I’ve been asked many times if it is better to eat vegetables raw or cooked. The answer to that question is a combination of both. Although some raw advocates may swear to eat only raw food to retain the most nutrient value, certain food’s bioactive availability is enhanced when cooked. To be clear, food is a source of both nutrients (vitamin, minerals, protein etc.), but also bioactives. Bioactives are non-nutrient compounds in food that can essentially connect with genes, turning them on or off to influence important biochemical processes that impact our health. Inspite of their importance, you won't find bioactives on a food label...yet.
To reap the benefits of nutrients and bioactives, it's useful to know which vegetables are best eaten raw or cooked, the best cooking methods to get the most from food's inherent bioactives, and which preparation methods have the lowest impact on reducing the availability of nutrients and bioactives for your body.
Raw Versus Cooked
Mix up how you eat your veggies and fruits. Applying heat and acid can denature certain bioactives and inhibit potential signals to your genes. On the other hand, applying heat can change textures and enhance, making them more palatable.
Which Foods to Serve Raw
Cruciferous Vegetables- kale, broccoli, radish, arugula, Brussels sprouts, cabbage for example. When chopped or chewed cruciferous vegetables produce sulforaphane by mixing their innate glucosinolate compounds with the myrosinase enzyme. Sulforaphane is a powerful bioactive when it comes to cross-talking with your genes. However, the enzyme is destroyed in most cooking processes.
Here's a Tip: If you want to cook your crucifers and get your sulforaphane too, do this.
Cut or slice the vegetables and hold for 40 to 90 minutes to maximize sulforaphane production before cooking. Sulforaphane, once formed, is more heat resistant. So give your crucifers a chance to produce their bioactive before you throw them in the pan.
Foods Containing Vitamin C- pink grapefruit, blackberries, elderberries, raspberries,
billiberries, strawberries, pomegranate, watermelon, tomato. These vitamin C rich foods are best eaten raw because vitamin C is partially destroyed by heat. What's more, importantly, the above-listed foods also contain the bioactives ellagic acid and lycopene. Both of these superstar bioactives can quench millions of reactive oxygen species (ROS) per second compared to vitamin C alone which quenches ROS on a basis of 1:1. But there is an exception!
Cooking tomatoes converts lycopene into its nutrigenomic, or food-gene connection form, Raw tomatoes retain Vitamin C in their antioxidant form. What's a person to do? Mix up how you eat tomatoes. Some raw. Some cooked. Get the best of both nutrition worlds.
Foods To Serve Cooked
As I mentioned at the beginning of this article, cooking adds flavor and improves texture. It also allows us to eat and digest foods that might be difficult in their raw form. When we look at cooking through the lens of nutrigenomics, or how food connects to our genes, some foods also serve us better in their cooked form. On that note, you just learned about cooking tomatoes. Here's some more bioactive-rich foods that do well during cooking
Foods containing the bioactive rutin, do well under heat because rutin is more heat stable. So grab your buckwheat and asparagus and cook them too.
Artichokes, sage, thyme, Mexican oregano, rosemary, olives contain many bioactives which might denature during the cooking process, but a resident bioactive in these foods, luteolin tolerates higher heat than other bioactives and saves the food-gene connection we strive for.
Onions, and all members of the allium family contain quercetin. Apples and fennel are also good sources of this potent bioactive which helps turn off pro-inflammatory genes. Fortunately, quercetin aalso belongs to the family of heat tolerant bioactives.
Roasting the turmeric root actually releases more bioactive compounds with nutrigenomic or food-gene connection activity than using the root in its raw form.
Best Cooking Methods to Preserve Bioactives and Nutrients
In general, low heat slow cooking methods retain the most nutrients and preserve bioactives.
Low Heat Dehydration
Microwave: this is a low heat, dry cooking method
Best Prep Methods
Many of the bioactives that connect with our genes are found in the peels of fruit and vegetables. This is why you should never juice an orange without zesting it first! In many cases, you can simply add the zest right into the recipe you are working on. If not, just store it in an airtight container in the refrigerator for later use.
The natural fermentation process is a long, slow process which gradually increases the acidity and associated effervescence or earthiness of a fermented product. This long slow process causes a gradual change in acidity which allows bioactives to survive. This versus pickling which uses vinegar and would likely denature bioactives. If you buy fermented products, try to buy the freshest available and from a local producer if possible. This way you know how the product has been produced and when. Of course, making your own fermented products trumps any product you buy!