I’ve broken a bone in my foot, which means I’ve spent a fair bit of the week in hospital and a fair bit of time hobbling around, very slowly, in a big plastic boot or weird and deeply uncomfortable, back-to-front footwear.
In the same week that Vitamin D made headlines, it’ll come as no surprise (given its reputation as a bone-builder) that today I’m writing about Vitamin D.
In case you missed the headlines, they went as follows: Vitamin D supplements reduce (by 13%) the risk of dying from cancer. The report author says he’d like to see more oncologists and doctors ‘prescribing Vitamin D.’ You need to take Vitamin D for at least three years, he adds, while conceding that Vitamin D supplementation won’t prevent cancer.
As it happens Vitamin D is the one supplement we routinely recommend: you can read our earlier post here or check out the chapter on supplements in our book. When I had my vitamin D levels measured last September, they were impressively high, according to my doctor. But that wasn’t because of supplements. I hadn’t touched a supplement for six months. Instead I’d conducted my own sunlight experiment, which involved spending a daily 15-20 minutes in the sun, shoulders, arms and upper back fully exposed, without sunscreen, for ten weeks.
I did this without sunscreen because the data on whether UVB (the rays which ultimately provide Vitamin D) penetrates sunscreen is ambiguous (scroll to the end to read about a new report suggesting Vitamin D can pass through factor 15 sunscreen – in Tenerife at any rate).
But I also conducted my sunlight experiment because it occurred to me that Vitamin D might not be the only beneficial component of sunlight.
For years it’s been assumed that sunlight – in moderation – is good for us because when it hits our skin, we make Vitamin D. But what if sun-skin exposure provides more than just Vitamin D?
Recently, a few oddities have alerted researchers to factors that might have been overlooked. At a lecture last month I learned about Multiple Sclerosis jumping eight fold in Iran after women stopped exposing their skin to sunlight. They were given Vitamin D supplements but these had no effect. And yet when the women resumed exposing their skin to the sun, MS rates duly fell, prompting scientists to ask what else the sun might be providing if it wasn’t Vitamin D?
Researchers at Georgetown University Medical Centre found a possible answer: sunlight appears to cause T cells to move more quickly. T cells are immune cells (sometimes called defender cells) that, once an infection is triggered, make their way to the infection and see off any invaders. Our skin carries a large number of T cells, twice as many as those circulating in our blood. Meanwhile the blue light in sunshine can reach not only the surface layer of our skin but the second layer, known as the dermis, enabling it to reach vast swathes of T cells.
When our white blood cells sense an infection, a compound called hydrogen peroxide is activated which kills invading bacteria and urges our immune cells to mount an immune response. Sunlight makes hydrogen peroxide in our T cells, enabling them to mobilise swiftly and efficiently. Sunlight (and specifically the blue light within it) may well boost immunity.
Meanwhile sunlight has also been found to lower blood pressure. A report from the University of Edinburgh found that twenty minutes of sunlight lowered blood pressure for more than an hour. The author speculated that exposure to sunlight might also reduce the risk of strokes and heart attacks as well as prolonging life.
To boot, there’s growing evidence that regular exposure to sunlight could help prevent colon, breast and prostate cancer, non-Hodgkin lymphoma and diabetes. The report headlining this week suggests the credit (at least as far as cancer is concerned) should go to Vitamin D supplements. But what if Vitamin D is only part of the answer?
Recently it’s become evident that the sun’s role in forming nitric oxide, melatonin and serotonin and its effect on our circadian rhythms are also involved. Some researchers now believe – paradoxically – that a little daily sunlight on unprotected skin might actually reduce our risk of skin cancer (particularly melanoma). They argue that most cases in Europe are caused by binge-bathing – exposing our unprepared skin for too long instead of regularly exposing skin which, apparently, confers a relatively low risk. Read more here.
Finally (and more on this in a future post), experiments with mice suggest that sunlight also has the power to change and improve our microbiome, even after controlling for Vitamin D. In other words Vitamin D might have nothing to do with it.
So what about my own experiment?
After an entire summer of moderated sun exposure (English sun for 15-20 minutes every day, then rigorous cover-up – not once did I burn) I had some extraordinary results.
For the first winter in my entire life I didn’t spend a single day sick. Not a single cold, cough or sore throat. For someone whose childhood was blighted by constant ear ache and whose adulthood involved several weeks of heavy colds every winter, this was a revelation.
More astonishingly, my autoimmune disease (Inflammatory Bowel Disease) went into remission and has been in remission ever since. At first I assumed this was merely coincidence. Later, I wondered if my ‘summer of sun’ had played a role. And last week a report popped into my in-box suggesting my hunch might be correct. An Australian study found that children given an extra half hour in the sun significantly reduced their risk of … IBD. The researchers found that even short periods of sun exposure were associated with a lower risk of children developing IBD.
