Naked Science Forum
General Science => General Science => Topic started by: thedoc on 24/01/2012 16:43:44
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I'm not happy about the Scottish Government who want to fortify even more foods with their version of Vitamin D, surely we can source our own if we want it. Chemically produced Vitamin D will be no better than most of the other chemically produced products they try to force on us!” what do you think?
Asked by James Veal, Facebook
Visit the webpage for the podcast in which this question is answered. (http://www.thenakedscientists.com/HTML/podcasts/show/20120122/)
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We answered this question on the show...
George - Well chemically, it’s a very simple molecule and it’s identical really to what you make in your skin, so I don't think there's any reason to think that it would be any different.
But I think the issue of supplementing the population is awkward.
Despite the fact there's a control study showing that folate prevents neural tube defects, it’s not added to the food and one can only compare what happened in America now.
I'm a Canadian, but I’d have to say, the way they dealt with this was the way it probably should’ve been done which is that they supplemented their food within a couple of years that the results coming available and they were able to show that as much as 80% of neural tube defects were prevented.
Here, I think these issues have been more controversial and just the fact that people want to put supplements then doesn’t mean that it’s bad. There are lots of examples where supplementation is very useful. Iodine and salt is a good example. No one argues about that and I think in a few years, nobody is going to be arguing about this as well.
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I think this gives the game away "Chemically produced Vitamin D..."
All vitamin D is produced chemically. It's a chemical.
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Rickets used to be very common in Scotland (you may have noticed a distinct lack of sunshine there.)
If I remember correctly, they started adding vitamin D to the milk a long time ago, and that pretty much took care of the problem.
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We've had Vitamin D supplemented milk in the USA for years, as well as various vitamin supplements in breakfast cereals. It is not a bad idea to hit the general population with a little, whether or not they also choose to take daily vitamins. And, some cereals advertize supplementing 100% of everything imaginable, as part of their marketing strategy.
My grandfather had fairly bad kyphosis, and I know that the elderly are at risk for broken bones. Unfortunately, it is best not to wait until one is 80 yrs old and already has problems. So, I've chosen to add both Vitamin D and Calcium supplements to my diet. I probably should have started earlier, but this will at least give me many years of preventative treatment.
The combination of Calcium + Vitamin D can be somewhat constipating... so a little magnesium also helps even things out a bit.
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I'm not happy with the way we are going on this.
- I think we have established that studies are well on the way to proving that large portions of the population will benefit from having more of the hormone vitamin D in their system. And that ways of getting into their system include tablets or supplements in food in the same way iodine & folic acid is.
- However this sets alarm bells ringing for me ... So we can sit all day in front of the computer & take tablets everyday & all we'll be OK ? No no, no ...our bodies have not evolved to do this. Surely the optimum solution is that a few times a week we should be doing enough activity, that we get sweaty enough to take our jumpers off. (...... or move to Florida)
- Dr Chris quite correctly normally pooh poohs the idea of "normal people" taking vitamin supplements as in a balanced diet we should be getting all the vitamins we need from the food we eat. And it sets on the wrong road saying we can continue to be couch potatoes", and funding a zillion dollar fake health industry ..and a fake view of the world.
- but I just heard all the doctors on this weeks Radio 4's Inside Health prog http://www.bbc.co.uk/programmes/b019rqcq say they are all taking vitamin D tablets
.... but me, I'm off out for a run
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- FOOD: I just checked the cornflakes box, one brand has 30% of the RDA (rec daily allowance) & since I eat 5 veg a day, fish 3 times/week & meat surely I'm getting most of my vitamin D from food
- RDA : Could it be that the current RDA is too low ?
- SUNCREAM : My mum recommends suncream & covering up against sun, but I bet if your ears and hands are uncovered it's probably enough.
(anyone else get this, that when you think about a topic it open up like a whole tree of web-links ?)
BTW very clever how these question threads are automatically inserted into the prog transcript ... well done web team.
