-
Re: Vegans, vitamin D and the sun
It's May, and spring in the Northern hemisphere... so, don't sit here and read about vitamin D generated from sun/daylight exposure... get out in the sun! :D
Remember, you'll get increased vitamin D levels even on cloudy days, and the body needs enough vitamin D to absorb calcium. The body also needs calcium to absorb B12, so the positive effect of not reading this post (or - hrmmm... writing it) and take a walk instead would be... triple-ish.
-
Re: Vegans, vitamin D and the sun
I avoid ultraviolet light because of its carcinogenicity. I take Deva Vegan Vitamin D 800 IU. I have ordered them on the Internet because D2 cannot be bought where I live.
-
Re: Vegans, vitamin D and the sun
-
Re: Vegans, vitamin D and the sun
'Epidemic' of vitamin D deficiency: MUHC study
An excerpt:
Quote:
McGill research has discovered that low levels of vitamin D is linked to muscle fat and decreased strength in young people.
A deficiency of vitamin D in study subjects has surprised doctors at the McGill University Health Centre.
A study, released Thursday, found that 59 per cent of study subjects had too little vitamin D in their blood and nearly a quarter of the group had serious deficiencies.
"Vitamin D insufficiency is a risk factor for other diseases," said Dr. Richard Kremer, the principal investigator of the study at the research institute.
"Because it is linked to increased body fat, it may affect many different parts of the body. Abnormal levels of vitamin D are associated with a whole spectrum of diseases, including cancer, osteoporosis, and diabetes, as well as cardiovascular and autoimmune disorders," he said.
The study is also referred to here:
Quote:
...about 59 percent of people evaluated were deficient in vitamin D and about 25 percent were severely deficient.
[...]
The main reason why people are generally lacking in vitamin D is because people spend much more time indoors than they used to. Especially with computers, people often spend their entire days inside cubicles where they are exposed to little or no sunlight.
-
Re: Vegans, vitamin D and the sun
i'm off to get the latest update on my vit d levels later today - i'll post the results. i've been taking a combined vit d & calcium supplement since around the end of last year.
-
Re: Vegans, vitamin D and the sun
How did you get on cedar? (How does one get a UK gp to check vitamin D levels? Or are you having it done privately?)
-
Re: Vegans, vitamin D and the sun
Here's a source that mentions vitamin D levels in some plants . I haven't checked this info, but here it is:
Quote:
Some of the students expressed a difficulty in finding foods which would measure up to the daily suggested requirement or Vitamin D, and Vitamin B-12, relying on the sun for Vitamin D, and the nutritional yeast for their B-12. But suppose a person lived in a foggy or rainy atmosphere, and did not get out into the sun? Well, here we can use alfalfa as a very good source of Vitamin D. According to Dr. Christopher's recent laboratory tests, we see that alfalfa contains 4740 IU of Vitamin D per pound. Alfalfa is an excellent source of Vitamin D. Viktoras Kulvinskas also documents this fact in many of his writings.
Here's som more info, suggesting that 12 flowering plants, mainly within the Solanaceae family, contains vitamin D:
Vitamin D compound in plants:
Quote:
An appreciable number (15) of flowering plants, specially within the Solanaceae family, have been shown to contain vitamin D3 and its hydroxylated derivatives, including 1α,25(OH)2-vitamin D3 [1α,25(OH)D3], a pluripotent hormone in animals. These secosteroids have also been detected in members of the Cucurbitaceae, Fabaceae and Poaceae families. On the basis of recent cladistic analysis it is possible to predict that the synthesis of these compounds is a characteristic of the Angiosperms. Highly specific and sensitive bioassays and analytical procedures of high resolution are now available which may allow confirmation of this hypothesis. Solanum glaucophyllum is the species which accumulates 1α,25(OH)D3 to the greatest extent. The metabolite is distributed among different tissues of the plant as a free steroid or glycoside derivatives. The presence of 7-dehydrocholesterol, vitamin D3, 25(OH)D3 and 1α,25(OH)2D3 in S. glaucophyllum and other species has been unequivocally demonstrated. Moreover, recent studies with radioactive precursors, protein immunoblot and RNA hybridization analysis suggest the presence of specific hydroxylases for vitamin D3 and 25(OH)D3 structurally related to the corresponding enzymes in vertebrates. It appears then that plants possess a similar synthetic route to 1α,25(OH)2D3 as in animals. However, of unique biological importance, evidence obtained with S. glaucophyllum and Nicotiana glauca supports the operation of a non-photolytic reaction of vitamin D3 synthesis. Both intermediates and enzymes of the vitamin D3 pathway can be detected in cell and tissue cultures thus affording a convenient experimental model for studies on its molecular characterization and regulation. This is also endowed with biotechnological significance. Vitamin D3 compounds may play a function in Angiosperms. Studies in vitro have shown that, like mitogenic plant hormones, they stimulate root growth and differentiation through activation of the Ca2+ messenger system. There are vitamin D3 and 1α,25(OH)2D3 binding proteins in plants which exhibit characteristics suggesting a regulatory function. It remains to be established whether these binders act as true steroid hormone receptors.
