Leek Nutrition Calculator — Calories & Nutrition per Serving

Raw leek (FDC 169246) provides 2.1mg iron per 100g (12% DV) — roughly 10x the iron content of yellow onion (0.21mg) and more than most non-legume vegetables. This puts leek alongside spinach (2.7mg) and Swiss chard (1.8mg) as one of the stronger plant-based iron sources in the vegetable category, though iron absorption from plant sources is lower than from animal sources ^[1].

Manganese at 0.481mg per 100g (21% DV) makes leek an excellent source of this trace mineral — one cup of chopped leek (~104g) delivers 0.5mg manganese (22% DV). Among allium vegetables, only garlic (1.672mg) surpasses leek in manganese content. The combination of meaningful iron and manganese in a single vegetable is uncommon ^[1][2].

The macro profile includes 1.5g protein, 0.3g fat, and 14.15g carbohydrates at 61 calories per 100g. Fiber is modest at 1.8g (6% DV), with 3.9g sugars contributing to leek's naturally mild sweetness. The calorie content places leek between onion (40 kcal) and garlic (149 kcal) among common alliums ^[1].

Boiled and drained leek contains approximately 31 calories per 100g — a 49% reduction from the raw value of 61 kcal. This dramatic drop occurs because boiling causes leek to absorb significant water, diluting the nutrient concentration per 100g of cooked weight. The carbohydrate content drops from 14.15g to approximately 7.6g per 100g cooked ^[1].

Mineral losses from boiling are substantial: potassium drops from 180mg to ~87mg (52% reduction) and iron from 2.1mg to ~1.1mg (48% reduction) due to leaching into cooking water. Vitamin C falls from 12mg to approximately 4mg (67% loss). If you're logging nutrients from boiled leeks, using raw-weight values would significantly overestimate your actual intake ^[2].

Sautéing preserves more nutrients while adding fat: approximately 78 calories per 100g with iron retained at ~2.2mg and potassium at ~190mg. Braising in broth is a middle ground at ~45 kcal/100g and retains more minerals than plain boiling because the broth itself captures leached nutrients. For maximum mineral retention per serving, sautéing or grilling are preferred methods ^[3].

Most recipes call for the white and light green portion of leek — discarding the darker green tops. But the green leaves concentrate significantly more beta-carotene (which converts to vitamin A) and vitamin K than the white bulb. The USDA entry specifies 'bulb and lower leaf-portion' — dark green tops would push vitamin A and K values even higher ^[1][2].

As listed, leek provides 83mcg vitamin A RAE per 100g (9% DV) from 1,000mcg beta-carotene — unusual among alliums, which are typically devoid of vitamin A. Onion has essentially 0mcg, garlic has 0mcg, and shallot has 0mcg vitamin A RAE. Leek also contains 1,900mcg lutein and zeaxanthin, carotenoid pigments concentrated in the green portions ^[1].

Vitamin K at 47mcg (39% DV) is similarly unique among alliums: onion has 0.4mcg, garlic 1.7mcg, shallot 0.8mcg. Leek's vitamin K comes from phylloquinone (K1), primarily in the green portions. For nutrition logging, using the whole leek including some of the green top gives a meaningfully different micronutrient profile than using the white part alone ^[2].

Among the three most commonly cooked alliums: leek has the lowest calorie density (61 kcal) compared to shallot (72 kcal) and garlic (149 kcal), though onion is lowest at 40 kcal. Leek's distinguishing feature is its 10x higher iron content than onion (2.1mg vs. 0.21mg) and its unique vitamin A and K content that other alliums lack ^[1].

Shallot leads in potassium (334mg vs. leek's 180mg) and total fiber (3.2g vs. 1.8g). Garlic dominates in protein (6.36g) and calcium (181mg) but at nearly 2.5x the calories. Leek's standout advantage is the combination of meaningful iron + vitamin K + vitamin A — no other common allium vegetable delivers all three ^[1].

In terms of culinary volume, leek provides the most visual bulk per calorie: a medium leek (~89g) at 54 calories delivers a substantial portion size, while the equivalent calories from shallot would be roughly 75g (one medium shallot) with a much smaller volume. This makes leek particularly useful for calorie-conscious recipes where plate coverage matters ^[3].

Leek delivers 64mcg folate per 100g (16% DV) — matching green onion and exceeding onion (19mcg) by over 3x. One cup of chopped raw leek (~104g) provides approximately 67mcg folate (17% DV). Folate is heat-sensitive: boiling reduces it to approximately 25mcg per 100g cooked, while sautéing retains more at approximately 55mcg ^[1].

Vitamin B6 at 0.233mg per 100g (14% DV) is another standout — higher than most vegetables and relevant for daily tracking since B6 is involved in over 100 enzyme reactions. Combined with folate, leek provides a meaningful contribution to two B vitamins from a single vegetable serving ^[1][2].

Additional micronutrients include vitamin C at 12mg (13% DV), vitamin E at 0.92mg (6% DV), and copper at 0.12mg (13% DV). The breadth of micronutrients at moderate percentages — four nutrients above 10% DV and two above 20% DV (manganese and vitamin K) — makes leek a nutritionally diverse allium for logging purposes ^[1].