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damm, I forgot to say that Vitamin D is already included in most calcium supplement tablets
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Fruit, veg and meat have practically NO vitamin D. Hardly ANY foods have vitamin D in. Oily fish is the best, but even that isn't super high, you'd have to have it several times a week to get your D, and most people don't have it that often.
In the UK it's virtually impossible to get enough vitamin D in winter unless you supplement. Going for a run at this time of year doesn't do a whole lot unless you do it in your swimming costume, at midday. Chilly! As they said on the program, it's NOT enough to just have your hands and face uncovered, even in summer.
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, since humans have been mostly fine for the last 20,000 years in the UK without vitamin D tablets or eating lots of oily fish (which as you say is the biggest dietary source, followed by a bit in eggs & liver). Are we really saying vegetarians don't get enough without tablets ..surely that would have shown up by now ?
more info on Wikipedia http://en.wikipedia.org/wiki/Vitamin_D
" Latitude does not consistently predict the average serum 25OHD level of a population" "there is sufficient opportunity during the spring, summer, and fall months at high latitude for humans to form and store vitamin D3."
THE EU RDA is 5 µg and (100g of fish is 8µg & egg/liver about 0.5µg, 1 codliver oil tablet is 35µg)
I note the quote today in the famous eminent science journal The Daily Mail , when reporting a statement by the Chief Medical Officer
"All children under five are at risk of developing rickets because of their couch potato lifestyles" .."so should take vitamin D pills" The Chief Medical Officer
"A spokesperson said: 'Vitamin D supplements are not recommended for the general population as most people get enough of the vitamin from their diet and from sunlight."
http://www.dailymail.co.uk/health/article-1350750/All-children-5-vitamin-D-avoid-rickets.html#ixzz1kaKyp1HR
- It would be interesting to hear more about how long vitamin D is stored in the body and how much size of skin area and time do we need.
- MEN : Balding maybe an evolved genetic advantage as it's said older people need more Vitamin D, but OTH since many men do the horribly mutilating thing of removing the hair from their faces perhaps they are increasing their vitamin D.
- WOMEN : who wear low cut tops & miniskirts would gain a similar advantage re- Vitamin D wouldn't they ? ...I'd prescribe this
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that story is repeated on the NHS's own website in more detail : http://www.nhs.uk/news/2012/01January/Pages/vitamin-d-medical-advice-and-supplements.aspx
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, since humans have been mostly fine for the last 20,000 years in the UK without vitamin D tablets or eating lots of oily fish (which as you say is the biggest dietary source, followed by a bit in eggs & liver). Are we really saying vegetarians don't get enough without tablets ..surely that would have shown up by now ?
The point, which you seem to have missed, is that food isn't it at all. Vitamin D is due mostly to sunlight.
If you go out in the summer and work hard in fields in strong sunlight then you probably won't have a problem; you'll build up massive amounts of vitamin D and that will last you till spring. You may well die of skin cancer, but you won't get osteoporosis.
But the idea that everyone was fine for 20,000 years when they'd never even heard of vitamin D; no, they weren't, at the very least for hundreds of years when people have lived and worked in cities, osteoporosis was and is not that uncommon.
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the argument that we have been okay for all these years is full of false assumptions. What do you mean by fine? When people died at an early age from infectious disease, malnutrition or whatever, then the effect of lack of vitamin D on bones was not much of an issue unless you count all the people with rickets. Very few people lived long enough to get osteoporosis, and probably those that did live long enough did get it--it just wasn't diagnosed. Old people just had crumpled spines and broke their hips.
Now we are living longer, and spend less time outdoors and doing less physical work/exercise, both of which help your bones. Sunscreens and the avoidance of sun exposure are prevalent only in the last 30 years, meaning we are making less vitamin D than we did in the days of children and adults spending hours in the sun working or playing. Supplementing milk, as is done here in the US benefits mainly children as many older adults have limited milk intake. The real question is; would supplementation with vitamin D HARM anyone?
