Is fresh always best?
It helps to know when to eat veggies raw and when to cook them to get all the health benefits they offer.
There’s nothing more nutritious than an ample salad containing lots of colourful raw vegetables, right?
“But not so fast!”, says recent research.
Scientists are finding that various methods of cooking veggies, from boiling carrots to steaming broccoli, can actually boost certain nutrients. Some of the healthiest plant nutrients in vegetables are released only when they’re cooked. These chemical compounds are mostly what 
you see as the pigments or colouring in plants. They don’t just make them look good, they are vital ingredients in our diet.
Many of our veggies are green. This colour is due to the presence of a chemical called Chlorophyll in their cells. However there is often so much of the green stuff present that you are unaware of the presence of nutritionally important Carotenoids which provide the red, yellow and orange colouration. Because such chemicals are firmly locked up inside plant cells, they are really difficult for your body to access and use. (If you want to know more about why this is click here!)
Sufficient to say that you can actually get more carotenoids, from steamed spinach than from raw baby spinach leaves added to a salad.
HOWEVER, THE IMPORTANT THING IS NEVER TO OVERCOOK ANY VEGETABLES AS THIS WILL DESTROY MOST NUTRIENTS.
Raw veggies are still a great way to get vitamins and minerals, but specific cooking tips can release additional nutrients — or at least preserve the health benefits. Next time you create a healthy salad or a plate of crudites, you may like to add in some of these steamed, boiled, baked, or roasted additions.
And yes! there are some scientific names of nutrients listed here. Some, you may well not have heard of. If you would like to know more about these nutrients click on them and this will take you to a more technical discussion.
BROCCOLI: Steam it until just tender!
Raw: Broccoli is high in antioxidants which are potential cancer-fighting nutrients such as beta-carotene, lutein, and flavonols.
Cooked: Steamed broccoli releases higher concentrations of many carotenoids (including beta-carotene and lutein) than when it is eaten raw. Additionally, it retains nearly 70 percent of its vitamin C and virtually all of its kaempferol, a cell-saving flavonoid.
Bonus: To maximize the nutrients you get from your broccoli, wait to wash and cut it until just before steaming,. There is evidence that washing, and cutting ahead of time speeds up deterioration.
Carrots: boil until just tender
Raw: Carrots are a good source of vitamin C and carotenoids, a family of antioxidants that includes beta-carotene. These contribute to good eye health and may also reduce your risk of heart attack and some forms of cancer.
Cooked: The compromise here is that by boiling carrots, you can lose some of Vitamin C which is water soluble. However boiling has been found to concentrate carotenoids present in the carrots by about 14 percent, (according to a recent study in the Journal of Agricultural and Food Chemistry). Cellulose fibres in the cell walls of carrots, traps the carotenoids. however, but high heat breaks down the cell’s fibrous walls, releasing and concentrating the compounds, making it easier for your digestive system to access them.
So, it’s a compromise! Raw v Boiled: Vitamin C v Carotenoids! So really you just need to cook until the carrots JUST begin to soften …..
Bonus: Add a drop of oil to your cooked carrots; the fat helps your body absorb more of the beta-carotene.
PS…. NOTHING can replace a good crunchy carrot so it’s also about texture too, isn’t it?
Garlic: crush or chop garlic finely before cooking or roast cloves for no more than 3 minutes
Raw: Garlic contains alliinase, an enzyme with anti-platelet properties that may help reduce blood pressure and prevent blood from clotting, which decreases your risk of heart disease.
Cooked: Roasting garlic cloves (for up to 3 minutes at no more than 180C) helps retain nearly all of their anti-platelet capabilities—with less of the smelly side effects of raw garlic! Turn off the heat after 3 minutes. It is interesting to note that garlic loses about 80 percent of its clot-busting abilities by 6 minutes; by 10 minutes, 100 percent. And don’t cook in the microwave; it destroys the alliinase enzyme.
Bonus: Crush or chop cloves before cooking to release even more alliinase, even as cooking times increase.
