of omega-3 (about 1.5 grams per day) should come from fresh food or high-quality, minimally-processed supplements. (50)

15. Sulfites
Antioxidant, antimicrobial dough conditioner, preservative. Includes potassium bisulfite, potassium metabisulfite, sodium metabisulfite, sodium sulfite, sulfur dioxide, sodium bisulfite. Can cause severe allergic reactions, especially to those with asthma. Can also cause migraines, hives, itching, and breathing problems. (51,52)

16. THBQ
Antioxidant, preservative. Has been shown to cause cancer in animals. (53)