Green beans pack a surprisingly broad range of vitamins, with vitamin K, vitamin C, vitamin A, and several B vitamins leading the list. A single cup (about 100 grams) of raw green beans delivers roughly 14 mg of vitamin C and meaningful amounts of folate, all for just 31 calories. Here’s a closer look at what’s inside and how to get the most from them.
Vitamin C and Vitamin A
One cup of raw green beans provides about 14 mg of vitamin C, covering roughly 15% of the daily target for most adults. Vitamin C supports your immune system and helps your body build collagen, the protein that keeps skin, tendons, and blood vessels strong. It also improves how well you absorb iron from plant foods, which matters if you eat green beans as part of a vegetarian or plant-heavy meal.
The vitamin A content is more modest at 4 mcg RAE per cup, but green beans make up for it with carotenoids, the pigments your body can partially convert into vitamin A. A cup of raw green beans contains about 417 mcg of beta-carotene and 76 mcg of alpha-carotene. These compounds act as antioxidants on their own, helping protect cells from damage.
Carotenoids That Support Eye Health
Beyond beta-carotene, green beans contain roughly 704 mcg of lutein and zeaxanthin per cup. These two carotenoids accumulate in the retina, where they filter blue light and help protect against age-related damage to the macula. Your body can’t manufacture lutein or zeaxanthin, so they have to come from food. Green beans won’t rival kale or spinach on this front, but they contribute a useful amount, especially if you eat them regularly.
B Vitamins and Folate
Green beans supply several B vitamins, including folate (B9), vitamin B6, and thiamine (B1). Folate is the standout. It plays a central role in cell division and DNA production, making it especially important during pregnancy. The American Heart Association also highlights folate in green beans as a nutrient that helps regulate blood pressure alongside potassium.
Thiamine helps your body convert carbohydrates into usable energy, while B6 is involved in over 100 enzyme reactions, many of them tied to protein metabolism and brain function. None of these B vitamins appear in blockbuster amounts in green beans, but they add up across a day of varied eating.
Vitamin K
Green beans are one of the better vegetable sources of vitamin K, which is essential for blood clotting and bone health. A single cup of cooked green beans can deliver a substantial portion of the daily recommended intake. If you take blood-thinning medication, it’s worth keeping your vitamin K intake consistent from day to day rather than eating large, irregular amounts.
Key Minerals Worth Noting
While the search was about vitamins, a few minerals in green beans are worth mentioning because they work hand in hand with those vitamins. Potassium is the most notable. One cup provides about 4% of the daily value, and combined with folate, it helps support healthy blood pressure. Green beans are also naturally very low in sodium, with just 6.6 mg per cup of fresh beans.
Green beans contain small amounts of iron, calcium, and magnesium as well, though a compound called phytic acid can reduce how well your body absorbs these minerals. Phytic acid binds to iron, zinc, calcium, and magnesium in the gut and carries them out before they’re fully absorbed. This only happens when phytic acid and those minerals are eaten together in the same meal, and cooking significantly reduces phytic acid levels.
How Cooking Affects the Vitamins
Vitamin C is the most fragile nutrient in green beans. It dissolves in water and breaks down with heat, so boiling green beans in a large pot of water for a long time drains a significant portion. Steaming or sautéing with minimal water preserves more. B vitamins are also water-soluble and can decline with prolonged high heat, with losses reaching up to 40% in some cooking methods.
The practical takeaway: cook green beans in a small amount of water for the shortest time that gets them tender. Steaming, microwaving, and quick stir-frying all retain more vitamins than boiling. If you use frozen green beans, cook them directly from frozen rather than thawing first, since the thawing process itself causes some vitamin C loss.
Fresh, Frozen, or Canned
Fresh and frozen green beans are nutritionally similar. Frozen beans are typically blanched and flash-frozen shortly after harvest, which locks in most of their vitamin content. The main difference shows up with canned green beans. While they still contain vitamins, the canning process involves high heat and long storage in liquid, both of which reduce water-soluble vitamins like C and folate.
Sodium is the bigger concern with canned varieties. One undrained cup of canned green beans contains 461 mg of sodium, compared to just 6.6 mg in fresh. Rinsing canned beans under water before eating removes a portion of that added sodium, and many brands now sell no-salt-added versions that sidestep the problem entirely.