Many reasons why vitamin D deficiency has become epidemic

23 of the 40 reasons for Vitamin D deficiency are new

People have gotten far less Vitamin D from the SUN in the past 40 years

Air conditioning - to avoid the hot sun
air conditioning in home, auto/bus/train, and workplace CLICK HERE
Air Conditioning probably has decreased vitamin D
Hypothesis – Air conditioning disease is the result of less vitamin D – China March 2011
Increased use of multi-media indoors - TV, DVD, video games, and internet access
Teens increasingly indoors - especially if have dark skin
Vitamin D is essential to the modern indoor lifestyle
Problems of increased TV watching by toddlers – May 2010
Analysis of the time people spend outdoors – Dec 2010
More indoor jobs - more office workers, fewer farmers
Jobs in cities around the world: 30% in 1950, 70% in 2050
4X more suburban UV than urban UV – Nov 2010
Urban residents had 2X less vitamin D – 2008
More people living in cities - where there is less UV and they have less opportunity to be outdoors
Air pollution reduces UV and thus vitamin D
UVB which produces vitamin D does not reflect off of buildings very well *
Want whiter skin especially women
Here and Here (Helen of Troy) and Being Fair-Skinned in Today's World
Suntan: Popularity is fading
Perhaps not burn from the sun if have enough vitamin D
Fear skin cancer -
Overview Suntans and melanoma Tanning from Wikipedia
Actually you can get enough vitamin D without getting much of a tan, much less get skin cancer
Melanoma probability increased 2X if have 5 or more sunburns (Not necessarily at the same location as the burn)
Most sunscreens increase the growth of skin cancer
Actually you get 1000X more cancer by not having the vitamin D *
Most sunscreens increase skin cancer - May 2010