-
Re: Vegans, vitamin D and the sun
From http://www.vitamins-supplements.org/...n-sources.php:
Quote:
The major source of vitamin D in active people is sunlight, as exposure of the skin to sunlight produces vitamin D in the body. Vitamin D is found in milk (fortified), cheese, whole eggs, liver, salmon, and fortified margarine. The skin can synthesize vitamin D if exposed to enough sunlight on a regular basis. Vitamin D is found in very few food sources including brewer's yeast, mushrooms and wheat bran, eggs, fish, and fish's oil.
More on mushrooms and vitamin D here:
Quote:
The Food and Drug Administration (FDA) in the USA has been seeking a natural, non-animal food, rich in Vitamin D. That led them to mushrooms. It has been demonstrated that when white button mushrooms are exposed to Ultraviolet B radiation, for a short period of time, the level of Vitamin D increases to levels many times the minimum daily requirement, i.e. 10 mcg. Normally, a serving** of white button mushrooms contains 18 IU (0.45 mcg.). Treated mushrooms contain over 80 mcg.***
Sundried mushrooms seems to be a useful solution...:
http://www.dried-mushrooms.us/
More about sun-treated mushrooms here:
Quote:
Most people are aware that the human body makes vitamin D in response to sunlight. Less known is the fact that mushrooms, even picked ones, can perform the same feat - which means that eating mushrooms that have been exposed to sunlight can be an excellent way to supplement your "D" levels.
In the summer of 2004, mycologist Paul Stamets discovered that the level of vitamin D in freshly picked, indoor- grown shiitake mushrooms rose from 110 IU (international units) to an astonishing 46,000 IU per 100 grams when the mushrooms were placed outdoors in the sun for just six hours with the gills facing up (when the gills were facing down, the level rose to 10,900 IU).
This means that eating just one gram of sun-treated shiitake - about one tenth of one mushroom - would give you 460 IU, close to the FDA's recommended daily dose of 400 IU, and about half of Dr. Weil's recommended 1,000 IU.
In his book, Mycelium Running: How Mushrooms Can Help Save the World, Stamets concluded, "(In) populations where vitamin D is seriously deficient, sun-exposed dried mushrooms can help address a serious health issue."
http://en.wikipedia.org/wiki/Shiitake:
Quote:
Shiitake are often dried and sold as preserved food in packages. These must be rehydrated by soaking in water before using. Many people prefer dried shiitake to fresh, considering that the sun-drying process draws out the umami flavour from the dried mushrooms by breaking down proteins into amino acids and transforms ergosterol to vitamin D. The stems of shiitake are rarely used in Japanese and other cuisines, primarily because the stems are harder and take longer to cook than the soft fleshy caps. The highest grade of shiitake are called donko in Japanese.
http://hypography.com/forums/medical...ushrooms.html:
Quote:
The ongoing work so far has found that a single serving of white button mushrooms the most commonly sold mushroom will contain 869 percent the daily value of vitamin D once exposed to just five minutes of UV light after being harvested . If confirmed, that would be more than what's in two tablespoons of cod liver oil, one of the richest and most detested natural sources of the vitamin, according to the National Institutes of Health.
According to this source, vitamin D can be found in these herbs: Alfalfa, Dandelion greens, Horsetail, Nettle and
Parsley. Who wants to play the source-police game and find sources for this? :)
There's even a book called "Mycelium running: how mushrooms can help save the world", which on p. 204 says that "500g of fresh maitake (more than one pound), or 50g dried, would provide enough vitamin D for 50 people!"
There are an 38,000 species of mushrooms. How the perform when sun-treated/dried, and how bioavailable the vitamin D is for most of these mushrooms is probably still unknown, but since plants are known to behave like humans when exposed to sun, it's very unlikely that we won't see a lot of info in the future about using mushroom and mushroom products as vitamin D sources.
-
Re: Vegans, vitamin D and the sun
About vitamin D in dandelion:
http://www.zhion.com/liver_issues/Dandelion.html
http://www.livestrong.com/article/10...andelion-root/
http://hartkeisonline.com/2010/04/08...g-properties/:
Quote:
According to the USDA, dandelions rank in the top 4 green vegetables in overall nutritional value. Dandelions are nature’s richest green vegetable source of beta carotene and outstanding source of vitamin K1. According to nutrition studies, dandelion supplies modest amounts of magnesium, phosphorus, copper, iron, potassium and manganese, as well as fiber (inulin), vitamins B6, C, E, (Alpha Tocopherol), thiamin, riboflavin, folate, and boron. Research from Russia and Eastern Europe shows that dandelion is also rich in vitamin D. Despite the fact that it does not contain large amounts of vitamin C, it has been used successfully to treat scurvy, which is caused by lack of vitamin C.
From information quoted on this site,
Quote:
According to the USDA Bulletin #8, “Composition of Foods” (Haytowitz and Matthews 1984), dandelions rank in the top 4 green vegetables in overall nutritional value. Minnich, in “Gardening for Better Nutrition” ranks them, out of all vegetables, including grains, seeds and greens, as tied for 9th best. According to these data, dandelions are nature’s richest green vegetable source of beta-carotene, from which Vitamin A is created, and the third richest source of Vitamin A of all foods, after cod-liver oil and beef liver! They also are particularly rich in potassium, iron, calcium, magnesium, phosphorus and the B vitamins, thiamine and riboflavin.
Marei (Hobbs 1985) indicated that dandelion is also rich in micronutrients such as copper, cobalt, zinc, boron, and molybdenum, as well as Vitamin D.
