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| Fanciulla_sulla_roccia_a_Sorrento by Filippo Palizzi |
We are told that a Mediterranean diet is one of the most
healthy – lots of colourful vegetables, olive oil, fish, grains, etc. But there
is something else that the Mediterranean has in abundance and is often celebrated
for and that is daylight (beautifully captured in the painting here by Filippo
Palizzi). Daylight is never mentioned as a component of a Mediterranean diet
but there is plenty of research that says it should be.
Daylight is vital to physical and psychological wellbeing in
many ways. Here are just a few.
Vitamin D
Sunlight on your skin produces Vitamin D – the vitamin your
body needs to absorb calcium. Calcium is necessary for strong healthy bones and
lack of calcium is a major factor in the development of osteoporosis. Vitamin D
deficiency has also been linked to several cancers and one study showed that
Vitamin D supplements for postmenopausal women reduced the chance of getting
any cancer by 60%. Now, we do need to be sceptical about such claims made by
researchers and about claims for taking vitamin supplements. But, with the
other benefits of daylight exposure described below, we should all prescribe
ourselves a daily dose of daylight to boost our Vitamin D levels.
In my blog post on our edition of Heath Robinson’s How to Make a Garden Grow I describe the
concerns about the health of the nation in the 1920s and 1930s. Many of the
working class recruited as soldiers for fighting in the First World War didn’t
not meet the health requirements. Rickets is also caused by Vitamin D
deficiency and many children who lived in slum housing at the beginning of the
twentieth century didn’t get enough daylight or enough Vitamin D in their diet
for healthy bone growth. At the time there was a lot of talk about fresh air
and exercise. What they didn’t know then but we do know now is that it was the
lack of daylight that was largely the cause of many of the health problems identified
during and after the First World War. The relationship between light and health
is also covered in my blog post on How to Live in a Flat by Heath Robinson and we see the impact of these concerns on
the design of housing in the early twentieth century.
Sleep
Our sleep patterns are regulated by the hormone melatonin. The
blue light part of the daylight spectrum enters the eye and sends a message
along the optic nerve to the gland that produces melatonin. While blue light is
entering our eyes, the amount of melatonin produced is suppressed and we feel
awake. When it gets dark and the amount of blue light entering the eye is
reduced, the amount of melatonin produced increases, we feel sleepy and our
body prepares for sleep.
There is a very interesting article about blue light on this
website http://moreintelligentlife.co.uk/content/features/rosie-blau/light-and-health?page=full
I quote one particularly interesting section from this article, relating to the
work of Kazuo Tsubota, professor of ophthalmology at Keio University School of
Medicine in Japan:
Tsubota’s ambition as an
ophthalmologist is “to protect the eye for this long-lived society”. We all
know that our eyesight fades with age—what he calls “the eye as a camera”—but
“the eye as a clock” does too. As we get older, our lens yellows, so less light
reaches the receptor at the back of the eye to tell our brains what time it
is—and we need more daytime rays to reset our body clock. “At 58 years, my lens
is a third as good at receiving blue light as the 20-year-old lens,” says
Tsubota, who talks with a wide smile and waving hands. “In order to have a
proper amount of light, I have to play outside three times as much as a
20-year-old boy,” he says and laughs. “That gives me a good excuse to ski, go
swimming, jogging.”
Tsubota says he is motivated
by gokigen, meaning a life filled with happiness. This is not idle
chat, he insists. Happiness is one of three things that help to stave off the
depredations of age, along with diet and exercise. His remedy is not to sing
and laugh, or even to get rich or get married, but to sleep: “It has almost the
same beneficial effect on health as smoking has a bad one.” And getting a good
night depends on having the right amount of light at the right time of day.
Much of his research focuses on
his own cataract patients. After a cataract operation, people usually have
fewer falls, their mood lifts and they think more sharply. Tsubota also found
that his patients’ sleep “dramatically improved”. He believes many of the other
benefits of the operation flow from this: “The surgery replaces the opaque lens
and suddenly 90% of the blue light is received, you are like a five-year-old.
So cataract is a treatment for the clock as well as the camera.”