Root vegetables: roast with skins on
Raw: Winter veggies such as potatoes, turnips, and parsnips are high in fibre and vitamins, but many are not commonly eaten raw.
Cooked: Roasting with skins intact helps retain all the nutrients and adds dietary fibre too. If you prefer boiling, leave the skins on (peel them after cooling, if necessary), and boil them in large chunks (preferably whole) to preserve the veggies’ water soluble nutrients.
Bonus: Choose a colourful variety for added health benefits. Several studies show that root 
vegetables with darker skins (red potatoes) or flesh (purple sweet potatoes) have more cancer fighting polyphenols than their lighter coloured cousins.
Brussels sprouts: steam or stir-fry
Raw: Brussels sprouts contain sulphoraphane, a powerful phytochemical that helps protect against breast cancer.
Cooked: Steaming or stir-frying as quickly as possible preserves more of the cancer-fighting compounds. (Boiling Brussels sprouts causes sulforaphane to leach into the water, according to research.)
Bonus: The tough cores will cook faster and more evenly if you cut an X into the bottom of each stem but beware of overcooking!!
Tomatoes: roast with olive oil
Raw: Tomatoes are rich in lycopene, a carotenoid that gives this fruit its red hue. Lycopene is also a powerful antioxidant that can reduce the risk of certain cancers and heart disease.
Cooked: Roasting tomatoes causes cell walls to burst, releasing more lycopene. A recent German study published in the British Journal of Nutrition found that 77 % of 198 people following a strict raw food diet had plasma lycopene levels below what’s considered optimal. A number of studies have demonstrated that men who get more lycopene in their diet have less risk of prostrate cancer and increases energy. In a 1995 Harvard University study conducted with 47,894 men, researchers found that eating 10 or more servings a week of tomato products was linked with a reduced risk of prostate cancer by as much a 34 percent. Although other factors are probably also involved, you can’t go wrong including more red fruits and vegetables in your diet.
Bonus: Splash cherry tomatoes with olive oil, then roast them in the oven until their skins rupture. Lycopene is fat soluble, so adding olive oil helps your body absorb it.
Asparagus: steam vertically!
Raw: One cup of asparagus contains nearly 20 percent of the recommended daily intake of folate, a B vitamin that helps protect your cardiovascular and nervous systems. Recent studies link a diet high in folate with a decreased risk of Alzheimer’s, stroke, and heart disease. Since folate is water soluble and sensitive to heat, cooking can diminish it.
Cooked: Steaming gently in a vertical steamer keeps the fragile tips—which contain most of the water-soluble nutrients—away from the liquid. (You can also steam them in a regular pot and keep the tips out of the water.) This imparts more flavour while retaining all the benefits of raw asparagus.
Bonus: Store asparagus in a cool, dark space (the back of your produce drawer, for example) to preserve the folate, which is sensitive to heat and light.
Beets: steam gently
Raw: Beets are high in betanin, a powerful plant pigment and antioxidant that can halt free-radical damage and may even stop the growth of tumor cells in the stomach, colon, lungs, and nervous system, according to several studies.
Cooked: Lightly steam beets only. Betanin is highly sensitive to heat, so intense cooking methods like boiling or roasting destroy the benefits.
Bonus: Peel and chop the beets before steaming to help release the betanin from the tough cell walls and allow the beets to cook faster.
Onions: bake for 5 minutes in foil
Raw: Onions are one of the best sources of quercetin, a flavonoid with anti-inflammatory powers that may help control allergies and asthma, as well as help treat Alzheimer’s and Parkinson’s diseases. They are also from the same family as garlic and like all of that family, contain alliinase.
Cooked: Baking thick chunks wrapped in foil for 5 minutes at 180C, preserves 99.5 percent of the quercetin compounds while diminishing the acidity and odour.
Bonus: Choose red or yellow onions over white; they have more flavonoids. As a general rule, the darker the colour, the greater the number of antioxidants.