Sun exposure: Is just a little bit enough?

http://blog.vitamindcouncil.org/2013/01/16/sun-exposure-is-just-a-little-bit-enough/

Posted on January 16, 2013 by John Cannell, MD

Some experts opine that brief sun exposure will supply all the vitamin D that one needs. However, there has never been a study of how much vitamin D such exposure generates.

Recently, researchers in Korea decided to find out. Dr. Sang-Hoon Lee and colleagues from the Ajou University School of Medicine in South Korea studied the effect of brief sun exposure on vitamin D levels in 20 young women for four weeks.

Lee SH, Park SJ, Kim KM, Lee DJ, Kim WJ, Park RW, Joo NS. Effect of sunlight exposure on serum 25-hydroxyvitamin d concentration in women with vitamin D deficiency: using ambulatory lux meter and sunlight exposure questionnaire. Korean J Fam Med. 2012 Nov;33(6):381-9.

The study was conducted between October and November at latitude 37 degrees north, about the latitude of Washington DC. Initial mean 25(OH)D levels were 11 ng/ml and no woman had levels greater than 20 ng/ml to begin the study. The women were told to get 20 minutes of midday sun exposure on their hands, forearms and face every weekday for four weeks. Facial sunblock and sunglasses were permitted.

Guess how much 25(OH)D levels increased after a month of daily sun exposure? Vitamin D levels did not increase at all; in fact, they were a little lower than when the study began!

Why? I think four reasons may explain the finding.

Perhaps the women did not go outside as often as required. Second is the latitude; I think less UVB is available in October and November than many people think at such latitudes. Perhaps the vitamin D winter begins in the fall at latitude 37 degrees. Third, perhaps forearms, face and hands are just not enough skin surface to make meaningful amount of vitamin D. And four, such brief sun exposure may not be long enough to make meaningful amount of vitamin D.

Our hunter-gatherer equatorial ancestors had very dark skin but wore no or little clothing and were outside most or all of the day. Recent studies indicate such people had vitamin D levels around 50 ng/ml. This indicates a vitamin D input of about 5,000 to 10,000 IU/day.

Vitamin D status in indigenous populations: Part 1. Posted on August 27, 2012 by John Cannell, MD

That’s why the Vitamin D Council recommends full body sunbathing, not incidental sun exposure. Make sure your shadow is shorter than you are so you know you are making vitamin D. Also, since most people can’t sunbath every day, and because the vitamin D winter is so severe, we recommend 5,000 IU/day on the days you don’t sunbathe.

About John Cannell, MD

Dr. John Cannell is founder of the Vitamin D Council. He has written many peer-reviewed papers on vitamin D and speaks frequently across the United States on the subject. Dr. Cannell holds an M.D. and has served the medical field as a general practitioner, itinerant emergency physician, and psychiatrist.

View all posts by John Cannell, MD →

The breastfeeding mother: Breast milk as a biomarker?

Posted on June 25, 2012 by John Cannell, MD

It just never made sense to me, 40 years ago, when my professors at UNC School of Medicine casually announced human breast milk contained no vitamin D.
“How can that be? How can that possibly be? That makes no sense,” I thought. “Was primitive man supposed to give their infants vitamin D pills that didn’t even exist?”
I have written before about biomarkers, such as:

• How high does your vitamin D level have to be to maximally suppress parathyroid hormone?
• How high does your vitamin D level have to be to maximally improve calcium absorption?
•  How high does your vitamin D level have to be to prevent abnormal bones?

The answer to these questions varies from 20 ng/ml to 40 ng/ml, depending on what study you decide to quote. But what about breast milk as a biomarker? Infants need vitamin D for strong bones and general development. Without vitamin D, the infant can develop rickets. In the 21^st century, this is treatable in a clinic. In the wild, the tribe may have left a screaming baby with soft bones at the wayside.

