Sunday, January 31, 2010

Vitamin D deficiency, seasonal depression, and diseases of civilization

George Hamilton admits that he has been addicted to sunbathing for much of his life. The photo below (from: phoenix.fanster.com), shows him at the age of about 70. In spite of possibly too much sun exposure, he looks young for his age, in remarkably good health, and free from skin cancer. How come? Maybe his secret is vitamin D.


Vitamin D is a fat-soluble pro-hormone; not actually a vitamin, technically speaking. That is, it is a substance that is a precursor to hormones, which are known as calcipherol hormones (calcidiol and calcitriols). The hormones synthesized by the human body from vitamin D have a number of functions. One of these functions is the regulation of calcium in the bloodstream via the parathyroid glands.

The biological design of humans suggests that we are meant to obtain most of our vitamin D from sunlight exposure. Vitamin D is produced from cholesterol as the skin is exposed to sunlight. This is one of the many reasons (see here for more) why cholesterol is very important for human health.

Seasonal depression is a sign of vitamin D deficiency. This often occurs during the winter, when sun exposure is significantly decreased, a phenomenon known as seasonal affective disorder (SAD). This alone is a cause of many other health problems, as depression (even if it is seasonal) may lead to obesity, injury due to accidents, and even suicide.

For most individuals, as little as 10 minutes of sunlight exposure generates many times the recommended daily value of vitamin D (400 IU), whereas a typical westernized diet yields about 100 IU. The recommended 400 IU (1 IU = 25 ng) is believed by many researchers to be too low, and levels of 1,000 IU or more to be advisable. The upper limit for optimal health seems to be around 10,000 IU. It is unlikely that this upper limit can be exceeded due to sunlight exposure, as noted below.

Cod liver oil is a good source of vitamin D, with one tablespoon providing approximately 1,360 IU. Certain oily fish species are also good sources; examples are herring, salmon and sardines. For optimal vitamin and mineral intake and absorption, it is a good idea to eat these fish whole. (See here for a post on eating sardines whole.)

Periodic sun exposure (e.g., every few days) has a similar effect to daily exposure, because vitamin D has a half-life of about 25 days. That is, without any use by the body, it would take approximately 25 days for vitamin D levels to fall to half of their maximum levels.

The body responds to vitamin D intake in a "battery-like" manner, fully replenishing the battery over a certain amount of time. This could be achieved by moderate (pre-sunburn) and regular sunlight exposure over a period of 1 to 2 months for most people. Like most fat-soluble vitamins, vitamin D is stored in fat tissue, and slowly used by the body.

Whenever sun exposure is limited or sunlight scarce for long periods of time, supplementation may be needed. Excessive supplementation of vitamin D (i.e., significantly more than 10,000 IU per day) can cause serious problems, as the relationship between vitamin D levels and health complications follows a U curve pattern. These problems can be acute or chronic. In other words, too little vitamin D is bad for our health, and too much is also bad.

The figure below (click on it to enlarge), from Tuohimaa et al. (2009), shows two mice. The one on the left has a genetic mutation that leads to high levels of vitamin D-derived hormones in the blood. Both mice have about the same age, 8 months, but the mutant mouse shows marked signs of premature aging.


It is important to note that the skin wrinkles of the mice on the left have nothing to do with sun exposure; they are associated with excessive vitamin D-derived hormone levels in the body (hypervitaminosis D) and related effects. They are a sign of accelerated aging.

Production of vitamin D and related hormones based on sunlight exposure is tightly regulated by various physiological and biochemical mechanisms. Because of that, it seems to be impossible for someone to develop hypervitaminosis D due to sunlight exposure. This does NOT seem to be the case with vitamin D supplementation, which can cause hypervitaminosis D.

In addition to winter depression, chronic vitamin D deficiency is associated with an increased risk of the following chronic diseases: osteoporosis, cancer, diabetes, autoimmune disorders, hypertension, and atherosclerosis.

The fact that these diseases are also known as the diseases of civilization should not be surprising to anyone. Industrialization has led to a significant decrease in sunlight exposure. In cold weather, our Paleolithic ancestors would probably seek sunlight. That would be one of their main sources of warmth. In fact, one does not have to go back that far in time (100 years should be enough) to find much higher average levels of sunlight exposure than today.

Modern humans, particularly in urban environments, have artificial heating, artificial lighting, and warm clothes. There is little or no incentive for them to try to increase their skin's sunlight exposure in cold weather.

References:

W. Hoogendijk, A. Beekman, D. Deeg, P. Lips, B. Penninx. Depression is associated with decreased 25-hydroxyvitamin-D and increased parathyroid hormone levels in old age. European Psychiatry, Volume 24, Supplement 1, 2009, Page S317.

