While roasted vegetables is my family’s most favorite way to enjoy them, it turns out that it’s not the healthiest way to cook vegetables.😔
So what is the healthiest way to cook vegetables? It’s an important question to ask and to know.
But it turns out that it’s not at all a simple answer for various reasons that we shall endeavor to touch on succinctly.
However, there is a general conclusion that tends to apply to most vegetables, so we’re starting there.
The Healthiest Way to Cook Vegetables
Steaming tends to be the best way to cook vegetables for the maximum nutrient retention and bioavailability of nutrients.
The following chart is from a study on the effect of different cooking methods on a handful of different kinds of vegetables as an overview.
Healthy Vegetable Cooking Methods
Unfortunately, this first cooking method study does not include information on roasted vegetables, so we’ll have to research and include that separately.
Unfortunately, roasted vegetables are not the healthiest method, so while we’re not roasting them all the time, we’re still enjoying wonderful roasted vegetable recipes for some meals.
NOTE: Mallow is included in this list because this is an Asian study where mallow is a common vegetable. While lesser known in North America, the leaves, seeds and roots of the mallow plant are all edible and medicinally beneficial vegetable.
Vitamin C and Vitamin K Content in Vegetables by Cooking Method
| Vegetable | Cooking treatment | Vitamin C mg/kg | % Vitamin C vs. Raw | Vitamin K mg/kg | % Vitamin K vs. raw |
|---|---|---|---|---|---|
| Broccoli | Raw | 668.04 | 100% | 1.54 | 100.00% |
| Boiled | 370.04 | 52.85% | 1.59 | 98.89% | |
| Blanched | 615.42 | 88.86% | 1.69 | 108.81% | |
| Steamed | 761.48 | 111.21% | 1.90 | 123.08% | |
| Microwaved | 836.15 | 112.76% | 1.71 | 101.76% | |
| Carrot | Raw | 39.92 | 100.00% | 0.04 | 100.00% |
| Boiled | 56.62 | 55.33% | 0.04 | 85.02% | |
| Blanched | 32.15 | 72.71% | 0.03 | 71.86% | |
| Steamed | 33.49 | 70.51% | 0.04 | 69.87% | |
| Microwaved | 63.00 | 92.02% | 0.06 | 85.35% | |
| Chard | Raw | 163.04 | 100.00% | 1.59 | 100.00% |
| Boiled | 0.00 | 0.00% | 2.95 | 116.23% | |
| Blanched | 124.58 | 59.69% | 2.38 | 116.73% | |
| Steamed | 0.00 | 0.00% | 2.24 | 105.60% | |
| Microwaved | 173.43 | 67.64% | 2.82 | 112.62% | |
| Mallow | Raw | ND | ND | 3.41 | 100.00% |
| Boiled | ND | ND | 3.00 | 81.75% | |
| Blanched | ND | ND | 2.17 | 56.71% | |
| Steamed | ND | ND | 2.66 | 69.33% | |
| Microwaved | ND | ND | 2.03 | 44.28% | |
| Potato | Raw | 58.30 | 100.00% | 0.02 | 100.00% |
| Boiled | 30.57 | 49.79% | 0.03 | 141.16% | |
| Blanched | 44.73 | 73.20% | 0.02 | 94.71% | |
| Steamed | 51.08 | 83.65% | 0.03 | 75.98% | |
| Microwaved | 62.98 | 76.86% | 0.03 | 95.32% | |
| Spinach | Raw | 337.48 | 100.00% | 2.34 | 100.00% |
| Boiled | 220.14 | 40.12% | 3.69 | 94.93% | |
| Blanched | 283.96 | 57.85% | 3.35 | 97.27% | |
| Steamed | 262.78 | 44.75% | 3.61 | 87.70% | |
| Microwaved | 499.26 | 91.10% | 4.67 | 121.21% | |
| Sweet Potato | Raw | 131.35 | 100.00% | ND | ND |
| Boiled | 95.20 | 73.86% | ND | ND | |
| Blanched | 88.92 | 67.70% | ND | ND | |
| Steamed | 81.32 | 59.44% | ND | ND | |
| Microwaved | 183.73 | 100.21% | ND | ND | |
| Zucchini | Raw | 151.30 | 100.00% | 0.19 | 100.00% |
| Boiled | 131.82 | 63.71% | 0.23 | 87.09% | |
| Blanched | 163.86 | 87.01% | 0.23 | 93.78% | |
| Steamed | 199.53 | 89.24% | 0.25 | 90.22% | |
| Microwaved | 205.80 | 92.73% | 0.29 | 101.95% |
ND = Not Detected. Note that for Vitamin C and Vitamin K relates to “content in water-soluble fraction after treatment”, and the percentage (%) retention is the respective cooking method compared to the raw sample as the baseline.
Total Vitamin E Tocopherols by Cooking Method
| Vegetable | Cooking treatment | Total-tocopherol CWa (mg/kg) | Total-tocopherol TRb (%) | <
|---|