The phrase "nasty additives" refers to harmful substances or ingredients that are added to something, like food or products, and can be bad for your health. Full definition
No added value Eating wisely is not just a matter of consuming all the right nutrients — it's about avoiding nasty additives too. (womenshealthandfitness.com.au)
I have eaten a lot of protein bars in my day and, while delicious, a lot of them are loaded with sugar and other nasty additives. (pencilsandpancakes.com)
And they won't have a ton of nasty additives or «mystery» ingredients in them, plus they are dairy - free. (mommypotamus.com)