Which diseases are caused by lack of sunlight?
No single disease goes by that name. What Dr. Martin gives is a list, taken from a 2020 review in the International Journal of Environmental Research and Public Health.
Dr. Martin on what the review found:
Dr. Martin, from The Doctor Is In, episode 613I'm happy to repeat it, but they're the ones who were saying it, especially breast and colon cancer, prostate cancer in men, hypertension, cardiovascular disease, metabolic syndrome, nevermind the psychological effects.
In episode 1058 he names more from it:
- MS, an autoimmune disease
- Alzheimer's
- Asthma and type 1 diabetes
- Myopia, or nearsightedness
The list is the researchers', not his. The thread he sees through it is vitamin D.
Can lack of sunlight kill you?
Not from one gray week. The number he cites is an estimate from a review of studies across whole countries.
Dr. Martin on the figure:
Dr. Martin, from The Doctor Is In, episode 613Estimated for people that don't get in the sun, estimated. Listen to this, every year in the U.S.A. they're saying, according to the review of all studies, 340,000 deaths per year in the U.S.A. alone are attributed to a lack of sunshine.
The same review put Europe at about 480,000 a year. He also describes a Swedish study of 30,000 women whose authors compared staying out of the sun with smoking.
In his telling, those deaths build up over years. His ask is modest: regular sun you never burn in.
What does lack of sun exposure do to your body?
It leaves you short of vitamin D, which your skin makes in sunshine. He calls that VitDerma.
Dr. Martin on what vitamin D does:
Dr. Martin, from The Doctor Is In, episode 870Vitamin D is a hormone. Your immune system doesn't work without it. Your bones don't work without it. Your muscles need it. Your eyeballs need it. Your brain needs it for serotonin and dopamine, melatonin.
After 60, bones are the big worry. See what weakens bone after 60 and vitamin D for women over 60.
Does lack of sunlight raise blood pressure?
He thinks it can. Sun on your skin raises nitric oxide, which relaxes your blood vessels, and high blood pressure sits on the review's list.
Dr. Martin on nitric oxide:
Dr. Martin, from The Doctor Is In, episode 613N-O spells nitric oxide and it opens up your blood vessels. It's good for your heart, it's good for your blood pressure, it's good for everything.
There is more in blood pressure in women over 60 and nitric oxide after 60. Keep your own doctor in charge of any blood pressure plan.
Is lack of sunlight linked to breast cancer?
In the studies he reads, yes. Breast cancer tops the review's list, and he adds a study from Denmark.
Dr. Martin on the Denmark study:
Dr. Martin, from The Doctor Is In, episode 581The more sun that you get, you decrease your risk of breast cancer by 17%.
That is a link in a study, not a promise, and never a reason to skip a mammogram or any screening your doctor suggests. His bigger point is for women.
"Because you never hear that if you are a woman, you need to get out in the sun. Get out in the sun."
Dr. Martin, from The Doctor Is In, episode 581Is lack of sunlight linked to Alzheimer's?
The review puts Alzheimer's on its list as well.
Dr. Martin on memory:
Dr. Martin, from The Doctor Is In, episode 1058Well, according to this study, if you don't get enough sun. You don't get enough sun exposure, you don't get enough Vitamin D. You are much more susceptible to Alzheimer's.
In episode 613 he gives two reasons: the brain needs vitamin D, and nitric oxide from the sun keeps blood moving through its small vessels.
Can lack of sunlight weaken your immune system?
Yes, in his view. He says every cell in your body has a receptor for vitamin D, your T-cells most of all.
Dr. Martin on the immune system:
Dr. Martin, from The Doctor Is In, episode 1208And today, we know that your T-cells, your navy seals of your immune system don't work properly without the sun.
He sees the same pattern in a slow thyroid, citing a 2021 analysis of 35 studies.
"When your thyroid's not working properly, almost invariably you have low levels of vitamin D. Aha. So what am I saying? You got a solar panel there too."
Dr. Martin, from The Doctor Is In, episode 1154Can lack of sunlight affect your mood?
Yes. Sunshine lifts serotonin, and he sees how many people sag once the days get short.
Dr. Martin on the dark months:
Dr. Martin, from The Doctor Is In, episode 1208Some people, they just don't do well, and especially as we get in those dark months, November, December, January, difficult months for a lot of people because they don't see the sun.
If low mood lasts more than two weeks, talk to your doctor. For a busy, worried mind, see anxiety in women over 60.
Why do women over 60 get so little sun?
He blames the advice his own generation grew up on.
Dr. Martin on who gets the least sun:
Dr. Martin, from The Doctor Is In, episode 613Where that occurs the most is when people get older, they were lied to, seniors, my generation, my parents' generation. They were told to stay out of the sun.
The review blames fear of the sun after skin cancer campaigns, indoor living, screens and air conditioning, and he says even Floridians stay inside. His clinic tested tens of thousands of seniors.
"I rarely ever, ever saw someone that had optimized vitamin D levels over 50 years old. They just didn't."
Dr. Martin, from The Doctor Is In, episode 1265How much sun do you need?
Less than most people think. His rule of thumb is about 20 minutes on bare arms and legs, never long enough to burn.
Dr. Martin on the 20 minutes:
Dr. Martin, from The Doctor Is In, episode 836And when you're in the sun for 20 minutes, no sunscreen, arms and legs especially, vitamin D is synthesized on your skin, 20 minutes, 10,000 IUs. But you'll never overdose. Now, I don't want you to burn in the sun.
Going without sunscreen for those minutes is his view. He would rather you wear a hat, find shade or cover up than put chemicals on your skin. Never let your skin turn pink, and take most care if your skin is fair. If you have had skin cancer, ask your doctor how much sun is safe for you.
What if you can't get out in the sun?
Then take vitamin D, he says. It is one of his three for a woman at 65.
Dr. Martin on skin that can't take sun:
Dr. Martin, from The Doctor Is In, episode 613If you got lupus or whatever... you know what? You and the sun don't get along. That's okay. Then take Vitamin D as a supplement.
With a condition like lupus, check any supplement with your doctor first. Sitting behind a glass window does not count, he says.
"Are sunrooms good? Yep, but not for vitamin D. Melatonin, yes. Vitamin D, no. You need the UVB radiation going to your skin to get vitamin D."
Dr. Martin, from The Doctor Is In, episode 836Watch episode 613
In Death By Lack of Sunshine he walks through the Swedish study and the 2020 review, and names VitDerma.
Common questions
Does darker skin need more sun?
Yes. Darker skin is built to shield itself, so he says it needs longer in the sun (episode 587), about twice as much (episode 570).
Does what you eat change how much sun you can take?
He says people who get off sugar, refined carbs and bad oils can take more sun (episode 836). Still, never burn.
Is winter sun still good for you?
Yes. Your skin makes little vitamin D then, but he says a sunny day still helps serotonin, dopamine and melatonin (episode 870).
Can you get too much vitamin D from the sun?
Not in his view. Once you are topped up, he says, your body stops taking it in, so watch for burning instead (episode 836).
When sunshine is hard to come by
Sunshine comes first for Dr. Martin. When winter, window glass or skin that burns easily keeps you out of it, his clinic makes Liquid Vitamin D + K2, a tasteless liquid that is easy to take and there to support your vitamin D levels. Taking a blood thinner? Ask your doctor before adding vitamin K2.
60-day money-back guarantee. Ask your doctor to check your vitamin D level before winter.
