Comment by pazimzadeh | Hacker News Reader

Comment by pazimzadeh | Hacker News Reader

Funny timing, I just went to a tanning salon for the first time yesterday. I asked for the weakest bed (level 1), which has the most UVB (for vitamin D production). They were shocked that I wanted to use level 1, apparently no one uses it. They also suggested starting at 5 mins instead of the 1-2 minutes I wanted to do. The machine itself has a notice saying not to go over 3 mins for the first week.

I was following the protocol from this paper, which started people at 2 mins and used low wattage UVB-heavy bulbs.

Sunbeds with UVB radiation can produce physiological levels of serum 25-Hydroxyvitamin D in healthy volunteers

https://pmc.ncbi.nlm.nih.gov/articles/PMC5821157/

Unfortunately the Science Advances paper being discussed is epidemiological and doesn't distinguish between the type of bulb, length of time, and other parameters used while tanning. However it is safe to say that the average tanner cares more about getting dark than anything else.

I think there would actually be a market for vitamin D centered "healthy tanning" where only low wattage, high-UVB bulbs are used particularly in cloudy areas or where the winter is long. I'm that guessing the operating costs for that kind of business would be cheaper than your average tanning salon, too.

Interesting... What benefits does this have over vitamin D supplements?

I've seen this "optimising for some perceived negative effects" thing with toothbrushes/toothpaste, where "whitening" and stiff bristles actually just means removing more (irreplaceable) enamel from your teeth.

Stiff bristles also damage your gum more easily and can lead to gum recessions. I needed gum transplants because of this and a wrong brushing technique. For me even medium stiffness is too hard.

My problem is that soft bristles don't remove much food/plaque from the teeth and I end up having to brush way too hard.

Do you really feel plaque on your teeth with your tongue after brushing gently with a soft brush? My teeth feel perfectly clean after brushing despite using the brush with the softest bristles I could find (Meridol extra soft). I'm brushing gently (sweeping from bottom to top) with little pressure. Regardless of the brush you're using, never use more than light pressure. If the brush looks worn out after a few weeks it's too much, if it looks new after 3 months (recommend change interval) you're good.

Vitamin D supplements don’t work consistently across different populations. Very few (~10%) of people can absorb dietary vitamin D. If you aren’t some form of Northern European, you probably need to take at least 10 times the daily recommended dose of vitamin D to influence your levels significantly.

Most people need sun!

Don't most people who take supplements just take 10X the RDA? It is still a tiny amount of supplement that is safer and costs a fraction of the indoor tanning or traveling often to somewhere with adequate Sun.

I’ve never talked to someone supplementing vitamin D who was aware at all.

I think that the correct approach would be start at 10x vitamin D with baseline bloodwork and adjust dosage from there.

But yeah I’m in the camp of “sun is good for you, in most cases.” I would be very unsurprised to find that there are precursor hormones released beyond vitamin D that impact efficacy. We don’t really understand the endocrine system very well.

I think that because we can see and understand the dermatological effects we overly weight them. Anecdotally older people I know who have not avoided the sun seem much better off mentally and physically, but I think because there isn’t a measurable reason we’re aware of, we completely discount any benefit.

    > Very few (~10%) of people can absorb dietary vitamin D.

If this is true, why do all rich countries (not just "The West") add Vit D to cow's milk?

Many people with inflammatory disease like IBD can't absorb oral vitamin D properly

Even in healthy people, oral vitamin D is not always sufficient (there was a study done in Japan where sunlight is low but Vitamin D from fish is high - can't find it right now) and sunlight exposure might have other benefits than vitamin D anyway

https://www.sciencedirect.com/science/article/pii/S0022202X2...

Vitamin D supplements are controversial on their own.

There is ample results on better health correlated with higher levels of Vitamin D, but the reverse is far more teneous: shoving in Vitamin D isn't guaranteed to be properly absorbed, and even when it is we don't see conparable results to people producing the Vitamin D themselves.

An example: https://academic.oup.com/jbmr/article/38/10/1391/7610360

The paper you linked is saying there is no benefit in Vitamin D supplementation in people who are not Vitamin D deficient. Which is not surprising.

