It's not just diacetyl, acetoin, et al, but there is also cause for concern over colorings (I listed source and details below). As a recent vapor, I can definitely feel an improvement over when I was smoking. A substantial improvement. So my body is telling me that vaping is better than smoking. I am certain that not vaping at all would be better for me than vaping, but I like the act of smoking, so I choose what my body perceives as a safer alternative.
On that same thinking I moved to DIY, because I didn't know what was in the mixes I bought. At least with DIY, I know, to an extent. Yet I still want more knowledge and more control. I know long term VG/PG alone is an unknown, but immediate results give me a feeling of drastic improvement in many ways over cigs...and long term cig use, I know those results. So I vape instead. Yet, I still want my vaping to be as safe as possible. I want to know what is in what I vape. I was a little shocked to see the listing showing daicetyl may be in so many flavors, I was working at avoiding it as much as possible for my own personal piece of mind. I am with what appears to be most people in that much more testing and disclosure is needed to help me make an informed choice for myself.
SRC:
Food Additives and colors
Tartrazine - Yellow 5 - known to provoke asthma attacks (though the US FDA** do not recognize this) and urticaria (nettle rash) in children (the US FDA** estimates 1:10 000); also linked to thyroid tumors, chromosomal damage, urticaria (hives) and hyperactivity; tartrazine sensitivity is also linked to aspirin sensitivity; used to color drinks, sweets, jams, cereals, snack foods, canned fish, packaged soups; banned in Norway and Austria
Quinoline Yellow - FD&C Yellow No.10; used in lipsticks hair products, colognes; also in a wide range of medications; cause dermatitis; banned in Australia, USA and Norway
Yellow 7G - yellow color; the HACSG* recommends to avoid it; people who suffer Asthma may also show an allergic reaction to it; typical products are soft drinks; banned in Australia and USA
Sunset Yellow FCF, Orange Yellow S - FD&C Yellow No.6; used in cereals, bakery, sweets, snack foods, ice cream, drinks and canned fish; synthetic; also in many medications including Berocca, Polaramine, Ventolin syrup; side effects are urticaria (hives), rhinitis (runny nose), nasal congestion, allergies, hyperactivity, kidney tumors, chromosomal damage, abdominal pain, nausea and vomiting, indigestion, distaste for food; seen increased incidence of tumors in animals; banned in Norway
Cochineal, Carminic acid, Carmines - red color; made from insects; rarely used; the HASCG* recommends to avoid it
Azorubine, Carmoisine - red color; coal tar derivative; can produce bad reactions in asthmatics and people allergic to aspirin; typical products are confectionary, marzipan, jelly crystals; banned in Sweden, USA, Austria and Norway
Amaranth - FD&C Red No.2; derived from the small herbaceous plant of the same name; used in cake mixes, fruit-flavoured fillings, jelly crystals; can provoke asthma, eczema and hyperactivity; it caused birth defects and foetal deaths in some animal tests, possibly also cancer; banned in the USA, Russia, Austria and Norway and other countries
Ponceau 4R, Cochineal Red A - FD&C Red No.4; synthetic coal tar and azo dye, carcinogen in animals, can produce bad reactions in asthmatics and people allergic to aspirin; banned in USA & Norway
Erythrosine - FD&C Red No.3; red color used in cherries, canned fruit, custard mix, sweets, bakery, snack foods; can cause sensitivity to light; can increase thyroid hormone levels and lead to hyperthyroidism, was shown to cause thyroid cancer in rats in a study in 1990; banned in January 1990, but not recalled by the US FDA**; banned in Norway
Red 2G - banned in Australia and many other places except UK
Allura red AC - FD&C Red No.40; Orange-red color used in sweets, drinks and condiments, medications and cosmetics, synthetic; introduced in the early eighties to replace amaranth which was considered not safe due to conflicting test results; allura red has also been connected with cancer in mice; banned in Denmark, Belgium, France, Germany, Switzerland, Sweden, Austria and Norway
Patent blue V - banned in Australia, USA and Norway
Indigotine, Indigo carmine - FD&C Blue No.2, commonly added to tablets and capsules; also used in ice cream, sweets, baked goods, confectionary, biscuits, synthetic coal tar derivative; may cause nausea, vomiting, high blood pressure, skin rashes, breathing problems and other allergic reactions. banned in Norway
Brilliant blue FCF - FD&C Blue Dye No.1; used in dairy products, sweets and drinks, synthetic usually occurring as aluminum lake (solution) or ammonium salt; banned in Belgium, France, Germany, Switzerland, Sweden, Austria, Norway
Green S - green color; synthetic coal tar derivative; used in canned peas, mint jelly and sauce, packet bread crumbs and cake mixes; banned inSweden, USA and Norway
Plain caramel (Caustic sulphite caramel, Ammonia caramel, Sulphite ammonia caramel) - dark brown color made from sucrose; the HACSG* recommends to avoid it. used in oyster, soy, fruit and canned sauces, beer, whiskey, biscuits, pickles
Brilliant Black BN, Black PN - coloor; coal tar derivative; used in brown sauces, blackcurrant cake mixes; banned in Denmark, Australia, Belgium, France, Germany, Switzerland, Sweden, Austria, USA, Norway
Vegetable carbon - black colour, charcoal pigment; used in jams, jelly crystals, liquorice; only the vegetable derived variety permitted in Australia, banned in the United States
Brown FK - banned in USA
Brown HT (Chocolate) - brown color, coal tar and azo dye; used in chocolate cake mixes; can produce bad reactions in asthmatics and people allergic to aspirin; also known to induce skin sensitivity; banned in Denmark, Belgium, France, Germany, Switzerland, Sweden, Austria, USA, Norway
Annatto (Arnatto, Annato), bixin, norbixin - red color; derived from a tree (Bixa orellana); used as a body paint, fabric dye, digestive aid and expectorant; used to dye cheese, butter, margarine, cereals, snack foods, soaps, textiles and varnishes; known to cause urticaria (nettle rash), the HACSG* recommends to avoid it
Paprika extract, capsanthin, capsorubin - avoid it, banned in some countries
* Hyperactive Children Support Group (HACSG)