Professor Lucas, author of the report said: “Taking children to play outside in the sun could be life-changing. It doesn’t have to be all at the same time. But we found children who were outside and exposed to the sun for an extra half hour a day in total, had a lower risk of developing IBD by almost 20 per cent. Every 10 minutes of sun exposure was associated with a lower risk of developing inflammatory bowel disease by six per cent.”
Australia, incidentally, has one of the highest rates of IBD.
This report adds to the growing body of evidence that sun exposure (and/or Vitamin D) might reduce the risk of autoimmune diseases in general. Similar reports suggest there may also be benefits to cumulative sun exposure. Which is why I’ll be repeating my ‘summer of sun’ experiment in the admittedly-meagre rays of the UK, every summer from now on.
And for those of you who live in locations where the sun is too strong to risk going without sunscreen (or who simply feel happier when lotioned), take heart – possibly – from a recent report that found Vitamin D levels increased despite the use of an SPF 15 sun screen. NB this was Tenerife ‘with a very high UV index’. If I restricted myself to SPF 15 while sunbathing in Tenerife I’d be burnt to a crisp within minutes. What we really need is research that investigates whether Vitamin D can be made on skin slathered in 30+ SPF sun screens (which is what most dermatologists recommend). So far, no one has done this. Why not?
More importantly, this study found that broad spectrum sunscreen enabled higher Vitamin D synthesis than a low UVA protective sunscreen. So if you’re buying a sunscreen make it one that protects from both UVA and UVB rays.
There’s another element to the story of sunlight which I’ll write about in an upcoming post: nitric oxide (NO). Nitric oxide – much of which is made in our skin from sunlight – is coming increasingly under the medical spotlight for its role in healthy longevity.
So. In the Northern hemisphere, sunlight (every sunny day, not too much, direct to the skin) may be more beneficial than we’ve previously thought.
Meanwhile if you’re taking a Vitamin D supplement it should be D3 not D2. And if, like me, you’re building new bone, be sure to include Vitamin K-rich foods in your diet. When it comes to building bone, new studies show that a combination of Vitamins D and K2 is particularly beneficial for post-menopausal women. Our chicken liver salad (while sitting in the sun) should do it.
My thanks to Linda Geddes, whose recent lecture and excellent book (Chasing the Sun: The New Science of Sunlight and How it Shapes our Bodies and Minds) helped inspire the research and writing of this post.
Annabel
My dermatologist (and all others I know) here in Switzerland recommend SPF 50+, not 30+
(Switzerland has (or had at some point anyway) the unenviable position of 2nd (to Australia) in the the number of skin cancer cases (pro-rata). Largely, I suspect, due to poor attitudes to dealing with sun protection/avoidance in childhood)
But, your point is correct, more research needed on the balance between the need for sunlight and to avoid skin cancer..
Oh that’s interesting and perhaps because of the higher altitude of much of Switzerland? It’s all about balance. Although many of our ancestors spent their days outside without sun lotion. I imagine they knew when to cover up and they all wore hats too! Thanks for your comment… Annabel
It’s almost unmentioned these days, but in the early 90s there used to be a summer thinning of the ozone over the alps, and maybe this resulted in much higher UV or, as you say, perhaps the altitude..
We were looked at weirdly by the locals for putting suntan lotion (daylong SPF 20 then was the max) on the kids..
You get burnt going skiing/snowboarding, so nowadays many use sun-cream, but the older swiss make fun etc..
I myself had to have an aggressive melanoma removed & a skin graft some 9 years back, so avoid direct sun now..
Ah yes, you need to be very careful. I’m quite partial to sitting in shade though. Just being outside. Interestingly, the only places where you can get Vitamin D from the sun year-round are those at high altitude. Hence the burnt ski-ers…
Your blog is fantastic , been getting it for a couple of weeks now and the value of it is great and the way it is written, everything backed up with easy to understand proof and experience makes it invaluable. Often it explains and proves my hunches, about sunlight for instance at other times opens up new areas for thought and general well-being. Thank you, it’s life enhancing and an act of generosity.
Thank you so much for your kind words. Glad you’re enjoying it. So interesting how our bodies seem to know, instinctively, what they needs – like light! Perhaps we need to trust our hunches a little bit more? Annabel
I now live in Spain and as you said, in the summer’s hottest months it would be impossible to sit out unprotected, however throughout the autumn and spring months, we have lovely sunny ( a good British summers day) days which are perfect for sitting out in….in fact they are my favourite because there are no mosquitoes then!.
But early mornings even in the summer, a quick 15 mins would be possible…..would mozzie spray make a difference as I can’t go out without it in the summer?
