The Reason We Need More Antioxidants (And Why We’re Not Getting Them)

Glucose is the primary fuel of the human body. We consume glucose and breathe in oxygen to make the energy needed to power our bodies. Plants then take the water and CO2 we breathe out to make oxygen and organic compounds like glucose—and the circle of life continues. The word carbohydrate means, basically, hydrated carbon, which is what plants use to make carbs and all that’s left after we burn them for energy in our muscles and brain.

This process of oxidizing glucose to make energy is messy, though, and generates free radicals. Chugging sugar water increases the level of oxidation in our bloodstreams over the next few hours as our bodies metabolize the glucose. (Digestion isn’t the only physiological source of free radicals—exercise is too. See Preventing Exercise-Induced Oxidative Stress With Watercress). Why would we evolve to have a negative reaction to our primary fuel? Because over the millions of years we evolved, there was no such thing as sugar water—all sugars and starches came pre-packaged with protective compounds: antioxidants. In nature, sugar always comes with phytonutrients.

If we drink the same amount of sugar in the form of orange juice, we don’t get that spike in oxidation, because the sugar in fruit comes prepackaged with antioxidants. We can’t just drink vitamin C enriched sugar water either, because it’s not the vitamin C in the OJ but the citrus phytonutrients like hesperetin and naringenin that beat back the oxidation. And it’s always better to eat the whole fruit than drink the juice (See Best Fruit Juice and Apple Juice May Be Worse Than Sugar Water).

If we don’t eat phytonutrient-rich plant foods with each meal, then for hours after we eat, our bodies are tipped out of balance into a pro-oxidative state, which can set us up for oxidant stress diseases. That’s why we need to ideally eat antioxidant rich foods with every meal.

In the above video, we can see the levels of oxidized fat in our blood one, two, and three hours after sugar water ingestion, and the corresponding drop in vitamin E levels in our blood as our body’s antioxidant stores are being used up. If we don’t eat phytonutrient-rich foods with our meals, our body has to dip into its backup supply of antioxidants. We can’t get away with that for long. So while ideally we should stuff our faces with as many phytonutrient-rich foods as we can. In  the very least we should eat enough antioxidants to counter the oxidation of digestion. We don’t want to slide backwards every day and end up with less antioxidants in our bodies than we woke up with.

A chart in the above video shows the amount of antioxidants we need every day, depending on how much we eat, just to counter the oxidation of digestion. Men in the U.S. average about 2500 calories a day and so should be getting at least 11,000 antioxidant units a day. Women eat about 1800 calories and so should get at least 8,000 units just to stay solvent. However, the average American doesn’t even get half the minimum–no wonder oxidant stress related diseases abound. We’re getting so few antioxidants in our diet that we can’t even keep up with the free radicals created by merely digesting our meals. We are a nation in chronic oxidative debt.

Developed societies eat a lot of food but not enough plants, which could result in exaggerated and prolonged metabolic, oxidative, and immune imbalance. This presents opportunity for biological insult that over time could supersede our defense and repair systems, and manifest in cellular dysfunction, disease, and ultimately death.

Is there a refined sweetener that doesn’t cause free radical formation? Yes: Erythritol May Be a Sweet Antioxidant.

What’s the best way of reaching our daily minimum of 8,000-11,000 antioxidant units a day? That’s covered in my video How to Reach the Antioxidant “RDA“.

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live year-in-review presentations Uprooting the Leading Causes of Death and More Than an Apple a Day.

Eating Outside Our Kingdom
Tricks to Get Adults to Eat Healthier
Combating Common Diseases With Plants


W. C
W. Cabout a year ago

Thank you.

William C
William Cabout a year ago


Jeanne Rogers
Jeanne Rogers2 years ago

Thank you for sharing.

Nina S.
Nina S2 years ago


Angela Malafouris

Let me get another apple and re-read this!

Angela J.
Angela B4 years ago

Great information.....thanks!!

Catrin Kroehler
Catrin S4 years ago

Thanks .

Tanya W.
Tanya W4 years ago


Tanya W.
Tanya W4 years ago


Elizabeth Brawn
Elizabeth Brawn4 years ago

Thank you