The relationship between sleep and wellbeing is now
well-known. However, I find this quotation fascinating for the insight it gives
into the interrelationship between eye health, light, sleep and wellbeing. But,
in simple terms, the equation is: more daylight = better sleep = health and
wellbeing.
You may also notice another thread running through several
of my blog posts – my references to Japanese philosophy such as Wabi Sabi and,
here, gokigen. The Japanese are
famously long-lived and are healthier for longer so they are able to add years
to their lives and life to their years. Their diet is often given as the reason
for this but I think there are other factors too, connected with their way of
living.
Psychological
wellbeing
We also know that quality sleep and physical health improve
our psychological wellbeing. But daylight itself improves our feelings of
wellbeing and quite a lot of research is now being done into the reasons why
this is the case. Much of this research is collated in the following literature
review http://www.nrel.gov/docs/fy02osti/30769.pdf
This is a long read so, again, I will quote the section that struck me
particularly:
Humans are affected both
psychologically and physiologically by the different spectrums provided by the
various types of light. These effects are the less quantifiable and easily
overlooked benefits of daylighting. Daylighting has been associated with
improved mood, enhanced morale, lower fatigue, and reduced eyestrain. One of the
important psychological aspects from daylighting is meeting a need for contact
with the outside living environment (Robbins 1986). According to Dr. Ott (Ott
Biolight Systems, Inc. 1997a), the body uses light as a nutrient for metabolic
processes similar to water or food. Natural light stimulates essential
biological functions in the brain and is divided into colors that are vital to
our health. On a cloudy day or under poor lighting conditions, the inability to
perceive the colors from light can affect our mood and energy level. Dr.
Liberman (1994) also mentioned that light plays a role in maintaining health:
When we speak about health, balance, and physiological regulation, we are
referring to the function of the body’s major health keepers; the nervous
system and the endocrine system. These major control centers of the body are
directly stimulated and regulated by light, to an extent far beyond what modern
science…has been willing to accept.
We know that being outside in the sunshine makes us feel
good – we don’t need research to tell us that. What the research is beginning
to confirm is that it is exposure to daylight that is the reason why we feel
good.
Recipe for the
daylight part of our Mediterranean diet
Hang on, you may say, we are constantly being warned about
spending too long in the sun, risking skin cancer, cataracts, wrinkles, etc.
How do we get more daylight without incurring all these risks? Well, here is
the Words to the Wise recipe for your daylight diet:
- Take a 20-minute walk every morning (even in winter – in fact, especially in winter) and expose as much skin to the daylight as is decent and without getting frostbite! You only need a 15-minute exposure to create enough Vitamin D for the day and walking in the morning means you are not exposed to strong mid-day sunlight that will damage your skin. A morning walk will also help to wake you up as the blue light will start the reduction in melatonin levels. Older Chinese people who start the day with Tai Chi outside have the right idea – gentle exercise in daylight (not artificial light) will help you to live longer, be healthier and feel good.
- For the rest of the day, take every opportunity to get some daylight. If you can’t go outside then sit near a window. Keep windows clean and open the curtains as soon as you get up. At work insist on your ‘right to light’ – show your employer the literature review I refer to above. I am sure he or she will be keen to improve productivity!
- In the evening turn off all screens (TV, tablet, mobile phone, etc.) at least two hours before you go to bed. Screens emit blue light and this will continue to suppress melatonin levels, which will make it harder to get to sleep. Make sure your bedroom is as dark as possible.
Add this recipe to your
vegetables, olive oil, nuts and fruit to get the full benefit of the
Mediterranean diet.
There is a lovely quotation that
accompanies the Filippo Palizzi painting above:
Sul bordo dello scoglio vi è una scritta: Egli,
che mi pose a giacere su questa roccia, mi dice di guardarti da mattina a sera
e dirti sempre: sii felice. Felice.
On
the edge of the cliff there is an inscription: He placed me to lie on this
rock, tells me to look at you from morning to night and tell you: be happy.
Happy.
P.S.: Our Photography books are all about
capturing and recording light. Photography also gets you outside for your daily
dose of daylight. Our first title on Developinga Photographic Style by David Penprase has just been published. For more
information about our Photography titles visit www.RHEMediaPhotography.co.uk
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