I do envy you in Spain! I don’t think mozzie spray would prevent UVB, so keep on using it! Thanks for your comment… Annabel
Having been to tropical countries & rainforests with mosquitos (Vietnam, Myanmar, Costa Rica) where DEET is used, I’d recommend to apply sunscreen first, allow to soak in, then apply DEET thinly (most people overdo it..)
Of course, DEET isn’t needed in Europe (yet..) but I’d follow the same advice..
https://www.worldnomads.com/travel-safety/worldwide/sunblock-or-insect-repellent-first
Note: “Basically, there is no clear, scientifically robust evidence that support these theories; therefore a substantial study needs to be done examining this issue further.”
Good advice, however we now have the tiger mosquitos here in Spain that bit day and night and the only thing that works for me is at least 30% deet!
What a FABULOUS post – so informative and uplifting ! I thought I was coming down with the 4th virus since Christmas – dosed self with echinacea/vitamin c zinc/ berocca (yes all of them as I had been neglecting this so far this year due to working hard as state pension-less ) and sat in sun all afternoon in shorts and strappy top. Luckily at 65 yrs – my garden is private lol – anyway feel like it might have worked : symptoms at bay. So breakfast outside as a base line minimum from now on altho not today as pouring ! Thank you Annabel – first class wrk xx
I can’t sleep when I’ve been out walking. From my own research it’s an excess of seratonin (I think) anyone got anything to offer on this ? It’s hugely irritating. Just a 4.5 mile walk yday – couldn’t sleep all night….. happens after every walk.
Thank you, Sally. I think a breakfast outdoors throughout the summer sounds fabulous. Actually, what I didn’t mention (lost in the reams of stats and data) is just how happy it made/makes me. I really look forward to my daily coffee in the sun and feel really annoyed when – like today – it’s raining! Are you referring to evening walks btw?
Yes I completely agree – when I make the choice to sit in garden SUCCESS and when I turn the other way to Sky News DURRRR !
Unfortunately its daytime walks. It’s excessive Cortisol I think after researching …… I’ve been taking Rhodiola Root – but like you Im not really into supplements so its a bit haphazard. its meant to help, but hasn’t…… It’s been like it for years. I only walk once a week max and sometimes far less so its very clear that it is the exercise that is keeping awake. An early evening swim the other day had the same effect.
Im a regular walker – favourite distance 8/9 miles but two recent walks 11miles and yesterday’s very modest 4.5 all had the same hours long insomnia. Its total wide-awake-ness. Therefore the cortisol theory makes sense to me, only discovered it the other day. Its a right pain – Im going on a walking holiday week after next, and what with the cortisol and lovely greek wine I should’t think I will get a wink until I get back !
Thanks so much for replying 🙂
Ps – get well soon xxx from someone whose broken two ankles but thankfully not at the same time !
Thank you! Ankles sound much more painful… poor you!
Thanks! Ankles sound much more painful… poor you!
Comfrey cream and lotion – good stuff – known as Knitbone.
That’s exactly what I need! Thanks for the recommendation and enjoy your walking holiday (perhaps walk very early in the day?)
Group walk and will be setting off mornings but due to prevailing circs re cortisol I may well re route to beach some days 👍
Was just reading through the comments on this fabulous post and was very thrilled to see Sally that you mentioned comfrey lotion, cream, oil ? as being known as “knitbone”. By chance this morning I asked at the local pharmacist for some because my mother has a broken hip and her good friend in the same ward in hospital recommended it. It is a naturopath’s product and pharmacists are not licensed to sell it here (Australia). I will absolutely be tracking it down though.
https://www.medscape.com/viewarticle/860805
There is a fabulous piece of research from Sweden that equates avoiding the sun with smoking in terms of its effects on longevity. It blows out of the water everything we currently believe. Thank you for your article. Nice and balanced and scientific. I’m not sure we are designed to live our indoor test tube lives with sterile environments and processed food. We need sun and dirt and movement and mess!!
Thanks, Clare. That’s an interesting piece and chimes exactly with my own feelings (not to mention the slowly growing body of evidence found from a good rummage on PubMed!). I agree. Sun, dirt, movement, mess! Although I could do with a bit more sun and a little less mess in my life… ha!
