Collard Greens: Nutrition, Benefits, Cooking and Safety Notes

Collard greens are broad, sturdy, blue-green leaves from the cabbage family, a staple of Southern US cooking and many other cuisines. They are low in calories and very high in vitamin K: one cup of chopped collards boiled without salt has about 63 calories, 27% of the Daily Value for fiber, 80% for vitamin A, 21% for calcium and more than six times the Daily Value for vitamin K, according to USDA data. Below are the USDA collard greens nutrition facts for raw, cooked and frozen collards, what the research does and does not show about collard greens benefits, what the vitamin K content means for people on warfarin, and how to cook collard greens without loading them with salt.

Peptide Labs does not sell collard greens or collard products. This article is general nutrition information, not medical advice.

What are collard greens?

Collards are a leafy vegetable in the Brassica genus, the cruciferous family that the National Cancer Institute lists alongside kale, cabbage, bok choy, turnips and arugula. Unlike kale, collard leaves are flat and smooth, with a thick central stem that is usually cut out before cooking. The leaves are tougher and milder than mustard greens, which is why they are often simmered or braised. Like other cruciferous vegetables, collards contain glucosinolates, sulfur-containing compounds that NCI says give these plants their sharp aroma and slightly bitter taste. For how collards compare with spinach, chard and lettuces, see our guide to green vegetables.

Collard greens nutrition: raw, cooked and frozen

The table uses three USDA FoodData Central SR Legacy entries: raw collards (FDC 170406), collards boiled and drained without salt (FDC 170407) and frozen chopped collards boiled without salt (FDC 169996), each at USDA’s portion weight for one cup. The percent Daily Value (%DV) uses the FDA Daily Values printed on Nutrition Facts labels.

Why do the cooked numbers look so much larger? A cup of raw chopped collards weighs only 36 grams, while a cup of cooked collards packs about five times as many leaves after they wilt. Cooking does not raise every value, though: per 100 grams, USDA lists much less folate for boiled collards than for raw. Collards also carry the carotenoid lutein: the Linus Pauling Institute ranks cooked collards among the top foods for lutein per cup, a pigment covered in our lutein guide, and much of their vitamin A comes from carotenoids such as those in our beta-carotene guide. For fiber across many foods, see our fiber-rich foods guide.

How collards compare with other cooked greens

This table compares one cup of each green boiled and drained without salt, using USDA SR Legacy portion weights.

Collards lead this group for fiber per cup, while spinach and mustard greens edge ahead on vitamin K. Our kale guide covers kale’s raw and cooked numbers in detail, and our sibling guide to mustard greens looks at the peppery green that often shares a pot with collards. For more vitamin C sources, see our guide to vitamin C foods.

Collard greens benefits: what the evidence says

Most of what can be said honestly about collard greens benefits comes from their nutrient profile, not from trials of collards themselves. They add fiber, vitamins A, C and K, manganese and some calcium for very few calories. Research on cruciferous vegetables as a group has looked at glucosinolates and the compounds they break down into during chopping, chewing and digestion. The National Cancer Institute notes that while these compounds show activity in lab and animal studies, studies in humans have shown mixed results. So collards are a nutritious vegetable, but claims that they protect against specific diseases go beyond the evidence.

Calcium in collards and oxalic acid

Collards are often listed as a plant source of calcium, and USDA data back that up: about a fifth of the Daily Value per cup cooked. There is a catch. The NIH Office of Dietary Supplements names collard greens, along with spinach, sweet potatoes, rhubarb and beans, among foods high in oxalic acid, which binds calcium and lowers how much the body absorbs. ODS notes that calcium from kale, broccoli and cabbage is absorbed about as well as milk’s, and that in a varied diet these effects probably matter little. Our guides to calcium in foods and oxalates explain more, including for people told to watch oxalate for kidney stones.

Vitamin K, warfarin and collard greens

Collards are one of the richest vitamin K foods in the USDA database. That matters mainly for people who take warfarin (Coumadin). The NIH Office of Dietary Supplements calls the interaction between vitamin K and warfarin serious and potentially dangerous, and says people taking warfarin need to keep their vitamin K intake from food and supplements consistent, because sudden changes can raise or lower the drug’s effect. MedlinePlus advises eating consistent amounts of vitamin K foods week to week and talking to your doctor before changing your diet.

• Consistency, not avoidance: a sudden switch from no greens to a big pot of collards several times a week, or the reverse, is the pattern to discuss with your care team.
• Frozen vs fresh: a cup of frozen boiled collards lists more vitamin K than a cup of fresh boiled collards in USDA data, so switching forms can change intake too.
• Other blood thinners: newer anticoagulants work differently; ask your prescriber whether diet matters for your medicine.

Our guide to vitamin K in foods lists many other sources and explains K1 and K2.

How to cook collard greens

• Rinse well: CDC advises rinsing produce under running water before eating, cutting or peeling. Collard leaves can trap grit, so swish them in water and rinse again.
• Strip the stems: fold each leaf in half and cut out the thick center rib, then stack, roll and slice the leaves into ribbons.
• Simmer or braise: slow simmering in broth softens the tough leaves; quick sauteing in a little oil works for thin ribbons. Raw collards can be used as sandwich wraps or shredded finely into slaw.
• Add some fat: NIH notes that eating vegetables with some fat improves vitamin K absorption, and carotenoids such as lutein are also absorbed with fat.
• Watch the salt: in USDA data, collards boiled in salted water list about 252 milligrams of sodium per 100 grams vs 15 without salt. Ham hocks, bacon and bouillon add more. Our low sodium foods guide has ideas for flavor without much salt.

Are collard greens healthy for everyone? Cautions

• Gas and bloating: the National Institute of Diabetes and Digestive and Kidney Diseases lists cruciferous vegetables, including collard greens, among foods that can cause gas. Adding them gradually may help; see our gas and bloating guide.
• Thyroid: NIH says cruciferous vegetables contain goitrogens, which interfere with iodine uptake, but that for most people in the US with adequate iodine, reasonable amounts are not a concern. Our iodine guide covers who may be at risk.
• Allergy: collards are not one of the nine major food allergens under US law, but any food can cause a reaction. Swelling or breathing trouble needs urgent care.
• Smaller appetites: if you are eating less on a GLP-1 medicine, our GLP-1 diet guide explains how fiber-rich vegetables fit in; ask your clinician about any digestive symptoms.

Frequently Asked Questions

Questions about a label? Contact us or read our Buyer’s Guide. Food comes first; follow the label and ask a healthcare provider before starting a supplement, especially if you take medicines such as blood thinners, are pregnant or have a kidney or thyroid condition. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

Last reviewed October 2026.

Related guides: Mustard Greens: Nutrition, Benefits, Cooking and Cautions, Leafy Greens: USDA List of Dark Greens, Spinach vs Kale and Tips, Foods High in Vitamin K: USDA List, K1 vs K2 and Warfarin Notes.