How high does the breastfeeding mom’s vitamin D level need to be for her infant to get natural vitamin D levels? This level is a biomarker because it gives us insight on how high vitamin D levels were for species survival. If the breastfeeding mom couldn’t supply vitamin D to the infant, our species may not have survived. Whatever vitamin D level that might be, that would be the level humans evolved to have.
Professors Wagner and Hollis and colleagues did an elegant randomized controlled trial 6 years ago that we have covered before, but it should be covered often. They simply gave two different doses of vitamin D to nursing mothers and measured the vitamin D levels of their infants and mothers. They used a small sample of breast feeding women, giving half the women a prenatal vitamin (containing 400 IU) and the other half a prenatal vitamin plus an extra 6,000 IU/day of vitamin D.
The suckling infants of the mothers given only the prenatal were also given 300 IU of vitamin D directly (it would have been unethical to deprive any of the infants of vitamin D). They noted no side effects with any dose, but the 6,000 IU/day arm of the study answered my 40-year-old question.
Wagner CL, Hulsey TC, Fanning D, Ebeling M, Hollis BW. High-dose vitamin D3 supplementation in a cohort of breastfeeding mothers and their infants: a 6-month follow-up pilot study. Breastfeed Med. 2006 Summer;1(2):59-70.
The 6,000 IU/day dose of vitamin D did three things.

1. It gave the mothers natural vitamin D levels (50 ng/ml or close to).
2. It transformed breast milk into a rich source of vitamin D.
3. It gave suckling infants natural blood levels of vitamin D (45 ng/ml).

Given this, if you are now breast-feeding and not taking vitamin D, then I hope you are giving your infant at least 400 IU of vitamin D per day as the American Academy of Pediatrics (AAP) recommends. If you want your infant to start getting their vitamin D from your breast milk, I recommend the following steps:

1. Take a loading dose of 10,000 IU/day for a month.
2. After one month on 10,000 IU/day, stop supplementing your infant with vitamin D as your breast milk should now be filled with vitamin D.
3. Take 6,000 IU/day maintenance dose thereafter, except on days you get full body sun exposure.

However — and this is important — when the breastfeeding stops, you need to start supplementing your child again, as the AAP recommends, unless the child is in the sun enough to have adequate levels, and very few are.
I’d like to reiterate, can you think of a better biomarker for how much vitamin D humans need?

• “How much vitamin D do human breast–feeding mothers have to take to transform their breast milk into an adequate source of vitamin D for their infants?”

This is a great biomarker question, one essential to the survival of our species. The answer is 50 ng/ml, which can be achieved by 6,000 IU/day for breastfeeding mothers.
Further reading:

• Taylor SN, Wagner CL, Hollis BW. Vitamin D supplementation during lactation to support infant and mother. J Am Coll Nutr. 2008 Dec;27(6):690-701. Review.

About John Cannell, MD

Dr. John Cannell is founder of the Vitamin D Council. He has written many peer-reviewed papers on vitamin D and speaks frequently across the United States on the subject. Dr. Cannell holds an M.D. and has served the medical field as a general practitioner, itinerant emergency physician, and psychiatrist.

View all posts by John Cannell, MD →

 

http://blog.vitamindcouncil.org/2012/06/25/the-breastfeeding-mother-breast-milk-as-a-biomarker/ 

Vitamin D linked to autoimmune disorders

Posted on April 12, 2012 by John Cannell, MD

There are more than 160 human autoimmune diseases, everything from type one diabetes to Lou Gehrig’s disease. They arise from an improper immune response to substances and tissues normally present in the body. In other words, the body mistakes itself as foreign and attacks its own self. The common treatment of autoimmune diseases today is to suppress the immune system in general with medications.

Recently a Chinese group led by Dr. C Mok and colleagues from Tuen Mun Hospital in Hong Kong studied 290 lupus patients and confirmed previous findings that the lower your vitamin D level, the worse your lupus. The association (remember association is not causation) was quite strong. Dr. Mok also found an amazing 96% of the lupus patients were vitamin D insufficient.

The lower your vitamin D level, the worse your lupus.

Mok CC, Birmingham DJ, Leung HW, Hebert LA, Song H, Rovin BH. Vitamin D levels in Chinese patients with systemic lupus erythematosus: relationship with disease activity, vascular risk factors and atherosclerosis Rheumatology (Oxford). 2012 Apr;51(4):644-52. Epub 2011 Jun 29.

In an accompanying editorial, Professor Luis Munoz and colleagues from Erlangen University Hospital in Germany supplied a new insight into how vitamin D is involved in autoimmune disorders, and, as far as I am aware, every one of the 160 autoimmune disorders studied so far is somehow involved with vitamin D. What could the connection be, what do 160 autoimmune diseases have in common with vitamin D?

Munoz LE, Schiller M, Zhao Y, Voll RE, Schett G, Herrmann M. Do low vitamin D levels cause problems of waste removal in patients with SLE? Rheumatology (Oxford). 2012 Apr;51(4):585-7. Epub 2011 Oct 27.

