We’ve all become only too aware of the COVID-19 pandemic. But there’s another pandemic taking place right under our noses. It has been going on for decades, yet few are aware of how it can destroy our health.

I’m talking about vitamin D deficiency. Now, new research demonstrates the importance of the so-called “sunshine vitamin” in keeping your memory sharp.

Vitamin D deficiency is estimated to affect over a billion people worldwide. It’s so common, in fact, that Michael Holick, PhD, M.D., a world-renowned vitamin D expert from Boston University Medical Center, describes it as a pandemic.

Dr. Holick says, “The consequences of vitamin D deficiency cannot be underestimated” as it’s linked to so many health problems including neurological disorders such as Alzheimer’s disease.

Memory Loss and Vitamin D 

In terms of the brain, research has uncovered three ways vitamin D potentially offers protection against memory loss. Vitamin D:

  1. Promotes the growth, development, and maturity of neurons
  2. Helps maintain the health of blood vessels
  3. Lowers inflammation

Despite abundant evidence documenting vitamin D’s ability to protect against disease, not all scientists are convinced. They maintain that vitamin D is important to bone health, but not much else. So, scientists from the University of South Australia wanted to see who is right.

Robust Genetic Study On Vitamin D 

For their study, published in The American Journal of Clinical Nutrition in April, scientists at the University of South Australia carried out an analysis involving British volunteers in the U.K. Biobank.

The U.K. Biobank is a large-scale biomedical database and research resource containing detailed information on participants’ socioeconomic status, lifestyle, and health, including genetic information. It also includes brain imaging on some of the Biobank participants.

The researchers analyzed 294,514 men and women to determine who had blood levels of vitamin D below 25 nmol/L (10 ng/mL) and how this affects the risk of dementia. Researchers also had access to imaging for 23,901 participants.

The team considered a wide range of variables including time spent outdoors, use of sun protection, diet, supplement use, and physical activity. They also used a statistical technique called Mendelian randomization, a robust genetic approach that allows testing for underlying causality—meaning the researchers can determine more than simply a link during the study, but an actual direct cause (or not).

Their findings?

One Person in Six Can Avoid Dementia By Getting More Vitamin D 

This study revealed a direct link between dementia, a deficiency in vitamin D and lack of sunlight. The team wrote that “this is the first study…to provide causal evidence.”

What’s more, they found a low level of vitamin D was associated with lower brain volume. You might recall that we’ve written in the past about several studies showing how the brain shrinks with age and how this loss of volume is linked to the development of dementia.

Senior investigator, Professor Elina Hyppönen, explained the results, saying, “Vitamin D is a hormone precursor that is increasingly recognized for widespread effects, including on brain health.

“In some contexts, where vitamin D deficiency is relatively common, our findings have important implications for dementia risks. Indeed, in this UK population we observed that up to 17 percent of dementia cases might have been avoided by boosting vitamin D levels to be within a normal range.

“If [we ensure] that none of us is severely vitamin D deficient, it would also have further benefits and we could change the health and wellbeing for thousands.”

In my view that’s a lot of dementia cases that could have been easily prevented with a simple, safe, affordable, and widely available supplement.

Prof. Hyppönen goes on to say, “…for anyone who for whatever reason may not receive enough vitamin D from the sun, modifications to diet may not be enough, and supplementation may well be needed.”

Expert Confusion Over How Much Vitamin D is Necessary 

Of course, the debate rages on over how much vitamin D is needed to avoid health problems like dementia.

Some leading epidemiologists and endocrinologists suggest 12.5 ng/mL of vitamin D is an acceptable blood level.

Meanwhile, the Institute of Medicine regards 20 ng/mL or higher as adequate for good bone health, and anything below this is seen as deficient.

The Endocrine Society regards 30 ng/mL to be the lowest acceptable level but recommends maintaining a level between 40 and 60 ng/mL for both adults and children.

In the current study, both low and high levels – greater than 125 nmol/L (50 ng/mL) – were linked to a lower brain volume, and a high level but not a low level was linked to lower volume in the hippocampus, a key memory area.

If the experts can’t agree, what are we non-scientists supposed to make of it?

My Takeaway 

My team and I have been writing on the importance of vitamin D for robust, good health for the last 15 years. We’ve seen the research and met with the patients who are living testimonies to the fact that increasing vitamin D levels can help improve everything from memory loss to cancer.

Most important, the only way to know if you’re deficient in vitamin D is to get your vitamin D blood levels checked every year. By the way, if you live in a cold climate and you’re not supplementing with a significant amount of vitamin D, chances are you’re deficient.

Personally, I think everyone can benefit from a good daily supplement of vitamin D3 (cholecalciferol, the most absorbable form). That’s why our sister company, Green Valley Natural Solutions, developed two of its leading anti-aging formulas with a healthy dose of Vitamin D3. I’m talking about Genesis, which promotes the health of cellular telomeres that are linked to longevity and Iuvenis, which supports strong blood flow and circulation for healthier aging.

So, what vitamin D blood level should you aim for?

Most natural health doctors will tell you that the conventional experts’ recommended vitamin D levels outlined above are woefully inadequate. Instead, many point out that maintaining a blood level between 50 ng/mL and 80 ng/mL is a better choice for your health, although some doctors suggest vitamin D blood levels as high as 80ng/mL to 100ng/mL.

When in doubt, I recommend working with a natural or alternative doctor that you trust.


  1. https://www.unisa.edu.au/media-centre/Releases/2022/vitamin-d-deficiency-leads-to-dementia/
  2. https://academic.oup.com/ajcn/advance-article/doi/10.1093/ajcn/nqac107/6572356?login=false 
  3. https://www.health.harvard.edu/blog/vitamin-d-whats-right-level-2016121910893