Vegetables and mushrooms: seasonality, freshness, storage, safety, nutrition and cooking.
Among leafy vegetables, beet greens stand out at more than 700 mg potassium per 100 g in common databases; spinach is around 560 mg, Swiss chard around 380 mg, and Brussels sprouts near 390 mg. Serving size and cooking method change the amount you actually eat.
Bell peppers are standouts: yellow peppers can exceed 180 mg vitamin C per 100 g and red peppers are around 125 mg in common composition tables. Raw broccoli and Brussels sprouts are often around 80–90 mg per 100 g.
Some leafy greens contain substantial calcium: raw collards and certain kale entries can exceed 200 mg per 100 g, bok choy is around 100 mg, and broccoli around 45–50 mg. The number alone is not enough, because spinach calcium is much less bioavailable due to oxalate.
Among common raw vegetables, cucumber and lettuce are near 15 calories per 100 g, zucchini about 17, tomato 18, green bell pepper around 20, and spinach about 23. Their very high water content explains the low energy density.
Yes. Sprouting is a sign of age and renewed plant growth, not toxicity. A firm, dry clove without mold or rot is still usable; the green center can taste sharper or more bitter and may be removed for flavor.
Among comparable cooked and drained vegetables, artichoke provides about 5.7 g fiber per 100 g, collard greens about 4.0 g, parsnips 3.6 g, broccoli 3.3 g and cooked carrots around 3.0 g. Those gaps are useful, but the amount you actually eat can matter more than a small difference in rank.
Intact garlic stores alliin and the enzyme alliinase separately. Cutting or crushing mixes them and rapidly forms thiosulfinates such as allicin. Strong heat inactivates alliinase; experimental studies suggest crushing garlic and allowing about 10 minutes before heating preserves more of this chemistry than heating whole cloves immediately.
A USDA raw tomato reference provides 18 calories, 1.2 g fiber and about 12.7 mg vitamin C per 100 g. Canned tomatoes packed in tomato juice provide about 16 calories, 1.9 g fiber, 2.6 mg vitamin C and 115 mg sodium. Heat can lower vitamin C while making tomato lycopene easier to absorb.
Cooking does not make a vegetable universally more nutritious, but it can improve carotenoid availability. Tomatoes, carrots, and spinach are clear examples, while long cooking can reduce vitamin C and folate. Eating both raw and cooked vegetables captures different advantages.
Cooking can make some carotenoids, including tomato lycopene and carrot beta-carotene, easier to access because heat and processing alter plant structure. The effect is not universal: vitamin C, for example, can decline with heat.
The biggest difference between raw and cooked spinach is volume. One hundred grams raw is a large bowl; 100 g cooked is compact. Iron and calcium therefore look higher per 100 g after cooking, while vitamin C and folate can fall with heat and water. Boiling can also remove some soluble oxalate into the cooking water.
Cooking vegetables can reduce heat- and water-sensitive vitamins, especially vitamin C and folate, but it does not destroy their nutritional value. Fiber and minerals largely remain, and heat can improve the availability of carotenoids such as lycopene and beta-carotene. Boiling and discarding water usually causes more loss than steaming, microwaving or short cooking.