Choy — the leafy green family that includes bok choy, napa cabbage, and Chinese broccoli — is a surprisingly good source of plant-based iron. But how much iron you actually get depends on the variety, how much you eat, and whether you pair it with vitamin C or avoid iron-blocking tannins. This calculator helps you estimate the iron content of your choy serving in milligrams, and shows how it stacks up against your daily needs.
Whether you're tracking micronutrients for a plant-based diet, managing anemia, or just curious about your greens, this tool gives you a quick, accurate estimate. Choose your choy type, enter your serving size, and optionally adjust for cooking method and vitamin C pairing to see a more realistic absorption estimate. The result includes a breakdown of iron per 100g, per serving, and a percentage of your daily value.
🥬 Choy Iron Calculator
Step-by-step
How to Use This Tool
Select your choy variety from the dropdown — each has a different iron density per 100 grams. Enter your serving size in grams, ounces, or cups (chopped). The quick-fill buttons let you instantly set common portions like 85 g or 1 cup. Choose your cooking method, because boiling can leach some minerals into the water, while stir-frying concentrates them slightly. Finally, indicate whether you're pairing the choy with a vitamin C source — this significantly boosts non-heme iron absorption. Click Calculate Iron to see your results.
How It Works
The calculator uses standard USDA food composition data for iron content per 100 grams of raw choy. It converts your serving to grams, applies a cooking adjustment factor, and then calculates total iron. The daily value (DV) is based on the FDA's 18 mg reference for adults. For vitamin C pairing, we apply a conservative 1.5× absorption enhancement factor, reflecting research that shows vitamin C can increase non-heme iron absorption by 2–3 times, but we use a moderate estimate to avoid overstating.
Note: Iron values are for the edible portion. Cooking water is not included, so boiled choy retains less iron than raw.
Worked Examples
Example 1: 150 g of raw bok choy (0.80 mg/100g). Iron = 0.80 × 150 / 100 = 1.20 mg. That's 6.7% of your DV. If you add lemon juice, estimated absorbed iron becomes 1.80 mg.
Example 2: 1 cup of chopped napa cabbage (about 70 g, 0.31 mg/100g). Iron = 0.31 × 70 / 100 = 0.22 mg. Very low, so pair with other iron-rich foods.
Tips & Best Practices
- Pair choy with vitamin C-rich foods like bell peppers, citrus, or tomatoes to enhance iron absorption.
- Avoid drinking tea or coffee within an hour of your meal, as tannins can inhibit iron uptake.
- For vegetarians and vegans, combine choy with legumes or fortified grains to meet daily iron needs.
- If you have iron-deficiency anemia, consult a healthcare professional before relying solely on dietary changes.
Factors Affecting Accuracy
Iron content can vary by growing conditions, soil, and cultivar. Cooking losses depend on water volume and cooking time. Our cooking factors are estimates based on typical preparation. The vitamin C enhancement factor is a simplified model; actual absorption depends on individual iron status and meal composition. Use this tool as a guide, not a medical diagnosis.
Frequently Asked Questions
Is choy a good source of iron?
Choy provides moderate amounts of non-heme iron. For example, 100 g of cooked bok choy offers about 0.8 mg, which is roughly 4% of the daily value. It's not as iron-dense as spinach or legumes, but it contributes to overall intake, especially when eaten in large portions.
Does cooking destroy iron?
Iron itself is not destroyed by heat, but boiling can cause water-soluble minerals to leach into the cooking water. Steaming and stir-frying preserve more iron. Our calculator accounts for these differences.
How can I maximize iron absorption from choy?
Combine choy with vitamin C (e.g., a squeeze of lemon, or add bell peppers). Also, avoid consuming calcium-rich dairy or tannin-containing tea/coffee at the same meal, as they can reduce absorption.
What is the daily iron requirement?
The FDA daily value is 18 mg for adults. However, individual needs vary: menstruating women may need more, while men and postmenopausal women need less. Check with your healthcare provider for personalized advice.
Additional Resources
For more detailed nutrient data, visit the USDA FoodData Central. For iron deficiency information, see the National Heart, Lung, and Blood Institute.