-
Re: Vegans, vitamin D and the sun
Update: My levels are fine. My endo said I should consider dropping my intake when summer rolls around. So now I'm just going for a blood test through my GP every 4 months or so.
-
Re: Vegans, vitamin D and the sun
Glad to hear that buttons.
-
Re: Vegans, vitamin D and the sun
-
Re: Vegans, vitamin D and the sun
Yet another reason to make sure you get enough sun/vitamin D:
Vitamin D May Influence Genes for Cancer, Autoimmune Disease
Findings could underscore why deficiency plays role in host of serious ills
An excerpt:
Quote:
TUESDAY, Aug. 24 (HealthDay News) -- Scientists have discovered a link between vitamin D and genes related to autoimmune diseases and cancer.
The finding may explain why vitamin D deficiency is a risk factor for a number of serious illnesses, including multiple sclerosis, type 1 diabetes and rheumatoid arthritis, according to researchers from the United Kingdom and Canada.
In the study, Sreeram Ramagopalan of Oxford University and colleagues noted there is a growing amount of evidence that vitamin D deficiency is a risk factor for a wide range of diseases, but it's not known exactly how vitamin D is involved. It has been suspected that genetics may contribute to this connection.
Vitamin D has an effect on genes through the vitamin D receptor, which binds to specific locations on the human genome to influence gene expression (the process by which a gene's information is converted into the structures operating in a cell). In this study, the researchers mapped sites of vitamin D receptor binding -- information that can be used to identify disease-related genes that might be influenced by vitamin D.
The investigators found that vitamin D receptor binding is significantly enhanced in regions of the human genome associated with several common autoimmune diseases, such as multiple sclerosis, type 1 diabetes and Crohn's disease, and in regions associated with cancers such as leukemia and colorectal cancer.
-
Re: Vegans, vitamin D and the sun
Lots of short quotes about the importance of vitamin D here:
Vitamin D Quotes
-
Re: Vegans, vitamin D and the sun
We don't have many sunny days in my country so I am taking Deva's vitamin D, when I remember to take it.
-
Low Vitamin D Levels - Help?
Hi, I am a new member of the forum, I have been vegan for about 4/5 months (since August 2010). I have M.E./Chronic Fatigue Syndrome, and my consultant tested me in Nov 2010 for Vitamin D and B12 (amongst a few other things).
The good news is that my B12 is sky high - good to know as thats the one I was worried about. However I found out today that my Vitamin D levels are very low - not quite at 'true' deficiency stage but a concern nonetheless, when I told him I was vegan he decided to prescribe me Adcal/D3 tablets which contain both Vit D3 and Calcium. I got the prescription straight away but have found out since coming home that this is not vegan, not even vegetarian! :sad::sad: I will take the tablets I have been prescribed as I have them now and I would consider it wasteful not to....but from what I understand D2 is vegan but I would have to take a higher amount to get the same benefit?
Please can anyone clarify and do you know of a good brand to look in to? I am in the UK.
Also is there anything I can do to boost Vit D in the meantime? There is a lack of sunshine in the UK right now. Vit D affects calcium too and I have had some dental problems lately as well which would explain.
I really dont want to get ill from this and I dont want it to mean I have to revert back to vegetarianism.
Sorry for the long post - any advice would be great, thank you.
-
Re: Low Vitamin D Levels - Help?
Hello! As you no doubt know there are various vegan vitamin D supplements on the market. I'm not sure if any are more reliable, or about the dosage thing, but someone else is sure to.
The Vegan Society sells a supplement that contains vitamin D but it also contains B12 so maybe you'd better not take that as your B12 levels are already so high.
-
Re: Low Vitamin D Levels - Help?
Hello Harpy, thank you for the reply. I dont know of any standalone D2 vegan supplements, but I could probably do a google search, unless you can tell me? Thanks.
I should have said that I have the VEG1 supplement from the Vegan Society, and I take that every few days (when I remember) which is why I am surprised that my B12 is so high! He said it was off the scale! Oooops! So yes I probably should just take a standalone supplement from now on, or at least for a while. Also is there a calcium supplement that is vegan? Just until I can up my dietary calcium. Thanks.
-
Re: Low Vitamin D Levels - Help?
I'm afraid I would only be googling as well, but someone else may have an actual recommendation. I know you can get both vegan vitamin D supplements and vegan calcium supplements, and possibly a combination of the two in one pill as well which might be handy if the doses were right.
I only take the Veg1 thing when I remember as well - perhaps I ought to get my levels checked in view of your experience!
-
Re: Low Vitamin D Levels - Help?
Thank you Harpy! I will have a little search myself. :) Please dont take the fact that my B12 levels are high as any kind of marker, as I may have taken the tablet not long before the blood test. Anyway he said it wasnt a concern because excess B12 is excreted in urine. But this has made me realise that, even though I thought a pretty well balanced diet, perhaps I really ought to be paying even more attention to it. Thanks again for your replies.
I was also wondering if there was anyone else on the forum that had been confirmed with low Vitamin D levels and whether this caused any problems or symptoms for them.
-
Re: Low Vitamin D Levels - Help?
I use Deva vegan calcium-magnesium plus, which also contains 100% RDA vitamin D as D2. I haven't had my levels checked, but I don't spend a lot of time outside and I've switched to organic soya milk, which isn't fortified.