P. Tuohimaa, T. Keisala, A. Minasyan, J. Cachat, A. Kalueff. Vitamin D, nervous system and aging. Psychoneuroendocrinology, Volume 34, Supplement 1, December 2009, Pages S278-S286.

18 comments:

winnie mandela said...

why does the vitamin D mouse have no hair? did it fall out because of too much D (the accelerated aging u mentioned), was it born like this as a result of the vitamin D mutation, or did the scientists deliberately use a hairless strain to more clearly show the wrinkles caused by vitamin D? if its because the hair fell out because of D then that is worrying as i've been supplementing with high strength (5000 IU/day) vit D capsules for a while (since i found out i had abnormally low blood calcium levels despite eating lots of calcium-rich food). i also take cod liver oil supplements which have vitamin D...

great blog by the way. im impressed u manage to bash out a post of such high qualidad every day. keep up the good work!

Ned Kock said...

From my reading of the article, my guess is that the hair loss and wrinkles are due to accelerated aging because of hypervitaminosis D.

Humans and mice have different physiologies, and you seem to be still below the 10,000 IU upper limit, even with the supplementation.

If I were you, I would check with a doctor to see if everything is okay.

Sunlight exposure would probably give you more vitamin D, and in a safer way, than supplementation.

Cod liver oil also can lead to hypervitaminosis A.

Scott W said...

I thought that I had heard somewhere that the ability of our skin to synthesize vitamin D diminishes as we hit middle age due to progressive thinning of the skin and that therefore supplementation remains important, even if you still get a tan when older. Thoughts?

Scott W

Ross said...

I think this article exaggerates the risk of hypervitaminosis D. While there have been cases of people obtaining too much Vitamin D from supplements without any sensitizing condition (like sarcoidosis), they are so extraordinarily rare that you can count them on two hands. Further, in all cases, it required months of excessive doses before serious health consequences appeared. For 99+% of people, 4000-10,000IU/day of Vitamin D3 will be well tolerated.

I do agree that people taking significant daily doses of D3 would be smart to get their levels checked every six months or so (with a goal of 50-70ng/ml 25(OH)D3) until they know their body's needs. For my wife, 4000IU/day yielded ~50ng/ml and 6000IU/day yielded 60ng/ml, so she's sticking with 6000IU/day and annual tests from now on. It takes me 10,000IU/day to have the same levels.

dr moron said...

thanks ned.

"Sunlight exposure would probably give you more vitamin D, and in a safer way, than supplementation."

ain't no sunshine (as bill withers might sing) in the uk this time of year

"If I were you, I would check with a doctor to see if everything is okay."

ha in this country? doctor would laugh in your face then tell u to stop wasting his time with such trivial nonsense. even getting tested for a semi-serious condition like celiac disease takes over 6 months (no exaggeration - i asked for a test in september, the biopsy is scheduled for march). unless u have cancer they dont want to know!

not so bad really, in my expereince most doctors are idiots who dont know what they are talking about so i wouldnt trust one as far as i could throw his fat paycheck. when u consider that 14% of UK doctors dont know their arse from their elbow it really does make u wanna live healthy so u never have to see one!

Ned Kock said...

Scott:

I would not be surprised, but I don't think the effect of age is dramatic. Sunlight exposure leads to significant vit. D production even in the elderly.

Ross:

You may be right. The article emphasizes chronic hyperv. D effects. In fact, it shows a photo of the same mice at 4 months of age, and they look the same. By the way, I don't think blood tests are very effective at measuring vit. D, because vit. D is stored in fat tissue and has a long half-life. That is, blood tests likely underestimate vit. D accumulated in the body. Better measure the hormones - calcidiol and calcitriols.

dr moron:

Mr. Obama needs to hear from you!

Jack Cameron said...

My wife has very low vitamin D of 15ng/ml in spite of taking 1000 IU/day in gelcap. She can not tolerate cod liver oil. Her doctor prescribed 50,000 IU vitamin D3 per week in a single pill, and made no mention of need for added vitamin A, calcium and magnesium. What is your opinion about taking vitamin D in this manner?

Ned Kock said...

Hi Jack.

The 50,000 IU per week is still below the maximum recommended 10,000 IU per day (or 70,000 IU per week).

Also, the doctor seems to think that low vit. D problems may be resolved with added vit. D, without the need for added vit. A, calcium or magnesium. This seems reasonable to me.

What I would do if I were you is to ask the doctor about the article by Tuohimaa and colleagues (full ref. at the end of the post), which is recent (2009), and its implications vis-a-vis your wife's case.

Dexter said...

The Vitamin D Council, Dr. Cannell points out
in response to letters into him that Vitamin A
blocks the benefits of Vit D3 supplementation.

