How do you like your veggies? Are you a boiler, a roaster, a steamer or maybe even a stir-fryer?
There’s no denying the goodness of vegetables. They provide essential nutrients for our everyday health and wellbeing. But can the way we prepare them alter how much nutrition we get out of them? The short answer is yes – and it’s all to do with their structure.
Carrots and turnips
For generations, many Aussies soaked their veggies in water, boiling them till they were soft and straining off the water they were cooked in. But this method leaches most of the vitamins and nutrients out of the plant and doesn’t leave much goodness other than fibre.
Vitamin C, for instance, is a delicate food micro-nutrient that’s essential for growth and development. But given that it’s water-soluble, it can be easily damaged by overcooking.
So is it better to eat our veggies raw? Snacking on a carrot when the nibbles hit during the day is more nutritious than eating over-cooked veg, but it’s not always the best way to make the most of the vitamins veggies have to offer.
Our research into food structures, digestion and health suggests a food’s structure has a huge impact on how nutrients are released in our bodies from the food.
Fruit and vegetables are built from millions of plant cells that lock up their vitamins in what’s called a ‘cell wall’ structure. For instance, when a carrot is fresh and raw, the cell walls are firmly attached to each other. This is partly what gives carrot its crunch.
The typical cell wall structure of a plant. Image: Flickr/Yersinia
Based on this work, we’re helping create a healthier Australian food supply by incorporating more positive nutrients – like vitamins and fibre from vegetables – into our everyday processed foods such as bakery products and yoghurts.
But in the mean time, how can we make the most of our veggies?
Gentle steaming with a very small amount of water, or even grating a fresh veggie like carrot, breaks the plants cell walls and makes the inherent nutrients more ‘bio-available’ – that is, available for absorption by the body as we digest it. Adding the water your veg is cooked in to your meal will help maximise the vitamins available for digestion.
The same goes for fruit. Fruit blitzed into smoothies, pureed and used in sauces and desserts breaks the cell walls and increases the bio-availability of many nutrients – but make sure you eat the pulp as well, as it contains valuable nutrients and fibre.
In many cases, veggies or fruit such as tomatoes can provide better nutrition processed than raw – as is the case for tinned tomatoes and pasta and passata sauces.
The antioxidant lycopene can be more easily absorbed by the body in cooked tomato products, compared with raw tomatoes. Image: Flickr/ devlyn
Time to lift the lid. The antioxidant lycopene can be more easily absorbed by the body in cooked tomato products compared with raw tomatoes. Image: Flickr/devlynShow descriptionHide description
Of course, some vegetables like potatoes have to be cooked to be able to eat them at all. But a mixture of raw and gently cooked vegetables and fruit in our diet is key to maximising their nutritional value.
We’re getting together with the food industry and researchers this week to talk more about the increasing awareness of food structures and what they mean for the bio-availability of nutrients at the Food Structures, Digestion and Health Conference.