I order it from this website, as this is the lowest price I could find it for and it also has quite low p&p.
http://www.shopvegan.co.uk/productdetail.asp?ItemRef=67
Hope this helps.
-
Re: Low Vitamin D Levels - Help?
I get mine from those Pure spreads (butter substitutes) - think the Soya one has the most in.
-
Re: Low Vitamin D Levels - Help?
Veganchef, thank you for that link, once my tablets are used up I will look at those I think, calcium and magnesium together is good, I may need to check how much Vitamin D I need to take to get up to optimum levels. I have been prescribed D3 and I think you need less equivalent of that to D2 - so I would need to check.
Thank you Daffodil too, I do use the Pure spreads, both the Sunflower one and the Soya one. It will be easier when spring and summer are here, I will just have to sit in the sun more, but this winter I am definitely struggling.
-
Re: Low Vitamin D Levels - Help?
Quote:
veganchef
I use Deva vegan calcium-magnesium plus, which also contains 100% RDA vitamin D as D2. I haven't had my levels checked, but I don't spend a lot of time outside and I've switched to organic soya milk, which isn't fortified.
...
I was looking at something similar in H&B today, theirs looked massive! Are they easy to swallow?
-
Re: Low Vitamin D Levels - Help?
I've been looking for vit D supplements too. The ones H&B sell aren't vegan, nor are the ones in Superdrug. H&B do a vegan mutli vitamin with D2 in but only 5mcg, which although is 100% EC RDA I understand that 15 or 20mcg would be better.
-
Re: Low Vitamin D Levels - Help?
I found some on ebay, 25mcg (500% EC RDA) £9 delivered for 4 months supply.
http://cgi.ebay.co.uk/Vitamin-D-2-Ve...item35a7c187f1
-
Re: Vegans, vitamin D and the sun
Here's some more vitamin D info (including some conflicting opinions):
http://www.dermnetnz.org/systemic/vitamin-d.html
Quote:
During winter months, vitamin D production is reduced. However, the body can rely on tissue stores of vitamin D for between 30 and 60 days assuming levels are adequate prior to winter. As summer approaches and more sunlight hours are available, vitamin D is produced by the skin to rebuild depleted stores.
http://mothering.com/breastfeeding/s...iew-literature
Quote:
Levels of vitamin D vary seasonally among people exposed to sunlight at higher latitudes, where UVB radiation is higher in the summer and lower in the winter.10, 11 With inadequate summer exposure, vitamin D deficiency and insufficiency can result, particularly during the winter.12, 13 However, with adequate exposure to sunlight in the summer, vitamin D can be stored in the body for winter use.14
(14: M. Holick, "Vitamin D and Bone Health," J Nutr 126 (1996): 1159S-1164S. )
Quote:
How Do Nurslings Get Enough Vitamin D?
The natural sources of vitamin D for nurslings are primarily the stores they developed prenatally (for newborns) and the vitamin D they produce with exposure of their skin to sunlight; a smaller additional contribution is from human milk.15, 16 The concentration of fat-soluble vitamin D in human milk varies from 5 to 136 IU/L, depending on how its activity is measured and on maternal vitamin D status during lactation.17-19 This concentration provides less than the 200 to 400 IU/day commonly recommended for infants under one year of age.20 However, human milk should not be considered "deficient" in vitamin D, because the biologically normal means of obtaining sufficient vitamin D in humans is via sunlight exposure, not diet.21-23
The neonate's stores of vitamin D depend on maternal vitamin D status during pregnancy.24, 25 A study of exclusively breastfed infants in Tampere, Finland (61° N) in winter showed that, without UVB exposure or vitamin D supplementation, vitamin D stores of fetal origin were depleted by eight weeks of age.26 Although these vitamin D-depleted infants had serum levels of vitamin D at which rickets can occur, none had active or biochemical rickets. The concentration of vitamin D in human milk increases significantly with what are currently considered pharmacological doses of vitamin D supplements.27, 28 Administration of 2,000 IU-but not 1,000 IU-to lactating mothers in another study normalized the 25-hydroxyvitamin D levels of their infants in winter.29 Supplementation with over 1,000 IU/d is currently considered to greatly exceed normal maternal vitamin D needs (200 IU/d).30
http://en.wikipedia.org/wiki/Vitamin_D
Quote:
The serum concentration of 25-hydroxy-vitamin D is typically used to determine vitamin D status. It reflects vitamin D produced in the skin as well as that acquired from the diet, and has a fairly long circulating half-life of 15 days. It does not, however, reveal the amount of vitamin D stored in other body tissues.
Here's some advice to non-vegans:
http://www.foodmatters.tv/_webapp_37...yths_and_Facts
Quote:
Don’t rely on food alone for your Vitamin D needs. It is almost impossible to get your Vitamin D needs met by food alone. Fatty wild fish (not farmed), like salmon and mackerel are the best food sources, but you would have to eat huge quantities of them daily to get anywhere near what your body needs. Although fortified milk and orange juice do contain Vitamin D, you would have to drink at least 10 glasses of each daily and I don’t recommend doing that.
http://www.drweil.com/drw/u/QAA40040...Vitamin-D.html
Quote:
As you probably know, darkly pigmented skin isn't efficient at inducing the synthesis of vitamin D. This isn't a problem in Africa where there's plenty of sun, but it often translates into vitamin D deficiency in areas of the world where sunshine is more limited. Fortunately, if you get enough sun exposure in the summer, your body will make and store enough D to get you through the winter. This doesn't work as well if you're obese because body fat holds onto vitamin D tenaciously and doesn't release it efficiently,says Michael Holick, Ph.D., M.D., an expert at Boston University.
