To Cook Vegetables, The Healthiest Way.
Keep it raw
Many vegetables of the Brassica family – such as broccoli, cauliflower, cabbage, brussels sprouts and kale – are known for their powerful anti-cancer chemicals called ‘glucosinolates’. The Brassicas also contain an enzyme called ‘myrosinase’ which provides protection against bacteria and other fungi and harmful organisms.
Green explains: ‘These health-giving compounds are released when the plant is chewed, or crushed. Cooking destroys enzymes and your body will struggle to use the glucosinolates from cooked Brassicas.’
Of all the vegetables, the one that produces really important nutrients when eaten raw, is onion, believes Green. ‘Chopping a raw onion releases anti-inflammatory, and anti-cancer substances called ‘organosulfides’: the compounds that make you cry when you are chopping a raw onion. Heat can deactivate these substances’.
Onion also contains an important nutrient which is great for curbing hunger, says Moore. ‘When eating raw onion, you get the most of this phytonutrient allicin’.
Mix cooked and raw
There is no single formula or preparation method that works for all vegetables. And certainly ‘eat all raw’ is not necessarily a golden rule. In general, experts recommend having a mix diet of both raw and cooked vegetables because research has shown that while cooking can degrade some nutrients, it can enhance the availability of others.
This applies in the case of peppers, spinach, carrots and other vegetables high in vitamin C. When cooked or heated, these vegetables can lose some vitamin C content. This is especially true when the vegetables are boiled because vitamin C and other nutrients such as vitamin B1 and folate are leaked into the water.
However, a 2008 report in the Journal of Agriculture and Food Chemistry found that cooking preserves antioxidant compounds, particularly carotenoids, in carrots, courgette and broccoli. Carotenoids are important because they decrease the risk of disease, particularly certain cancers and eye disease.