Onion traces have been found in Bronze Age settlements, dating back to 5000 BC.
The first traces of onions found in connection with people are believed to be traces of wild onions. The oldest evidence of onions has been cultivated dates back to ancient Egypt about 3000 BC. The workers there have built the pyramids had properly had onion as a part of their diet.
In ancient Greece, onions were used in traditional medicine. In the middle ages, it had become such an important source os food it was used bout for gifts and a method of payment.
The reason why a slicing onion can make can make us cry is the cutting releases stored sulfuric acid in the onion. There are many advises about how to avoid crying when cutting onions. A sure way avoid is to use a big bowl of water and then cut and slice the onion under water.
In traditional Thai medicine, it is believed that for internal use onions are beneficial for treating colds, cough, and upper respiratory ailments.
And for external use, it is used in herbal compresses to draw out toxins.
The nutrient fact, below, is based on 100 gram of raw Onion.
Vitamins
Vitamin C, total ascorbic acid mg 7.4
Thiamin mg 0.046
Riboflavin mg 0.027
Niacin mg 0.116
Vitamin B-6 mg 0.12
Folate, DFE µg 19
Vitamin B-12 µg 0
Vitamin A, RAE µg 0
Vitamin A, IU IU 2
Vitamin E (alpha-tocopherol) mg 0.02
Vitamin D (D2 + D3) µg 0
Vitamin D IU 0
Vitamin K (phylloquinone) µg 0.4
Lipids
Fatty acids, total saturated g 0.042
Fatty acids, total monounsaturated g 0.013
Fatty acids, total polyunsaturated g 0.017
Fatty acids, total trans g 0
Proximates
Water g 89.11
Energy kcal 40
Protein g 1.1
Total lipid (fat) g 0.1
Carbohydrate, by difference g 9.34
Fiber, total dietary g 1.7
Sugars, total g 4.24
Minerals
Calcium, Ca mg 23
Iron, Fe mg 0.21
Magnesium, Mg mg 10
Phosphorus, P mg 29
Potassium, K mg 146
Sodium, Na mg 4
Zinc, Zn mg 0.17