http://www.jbc.org/content/118/2/371.full.pdf (An old study, unfortunately on animals, from 1936):
Quote:
The time required for depletion of vitamin D in the skin, lungs, kidneys, and small and large intestines did not show much variation. It can only be stated that vitamin D was stored in all thescl
1,isxues to about the same extent; that is, for about 5 to 8 weeks. It seems as if the liver can hold vitamin D more tenaciously than can the other organs. The results obtained, however, are
not sufficiently uniform and the difference in storage time in the liver, on the one hand, and in the skin, lungs, kidneys, and small and large intestines, on the other, is not sufficiently great to justify
a more positive statement at this time. To have found that only the liver retained vitamin D for from 6 to 8 to 12 weeks is certainly suggestive of the hypothesis advanced by Gerstenberger (4) that
the liver probably plays a decisive r81e in the functioning of vitamin D.
[...]
Under these conditions it was found that vitamin D was stored in the brain for 1 to 2 weeks, in crythrocytes for 5 to 6 weeks, in the small intestines for 5 to 8 weeks, in the large intestines for 6 to 8 weeks, in the skin for 6 to 8 weeks, in the lungs for 6 to 9 weeks, in the kidneys for 6 to 9 weeks, in the liver for 6 to 8 to 12 weeks, and in blood plasma for 8 to 12 weeks and more. It is assumed that consumption of vitamin D within the tissues, if it exists at all, must be very slight. It seems more likely that excretion is the chief means by which the body is depleted of its vitamin D depots.
http://www.netdoctor.co.uk/diseases/...ciarickets.htm (
Quote:
Most people in the UK get most of their vitamin D from exposure of the skin to sunlight. The average person has enough vitamin D stored in their body to last for two or three years.
Who is at risk of vitamin D deficiency?
People who get little exposure to sunlight are most at risk of vitamin D deficiency in the UK. Immigrants from Asia, particularly women and children, are at risk, as are elderly people who are housebound or confined to residential and nursing homes.
Recent surveys have shown that significant vitamin D deficiency is not uncommon in the general population.
Some people with intestinal problems, such as Crohn's disease, coeliac disease and cystic fibrosis, may also become short of vitamin D, as do some patients with liver disease.
[...]
An alternative is a single injection of vitamin D, in the form of calciferol (vitamin D2). This is stored in the body and can last up to a year before another injection may be needed. People with vitamin D deficiency due to intestinal problems are best treated with calciferol injections.
One year - or 2-3 years.... but no references to actual studies? Hmmm....
http://www.naturalnews.com/003838.html
Quote:
So if a person has all the vitamin D that their body wants, and it's stored in the fat tissues, how long can they go, is it a period of months?
Dr. Holick: Yeah, I mean if you're getting a really adequate source in the spring, summer and fall, it'll last two to three months. So it'll get you through the winter. But for those that are concerned about this issue, what I always tell my patients is, take a multivitamin, you're getting 400 units and get some sun exposure to really make sure that you're building up your stores of vitamin D. And then during the wintertime especially take at least a multivitamin, and maybe take an additional supplement, a vitamin D supplement that contains another 400-1000 units of vitamin D.
Dr. Michael Holick, author of "The UV advantage" has been mentioned in an earlier quote, and is "one of the world's most respected authorities on vitamin D and the health benefits of natural sunlight".)
http://www.pubarticles.com/article-t...294918927.html
Quote:
The researchers found that Influenza A occurred in 18 of 167 (10.8%) children in the vitamin D(3) group, compared with 31 of 167 (18.6%) children in the placebo group (an almost two-fold increase). The researchers also found that, for children with a previous diagnosis of asthma, asthma attacks as a secondary outcome occurred in two children receiving vitamin D(3), compared with 12 children in the placebo group — a significant increase!
The research team concluded that vitamin-D(3) supplementation during the winter may reduce the incidence of influenza A.
The best source of vitamin D is the sun, of course. UV rays from the sun trigger vitamin-D synthesis in your skin. Ten to 15 minutes of sun exposure at least two times a week to your face, arms, hands or back is enough to give you a healthy dose of vitamin D. Keep in mind, however, that long winters and sun avoidance in the summer mean that you may not be getting enough vitamin D this way.
One other note: vitamin-D synthesis is less efficient in people with darker skin, and African Americans are at higher risk of deficiency than whites. Overweight adults can also be at risk because vitamin D is stored in body fat. The more vitamin D that gets stored into fat tissue, the less active vitamin there is in the blood.
Daily Duration of Vitamin D Synthesis in Human Skin with Relation to Latitude, Total Ozone, Altitude, Ground Cover, Aerosols and Cloud Thickness
Quote:
Ozone strongly absorbs UV-B radiation. Extremely high/low ozone levels (500 DU / 100 DU) can decrease / increase the latitude of vitamin D winter incidence by about 10 degrees, and extend / shorten its period of duration by about two months.
