Kale, frozen, cooked, boiled, drained, without salt

Kale (Brassica oleracea var. acephala) is a leafy green cruciferous vegetable belonging to the Brassicaceae family. It is among the oldest known cultivated vegetables, originating in eastern Turkey and spreading through Europe by the Middle Ages before eventually arriving in North America. This hardy plant is closely related to cabbage, broccoli, Brussels sprouts, and collards, sharing many of the same phytochemicals and nutritional benefits. Kale is typically grown as cool‑weather crop, thriving in temperatures that might damage other leafy greens. Its resilience allows it to be harvested throughout much of the year in temperate regions. Commercial production often uses controlled environments and seasonal outdoor fields, with harvesting occurring when leaves reach mature size. There are several varieties of kale, each with distinct flavors, textures, and colors. Curly kale is the most common in supermarkets, characterized by its frilly, robust leaves and slightly bitter taste. Lacinato or Tuscan kale, also known as 'dinosaur kale,’ stands out with its dark, applied surface and sweeter, earthier flavor. Red Russian kale has flatter leaves with reddish stems and a milder taste, making it popular in salads and sautés. Siberian kale varieties are known for their cold tolerance and large, tender leaves. These varieties are all nutritionally dense but differ slightly in their proportion of micronutrients and antioxidants. Kale’s popularity in modern nutrition stems from its exceptionally high levels of vitamins K, A, and C, alongside mineral content and phytochemicals such as glucosinolates, carotenoids, and flavonoids. Mimicked across media as a 'superfood,’ kale offers a combination of nutrients often lacking in other greens. Glucosinolates are sulfur‑containing compounds that, when broken down during chopping or chewing, form biologically active compounds like isothiocyanates with potential health benefits. Carotenoids including beta‑carotene, lutein, and zeaxanthin contribute to eye health, while polyphenols and flavonoids like quercetin and kaempferol exhibit antioxidant and anti‑inflammatory actions. Kale’s texture and flavor vary with cooking methods; raw kale has a more fibrous structure and bitter profile, whereas cooking softens texture and can enhance palatability. Frozen kale, specifically, is harvested at peak ripeness and flash‑frozen to preserve nutrients before distribution. Cooked frozen kale, such as the boiled, drained version without salt described here, retains much of its nutritional value, especially fat‑soluble vitamins and minerals, while reducing volume and concentrating tastes. While some water‑soluble vitamins like vitamin C may decrease with cooking, the overall nutrient density remains high compared to many other vegetables. Consumers can enjoy kale in salads, smoothies, soups, stews, and as a nutrient‑rich side dish. With its long growing history and versatile applications, kale continues to be a staple for health‑oriented diets and culinary creativity.

Kale’s nutrient profile is remarkable for its depth across macro‑ and micronutrients when measured per typical cooked serving. Per 1 cup (130g) of cooked, boiled frozen kale without added salt, there are 47 kcal and 3.8g protein – nearly 8% of daily protein needs for an average adult eating a 2,000‑calorie diet. Its 1.6g total fat includes only 0.21g saturated fat and no trans fats, making it extremely heart‑healthy at baseline. Liquid water constitutes the majority of this vegetable, giving kale a low energy density but high nutrient yield per calorie. The carbohydrate content at 6.9g includes 3g dietary fiber, which contributes to digestive health and helps regulate blood glucose and cholesterol levels. Kale is naturally very low in sugars and contains virtually no added sugars, making its 1.6g sugars mainly from intrinsic vegetable sources. From a micronutrient perspective, this kale serving delivers astounding levels of vitamin K (544µg), more than 450% of the recommended daily value, which plays a crucial role in blood clotting and bone metabolism. Vitamin A (as retinol activity equivalents at 189.8µg RAE) and vitamin C (23.1mg) further support immune function, skin health, and antioxidant defenses. Folate (84.5µg) is important for DNA synthesis and repair, especially in populations such as pregnant individuals. Among minerals, calcium (195mg) supports bone and cellular functions, while potassium (187.2mg) aids in nerve transmission and blood pressure regulation. Iron (1.1mg) and magnesium (32.5mg) contribute to oxygen transport and enzymatic activities across systems. Comparisons with other leafy greens illustrate kale’s nutritional density. Unlike raw kale, which may have higher vitamin C and folate due to minimal heat exposure, cooked frozen kale often shows boosted bioavailability of antioxidants like beta‑carotene and lutein due to cell wall breakdown during cooking. Additionally, freezing at harvest captures nutrients near their peak. In contrast, other leafy greens such as spinach and Swiss chard can have higher levels of certain minerals like iron or magnesium but often lack kale’s vitamin K and A density. Compared to boiled spinach, kale generally provides more beta‑carotene and vitamin K per cup after cooking, which gives it a distinct edge for supporting vision and clotting functions. The balance of macronutrients positions kale as a nearly complete plant food: it offers protein with all essential amino acids in small amounts, a spectrum of vitamins, and phytonutrients without extraneous calories or fats. In the context of nutrient density metrics – the quantity of nutrients per calorie – kale ranks extremely high among vegetables. This is largely due to its low caloric content and abundance of micronutrients. Nutrition researchers often highlight kale in nutrient profiling indices that assess the ability of foods to supply a wide array of vitamins and minerals without excessive energy. Therefore, kale is frequently recommended as a cornerstone of nutrient‑dense eating patterns such as the DASH or Mediterranean diets. Its fiber, antioxidants, and vitamins contribute synergistically to metabolic health, immune resilience, and long‑term disease prevention strategies. For individuals focused on maximizing nutrient intake per serving – especially those with increased needs for vitamin K or vitamin A – regular inclusion of kale can substantially improve overall dietary quality and micronutrient status.

Source: USDA FoodData Central (FDC ID: 326196)