So is a carrot “worth” the same cooked as it is raw? Is an apple picked in the United States as nutritious as one picked in Warkworth? Hmmm, no I am not posing deep philosophical questions- I am talking about Bioavailability. What? Bioavailability – is simply, how easily a nutrient you ingest is absorbed into your body and used. After you take your beautiful picture of a brunch meal with friends and take that first bite, the magic begins. Well, the science… Let’s chat about the factors surrounding different nutrients + how well they are absorbed. Bearing in mind that if I mention that a certain cooking choice for a certain vegetable decreases the nutrients absorbed in your body – don’t be alarmed. 60% of absorption is better than 0% absorption. A microwaved broccoli will likely have more nutritional benefit to you than a large cheese pizza. Some foods are better cooked. Some are better raw. Some are better soaked or crushed or chopped. Some foods are better with a glass of wine (this has nothing to do with bioavailability whatsoever, but the enjoyment factor).
Food Preparation: Chopping, crushing, soaking produce
This can release nutrients available for your body to absorb by breaking down plant walls and releasing different enzymes that help to form other nutrients. Here’s an example: crushing garlic releases alliinase – this enzyme helps to create allicin, a compound that can protect against disease in our bodies. Soaking grains, pulses + legumes (dried) can reduce phytic acid – phytic acid can block zinc, iron, calcium and magnesium absorption. It’s favourable that many cooking techniques we know or that were told to us from our mummas actually had nutritional value, whether they knew that or not!
Timing of preparation
If you cut up a vegetable or fruit, it’s ideal to consume as soon as you can, particularly if the food has been finely chopped- this is so not to allow too much oxygen to have an effect on the nutrients. Lemon juice or a similar acid squeezed on foods like potatoes or apples that discolour quite quickly can slow this factor down.
Local Love: ASAP (As Soon After Picked!)
Local produce is not just for the hippy-hearted amongst us, it’s actually the best option for maximised nutrients in a food. The main plant is the life source for a food, once plucked from the life source, it makes sense that nutrient flow is decreased in that food right? To maximise vitamin + mineral content (and taste!), eat local where you can: maybe plant a small herb garden? I may live in the smallest flat in the whole of Auckland, but there’s a few little pots of edibles happening for me. I encourage you to have a go! Radishes are easy, herbs, lettuces, spinach + chards are all best to plant around this time of year. A farmers market kg of ugly apples may be more nutrient dense than a kg of organic apples from Spain.
Cooked versus Raw
Simply, both- depending on the actual food. Heat breaks down B vitamins, folate + vitamin C in foods so that suggests that they should be eaten raw for less nutrient loss. For example, sunflower seeds, peas, brussels sprouts (I admit, this one might be a tad hard for me to enjoy!), broccoli, avocado, cauliflower, kale, capsicum and spinach. There is 3 times MORE vitamin C present in raw spinach then there is found on cooked spinach. You will tend to lose these water-soluble vitamins with rapid boiling + extreme heat. So slow and low is a better way to keep them better intact. Sautéing, roasting, steaming, even microwaving (technically) are good ways to keep higher nutrient density when you choose to cook. That old style of boiling is the best way to lose those nutrients friends! Time to teach Nana an updated cooking method for her green veggies. Though you know what? You can KEEP the water from the boiling veg process and use as a stock or broth in other cooking, there you go! Recycled nutrients? I’m going to copyright that. Cooking can give the best nutrient content in many cases though. For example, your yummy tomatoes have lycopene (an awesome antioxidant) inside them. When they are boiled, research shows that lycopene is increased by 25%. Cooking your vegetables that have beta-carotene significantly increases the absorption ability. For your carrots, sweet potato + tomatoes (think of those colours – red, yellows + oranges – as generally contain beta-carotene) cooking breaks down the tough plant cell walls, so go for it! Cooking can make meats + eggs more absorbable by denaturing the protein (don’t worry, you can still get ‘them gains’), it is definitely a better option for your digestive health.
One last thing
I’d like to quickly mention that coupling certain foods can increase the bioavailability of nutrients. Many of us know the classic “Vitamin C + Iron pairing” and it works naturally in many dishes thankfully! Oats + mixed berries are a staple for me and getting lemon squeezed onto your eye fillet + kale side is an absorption dream.
Bioavailability is a fascinating topic and worth delving further into. However, I will say don’t stress too much if you boiled, ate raw, chopped sideways or forgot to squeeze your citrus. Nutrients are still present. As we said at the beginning, 60% absorption is better than none. If you are eating beautiful colours from plants, healthy happy meat, variety in whole grains then I can safely say, you are getting some good nutrients flowing through your body. For further questions or references for the above articles please contact Bess Kilpatrick Mason.