Atmospheric aerosols attenuate surface UV-B radiation. On the other hand, reflection of UV radiation from the Earth’s surface enhances UV-B radiation. Snow cover or a turbid atmosphere (5 km visibility, i.e. Ångström β = 0.4) can change the lower latitude of occurrence for the vitamin D winter by a couple of degrees and alter the duration of dermal vitamin D synthesis by about 1-2 weeks. Increasing the surface elevation to 3000 m has about the same effect as covering the ground with snow at sea level.
Clouds generally attenuate UV-B radiation. Thick clouds can reduce surface UV-B radiation to as much as 1% of clear sky levels. Even scattered clouds on the horizon may lower the UV radiation significantly. Dermal vitamin D synthesis can halt completely at the equator for a very thick overcast cloud with a liquid water column of 3600 g m-2 or higher (not shown in table 1). At 70 degrees latitude the vitamin D production in skin can disappear even at midsummer for a medium thick cloud cover with a liquid water column of 2000 g m-2.
About various vitamin D myths, from Reinhold Vieth, a leading expert on vitamin D and director of the Bone and Mineral Laboratory at Toronto’s Mount Sinai Hospital.
An excerpt:
Quote:
Myth: You don’t need a supplement if you spend a lot of time outside.
Truth: If you work outside year-round, you may not need a vitamin D supplement, says Vieth. But since the majority of us cannot be guaranteed to receive consistent, safe exposure to UVB rays, it’s best to ask your doctor whether taking a vitamin D supplement is right for you.
And finally, an online vitamin D calculator:
Duration of Vitamin D Synthesis in Human Skin
And, a non-expert version: http://zardoz.nilu.no/~olaeng/fastrt/VitD-ez.html
-
Re: Vegans, vitamin D and the sun
Here's a typical example of a situation where testing on animals make no sense whatsoever:
Solanum glaucophyllum as source of 1,25-dihydroxyvitamin D3.
Quote:
Vitamin D-deficient rats given an aqueous extract of the South American plant Solanum glaucophyllum accumulate 1,25-dihydroxyvitamin D3 in their blood and intestines at the time they show enhanced intestinal calcium absorption. The identity of the 1,25-dihydroxyvitamin D3 was established by co-chromatography with 1,25-dihydroxy[23,24-3H]vitamin D3 on Sephadex LH-20 columns, microparticulate silica gel columns, a reversed-phase column developed under high pressure, and by a specific 1,25-dihydroxyvitamin D3 binding assay. The chromatographic systems used are fully capable of resolving all of the known metabolites of vitamin D3. Serum of the S. glaucophyllum-treated rats showed 300 pg/ml of 1,25-dihydroxyvitamin D3 and no detectable 1,25-dihydroxyvitamin D2. Similarly, intestine of such rats had 230 pg/g of 1,25-dihydroxyvitamin D3. Control animals which received the vehicle instead of S. glaucophyllum had only 20 pg/ml of 1,25-dihydroxyvitamin D3 in their serum and 4.4 pg/g of 1,25-dihydroxyvitamin D2 in their intestine. These results demonstrate that S. glaucophyllum extracts must be a source of 1,25-dihydroxyvitamin D3; thus a significant basis for the calcinogenic properties of S. glaucophyllum must be the presence of a conjugated form of 1,25-dihydroxyvitamin D3, which is rendered available by digestion.
It's of course great that these plants contain bioavailable 1,25-dihydroxyvitamin D3, but why don't they perform these tests on humans instead? A lot of foods that are toxic in large amounts are beneficial in small amounts, and more research is needed on vit. D in plants and how to extract the useful components from plants that have undesirable effect on us in large amounts.
-
Re: Vegans, vitamin D and the sun
From Medicinal and aromatic plants, volume 11:
First, this book suggests that P. orientalis leafs contain between 0.15 and 120 mcg vitamin D3 per gram dry weight (Boland 1986).
It's also mentioned that Cestrum diurnum's apical leaves contained much higher concentrations of free vitamin D than those of their corresponding glycosides. (But don't eat Cestrum diurnum.... see below!)
Next up is alfalfa (Medicago sattiva) - and both D2 and D3 were detected in different tissues of this plant. Stem, flowers, seeds and roots had low vitaminD concentrations, but there were high concentrations in the leaves (Horst et al. 1994).
Vitamin D was also found in the tomato plant (Lycopersicum esculentum), but only in the leaves.
Vitamin D2 and D3 is also plays an important role in the creation of adventitious roots on green cuttings of Poplus tremula (aspen) and mung beans (Vigna radiata). Vitamin D2 also improves root formation on artichoke (Cynara scolimus) shots (Moncousin and Gaspar 1983). The table on page 367 suggests that the leaves of yellow oatgrass (Trisetum flavescens) contain D3 (Ramveck et al. 1979).
Some of the vitamin D found in these plants are low, but there are also examples of the opposite. The book Veterinary toxology - basic and clinical principles, for instance, suggests that the toxicityn is attributed to 1,25-dihydroxy-vitamin D-glycoside and that the toxicity of Solanum malacoxylon is due to a molecule similar or identical to 1.25-dihydroxy vitamin D.
(1,25-dihydroxyvitamin D3, is the hormonally active form of vitamin D).
I need to read more about this... it's kind of surprising to read that some plants contain so much D3 that the effect is toxic (at least on horses and cows eating a lot of these plants) while others claim that there's no vitamin D in plants at all. According to this link (mentioned earlier), "an appreciable number (15) of flowering plants, specially within the Solanaceae family, have been shown to contain vitamin D3 and its hydroxylated derivatives, including 1α,25(OH)2-vitamin D3 [1α,25(OH)D3], a pluripotent hormone in animals. These secosteroids have also been detected in members of the Cucurbitaceae, Fabaceae and Poaceae families."