Dr. Munoz points out that vitamin D (the repair and maintenance man of the human body) has a “waste removal” function mediated via the immune system. That’s right, vitamin D is also a garbage man for the human body; it stimulates the immune system to come around and collect the debris and detritus of what is left of cells that have gone through the normal process of apoptosis, or cell death.

Evidence that a similar defect links all 160 autoimmune diseases in this garbage man process is not complete but increasingly likely. To quote Professor Munoz, “Considering these robust epidemiological data, one might believe that vitamin D deficiency plays a pivotal role in the multifaceted (cause) of autoimmunity that deserves further scientific research to pinpoint the mechanisms of action of vitamin D in the phagocytosis (eating) and clearance of dying cells.”

About John Cannell, MD

Dr. John Cannell is founder of the Vitamin D Council. He has written many peer-reviewed papers on vitamin D and speaks frequently across the United States on the subject. Dr. Cannell holds an M.D. and has served the medical field as a general practitioner, itinerant emergency physician, and psychiatrist.

View all posts by John Cannell, MD →

http://blog.vitamindcouncil.org/2012/04/12/vitamin-d-linked-to-autoimmune-disorders/

Optimal levels of vitamin D during pregnancy

March 13, 2012 -- John Cannell, MD

More than 60 years ago, based on the science of the time (science that has stagnated for 60 years), Dr. E. Orbermer of Italy wrote the following:

“Until further experimental evidence, adequate and incontrovertible, is made available, I submit that we should play for safety. In a climate like that of England every pregnant woman should be given a supplement of vitamin D in doses of not less than 10,000 IU per day in the first 7 months, and 20,000 IU (per day) during the 8th and 9th months.”

OBERMER E. Vitamin-D requirements in pregnancy. Br Med J. 1947 Dec 6;2(4535):927.

The “adequate and incontrovertible evidence” that Dr. Orbermer wanted, to a certain extent, is finally here, 60 years later. As it has to do with developing human beings, it could not be more important. The study is the highest standard of proof, a randomized controlled trial, conducted by Professor Bruce Hollis and colleagues at the Medical University of South Carolina. They took 350 pregnant women, gave 1/3 of them 600 IU/day, 1/3 of them 2,000 IU/day, and 1/3 4,000 IU/day. Then they waited to see, among many things, which group would produce infants with at least 20 ng/ml of vitamin D in their blood, the lowest limit the 2010 Food and Nutrition Board (FNB) says is needed for good fetal health.

Hollis BW, Johnson D, Hulsey TC, Ebeling M, Wagner CL. Vitamin D supplementation during pregnancy: double-blind, randomized clinical trial of safety and effectiveness. J Bone Miner Res. 2011 Oct;26(10):2341-57. doi: 10.1002/jbmr.463

Surprise surprise, only the 4,000 IU/day pregnant women group even approached the minimal safety level of 20 ng/ml in their infants. Furthermore, the 2010 FNB recommendations of vitamin D in prenatal vitamins would have left 50% of the White women and 80% of the Black women with fetuses below 20 ng/ml.

However, Professor Hollis found something else, something potentially much more important. He found that the average fetus in the USA is starved for enough building blocks for his or her mother to make adequate activated vitamin D to ship to the baby; activated vitamin D that is probably used for microscopic organ development, such as in the brain.

Activated vitamin D in pregnancy is mysterious. It appears the mother makes it in her kidney (maybe some in her placenta) at levels up to 3 to 4 times normal (without maternal hypercalcemia) and ships it across to the fetus. This only happens if the mother has enough of this vital steroid hormone in her body to ship to the fetus and most mothers do not. If she can’t make it, she can’t ship it maximally, and the 38 fetal organs depending on activated vitamin D to fully develop must do the best they can do with inadequate amounts of this steroid. Of course, none of this applies to mothers who frequently sunbathe, or who take 5,000 IU/day while they are pregnant.

To quote Professor Hollis: “These findings suggest that the current vitamin D (requirements for pregnancy, currently 600 IU/day) issued in 2010 by the Food and Nutrition Board should be raised to 4,000 IU of vitamin D per day so that all women, regardless of race, can attain optimal nutritional and hormonal vitamin D status throughout pregnancy.”

The Vitamin D Council agrees and considers this an important study in support of why adults and pregnant women need at least 4,000 IU/day to elevate blood levels and improve fetal health and birth outcomes. Although there are no trials that support taking more, the Vitamin D Council believes 5,000 IU/day is equally safe and would be more effective at maintaining adequate fetal blood levels of vitamin D.