SUGAR:
Most of us do not think of sugar as a food additive, but it meets the exact definition; a substance intentionally added to food to affect it's characteristics, i.e., flavor. Sugar and its derivatives, corn syrup corn sweeteners and high fructose are the most widely added substances to our food. Sugar is at the root of type 2 diabetes, metabolic syndrome and obesity.

Sugar increases the caloric density of foods to very high levels and is so widely prevelant as an addtive that it is the single substance added to our food responsible for the widest and most pervasive range of health issues

HYDROGENATED OILS
Every 1% of your diet that is comprised of hydrogenated oils increases your LDL profile by .032. Oil hydrogenation was first developed by Proctor and Gamble as a technique for enhancing the shelf life of processed food. Hydrogenated oils interfere with insulin signaling, promote cardiovascular disease and damage your body at a cellular level. These types of manufactured fats are still widely distrubted in most processed food, even in todays era of 'no trans fats'. Worse, hydrogenated oils are most often present in foods with excess sugar.

SODIUM
As a food additive, sodium makes this list because of it's ever present ubiquity. Sodium is added to virtually everything processed. Excess sodium is now directly correlated with elevated free fatty acids in the blood stream which interferes with Leptin signaling and drives feeding behavior. Excess sodium is also correlated with increased blood pressure, cardiovascular disease, kidney problems and elevated risk of having a stroke.

COLORINGS
Food colorings are another additive widely present in processed foods. Research shows that the current seven food colorings permitted by the FDA, particularly Tartrazine (Red no 3) can impair mitochondrial function, cause edema in the heart, asthma, rashes, and hyperactivity in children. Colorings are high in Maillard reactive products, which are oxidative reactions that in the case of colorings impair protein digestion.

NITRITES AND SULPHATES
Both of these additives are so widely prevalent that it's difficult to choose which has the greater negative impact. Glutamates that convert to glutamic acid are excitotoxins. The most well known is MSG. There are others, much less widely known or understood. Hydrolyzed protein is a good example. Excess excitotoxins damage the blood brain barrier.

Sulphites are widely used as preservatives in meats. Sulphites can cause severe allergic reactions, even fatalities in about 1% of the population. People with asthma are particularly vulnerable to sulphites. Reactions can range from dermatitis to stomach disorders.