by Ian Wishart
[23] “Factors related to being sunburnt in 7-year-old children in Sweden”, Rodvall et al, European Journal of Cancer, 2010 Feb;46(3):566-72, http://www.ncbi.nlm.nih.gov/pubmed/19815405?dopt=Abstract
[24] “Sunscreen and Melanoma: Is Our Prevention Message Correct?”, Margaret B. Planta MD, Journal of the American Board of Family Medicine, Nov-Dec 2011, vol 24 no. 6, 735-739 doi: 10.3122/jabfm.2011.06.100178
[25] United States Environmental Protection Agency. Sunscreen: The Burning Facts. http://www.epa.gov/sunwise/doc/sunscreen.pdf.
[26] “Does vitamin D protect against DNA damage?,” Nair-Shalliker et al, Mutation Research, 2012 May 1;733(1-2):50-7. See also “The Role of the Vitamin D Receptor and ERp57 in Photoprotection by 1α,25-Dihydroxyvitamin D3,” Sequiera et al, Molecular Endocrinology February 9, 2012 me.2011-1161. See also “Vitamin D and skin cancer,” Dixon et al, Human Health Handbooks no. 1, 2012, Volume 2, Part 5, 394-411, DOI: 10.3920/978-90-8686-729-5_24
[27] “Vitamin D may indeed help fight cancer,” by David Liu, Food Consumer.org, 27 April 2012
[28] “Moles and melanoma – researchers find genetic links to skin cancer”, news release from Leeds Institute of Molecular Medicine and the Cancer Research UK Centre, 6 July 2009
[29] In late 2011, the same research team uncovered three more genes adding to the risk. One DNA fault is linked to narcolepsy (suddenly falling asleep), the second is a faulty gene that fails to repair damaged DNA in cells as it should, and the third risk factor is in a faulty gene that is supposed to prevent cancerous cells from spreading. If you are carrying all three of these gene faults, your risk of developing melanoma in your life is one in 46. See “Genome-wide association study identifies three new melanoma susceptibility loci”, Barret et al, Nature Genetics [doi: 10.1038/10.1038/ng.959]
[30] “Sun sensitivity linked to decreased pancreatic cancer risk, study suggests,” Amanda Chan, Huffington Post, June 20, 2012, http://www.huffingtonpost.com/2012/06/20/sun-pancreatic-cancer-risk-sensitivity-uv-rays-vitamin-d_n_1609095.html
[31] “The Good, the Bad, and the Ugly of Sunscreens,” M Berwick, Clinical Pharmacology & Therapeutics, Jan 2011, doi:10.1038/clpt.2010.227
[32] It is not true to claim, as some do, that slip, slop, slap has not impacted vitamin D levels, as this snippet from a bowel cancer study illustrates: “Our findings are consistent with a recent analysis of the National Health and Nutrition Examination Survey (NHANES), which found a low mean plasma 25(OH)D level of 24 ng/mL among 13,369 participants between 2001 and 2004.1 This represented a marked decrease from NHANES III (1988 to 1994), when the mean 25(OH)D level was 30 ng/mL. Potential explanations for the rise in vitamin D insufficiency include increasing use of sunscreen for skin cancer prevention, decreased outdoor activity, and the rising prevalence of obesity.” See http://jco.ascopubs.org/content/29/12/1599.full
CHAPTER 15
VITAMIN D: BEST SOURCES
“A wide range of epidemiologic and laboratory studies combined provide compelling evidence of a protective role of vitamin D on risk of breast cancer”
– Dermato-Endocrinology Journal, 2012
How much vitamin D should we consume? How much is poisonous? Where do we get it?
To answer the questions, we first have to understand the process. Food supplies only a limited amount of vitamin D.
“Unless those diets are rich in wild-caught fatty fish, sun dried Shitake mushrooms or wild reindeer meat,” you can forget about “adequate” vitamin D intake from a healthy diet, says the Vitamin D Council’s Dr John Cannell.
To get to 2,000IU a day through food alone, you would need to eat 50 eggs a day, or nine 1kg blocks of Swiss cheese, or 2kg of salmon. Anything less than that is playing.
