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Matti Narkia

How this horrible weather could give you heart disease | Mail Online - 0 views

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    "We are fond of grumbling about Britain's grey skies, but there may be a good medical reason for doing so. It seems the dreary weather is bad for our hearts - worse, even, than raised cholesterol and an unhealthy diet. That's the controversial claim being made by Dr David Grimes, a gastroenterologist from Blackburn. He's been gazing at the sky for 20 years for clues about why his patients get more sick than those in the south of the country. And what he's found turns key assumptions about heart disease on their head. 'It's not diet or cholesterol levels that raise your risk of heart disease,' he claims. 'It's where you live. People in the north are more likely to be ill because they get less sunshine Basically they are suffering from 'latitude' sickness. The link is vitamin D. While we get some from our diet, the main source is the sun - sunlight converts a compound in the skin into vitamin D, so the amount you make is directly related to the amount of sunshine you get. In a new book Dr Grimes argues the higher the level of vitamin D in your blood, the lower your risk of heart disease and a range of other illnesses. If he's right, what we need is not diet and lifestyle advice, but food fortified with vitamin D. For years the vitamin was thought to be useful only for preventing rickets. So how does he treat them? 'You can do it with diet,' he says 'One Bangladeshi woman eats oily fish every day and now has a vitamin D blood level of 40. 'We give supplements of 1,000 international units (IU) a day or we can give an injection of 300,000 IU that lasts for a year. 'The patients respond well,' says Grimes 'but what's needed is a proper controlled, long-term trial and who is going to fund that? Not a drug company.'"
Matti Narkia

Duration of vitamin D synthesis from weather model data for use in prospective epidemio... - 0 views

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    Duration of vitamin D synthesis from weather model data for use in prospective epidemiological studies. Edvardsen K, Engelsen O, Brustad M. Int J Biometeorol. 2009 Sep;53(5):451-9. Epub 2009 May 15. PMID: 19444487
Matti Narkia

VitD Duration of Vitamin D Synthesis in Human Skin - 0 views

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    Vitamin D production in human skin occurs only when UV radiation exceeds a threshold. From simulations of UV irradiances, the VitD www page ( http://zardoz.nilu.no/~olaeng/fastrt/VitD.html) computes the daily duration of dermal vitamin D production at midday when UV radiation exceeds the required threshold. The daily duration depends on latitude, time, total ozone, clouds, aerosols, surface reflectivity and altitude all of which can be specified by the user
Matti Narkia

VitD-ez Easy Duration of Vitamin D Synthesis in Human Skin - 0 views

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    Vitamin D production in human skin occurs only when UV radiation exceeds a threshold. From simulations of UV irradiances, the VitD-ez www page ( http://zardoz.nilu.no/~olaeng/fastrt/VitD-ez.html) computes the daily duration of dermal vitamin D production at midday when UV radiation exceeds the required threshold. The VitD-ez www page is a simplified version of the more complex VitD web page ( http://zardoz.nilu.no/~olaeng/fastrt/VitD.html). The simplified VitD-ez www page is convenient for users unfamiliar to radiative transfer modelling, because the model input is limited and more intuitive.
Matti Narkia

Daily duration of vitamin D synthesis in human skin with relation to latitude, total oz... - 1 views

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    Daily duration of vitamin D synthesis in human skin with relation to latitude, total ozone, altitude, ground cover, aerosols and cloud thickness. Engelsen O, Brustad M, Aksnes L, Lund E. Photochem Photobiol. 2005 Nov-Dec;81(6):1287-90. PMID: 16354110 Vitamin D production in human skin occurs only when incident UV radiation exceeds a certain threshold. From simulations of UV irradiances worldwide and throughout the year, we have studied the dependency of the extent and duration of cutaneous vitamin D production in terms of latitude, time, total ozone, clouds, aerosols, surface reflectivity and altitude. For clear atmospheric conditions, no cutaneous vitamin D production occurs at 51 degrees latitude and higher during some periods of the year. At 70 degrees latitude, vitamin D synthesis can be absent for 5 months. Clouds, aerosols and thick ozone events reduce the duration of vitamin D synthesis considerably, and can suppress vitamin D synthesis completely even at the equator. A web page allowing the computation of the duration of cutaneous vitamin D production worldwide throughout the year, for various atmospheric and surface conditions, is available on the Internet at http://zardoz.nilu.no/~olaeng/fastrt/VitD.html and http://zardoz.nilu.no/~olaeng/fastrt/VitD-ez.html. The computational methodology is outlined here.
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