At the Home Grown Farm we grow 1015, red, and green varieties.
Major nutrients such as carbohydrates and vitamin C are generally similar from one color and variety of onion to another. Color and pungency, however, indicate the presence of beneficial anti-oxidants that do vary in amount and type with the onion variety. If you use both red and yellow onions, you can take advantage of the best qualities of each. Yellow storage onions keep their nutritional qualities longer than mild red bulb onions because of higher levels of protective chemical compounds. These phytochemicals preserve the major nutrients in the onion bulb and prevent bulb rot. Phytochemicals also provide important health benefits.
Differences in the nutritional content of onions arise as the bulbs mature. Yellow storage onions develop tough-skinned pungent bulbs with high levels of anti-oxidant phytochemicals. Phytochemicals such as phenolics and flavonoids protect onions from fungal diseases, viruses and bacteria. Onions with greater pungency have higher levels of these anti-oxidants. Of the 10 most common onion varieties sold in the United States, Western Yellow onions rank highest in flavonoids, according to an article published in 2004 in the Journal of Agricultural and Food Chemistry. Northern Red onions rank fourth. Western Yellow onions rank second in overall anti-oxidant activity, while Northern Red onions again rank fourth.
Red vegetables including red onions contain phytochemicals with unique anti-oxidant properties. Chemical compounds such as lycopene and anthocyanin give onions a red or reddish purple color. These anti-oxidants help prevent cholesterol from sticking to the walls of your arteries. Other health benefits include better memory and fewer urinary tract infections. Further, Western Yellow and Northern Red onions contain high amounts of anti-oxidants that slow the growth of cancer cells in the liver and the colon, according to the 2007 issue of the “Journal of Agricultural and Food Chemistry.”