Cell-damaging free radicals in the brain are considered a consequence of Alzheimer’s. But in breakthrough new research, scientists now believe that free radicals, far from being a result of the disease, are a warning that an Alzheimer’s diagnosis lies ahead. A warning that we should heed and try to change.

Free radicals are produced as a byproduct of normal metabolism that involves the splitting of oxygen molecules. While free radicals have positive roles to play in the body, they are highly unstable and reactive, so an overabundance will cause harmful chemical reactions (called oxidation) that damage cells and cause numerous health problems.

That’s where antioxidants come in.

Antioxidants mop up excess free radicals, but if there aren’t enough antioxidants to accomplish this important task, a damaging cellular process called oxidative stress is set in motion.

The Brain is Highly Susceptible to Oxidative Stress 

The brain is susceptible to oxidative stress because it has a high requirement for oxygen and contains an abundance of unsaturated fats that are particularly vulnerable to oxidation by free radicals.

A great deal of evidence now supports the view that oxidative stress is an early event in Alzheimer’s. It’s believed to play a role in the disease pathology because autopsies of people who die with Alzheimer’s disease reveal lesions in the brain that are typically seen after free radical exposure.

Oxidative stress is also linked to the two hallmarks of Alzheimer’s – plaque formation and abnormal tau proteins – and is also associated with decreased cellular communication, neuroinflammation, and loss of cellular mitochondrial (energy) function.

Higher levels of antioxidants can also be found in the brains of Alzheimer’s victims, suggesting an attempt was made to combat oxidative stress.

The new research findings demonstrate that oxidative stress is not just a bystander in Alzheimer’s pathology but could also be a cause of the disease.

A Five-Year Warning 

The breakthrough was made by Professor Charles Ramassamy and his team at the Institut National De La Recherche Scientifique in Quebec, Canada. Together they demonstrated that levels of oxidative markers known to be involved in Alzheimer’s dramatically increase as early as five years before the onset of the disease.

These oxidative markers are found in plasma extracellular vesicles, which are pockets released by all cells in the body, including those in the brain. They can be detected by a blood test.

Prof. Ramassamy explained, saying, “Given that there is an increase in oxidative stress in people who develop the disease, we may regulate the antioxidant systems. For example, we could modulate the antioxidant systems, such as apolipoproteins J and D, which transport lipids and cholesterol in the blood and play an important role in brain function and Alzheimer’s disease.”

This means we have an early indicator of the disease through a blood test that reveals markers for these damaging molecules.

Prof. Ramassamy also suggests an alternative to chemical antioxidant manipulation that we can all engage in. “Another avenue would be to increase the intake of antioxidants through nutrition.”

It’s sage advice that we should all get behind. As numerous studies have shown, we can help protect ourselves against Alzheimer’s disease—and many other so-called diseases of aging—by boosting our antioxidant intake.

Antioxidants in Food 

Many different antioxidants can be found in a healthy diet. Vitamin C is the best-known antioxidant but vitamin E, beta carotene, other carotenoids, flavonoids, phenols, and many other plant chemicals can be found in diets that include plenty of fruits and vegetables. Best of all, these nutrients also have many other health benefits that go beyond their role as antioxidants.

In 2020, Tufts University published research showing that a low intake of flavonols (apples, pears, and tea) was associated with twice the risk of developing Alzheimer’s and related dementias. Low intake of anthocyanins (blueberries, strawberries, and red wine) was associated with a four-fold risk.

Lowers Your Risk by 48 Percent 

In the same year, Thomas Holland, from Rush University Chicago, led a study that showed people consuming the most flavonols were 48 percent less likely to develop Alzheimer’s than those who were consuming the least.

In addition to apples, pears, and tea, flavonols are found in kale, spinach, broccoli, tomatoes, beans, oranges, olive oil and wine.

Dr. Holland said, “Eat your fruits and vegetables, particularly dark leafy greens, and drink some tea every now and again. A healthy diet that contains various fruits and vegetables is critical for continued health, especially brain health.”


  1. https://www.alzheimers.org.uk/about-dementia/risk-factors-and-prevention/antioxidants
  2. https://alz-journals.onlinelibrary.wiley.com/doi/10.1002/dad2.12231 
  3. https://inrs.ca/en/news/antioxidants-a-potential-pathway-to-prevent-alzheimers-disease/ 
  4. https://now.tufts.edu/2020/05/05/more-berries-apples-and-tea-may-have-protective-
    benefits-against-alzheimers 
  5. https://www.reuters.com/article/us-health-diet-dementia-idINKBN1ZS2YX 

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