By: Michael Greger,MD. is a physician, author, and internationally recognized professional speaker on a number of important public health issues.
Glucose is the primary fuel of the human body, that’s what starches are broken down into. Our body takes glucose in our diet and the oxygen we breathe in and makes energy to power our bodies, water, and carbon dioxide that we breathe out. Plants then take the water and CO2 and make oxygen and organic compounds like glucose and the cycle continues in this circle of life.
That’s what carbohydrate means, basically hydrated carbon–carbon and water, which is what plants use to make carbs with, and all that’s left after we burn them for energy in our muscles and brain, but this process of oxidizing glucose to make energy is messy, and generates free radicals, such that if we chug down straight sugar-water the level of oxidation in our bloodstream goes up over the next few hours.
Why would our bodies 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 what? Anti-oxidants. In nature sugar always comes with phytonutrients.
If you drink the same amount of sugar in the form of orange juice you don’t get that spike in oxidation. Why?
Because the sugar in fruit comes prepackaged with antioxidants.
Can’t we just drink vitamin C enriched sugar-water?
No, it wasn’t the vitamin C in the OJ, but the citrus phytonutrients like hesperetin and naringenin that beat back the oxidation.
If we don’t eat phytonutrient-rich plant foods with each meal like fruit, 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.
- The free radicals in our body can oxidize the fats in our blood and help set us up for heart disease.
Here’re the levels of oxidized fat in our blood 1,2,3 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, within hours.
- If we don’t eat phytonutrient-rich foods with our meals, our body has to dip into its backup supply of antioxidants and you 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. In the very least we don’t want to slide backwards every day and end up with less antioxidants in our bodies than we woke up with.
Just to break even here’s about how many antioxidants we need every day, depending on how much we eat, just to counter the oxidation of digestion. (This is measured in millimoles of trolox equivalents).
- Men in the U.S. average about 2500 calories a day, and so should be getting at least 11,000 micromoles a day.
- Women eat about 1800 calories so should get at least 8,000 just to stay solvent.
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 we can’t even keep up with the free radicals created just digesting our meals. We are a nation in chronic oxidative debt.
In developed societies we eat a lot of food, but not enough plants, which could result in exaggerated and prolonged metabolic, oxidative, and immune imbalance, presenting opportunity for biological insult that over time could supersede biological defense and repair systems manifesting in cellular dysfunction, disease, and ultimately death.
If those citrus phytonutrients sounded familiar to you, it’s because I mentioned them before in videos like Keeping Your Hands Warm With Citrus and Reducing Muscle Fatigue With Citrus. It’s still better to eat the whole fruit though (See Best Fruit Juice and Apple Juice May Be Worse Than Sugar Water).
Digestion isn’t the only physiological source of free radicals—exercise is too. See Preventing Exercise-Induced Oxidative Stress With Watercress.
Background on the role free radicals play in aging and disease can be found in my video Mitochondrial Theory of Aging. Antioxidant-rich diets can even change gene expression: Plant-Based Diets and Cellular Stress Defenses.
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 8-11,000 antioxidant units a day? So glad you asked! Covered in my next video, How to Reach the Antioxidant RDA.
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About Michael Greger M.D.
Michael Greger, M.D., is a physician, author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous “meat defamation” trial. Currently Dr. Greger proudly serves as the Director of Public Health and Animal Agriculture at the Humane Society of the United States.