The only food that comes close to giving you a decent vitamin D hit is sun-dried mushrooms. Shitake are the best to use, although you can use button or flat browns. Mushrooms, like humans, manufacture vitamin D when sunlight hits them. It’s not the D3 variety that’s best for us, but vitamin D2, created by plants and known as ergocalciferol. It is not quite as efficiently processed by our bodies, and most reports of vitamin D toxicity have arisen from being prescribed this vegan form of vitamin D2.
Where vitamin D3 is stored in our bodies for weeks, vitamin D2 is processed in hours or days.
However, here’s the news. A hundred grams of mushrooms left to dry gills-up on the back porch in the summer sun for six hours a day, two days in a row, will create somewhere in the region of 46,000 units of vitamin D2 per 100 grams of mushroom. If you dry enough of them, and store them well, you’ll have a weekly vitamin D2 hit available through winter.[1]
In Western Australia, commercial mushroom growers have cottoned onto this and are about to put vitamin D2 enhanced button mushrooms into supermarkets at the time of writing. They’re using large, powerful UV lights to run their mushrooms under, and the growers say three button mushrooms will provide the recommended daily intake of vitamin D for Australians.
“It takes just two to three seconds for the mushrooms to generate an amount of vitamin D in excess of the daily recommended intake,” reported a food industry paper.[2]
It’s a good way of turning a public health issue into a daily meal marketing opportunity.
By far the biggest source of vitamin D, however, is solar.
If you sunbathe for half an hour, you will generate somewhere between 20,000 and 30,000 IU of vitamin D. That’s the upper limit. After you reach those levels, the skin allows the excess vitamin D to be broken down by further sunlight. In other words, the body creates and stores as much as it needs, and no more.
To get that 20,000IU from your diet in half an hour, you would have to eat either forty servings of salmon, drink between 200 and 500 glasses of D-fortified milk (different countries fortify at different levels), or swallow twenty 1,000IU supplement pills. Obviously, that isn’t going to happen.
The stores of vitamin D your body builds over summer and autumn are needed to carry you through winter, but by mid winter they’ll have been used up, leaving you at the mercy of disease, which often hits hard in the winter and spring seasons.
As you’ve read in this book, many studies have shown a strong beneficial effect from higher daily doses (2000 to 4000IU) than are officially recommended.[3] While government health regulators drag their heels over boosting vitamin D levels, the public and their GPs are frequently taking matters into their own hands. But even then, without a good baseline of vitamin D, you may not be getting the full advantage.
“Very few humans obtain enough vitamin D even if they take several thousand units per day,” warns researcher John Cannell. He cites a study of Hawaiian sunbathers which compared their vitamin D levels to a group of breastfeeding mothers being given 6,400IU in daily supplements. The study found that even mothers receiving that much vitamin D were using so much of it for their daily metabolism that almost none was being stored to fight diseases and boost immunity.[4]
“This implies virtually everyone has a chronic [vitamin D] deficiency, at least in the winter,” says Cannell. “Because of this, most individuals have chronic substrate starvation, functional vitamin D deficiency, and thus, perhaps, higher risk for the ‘diseases of civilisation’.”
The problem can be expressed in laptop battery terms. Summer sun is like a full overnight charge for your computer battery. Daily supplements are like the trickle charge your battery receives while you use the laptop with the power cord plugged in. If your battery is low charged and you pull the cord out, it will go flat rapidly.
Think about that for a moment. If you don’t build up good vitamin D stores in summer, or through some other means, even high daily supplements are not doing as much for your health as they could. Sure, they are better than nothing, but that’s one of the reasons it is hard to turn your back on sunlight. It is impossible to overdose on vitamin D generated through UV rays, but it is possible to overdose on vitamin D taken orally.
Health authorities have sent out messages to medical
practitioners urging them not to order blood tests for vitamin D deficiency because they are expensive, at around $50 to $100. Better, and cheaper, say the health agencies, simply to supply a prescription, no questions asked.
The only problem with that logic is that if your doctor doesn’t know what your vitamin D levels actually are, how do they know what levels of the vitamin to give you for storage, and then how much to give you for daily maintenance? International research indicates a patient should be tested twice. Once in early spring to find their lowest vitamin D levels, and once in late summer for their peak level.