Do you have research showing sunlight Vitamin D has benefit for someone who is not deficient?

The paper covers a lot, some are administrating vitamin D as a prevention measure, most are on vitamin D deficient patients. e.g

> Even in the small subgroup of subjects with a poorer vitamin D status (serum 25OHD < 20 ng/mL), no effect on fracture risk was observed (hazard ratio [HR] = 1.07; 95% confidence interval [CI] 0.91–1.25).

> A large RCT in Mongolian children with severe vitamin D deficiency did not find a beneficial effect of vitamin D supplementation on the subsequent risk of subclinical or clinical tuberculosis.

Unless you are deficient it's not the vitamin D. It's a whole host of other processes that benefit your body from sun exposure and the activities that go along with it. The Vitamin D is just a marker that we can detect that can also be related to that same exposure. So there's a huge number of things for which people with high levels of Vitamin D do not suffer but supplementing has no effect because the vitamin D is only correlated not causative.

But wouldn’t this imply that optimizing the tanning bed properties for vitamin D production is worse than looking for as-close-to-sun-like sources of light?

Yes, there's much more to sunlight than vitamin D so a more generic "almost the sun" source of light could be overall better.

Even just for vitamins, many precursor are found related to light: https://arc.aiaa.org/doi/10.2514/6.2023-4698

I have issues with low vitamin D and even really high supplement doses like 10,000iu/d do nothing at all- my level keeps dropping no matter how much I supplement. Sunlight brings it up quickly but not in the winter from Nov-Jan.

What's old is new again:

https://img.ifunny.co/images/5ab4dda29b9dd88acc439076537e0c4...

as a man of south asian descent growing up in massachusetts, I would find myself getting very depressed around the middle of the winter. I actually found a huge amount of relief by going into a sunbed for 2 min a month. I'd feel much better and my cravings would change from fried food to salads.

    > 2 min a month

That is incredibly short! Was it not possible to get a special lightbulb for your room to give you more UV light to produce Vit D?

I looked into this extensively during lockdowns. There is a specific wavelength that maximises Vitamin D. And there are medically approved devices that use special fluorescent bulbs that output this. It's mainly used in Nordic countries.

I tried to find an LED strip equivalent but couldn't not - there are strips that produce a lower wavelength than UV-A but from what I remember it was too low of a nm for good vitamin D.

Could be an interesting product however ! I wanted to hand two strips in my shower and turn them on for a few minutes while I washed up during the winter.

Unfortunately even the tanning beds you were using still produce a lot of UV-A which will age your skin. And funnily enough UV-B also produces a much longer lasting tan (though slower) which would mean less return trips for people who are just looking for aesthetics

I do exactly what you are describing and it seems to work for me, from a vitamin D perspective. I started this because I read a paper stating the same health benefits were not seen from supplements as with people who got the vitamin D from sunlight. I believe that is true, but of course can not be certain.

I use the Sperti Vitamin D sunlamp at home during the winter months. It wasn't cheap but wasn't crazy expensive either and seems to be what you want (e.g. UVB).

It's $640.

https://www.sperti.com/product/sperti-vitamin-d-light-box/

There are handheld UVB 311 nm dispensers, which are not as efficient as whole UVB spectrum for Vitamin D production but still work and are safer.

https://www.dermahealer.com/products/dermahealer-uvb-light-t...

https://heymedsupply.com/kernel-corded-handheld-311nm-narrow...

I might use one of those for most days and a lizard UV lamp one day a week too (1 minute)

But if you find a more affordable to the Sperti please let me know

Well, the 'active ingredient' in these things is the bulb and a reputable brand (Philips medical) runs about 150 euros for a 100w tube with a R17d plug:

https://www.francelampes.com/en/30214-r17d-tl-100w-01-uvb-17...

You then just need the right ballast for it and a basic timer, maybe a reflector and stand and you're in business. Getting smaller qty is going to be an issue since these suppliers tend to sell in packs of 10.

Apparently the a ballast runs about 70 euros and can power two bulbs.

I might look into it since it's down right affordable compared to the alternatives.

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