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Yes coincidentally I was just about to post the same message ...when I read that NHS report I realised 90% of our supply comes from sunlight so counting the value in food is a bit of a red- herring, "We therefore rely on accumulated fat deposits of vitamin D over winter "
- When I said everyone was fine I meant in an evolutionary way. People have evolved to function with the sunlight at these latitudes without Vitamin D tablets". Those gene strains which didn't produce enough vitamin D should have been killed out by evolution.
- The time people have lived in cities is not evolutionary significant .
- I'll get back to my original point which was that thinking of supplements as a magic solution is wrong as it's akin to tinkering with an F1 car cos you are trying to run it on a mudfield, when in fact you should be running it on the tarmac surface it was designed for. The human body should be running in the environment more akin to the one it's spent 100,000s of year evolving for. Good health should be more about lifestyle rather than pushing in magic pills cos we are couch potatoes.
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" humans have been mostly fine for the last 20,000 years"
Not really, they got rickets.
http://en.wikipedia.org/wiki/Prehistoric_medicine#Disease_and_mortality
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One should also consider the major advancements in medicine over the last century or so.
Childhood mortality has dropped considerably in the advanced societies, and prenatal vitamins have their role.
And, we are living longer.
Osteoporosis would have been rare 20,000 years ago... as very few people lived to the ripe old age of 40. Now, with people often living into their 80's and 90's, we are plagued by issues of bone weakness that our ancestors didn't have to deal with.
As mentioned, brittle bones are much easier to treat if you start young, rather than waiting until one is at risk of fracturing a hip.
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small point - WINTER-SUN holidays - If 12 minutes per day on face and hands is sufficient in summer is there any topping up effect when people take a holiday to Canaries etc. in the winter
- I still stand by the mostly fine in last last 20,000 years or from beginning of habitation in northern latitudes. We have no evidence of what rickets level was in prehistoric times, except it wasn't bad enough to kill the human population off. Rickets in the recent 300 years occurred when lifestyles were different from that during most of evolution i.e. being all day in school in school rooms in smokey cities or working down coal mines etc
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Uh huh. Rickets is on the increase in the UK. But you're fine, with your WINTER-SUN holidays, sod anyone that doesn't want to, or can't afford to go on one.
Meanwhile, wiping out ill health with sensible, safe supplementation of the UK diet, even though we're much further North than Canada, who supplement, is supposed to be controversial.
Supplementing milk, as is done here in the US benefits mainly children as many older adults have limited milk intake. The real question is; would supplementation with vitamin D HARM anyone?
It's very, very unlikely. The lethal dose of vitamin D is gigantic; about two hundred pills of 200 IU per DAY (a whole bottle of pills), for three solid months or more. The kind of supplementation that's being talked about is a fraction of one pill per day.
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D is oil based vitamin & not urine flushable?
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Yup, it's fat soluble, and can't be excreted.
But the amount of vitamin D you need to kill you is so incredibly enormous, it doesn't really matter very much.
Also there's processes in the body that destroy it, that top out at up to maybe 30,000 IU/day or something.
But that's not to say that having stupidly high vitamin D levels is necessarily healthy, just that it's not a poison in any sane amounts.
And from an RDI point of view, there will be some fraction of the population that can't handle vitamin D in large doses.
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Yup, it's fat soluble, and can't be excreted.
But the amount of vitamin D you need to kill you is so incredibly enormous, it doesn't really matter very much.
Also there's processes in the body that destroy it, that top out at up to maybe 30,000 IU/day or something.
But that's not to say that having high vitamin D levels is necessarily healthy, just that it's not a poison in any sane amounts.
And from an RDI point of view, there will be some fraction of the population that can't handle vitamin D in large doses.
thanx, cholesterol + sunlight= D?
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Yes, cholesterol + UV B. It's incredibly cheap to manufacture, and seems to be very safe.
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Yes, cholesterol + UV B. It's incredibly cheap to manufacture, and seems to be very safe.
Possible that excess D intake results in unconverted/accumulated cholesterol?
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Not really, it's a hormone, it's present in microgram quantities, whereas normal fats are grams/kilograms.