In New Zealand, for example, the standard medical prescription is a pill offering 50,000IU a month – roughly equivalent to sunbathing for 30 minutes twice in two days. Taken over a month, it averages out at a dose of around 1,500IU a day which, when you compare against the 6,400IU per day given to the breastfeeding women, is nothing. The mothers failed to store much of that 6,400 to fight cancers, so how much of the 1,500IU prescription dose will go to recharging batteries? Not a lot.
As if to prove the point, one study that gave vitamin D deficient patients 50,000IU a week for four weeks, and then 50,000IU a month for a year, managed to boost blood levels from 11 ng/ml at the start to 30 ng/ml by six months, and that’s basically where it stayed for the rest of the trial, despite the seemingly large doses
It’s the surplus amounts of vitamin D in your system, after basic bodily functions are taken care of, that are seized by the various vitamin D receptors (VDRs) throughout your organs and used to protect you, which is why the health effects of vitamin D can be seen on a sliding scale. People with blood levels of 30 ng/ml do better than people on 20 ng/ml, but people with enough vitamin D for 50ng/ml do better than all of them.
“If enough 25(OH)D substrate is available, multiple tissues are free to autonomously produce and locally regulate the amount of steroid needed for any particular disease state,” says John Cannell.
“The fact that 20,000IU vitamin D can be produced in the skin in 30 minutes of sun exposure, combined with vitamin D’s basic genomic mechanism of action, raises profound questions.
“Why did nature develop a system that delivers huge quantities of a steroid precursor after only brief periods of sun exposure? Would natural selection evolve such a system if the remarkably high input that system achieved were unimportant?”
Most people who manage to achieve the ideal 50-70 ng/ml of vitamin D in their blood have only done so through relying on UV rays, aided and abetted with high supplementation in the colder months.
Cannell’s researchers estimate that a 1000IU daily supplement will boost your blood levels by about 10 ng/ml over a period of three months, so an average adult taking 2,000IU should be able to go from 10 to 30 ng/ml over that time. However, moving further up the range the increases are not linear, and if you begin with a baseline of 30 it might require higher amounts to reach 50 ng/ml than 2,000IU.
A study of middle-aged Canadians given supplements of 4,000IU a day for six months managed to punch their average blood levels up to 44 ng/ml with no side effects.[5] Another study shows healthy adult men can usefully convert 5,000IU a day of vitamin day.[6]
“With regard to safety, sunlight is superior to oral supplementation,” writes researcher Carol Wagner.[7] “One does not become vitamin D toxic from sunlight exposure; however, in comparison, people have become toxic from ingesting too much oral vitamin D. In an adult, it appears that the upper limit of tolerability of vitamin D is a daily consumption of thousands of international units of vitamin D—above 10,000 IU/day.
“There is a safety mechanism in place with sunlight: sunlight-derived vitamin D triggers downregulation of certain enzyme systems and upregulation of others in the body to dispose of any vitamin D and its metabolites not needed by the body. Judicious sunlight exposure is not a clear cut entity; however, as too much sun exposure can lead to sunburn, photoaging, and skin cancer.”
There are important reasons not to simply self-medicate, even if tempted. In an advisory to medical practitioners on how to prescribe vitamin D, John Cannell warns that an enzyme known as Cytochrome P-450 plays a key role in the body’s usage of vitamin D. “Therefore, drugs dependent on cytochrome P-450 enzymes – and there are many – may affect vitamin D metabolism.” Cannell says some medications raise D-levels, and others drop them, so it’s up to doctors to test blood frequently if patients are taking medicines and more than 2000IU of vitamin D a day.
As a rule of thumb, Cannell advises pregnant mothers to seek 5000IU of vitamin a day from their doctors, on the grounds that not only is the vitamin crucial for human development but also that animal testing (controlled human testing on this aspect cannot be done for ethical reasons) has shown that when pregnant animals are deprived of vitamin D, their offspring are left with permanent brain injury.[8]
For mothers who are breastfeeding, Cannell recommends 7000IU a day which researchers say is enough to maintain maternal vitamin D levels and provide enough for the baby. If women do not have optimal blood levels, breastfed babies will need a further 800IU in supplements per day.[9]
Existing baby milk formulas contain vitamin D, but Cannell says babies should be getting a further 400IU daily on top of what’s already in the milk powder, and toddlers and young children should be supplemented with 1000IU to 2000IU daily all year around. Dosages of 2000IU a day have been ruled safe for children over the age of one.
