As you know, scientists are now unanimous in saying that a regular intake of antioxidants through diet or supplementation is certainly a reflex that we must have today in terms of prevention of our health.
All current studies indicate that the regular intake of fruits and vegetables rich in antioxidants has undeniable positive effects on health. The only question to ask is whether the amount of antioxidants in these foods is what I want it to be.
Because between the moment of harvest and the moment you put your fork in your mouth, there are a few steps that can significantly alter the antioxidant content of these foods: place and temperature of storage, exposure to light, cooking time, etc. (this is why frozen products are certainly not to be denigrated, if they are organic, preferably).
A little reminder: the top antioxidants.
According to a study conducted in the USA on the antioxidant content of foods, published in the American Journal of Clinical Nutrition, the foods richest in antioxidants are the following (per 100g):
- Blackberries (5.75)
- Walnuts (3.72)
- Strawberries (3.58)
- Artichokes (cooked) (3.56)
- Cranberries (3.13)
- Raspberries (2.87)
- Blueberries (2.68)
- Cloves (2.64)
- Grape juice (2.56)
- Cranberry juice (2.47)
- Grapefruit juice (1.86)
- Plums (1.72)
- Cabbage, red, cooked 1.61
- Orange juice (1.5)
- Pineapple (1.28 )
- Oranges (1.26)
- Black plums (1.21)
- Dried pinto (pink) beans (1.14)
- Frozen spinach (1.05)
- Kiwi (0.99)
- Molasses (0.98)
- Cooked red potatoes (0.96)
- Cooked white potatoes (0.94)
- Iced, unsweetened tea (0.88)
- Cooked red peppers (0.82 )
- Cooked broccoli (0.78)
Effects of food preparation on its antioxidant content
The researchers also examined the effect of preparation (peeling, steaming, or boiling) on some of these foods and confirmed that this food preparation step inevitably affects its antioxidant content. Surprisingly, they found that the antioxidant content increased for the following foods when they were cooked: carrots, spinach, mushrooms, asparagus, broccoli, red cabbage, green and red peppers, potatoes, and tomatoes.
In addition, steaming was the recommended method of cooking, as it results in the deployment of maximum antioxidants. Finally, peeling apples or cucumbers decreased their antioxidant content by 33-66% and 50% respectively.
Food preparation methods and their impact on antioxidant content
FoodsPreparation% Antioxidants compared to unprepared foodsApplesPealed(-)33-66%Steamed(+)291%Boiled(+)121-159%CucumbersPealed(-)50%SparagusSteamed(+)205%Steamed Broccoli(+)122-654%Green cabbageSteamed(+)448%Red cabbageSteamed(+)270%Green pepperSteamed(+)467Red pepperSteamed(+)180%PotatoesSteamed(+)105-242%TomatoesSteamed(+)112-164%SpinachSteamed(+)84-114%Sweet potatoesSteamed(+)413%The right cooking time for each food
That's essential, too. Nutrition research has shown that even 5 minutes of extra cooking time can make a huge difference in the nutritional quality of a dish (that's when you answer the phone, for example!).
In fact, each food is unique and should be considered as such when considering temperature and cooking time. For example, to protect its nutrients, spinach should never be boiled for more than one minute. Kale, on the other hand, should be steamed for 5 minutes to make a maximum of nutrients available.
The general rule, of course, is to cook less rather than more. The problem of cooking is less of an issue with fruits, so for their antioxidants, abuse them anyway!... organic, of course.
An apple a day....yes, but with the peel!