This link to letters regarding autism. As Dr. Cannell points out, probably not all autistic
persons will benefit from Vit D supplementation...but it sure seems to raise the spirits of many who do supplement Vit D3 up to 60-80ng/ml serum.

http://www.vitamindcouncil.org/newsletter/2008-june.shtml

Ellen said...

Ned, what's your opinion of tanning beds?

Ned Kock said...
This comment has been removed by the author.
Ned Kock said...
This comment has been removed by the author.
Ellen said...

I know when I was using them for 10 mins a week, I felt a definite improvement in mood. Thanks for the feedback.

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gwarm said...

DrGreger had this to say about tanning beds:
http://www.youtube.com/watch?v=jPjd_W5EfGU&feature=BFa&list=PL53AA35449C7DD652&lf=PlayList#t=29m30s

From his 'tanning beds.pdf'
http://is.gd/vT4Ogh "
Multiple studies have shown concerning evidence that tanning bed patrons are receiving
much higher doses of UV radiation than they
would from summer sun exposure. Summer solar
noon output in Washington, DC, is estimated to
be 48 W/m2
UVA and 0.18 W/m2
erythemally
weighted UVB (20). In contrast, in a study in
North Carolina, UV output in standard tanning
facility beds was found to be much higher, with a
mean of 192.1 W/m2
UVA and 0.35 W/m2
erythemally weighted UVB (23). In a study by the FDA,
for a typical tanner (20 sessions at two minimal
erythema dose (MED)/session), the annual UVA
doses from commonly used fluorescent sunlamps
were 0.3–1.2 times that received from the sun. For
a frequent tanner (100 sessions at four MED/
session), the annual UVA doses from fluorescent
sunlamps were 1.2–4.7 times that received from
the sun and 12 times for recently available, highpressure sunlamps (20).
Another study in Switzerland found that sunbed
emission spectra are similar to the sun spectrum in
the UVB range, but reach values 10–15 times higher
in the UVA range (24) An average erythemaeffective irradiance of 0.33 W/m2
was determined
for sunbeds. This corresponds to a UV index of 13,
which is significantly higher than the UV index of
8.5 of the high summer sun at noon at intermediate
latitudes. In such a sunbed, the MED threshold of
a person with skin type II is reached after 12.6
minutes (250 J/m2
), and that of a person with skin
type III after 17.7 minutes (350 J/m2
). As visitors of
tanning salons with skin types II and III spend, on
average, 20 minutes in sunbeds, overexposure to
UV radiation is very likely (25).
...
y
UV carcinogenesis pathway
UV irradiation causes DNA damage that can lead to
carcinogenesis. Sunburn is primarily caused by
UVB (31). UVB is also far more effective at inducing
inflammation than UVA, and in murine studies, it
has been estimated to be 1000–10,000 times more
effective for inducing skin cancer (32,33). In the
past, UVB was considered the only carcinogenic
part of the solar spectrum, through the generation
of cyclobutane pyrimidine dimers (CPDs) that
cause C →T and CC →TT mutations, also known as
UVB fingerprint mutations (34). Recent evidence
suggests that radiation in the UVA range can also
trigger DNA damage via cyclobutane pyrimidine
dimer formation and C →T mutations (35,36). Normally, p53, a tumor-suppressor gene, is upregulated
by sunlight exposure, leading to increased DNA
repair, cell cycle arrest, and apoptosis of damaged
keratinocytes. However, p53 itself is also susceptible
to mutagenesis, and sunlight-induced p53 mutations have been found in skin precancers and even
in sun-exposed skin, rendering these cells apoptosis resistant (37). In vitro studies have confirmed
that chronic UVA exposures at environmentally relevant doses can induce malignant transformation
of human keratinocytes associated with acquired
apoptotic resistance. Malignant transformation
was established by the production of aggressive
squamous cell carcinomas (SCCs) after inoculation
of cells into nude mice (38)."

--
And I believe he lowered his VitD supplement recommendations

http://www.longecity.org/forum/topic/51291-vitamin-d-20n-30ngml-recommended-over-50-60ngml/

gwarm said...

Mark Sisson had a post on foods to eat to protect against the sun damage http://www.marksdailyapple.com/8-natural-ways-to-prevent-a-sunburn-and-sunscreens-not-one-of-them/ He kind of looks sun damaged himself (some say: http://www.longecity.org/forum/topic/25988-i-have-yet-to-see-somebody-who-looks-as-young-as-they-claim/page__st__540__p__366036#entry366036 http://i247.photobucket.com/albums/gg158/MDA2008/MDA2009/BodyFat.jpg)

Ned Kock said...

A comment on tanning booths, related to the discussion above: There is strong evidence that they are NOT safe, at least with the current technology used.