Vitamin D can be toxic in high doses. How high? Well, the upper limits are still being tested. Whilst it’s not considered desirable to routinely have blood levels above 100 ng/ml, that’s a target you won’t hit even if you sunbathe all summer and take ordinary supplements – most of us would be struggling to hit 50 ng/ml.[10]
In some parts of the world and for some individuals, vitamin D levels are so bad that doctors have delivered injections containing 600,000IU to elderly patients, successfully raising blood levels from a death’s door rate of 2 ng/ml to 27 ng/ml over six weeks. A study in the Australian Medical Journal has recommended 600,000IU doses for the elderly each autumn to cover them over winter and spring.[11]
In New Zealand, doctors have administered doses of 50,000IU a day for ten days to kick start patients’ vitamin D storage, and found no ill effects: “This regimen provides a simple, safe and effective way of managing vitamin D deficiency. Its short-term nature may result in higher compliance than daily dosing regimens,” reported the study.[12]
In late 2010, however, the US health bureaucracy weighed into the vitamin D debate with a controversial report[13] that many in the industry saw as far too cautious. It pre-dated many of the studies detailed in this book, so some of its arguments have now been superseded, but essentially its line of reasoning was this:
Vitamin D is of proven benefit to the musculo-skeletal system, and increased intake can be justified on that basis alone. In the meantime, while there is evidence of an association between vitamin D and a number of other issues like cancer and cardiovascular disease, not enough randomized controlled trials have been done, the hard evidence is not yet there.
Collectively, thousands of scientists and medical researchers at the cutting edge of vitamin D studies fell off their perches in surprise. While they knew that more randomised trials were needed, they also knew that if something walked like a duck, looked like a duck and quacked like one, chances are it wasn’t a sparrow. The research on vitamin D, they pointed out, is extremely strong in some cases.
It seemed, to many, as if politics was intruding into science.
Among the critics, Vitamin D Council executive director Dr John Cannell, who issued this statement:
Today, the Institute of Medicine’s Food and Nutrition Board has failed millions...
3:00 PM PST November 30, 2010
After 13 years of silence, the quasi governmental agency, the Institute of Medicine’s (IOM) Food and Nutrition Board (FNB), today recommended that a three-pound premature infant take virtually the same amount of vitamin D as a 300 pound preg
nant woman. While that 400 IU/day dose is close to adequate for infants, 600 IU/day in pregnant women will do nothing to help the three childhood epidemics most closely associated with gestational and early childhood vitamin D deficiencies: asthma, auto-immune disorders, and, as recently reported in the largest pediatric journal in the world, autism. Professor Bruce Hollis of the Medical University of South Carolina has shown pregnant and lactating women need at least 5,000 IU/day, not 600.
The FNB also reported that vitamin D toxicity might occur at an intake of 10,000 IU/day (250 micrograms/day), although they could produce no reproducible evidence that 10,000 IU/day has ever caused toxicity in humans and only one poorly conducted study indicating 20,000 IU/day may cause mild elevations in serum calcium, but not clinical toxicity.
Viewed with different measure, this FNB report recommends that an infant should take 10 micrograms/day (400 IU) and a pregnant woman 15 micrograms/day (600 IU). As a single, 30 minute dose of summer sunshine gives adults more than 10,000 IU (250 micrograms), the FNB is apparently also warning that natural vitamin D input – as occurred from the sun before the widespread use of sunscreen – is dangerous. That is, the FNB is implying that God does not know what she is doing.
Disturbingly, this FNB committee focused on bone health, just like they did 14 years ago. They ignored the thousands of studies from the last ten years that showed higher doses of vitamin D helps: heart health, brain health, breast health, prostate health, pancreatic health, muscle health, nerve health, eye health, immune health, colon health, liver health, mood health, skin health, and especially fetal health.
Tens of millions of pregnant women and their breast-feeding infants are severely vitamin D deficient, resulting in a great increase in the medieval disease, rickets. The FNB report seems to reason that if so many pregnant women have low vitamin D blood levels then it must be OK because such low levels are so common. However, such circular logic simply represents the cave man existence (never exposed to the light of the sun) of most modern-day pregnant women.