On May 6-7, 2019 the Sunshine Health Foundation hosted a meeting in Washington DC of 24 of the world’s leading scientists from six countries on all the subjects you mention. Inadequate sun exposure is the nation’s #2 public health problem, resulting in 340,000 preventable deaths per year in the US (tobacco kills 480,000). In addition to MS and the other items you mention, inadequate sun exposure has been linked to a 400% increase in the risk of getting breast cancer, a 79% increased risk of dying from breast cancer if you get it, a 100% increased risk of colon cancer, high blood pressure, increased risk of cardiovascular disease, a 35% increased risk of type 2 diabetes, a 64% increased risk of metabolic syndrome in the elderly, a 122% increased risk of Alzheimer’s disease, a 43% increased risk of MS in women, a 90% increased risk of MS in offspring, a 142% increased risk of autism in offspring, a 67% increased risk of type 1 diabetes in offspring, and a host of other problems including myopia, psoriasis, non-alcoholic fatty liver disease, eczema in infants and age-related macular degeneration. The reason for all this is that photons from the sun interact with the human body to produce vitamin D, nitric oxide, dopamine and other known and unknown substances which are required for the proper functioning of the human body. Shortage of these substances manifests as the foregoing and other adverse health events. I will tell you more about this if you will email me back. Allen Miller, President, Sunshine Health Foundation, Dallas, Texas, 214-766-7283.
Have emailed you. Thanks for getting in touch!
Thank you Annabel for yet another great post. As everybody knows Australia (my current place of abode) has the highest incidence of skin cancer in the world, but I didn’t know about the incidence of IBS. I do know that many people living in Australia are fearful of getting skin cancer and don’t go out in the sun. Perhaps they are only increasing their chances of suffering from IBS. A balance with short sessions in the sun seems to be the answer. As they say here “10 till 3, sit under a tree” and “slip (on a t-shirt), slop (on some sunscreen) slap (on a hat).
I am very interested in the connection between multiple sclerosis and lack of sunlight too. My husband’s nephew suffered from serious depression every winter and now has multiple sclerosis. What does it all mean? I am so glad that when we visited last it was a lovely sunny day and we sat outside in the sun for ages. He seemed to enjoy it.
Sorry that my contribution is anecdotal only – not particularly scientific.
Glad you enjoyed, Gaynor. Life is all about balance, but we seem to find balance very hard to achieve! More to come on sunlight as several people have been in touch and sent me many more reports to read through. Sadly in the UK it’s been raining for a week! Annabel
This is all so interesting to me. It never sat well with me, or made any sense that we should be protecting ourselves from all sunshine all the time. So un-natural. I have also been trying to get into sunlight for at least 15 minutes on bright days and have noticed I sleep better and my skin is clearer. I’m hoping to see a difference in my winter SAD symptoms if I can store up this summer.
Glad you found it interesting. I’m fascinated by it, so there’ll be more to come as I delve more deeply into the mysteries of sunlight! Annabel
Ganynor –
MS is highly related to inadequate sun exposure. The leading scientists in the world on this issue are Kassandra Munger and Alberto Ascherio at Harvard University T.H. Chan School of Public Health. Following is synopsis of their most recent publication in 2017 in the medical journal Neurology. You should note that they are talking about serum 25(OH)D levels (blood test for 25-Hydroxyvitamin D) which are obtained by sun exposure, not vitamin D supplements.
25-Hydroxyvitamin D deficiency and risk
of MS among women in the Finnish
Maternity Cohort
ABSTRACT
Objective: To determine whether and to what extent vitamin D deficiency is associated with multiple
sclerosis (MS) risk.
Methods: We conducted a prospective nested case-control study among women in the Finnish
Maternity Cohort (FMC). The FMC had 1.8 million stored serum samples taken during the pregnancies
of over 800,000 women at the time of this study. Through linkages with hospital and prescription
registries, we identified 1,092 women with MS diagnosed between 1983 and 2009 with
at least 1 serum sample collected prior to date of MS diagnosis; $2 serum samples were available
for 511 cases. Cases were matched to up to 3 controls (n 5 2,123) on date of birth (62 years) and
area of residence. 25-Hydroxyvitamin D (25[OH]D) levels weremeasured using a chemiluminescence
assay. We used conditional logistic regression adjusted for year of sample collection, gravidity, and
parity to estimate relative risks (RRs) and 95% confidence intervals (CIs).
Results: A 50 nmol/L increase in 25(OH)D was associated with a 39%reduced risk of MS (RR 0.61,
95%CI 0.44–0.85), p50.003.Women with 25(OH)D levels,30 nmol/L had a 43%higherMSrisk
(RR 1.43, 95% CI 1.02–1.99, p 5 0.04) as compared to women with levels $50 nmol/L. In women
with $2 samples, MS risk was 2-fold higher in women with 25(OH)D ,30 nmol/L as compared to
women with 25(OH)D $50 nmol/L (RR 2.02, 95% CI 1.18–3.45, p 5 0.01).
Conclusions: These results directly support vitamin D deficiency as a risk factor for MS and
strengthen the rationale for broad public health interventions to improve vitamin D levels.