Additional reasons for less vitamin D in past 40 years (beyond lack of sun)
Less cholesterol - which the skin needs to produce vitamin D
Overview of Cholesterol and Vitamin D
Less cholesterol in diet resulted in less vitamin D in blood (in mice) – Feb 2016
More Obesity
Obese people need more vitamin D PDF file - 2000
Map of BMI increase - Feb 2011 with many links
Obese people spend less time in the sun
Livers of those who are Obese do not function as well, and so do not provide as much vitamin D
More soft drinks and fructose - uses up Calcium which uses up vitamin D
surfers in Hawaii (PDF), who drank a large amount of cola soft drink, had low levels of vitamin D
Too much fructose reduced both serum and active vitamin D in rats – April 2013
HFCS consumes Magnesium needed by Vitamin D
note: Fructose also reduces active vitamin D actually getting to cells - not seen by blood tests
Increased consumption of Ultra-processed foods
Ultra-processed food consumption: 2X increased risk of vitamin D deficiency – Dec 2023
Meat from factory farms - has far less vitamin D than from free-range farms
eggs, chickens, sheep, pigs (500 IU/teaspoon of lard), farmed salmon has 4X less vitamin D than wild salmon
Wild game, which has been outdoors all of the time, has much more vitamin D - especially in the organ meats
Eating less fatty meat and eggs in an attempt to reduce cholesterol. fatty meat was discovered to have a liver-activated form of vitamin D in 2014
Note: Meat eaters haave 8 ng higher vitamin D levels than vegetarians
Drinking low-fat milk which provides only 40% of the vitamin D to the blood compared to whole milk
6X reduction in consumption of whole milk (1970 ==> 2010), thus 100 IU/glass ==> 40 IU/glass for most people
Reminder: Most Vitamin D is fat soluble, less fat ==> less vitamin D
More drugs which consume or block vitamin D
Antiseizure, Prednisone, AIDS drugs, Orlistat, Questran, Dilatin, Phenobarbital, Rifampin, Steroids, Calcium channel blockers
Cholestyramine, Mineral Oil, , St Johns Wort
More use of polyunsaturated fats decreased bio-availability of vitamin D
More windows: UVA from windows appears to destroy vitamin D (produced by UVB which is blocked by windows)
More wall space devoted to windows in homes, offices, and public buildings
Increased salt consumption which decreases essential Vitamin D cofactors: Magnesium and Calcium
Fluoridated water decreases Magnesium essential for use of vitamin D - Hypothesis?
Strong magnetic fields reduce vitamin D levels Perhaps from MRI
PCBs increase the chance of deficiency by 3%
Plastics in pregnant women increased risk of deficiency by 22%
Roundup (glyphosate) decreases vitamin D
Flame Retardants also retard active vitamin D
Flame Retardants were added to US clothing, mattresses, and cushions by 1980
Doubt that flame retardants are used in developing countries
Reasons for low vitamin D levels which go back more than 40 years
Less liver eaten - which used to have very large amounts of vitamin D
A way to get 40X more vitamin D from beef liver back were it used to be
Iron deficiency is a cause of Vitamin D deficiency
Less Magnesium in foods and drink - Magnesium is needed to utilize vitamin D (as well as build bones)
Magnesium and vitamin D
Magnesium deficiency epidemic is similar to the Vitamin D epidemic
Reasons for lower Mg:
   Use of artificial fertilizers rarely restore Magnesium
       Refined grains and refined sugar have very little Magnesium
   Softened water/bottled water usually have all of the Magnesium removed
   Floridation of water blocks Magnesium
More seniors
seniors get 4X less vitamin D from the sun than youths (less Cholesterol in skin) *
more people are now living >50 years
Seniors tend to be outdoors less+In vicious circle: low D makes for lower D
Also: seniors appear to not activate vitamin D as well (in liver, kidney, skin, etc)
More cataract surgery ==> avoid bright light
Excessive clothing (burka, nun habit, . . .)
especially if also living far from equator or avoiding the hot sun
Have a condition which Consumes vitamin D
Chemotherapy - (be careful, adding vitamin D increases the impact of some Chemo)
MS prevented AND treated by vitamin D, a mountain of evidence
Have a condition which Prevents Adsorption in the gut
Bariatric Surgery, Colon Cancer, IBD UC and CD, Crohn's
Gluten Intolerance, Celiac Disease, Cystic Fibrosis
Fat malabsorption syndromes from 1985 PDF file
(Supplement options if have gut problem: Option 1 - Option 2)
Have a condition which Prevents Conversion to active vitamin D
Kidney vicious cycle
HIV both prevents conversion and consumes vitamin D
Have 1 or more of 6 genes which restrict how much vitamin D gets to cells
Restrict how much Vitamin D is semi-activated by liver or tissues
Restict how much semi-activated Vitamin D is carried to kidneys for full activation - not seen by blood test
Restrict how much Vitamin D is activated by kidneys or tissues - not seen by blood test
Destroy Vitamin D before it can be used - not seen by blood test
Restrict activated vitamin D from actually getting into cells - Vitamin D Receptor - not seen by blood test
Have a condition which requires more vitamin D - or time in the sun
Pregnancy Not just bone. Need lots of vitamin D - Before , During, and After
Dark Skinned and living far from equator or avoiding the hot sun
Surgery and trauma many files
Lactose Intolerance or Vegan – and thus not get vitamin D from milk in US and a few other countries
also reduces Calcium intake, needed to build bones, prevent Myopia, prevent cardiovascular disease
Health reasons to avoid sun (other than skin cancer) burn easily - redhead, etc - there are alternatives
If avoiding sun you need to supplement with vitamin D – April 2011
Work long hours or night shift Long hours reduced vitamin D by 8% – April 2011
Live far from equator even more of a problem if the region is also cloudy (Washington State, Scotland)
10X more SAD in Seattle than Miami
DDT and some other pesticides in our bodies reduce the vitamin D perhaps 3 ng
Smoking reduces Calcium, which reduces vitamin D
Winter births - 11% more likely for adult to be deficient
Need to take more vitamin D as an adult if born in winter
Myths about vitamin D caused people and researchers to not consider useful amounts
Myth You can easily take a toxic amount of vitamin D - started in the 1950's by a wrong diagnosis -scared off research and use for 50 years
Myth Spend 10-15 minutes in the sun three times a week and your vitamin D will be fine. (This myth started out as a hypothesis)
Myth Eat fish three times a week and your vitamin D will be adequate
Myth Can get all of your vitamin D needs from food
Myth Drink a cup of milk every day and your vitamin D will be okay
Myth A daily multivitamin will meet your vitamin D needs
Myth You do not develop vitamin D deficiency if you live in a warm, sunny place
Myth Eating a healthy diet will take care of your vitamin D needs as well
Myth More Kidney stones if take more vitamin D
Myth Need lots of Calcium while getting lots of vitamin D ( just the opposite actually)
Myth No tan is a safe tan (skin cancer can happen in just a few minutes)
Myth If I sunburn easily I need to stay out of the sum ( No, being sunburned easily is often a sign of being very vitamin D deficient)
Myth Should reduce cholesterol ( no, actually should increase cholesterol - to produce vitamin D)
Myth Sunlight alone causes skin cancer (so why does melanoma often occur where the sun does not shine)
Myth Can get enough vitamin D from the sun to last you thru the winter
Myth Can get enough vitamin D even if wearing lots of sunscreen
Myth You can be allergic to vitamin D (allergic reaction is often an indication of low Magnesium)
Myth Vitamin D2 is almost as good as vitamin D3 (several studies have shown that vitamin D2 DECREASES serum levels of D3)
See also Vitamin D - Facts and Myths

Lets look at vitamin D deficiency from another point of view

People were evolved under conditions which have since changed

People were outdoors everyday (so we could slowly adjust to the annual increase of UVB without sunburn)
The bright sun was available throughout the year (this assumes during the last 20,000 years that most people lived within 30 degrees of the equator)
That each person would not live very long (seniors get far less vitamin D from the sun than youth)
That people were not obese (obese people need at least 2X more vitamin D, which is secreted away in their fat)
If there was any weight gain, it happened near harvest time when there was lots of vitamin D and that added weight/vitamin D was gone before the next harvest
People ate animals which lived out of doors, so there was lots of vitamin D in the meat, especially the organ meats
Also, the animals generally ate green grass, etc. had lots of vitamin K2, which is a vitamin D cofactor