Yes, onions contain Vitamin C, and it is far more significant to their nutritional profile than most people realize.
According to research published in PMC by the NIH, onions are a meaningful dietary source of ascorbic acid, the scientific name for Vitamin C, and they deliver it alongside a broader array of antioxidants and phytochemicals that work together in the body.
Vitamin C serves a dual purpose. For the plant itself, it acts as a protective antioxidant, shielding cells from oxidative stress during growth. For the consumer, that same antioxidant activity translates into immune support, collagen synthesis, and reduced cellular inflammation. The Onion Health Research database reinforces that these compounds remain bioavailable even after light cooking.
What many people overlook is that variety and growing conditions directly shape how nutrient-dense any given onion will be. Soil mineral content, climate, and cultivation methods all influence the final concentration of vitamins in the bulb, as we’ll break down in this article.
The Veritable Vidalia’s Vitamin Profile
A single raw Vidalia onion delivers a measurable, meaningful dose of Vitamin C alongside a supporting cast of B-vitamins and minerals that make it genuinely worth including in your diet.
A 150g raw Vidalia onion contains 15mg of Vitamin C — and one medium serving (148g) accounts for 7% of your Daily Value for that nutrient. That is not a trivial contribution for a vegetable most people treat purely as a flavor base, especially since a bulb ends up giving you as much Vitamin C as a tenth of an orange, which can contribute over time.
Low-sulfur soil is what gives Vidalia onions their famously mild, sweet flavor, but it does not strip away nutritional value. The reduced sulfur content affects the compounds responsible for pungency, not the water-soluble vitamins. You still get folate, Vitamin B6, and potassium alongside the Vitamin C, making Vidalia onions a surprisingly well-rounded micronutrient source.
But vitamins and minerals are only part of the story. Onions also contain a dense layer of protective plant compounds that work alongside Vitamin C in ways that pure supplementation simply cannot replicate.
Nutrients Beyond Vitamins
The full spectrum of nutrients in an onion extends well beyond Vitamin C; polyphenols, the plant-based compounds responsible for much of the onion's color and bite, may be its most potent health asset.
Polyphenols are naturally occurring micronutrients found in plant foods that act as antioxidants, partly neutralizing the unstable molecules that drive inflammation, cellular decay, and cardiovascular stress. Onions are one of the richest polyphenol sources in the average American diet, and Georgia-grown Vidalias are no exception. Research published via the NIH found that total polyphenols in Vidalia onions range from 73.33 to 180.84 mg per 100g of fresh weight, which is quite high for an everyday food.
One often-overlooked detail worth noting, however: the outermost dry layers of an onion contain the highest concentration of polyphenols. Most of that value is discarded during prep. Keeping even one thin layer of the edible flesh closest to the skin preserves more of these compounds.
Vidalia vs. Red and Yellow Onions: Which is Healthier?
The health benefits of Vidalia onions hold up well against other common varieties, and all are quite healthy!
Standard yellow onions and Vidalias are nutritionally closer than most shoppers assume, with Vitamin C content being a near-draw between the two.
Red onions do hold one notable advantage: anthocyanins, the pigments that give them their deep color and contribute meaningful antioxidant activity. But Vidalia onions counter with an exceptionally high concentration of quercetin and other polyphenols discussed in the previous section. There’s a tradeoff, but it is not a clear win for either side.
As far as sweetness goes, the Vidalia's sweetness comes from low soil sulfur, not added sugar or reduced nutritional density. According to the Vidalia Onion Committee, they remain naturally low in calories and fat-free. And yes, their high water content does dilute nutrient concentration slightly per gram… but that same water content supports hydration and makes them easier to consume in larger quantities raw, which ultimately increases your total nutrient intake.
Each variety brings something distinct to the table, in other words.
Maximizing Nutrients with Farm-to-Table Onions
Understanding onion nutrition facts is only half the equation — how you acquire, store, and prepare Vidalias determines how much of that Vitamin C actually reaches your plate.
Raw vs. cooked applications matter significantly when it comes to Vitamin C retention. Heat degrades this water-soluble vitamin quickly, so raw preparations preserve the most. Tossing sliced Vidalias into salads, fresh salsas, or sandwich toppings keeps their nutritional profile fully intact. When cooking is unavoidable, quick methods like a light sauté or brief stir-fry cause far less nutrient loss than prolonged roasting or boiling.
Proper storage also plays a bigger role than most home cooks expect. Vidalias have a higher moisture content than pungent varieties, which makes them more susceptible to spoilage. Store them in a cool, dry, well-ventilated space, individually wrapped in paper towels or hung in a mesh bag, to slow degradation and protect their nutrients.
Vidalia onions are naturally low-calorie and fat-free, making them a perfect addition to a heart-healthy diet. Not to mention, they’re delicious! Vidalias are so mild that you can eat them raw, without any tears or bitterness; we do so all the time here at the farm.
This spring and summer, let Vidalia season be your cue to eat with intention. Order fresh Vidalias from our Georgia farm, and build meals that let their natural nutrition shine.