-
Re: Vegans, vitamin D and the sun
-
Re: Vegans, vitamin D and the sun
Quote:
Korn
According to
this source, vitamin D can be found in these herbs: Alfalfa, Dandelion greens, Horsetail, Nettle and Parsley. Who wants to play the source-police game and find sources for this? :)
Here's another comment on vitamin D in nettle:
Quote:
Stinging Nettle
Stinging nettle leaf (Urtica dioica L. [Urticaceae]) was one of the less-used galactagogue herbs among the participants in this study, though has a long-standing reputation for enriching breast milk (Bartram, 1998; Bombardelli and Marazzoni, 1997; Gladstar, 1993; Weed, 1986; Yarnell, 1998). The herb is believed to be completely non-toxic (Yarnell, 1998). Nettle contains many nutrients, including iron, calcium, and vitamins A, C, and K (Lieberman, 1995), as well as phosphorus, potassium, sulphur, and vitamin D (Weed, 1986). They also contain some B vitamins and appreciable amounts of magnesium (Duke, 1992). They contain up to 20% mineral salts, mainly calcium, potassium, silicon, and nitrates (Blumenthal et al., 2000). Nettle extract has been found to contain all of the essential amino acids (Bombardelli and Morazzoni, 1997).
I googled the source, and it does claim that there's vitamin D in nettle, sunshine and alfalfa - but doesn't mention where the info about nettle comes from. The same book also claims that there's B12 in miso, which is what many assumed to be a truth in the 80s, which is when the book was written.
Some more googling revealed that several other sites claim that there's vit. D in nettle...
http://www.herbsarespecial.com.au/fr...on/nettle.html
http://rawepicurean.net/2009/04/16/n...-of-the-month/
http://www.greenmuze.com/nurture/loc...s-nettles.html
...but they may all quote each other or that book from the 80s.
ETA: according to this link, "Drug plants - Recent Progress in Medicinal Plants, Volume 27" (ISBN 1-933699-17-5) also claim that nettle contains B12:
Quote:
Urtica dioica, commonly called stinging nettle, is a herbaceous perennial flowering plant, native to Europe, Asia, northern Africa, and North America, and is the best known member of the nettle genus Urtica. Originally from the colder regions of northern Europe and Asia, today this herbaceous shrub grows all over the world. Stinging nettles are a dioecious herbaceous perennial, the soft green leaves are 3-15 cm long, with a strongly serrated margin, a cordate base and an acuminate tip. Stinging nettle is available as dried leaf, as tea, and as root tincture, It is rich in vitamins A, C, D, iron, potassium, manganese, and calcium. Nettle leaf extract contains active compound that reduce TNF-α and other inflammatory cytokines. Stinging nettle has a long medicinal history, Stinging nettle has been used for hundreds of years to treat rheumatism, eczema, arthritis, gout, and anemia. Today, many people use it to treat urinary problems during the early stages of an enlarged prostate, for urinary tract infections, for kidney stones, for hay fever, or in compresses or creams for treating joint pain, sprains and strains, tendonitis, and insect bites.
-
Nov. 2010: New Dietary Intake Levels for Calcium and Vitamin D
IOM Report Sets New Dietary Intake Levels for Calcium and Vitamin D To Maintain Health and Avoid Risks Associated With Excess
Quote:
WASHINGTON — Most Americans and Canadians up to age 70 need no more than 600 international units (IUs) of vitamin D per day to maintain health, and those 71 and older may need as much as 800 IUs, says a new report from the Institute of Medicine. The amount of calcium needed ranges, based on age, from 700 to 1,300 milligrams per day, according to the report, which updates the nutritional reference values known as Dietary Reference Intakes (DRIs) for these interrelated nutrients.
The report's recommendations take into account nearly 1,000 published studies as well as testimony from scientists and stakeholders. A large amount of evidence, which formed the basis of the new intake values, confirms the roles of calcium and vitamin D in promoting skeletal growth and maintenance and the amounts needed to avoid poor bone health. The committee that wrote the report also reviewed hundreds of studies and reports on other possible health effects of vitamin D, such as protection against cancer, heart disease, autoimmune diseases, and diabetes. While these studies point to possibilities that warrant further investigation, they have yielded conflicting and mixed results and do not offer the evidence needed to confirm that vitamin D has these effects. Rigorous trials that yield consistent results are vital for reaching conclusions, as past experiences have shown. Vitamin E, for example, was believed to protect against heart disease before further studies disproved it.
"There is abundant science to confidently state how much vitamin D and calcium people need," said committee chair Catharine Ross, professor and Dorothy Foehr Huck Chair, department of nutritional sciences, Pennsylvania State University, University Park. "We scrutinized the evidence, looking for indications of beneficial effects at all levels of intake. Amounts higher than those specified in this report are not necessary to maintain bone health."
The science on calcium's role in bone health shows that 700 milligrams per day meets the needs of almost all children ages 1 through 3, and 1,000 milligrams daily is appropriate for almost all children ages 4 through 8. Adolescents ages 9 through 18 require no more than 1,300 milligrams per day. For practically all adults ages 19 through 50 and for men until age 71, 1,000 milligrams covers daily calcium needs. Women starting at age 51 and both men and women age 71 and older need no more than 1,200 milligrams per day.
