After investigating a crucial nutrient that contributes to a better memory, researchers are still largely in the dark on how it influences neurons as we get older.

But there’s one thing the scientists know for sure about vitamin A — if you run short of this natural chemical, your thinking processes will slow with the passing years.

Paradoxical Nutrient

Investigations into the influence of vitamin A on cognitive abilities have proven that older people with a vitamin A deficiency suffer memory and other thinking impairments.

A study conducted by Canadian and Chinese scientists found that having just slightly less vitamin A than you need significantly increases your risk of Alzheimer’s disease. In this study, the researchers found that folks with the lowest vitamin A levels experienced the most drastic decline in their memories as they aged.

In addition, the researchers discovered that some older people recover their memory when given vitamin A. And that led to the conclusion that vitamin A supplementation “might be a potential approach for AD prevention and treatment.”1

At the same time, researchers at the Oregon Health and Science University have reviewed a wide range of studies on how vitamin A affects the brain. They found that the body has to keep vitamin A in careful balance to maintain the brain’s ability to continually form new memories.2

And while the Oregon academics agree that vitamin A can be used as a therapy against memory and dementia problems as people get older, they caution that we still don’t fully understand all of the physiological roles vitamin A plays in the brain.

Even though vitamin A is necessary for proper brain function and a host of other vital processes in the body, it has presented medical researchers with a puzzle over the years. Over and over again, studies have shown that too much vitamin A is just as bad for your health as too little. The trick is to reach just the right balance.

Massive Doses are a Bad Idea

With that in mind, I want to make it clear that mega-doses of vitamin A are always a bad idea.

Research shows that too much vitamin A can:

  • Cause the immune system to malfunction and make you more vulnerable to illness by “downregulating” the activity of some immune cells.3
  • Impair the function of mitochondria (the cells’ “batteries”) and disrupt their production of cellular energy.4
  • Help cancerous tumors grow bigger by enabling them to generate a bigger supply of blood vessels. (Cancer tumors grow their own network of blood vessels in a process called angiogenesis.)5

Make Sure You Get the Right Amount of A

The best way to get vitamin A is to eat plenty of fruits and vegetables that are rich in carotenoids – plant pigments that the body makes into vitamin A. The foods richest in carotenoids include carrots, sweet potatoes, pumpkin, spinach, cantaloupe, apricots and mangoes.

Eating those foods allows the body to make the right amount of vitamin A it needs and avoids an overload.

If you take supplements, take those with very small amounts of vitamin A or beta carotene – 10,000 IU is plenty. Too much does more harm than good. I’m appalled when I see supplements for sale offering 25,000 or even 50,000 units of A or beta carotene.


  1. https://www.ncbi.nlm.nih.gov/pubmed/28130638
  2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3169332/
  3. http://www.jleukbio.org/content/98/1/129.abstract
  4. https://www.ncbi.nlm.nih.gov/pubmed/?term=Ulrich+Hammerling%2C+2009
  5. https://www.ncbi.nlm.nih.gov/pubmed/?term=Stephen+W.+Byers%2C+2008