BIOCHEMICAL COMPOSITION :: PROPERTIES :: ACEC: Asociación Española Cosecheros Exportadores de Cebollas


Onions’ biochemical composition shows a surprising abundance of vitamins and essential nutritious elements, which means onions are an unusually rich source. However, we will only outline the key and most interesting substances for our health. We are using statistics resulting from Cajal Institute’s studies.

First, we would like to mention protides and lipids as well as sugars and celluloses. Afterwards, vitamins A, B, C, and E with high levels of calcium, phosphoric acid, iron, and iodine. Onions’ therapeutic effects are also due to the “allyl propyl disulfide”, a volatile, tear gas not found in any other plant. According to its composition, onions have priceless worth both for health and nutrition.
Finally, it is also worth mentioning that only 20 calories are entailed in every 100 grams.

As mentioned above, we are exclusively sticking to onions’ biochemical composition. Let’s start by looking into onions’ high nutritional value. It is vital to eat substances which maintain an organic and caloric balance on a daily basis. These three substances are: carbohydrates, proteins, and lipids. Onions contain all of them.

To complete the nutritional programme, it is also essential to take vitamins and mineral salts, which have an impact in small doses and are paramount to stimulating growth. Onions contain both substances as well.

  • Onions have cardiovascular benefits, and they are also anti-inflammatory, and antibacterial.
  • They can also improve blood sugar balance.

Evidence shows that onions’ sulphur components decrease cholesterol and triglyceride levels in blood. They also enhance the cell membrane’s function on red blood cells. 

Onions’ nutritional composition:

  • Biotin, vitamin B7: 26.60 %
  • Manganese: 16.00 %
  • Vitamin B6: 15.80 %
  • Vitamin C: 14.50 %
  • Fibre: 11.70 %
  • Potassium: 9.90 %