As for vitamin D, 600 IUs daily meets the needs of almost everyone in the United States and Canada, although people 71 and older may require as much as 800 IUs per day because of potential physical and behavioral changes related to aging.
The majority of Americans and Canadians are getting enough vitamin D and calcium, the committee determined from reviewing national surveys of blood levels. Some adolescent girls may not get quite enough calcium, and there is a greater chance that elderly individuals may fall short of the necessary amounts of calcium and vitamin D. These individuals should increase their intake of foods containing these nutrients and possibly take a supplement.
Confusion about the amount of vitamin D necessary to ward off deficiency has arisen in recent years as tests that measure levels in patients' blood have become widely used. The measurements of sufficiency and deficiency — the cutpoints — that clinical laboratories use to report test results have not been based on rigorous scientific studies and are not standardized. This lack of agreement means the same individual could be declared deficient or sufficient depending on which laboratory reads the test. There may be an overestimation of the number of people with vitamin D deficiency because many labs appear to be using cutpoints that are higher than the evidence indicates are appropriate. Based on available data, almost all individuals get sufficient vitamin D when their blood levels are at or above 20 nanograms per milliliter as it is measured in America, or 50 nanomoles per liter as measured in Canada.
Although sunlight triggers the natural production of vitamin D in skin and contributes to people's vitamin D levels, individuals' sun exposure varies greatly and many people are told to minimize their exposure, so the committee assumed minimal sun exposure to establish the DRIs. The new intake levels for vitamin D cover the needs of individuals who get little sun.
Greater amounts of food fortification and rising rates of supplement use have increased the chances that people consume high amounts of these nutrients. Getting too much calcium from dietary supplements has been associated with kidney stones, while excessive vitamin D can damage the kidneys and heart. Evidence about other possible risks associated with routine vitamin D supplementation is still tentative, and most studies have focused on very high doses taken short term rather than on routine, long-term consumption of large amounts. However, some signals suggest there are greater risks of death and chronic disease associated with long-term high vitamin D intake, which informed the committee's conclusions about levels that consumers should not exceed.
More here.
-
Re: Vegans, vitamin D and the sun
-
Re: Vegans, vitamin D and the sun
I wouldn't even entertain the idea that because something is used as an animal poison it is unsafe for humans. Everything is a poison, it just depends on the dose. For a long time I was on warfarin and that is also used as a rat poison but I'm still here, sorry everyone.
-
Re: Vegans, vitamin D and the sun
Quote:
Risker
I wouldn't even entertain the idea that because something is used as an animal poison it is unsafe for humans. Everything is a poison, it just depends on the dose.
Sure. Still - although there's no common agreement about an upper, safe level of vitamin D3 from supplements - max. vitamin D(3) levels is a hot topic.
Here's one of many studies on that topic.
After a long winter, the problem today is of course the opposite - that lots of people have very low vitamin D levels.
-
Re: Vegans, vitamin D and the sun
I am slightly vitamin D deficient...I take a 2400ui supplement a day now...as I read somewhere you need to take more if you have recent ceoliac issues (or like me have been very bad with your gluten free diet)...I've been trying to waft about in the sun more...I hate taking supplements.
http://www.veganhealthandbeauty.com/...sp?ItemRef=293
I was taking 800ui a day but I was still deficient!!! So confusing. As I also drink rice milk (with D2) and Pure (with D2)!!!
I told the doctor and he said maybe my pills are not good enough (?!) and to take the toxic waste with aspartamene (ill!) and D3 in!! I refused. As his pills give me an allergic reaction.
All I can think is...I'm not absorbing most of the vitamins...hence taking nearly 3000ui a day...in the hope that even if 2000 get washed away I'll still bet getting above the recommended dose a day.
-
Re: Vegans, vitamin D and the sun
Yeah you are right that sun light is the good source of Vitamin D...
With nude body you can get the maximum quantity of Vitamin D..
Thanks
-
Re: Vegans, vitamin D and the sun
Hey, the Vegan Society has just approved a D3 product:
http://www.vitashine-d3.com/
Here is their statement on Vitamin D3:
http://www.vegansociety.com/news/Sta...itamin-D3.aspx
Quote:
Statement from The Vegan Society about Vitamin D3
Tuesday 9 August 2011
In the past to the best of our knowledge there has not been any commercially available vegan vitamin D3. However, based on evidence recently presented to us we have now Trademarked a vitamin D3 product.
Claims on products which do not carry The Vegan Society Trademark that they provide vegan vitamin D3 continue to be questionable and if you come across any of these products please let us know.
I still don't know what to think of this. I wonder what any of you thinks?
-
Re: Vegans, vitamin D and the sun
Sounds good, be interesting to find out what the source is.
EDIT: Only read the second link, apparently it's Lichen extract
Pretty good price really, it suggests you take 5 times the EU RDA daily so if you only took 1 shot a day each bottle should last 5 months.
-
Re: Vegans, vitamin D and the sun
It does sound good, although if it starts being used to fortify products they will have to be careful that it doesn't cause any confusion about which products are/aren't vegan. It could also cause some new vegans to mistakenly think that all D3 is Vegan.
The upside is that any companies that use refuse to use D2 (I'm thinking Kelloggs) could use this, making more vegan products.