Alumina is a natural inert mineral like zinc and titanium. It is a constituent of many rocks and soils and is the third most abundant element on earth making up close to 8% of the earth’s crust. Alumina is naturally found in fruits and vegetables because plants absorb it from the soil. It is also naturally found in small amounts in ground water.
Alumina is rated as a safe “green light” ingredient by EWG skin deep. http://www.ewg.org/skindeep/ingredient/700309/ALUMINA/
Alumina actually scores better than zinc which is also rated safe. Alumina is approved by Ecocert, NSF and by USDA organic.
Alumina is used in food as coloring agent, anticaking agent, dough strengthener, leavening agent, etc. Alumina is also a homeopathic medicine used to treat dementia, fatigue and nervous disorders. It is also used in combination with potassium salt to make alum which is more commonly known as crystal rock deodorant. When used in sunscreens, it sits on top of the skin and can help other natural minerals such as zinc oxide and titanium dioxide to reflect harmful UV rays. It is also used as an absorbent in natural cosmetics to eliminate any greasy feel and to give products a dry feel.
Alumina is not the toxic aluminum as we know it in antiperspirants, cans, cookware, etc. Aluminum found in these products actually does not exist in nature. It is a synthetic element that is made by treating alumina with chemicals then positively charged by electrolysis (yiks!). That is why aluminum processing plants are located besides electricity plants. There are many different toxic aluminum compounds manufactured e.g., aluminium arsenate, aluminium borohydride, aluminium chlorohydrate, aluminum zirconium, etc… These are not alumina but rather man-made positively charged synthetic chemicals that are toxic to humans and has been linked to chronic kidney disease, Alzheimer, breast cancer, etc.