Major mental illness linked to low winter levels of this crucial vitamin

If there’s one thing you decide to improve upon in the New Year, I suggest making sure to supplement with the right amount of vitamin D3.

The truth is, more than 40 percent of Americans have a vitamin D deficiency, which research links to a growing list of chronic diseases.

In fact, a recent study found a disturbing connection between low vitamin D and the onset of major mental illness. I’ll tell you all about that study in a moment. But first, let’s take a look at why supplementing with vitamin D makes an especially good New Year’s resolution.

The effects of wintertime vitamin D depletion

In most parts of North America and all of Europe, the sun just doesn’t get high enough in the sky to activate D production in your skin during winter months — even when it’s shining bright.

So, unless you supplement daily with adequate amounts of vitamin D (I recommend 10,000 IU), your blood levels of this critical nutrient will significantly drop.

Unfortunately, as I reported in September, The New York Times and other mainstream news outlets continue to ignore — and even criticize — the clear science supporting vitamin D supplementation.

It’s frustrating, because it seems we’ve only just begun to scratch the surface in terms of understanding the degree to which low vitamin D can damage your health…

Of course, research has already revealed clear associations between low levels of vitamin D and increased risk of chronic conditions like Alzheimer’s, cancer, and multiple sclerosis (MS). And now, we can add major mental illness to that list…

New study links major mental illness to low vitamin D

In this new study, researchers from the U.K. investigated the association between low vitamin D and schizophrenia, a major mental illness suffered by more than three million Americans.

Previously published studies have demonstrated that psychotic men and women at in-patient facilities frequently suffer from low vitamin D. But I have always been reluctant to put too much stock into that correlation — especially since those earlier studies used blood samples taken well after the patient had been diagnosed with a mental disorder. And it’s quite possible that they suffered from low vitamin D because they didn’t go outside enough once placed at the in-patient facility.

However, this new study took a different approach…

They looked specifically at the patients’ vitamin D blood levels at their first episode of psychosis (FOP). In other words, they wanted to see if the patients had low vitamin D when they experienced their first symptoms of mental illness.

For this analysis, the researchers defined vitamin D levels between 25 and 50 nanomoles per liter (nmol/L) as “insufficient.” And they defined levels lower than 25 nmol/L as “deficient.”

Overall, they found that FOP patients had significantly lower levels of vitamin D than their healthy, age-matched peers. In fact, the FOP patients were almost three times more likely to have a vitamin D deficiency.

The researchers say these findings suggest that low vitamin D might be a “risk factor” for psychosis.

But I’d take it a step further…

In my view, these findings suggest low vitamin D may even play a role in “triggering” the initial episode in vulnerable people.

Lack of sun exposure has always affected mental health

Of course, we’ve actually known about the significant association between low light, low vitamin D, and low mood for a long time…

Even mainstream experts now recognize that low sun (aka vitamin D) exposure causes Seasonal Affective Disorder (SAD) in millions of people.

And without a doubt, not seeing the sun for extended periods bothers people…and can even cause mental changes.

For example, in Polar Regions in the Arctic and Antarctic, where the sun disappears below the horizon for months at a time, some people suffer from a mental disorder called “Arctic hysteria.”

The Eskimos call it “piblokto.” And my professor at the University of Pennsylvania, Edward Foulkes, M.D., Ph.D., wrote a book about it. (Dr. Foulkes was a fascinating fellow. He was both an anthropologist and psychiatrist. He also “secretly” worked with the CIA.)

Of course, in New England where I grew up, folks simply call it “cabin fever.” Granted, the degree of vitamin D deficiency experienced in New England is probably less serious than in the Arctic.

I found it curious the U.K. researchers didn’t mention this well-known research on the Arctic hysterias or piblokto. Especially since the British were actually the first to seriously explore polar regions during expeditions in the early 1800s — and they often got their ships trapped in the polar ice for years at a time, like the doomed Franklin expedition, looking for the fabled “Northwest Passage” from the Atlantic to the Pacific.

We have the science, but continue to ignore it

When I think about all this historical and scientific evidence on the importance of sun exposure and vitamin D, it makes me wonder…

How can psychiatrists be “experts” on behavior in people if they aren’t aware of the decades’ worth of studies on emotional health, culture, and personality conducted by anthropologists and social scientists? Let alone all the nutritional studies on vitamin D as it relates to mental and physical health?

Granted, the researchers did acknowledge that the role of vitamin D in mental health is overlooked and under-researched. And they even pointed out that patients with schizophrenia often suffer from early-onset osteoporosis, which also relates to low vitamin D.

In the end, I found it fitting that the study came from the U.K., where low vitamin D is a vast epidemic. In fact, I’m sure natural vitamin D production in the skin is a problem throughout most of the year in the U.K., with their gloomy, cloudy skies.

At least the Brits do indeed seem to know lack of sunshine is a problem! Perhaps someday American medicine will follow suit…

In the meantime, while all these mainstream minions continue to dither, here are three actions you can start taking now to make sure you’re getting enough vitamin D.

  1. Ask your doctor for a 25(OH)D blood test. This will tell you your vitamin D levels and determine whether or not you need to take the next two steps. I recommend keeping your levels between 50 nmol/L and 70 nmol/L.
  2. Use a light therapy lamp. During the wintertime, when we’re most prone to SAD due to lack of sunlight, I recommend using light therapy to soak up some UV rays each day and trigger vitamin D production in the skin. These lamps come in all shapes and sizes to fit your home and your budget. Just make sure you look for a lamp with full spectrum LED light. offers a wide selection — simply search “light therapy lamp.”
  3. Supplement daily with 10,000 IU of vitamin D3. This is perhaps the most important step of them all in building — or maintaining — your vitamin D levels.

You can find it in easy-to-take liquid form, together with the potent marine carotenoid called astaxanthin for added benefits. (For more information, simply type “astaxanthin” into the top right search bar of my website,

New science is published regularly highlighting the importance of vitamin D for our body and mind. So, do what you can now to make sure you’re getting enough of this essential nutrient.

And as always, I’ll keep bringing you the latest science-backed health recommendations on how you can lead a stronger, longer life…no matter the season.


“Vitamin D deficiency in first episode psychosis: A case-control study,” Schizophrenia Research 2013; 150(2): 533-537