At its most basic level, oxidation is the loss of electrons. And when a compound loses electrons, its properties change.
You can see oxidation in every-day life: a rusted nail, an apple turning brown. In these two cases, the surfaces that become oxidized are exposed to air – which has, you guessed it, oxygen.
Oxidation also happens where we can’t see it – in your body. Oxidation causes the production of free radicals. Free radicals are molecules that have lost an electron (become oxidized). If you remember anything from your high school chemistry class, you may recall that molecules like to be whole, which in this case means they want to have the right number of electrons.
You can picture them as bratty kids that NEED to have their arms stuffed with teddy bears. The length of their arms determines how many teddy bears they can hold, and if one goes missing, they freak out. They run around until they find a teddy bear, then steal it from whoever is holding it.
These bratty kids (aka free radicals) are bad news. If they steal a teddy bear (aka an electron) from a molecule that is part of an organ in your body, it can cause damage. It is thought that this damage underlies the cause of many chronic diseases such as diabetes, cancer, cardiovascular disease, and others.
Antioxidants are therefore (can you guess?) anti-oxidation. They are teddy bear givers. They give away teddy bears (aka electrons) to whoever needs them. This calms down the bratty kids, and neutralizes free radical damage.
You can see antioxidants at work if you slice an apple and then sprinkle it with lemon juice (which contains vitamin C, an antioxidant). The apple resists browning.
The main categories of dietary antioxidants include vitamin A, vitamin C, vitamin E, carotenoids, and phenols. While selenium, zinc, manganese, and some other nutrients are often referred to as antioxidants, they don’t actually have antioxidant potential themselves, but rather act as co-factors in the antioxidant activity of other compounds. They help the real antioxidants with the teddy bear dispersal.
Now, oxidation is normal – it happens all the time in our bodies as part of normal processes. It is a natural by-product of digestion, exercise, excessive sun exposure, and the aging process. But when oxidation becomes rampantly unmanaged, it can be destructive (like a whole room full of bratty kids without enough teddy bears – can you imagine?). And oxidation can also be induced by exposure to toxins such as alcohol, cigarette smoke, and environmental pollutants.
Due to their ability to offset the oxidation process, dietary antioxidants ensure that we age well, resist disease, and recover properly, whether from exercise, an infection, a sunburn, or a scraped knee.
Because oxidation is always occurring, our need for antioxidants is ongoing. Luckily, antioxidants are abundant in whole foods, particularly in colorful plants. So as long as we keep eating a diet rich in antioxidants (read: plates covered in colorful plants), we can keep oxidation in check.
As mentioned, the best sources of antioxidants are found in colorful plants. Generally, the deeper pigmented the plant is, the more antioxidants it will have. For example, purple cabbage will have more antioxidants than regular cabbage, which is pale green.
Although there is a lot of overlap, certain foods are better sources than others for specific antioxidants.
Good sources: Animal liver and cod liver oil; dark green, yellow, orange, or coral-colored plants (e.g. kale, collard greens, carrots, squash, mangos, oranges, goji berries, apricots, watermelon)
Vitamin A is fat-soluble, so make sure you eat some fat/oil with these fruits and vegetables.
Very heat sensitive so only present in raw or very lightly cooked plants
Good sources: (raw) Red pepper, citrus fruits, leafy greens, berries
Good sources: Nuts, seeds, whole grains (particularly the germ portion, such as wheat germ), leafy greens
Vitamin E is fat-soluble, so make sure you eat some fat/oil with your leafy greens.
Good sources: Dark leafy greens, spirulina, tomatoes, guava, goji berries, salmon, squash, carrots, sweet potatoes
Good sources: Green tea, black tea, cocoa, red wine, berries, herbs / spices (e.g. turmeric, clove, oregano), vegetables, coffee, olives, extra virgin olive oil.
The best tip for “getting enough”? Turn your plate into a rainbow of colorful whole foods at every meal.
Although no-one likes too many bratty kids (free radicals), they do serve a purpose in the body and oxidation should occur as a natural and healthy part of human metabolism.
Managing oxidation is about balance, not about making it go away completely, so before you start taking antioxidant supplements with abandon, thinking “more is better”, try a bowl of blueberries instead.