Dr. Mercola January 01 2008 65,281 views
A new study indicates that at least 2,000 International Units (IU) of vitamin D3 -- which is currently considered the upper limit of intake -- are needed to ensure adequate blood levels of the vitamin for post-menopausal African-American women.Over 200 women took part in this three-year, double-blind, placebo-controlled study, which adds to a growing body of evidence suggesting that there is an urgent need to review current recommended daily intake levels of the vitamin. Vitamin D3 is produced in the skin during exposure to sunlight. However, increased skin pigmentation reduces the effect of UVB radiation, meaning darker-skinned people are more at risk of vitamin D deficiency.
As much as 4000 IU per day may be required for individuals who are already deficient in the vitamin.
Vitamin D, often referred to as “the sunshine vitamin,” is different from other vitamins in that it influences your entire body. Receptors that respond to vitamin D have been found in almost every type of human cell, from your brain to your bones.Optimizing your vitamin D levels could help you to prevent as many as 16 different types of cancer including pancreatic, lung, breast, ovarian, prostate, and colon cancers.
In fact, a previous landmark study from the Moores Cancer Center at the University of California, San Diego (UCSD), found that some 600,000 cases of breast and colorectal cancers could be prevented each year, if only vitamin D3 levels among populations worldwide were increased.
Beyond cancer, the researchers pointed out that increasing levels of vitamin D3 could prevent diseases that claim nearly 1 million lives throughout the world each year! And other studies showed that you can decrease your risk of cancer by MORE THAN HALF simply by optimizing your vitamin D levels with sun exposure.Further, optimal vitamin D levels are also known to positively influence the following conditions:
How Much Vitamin D do You Need?
Your doctor can measure your serum 25-hydroxyvitamin D (25(OH)D) to determine your vitamin D status. Your vitamin D level should NEVER be below 32 ng/ml, and anything below 20 ng/ml is considered a serious deficiency state, which will increase your risk of breast and prostate cancers and autoimmune diseases like multiple sclerosis and rheumatoid arthritis.
In the United States, late winter 25-hydroxyvitamin D levels generally range from 15 to 18 ng/ml, so this vitamin deficiency affects a very large portion of the U.S. population.
The OPTIMAL value that you’re looking for is 45-52 ng/ml (115-128 nmol/l), but previous research has suggested that maintaining a slightly higher level of 55 ng/ml (nanograms per milliliter) is optimal for cancer prevention. African Americans are even more prone to vitamin D deficiencies, as they produce less vitamin D3 than do whites in response to usual levels of sun exposure, and therefore have lower vitamin D serum concentrations year-round. In fact, as many as 42 percent of African American women, compared to just over 4 percent of white women of childbearing age have serum 25 (OH)D concentrations that are less than 62.5 nmol/L during the summer months.
RDA Too Low for Achieving Optimal Vitamin D Levels
This latest study, published in the December issue of the American Journal of Clinical Nutrition points out that many African Americans simply cannot reach optimal vitamin D levels under the current recommended daily allowance (RDA) guidelines.
The 1997 Panel on Calcium and Related Nutrients considers 2,000 IU’s as the upper limit of intake, with a recommended daily allowance of just 400 to 600 IU’s per day.
In fact, the new dosing algorithm that this study proposes calls for a daily dose of 2,800 IU’s for African Americans with a serum level of at least 45 nmol/L, and 4,000 IU’s per day if your serum level is below 45 nmol/L.
In addition to this one-measurement, one-dose adjustment algorithm, they point out that given the individual variability in your response to vitamin D, the best result would be expected if your 25 (OH)D was measured and your dose of vitamin D is adjusted a second time.
I also recommend you check your vitamin D levels regularly as overdosing on oral vitamin D supplements IS possible. (There’s very little risk of overdosing on vitamin D from the sun, however.)
What is Your Best Source of Vitamin D?
Sun exposure (without sunscreen) of about 10 to 15 minutes a day, with at least 40 percent of your skin exposed is your best source of vitamin D. Sometimes, however (such as if you happen to live in the Chicago area like I do), you may not be able to get enough sun exposure during certain parts of the year. In that case supplementation is an option.
Obviously, it will be very difficult for many to get adequate sun exposure in the winter, which is why I also advise using a safe tanning bed to have your own body produce vitamin D naturally.
The most important thing to keep in mind if you opt for oral supplementation is that you only want to supplement with natural vitamin D3 (cholecalciferol), which is the type of vitamin D found in foods like eggs, organ meats, animal fat, cod liver oil, and fish. Do NOT use the synthetic and highly inferior vitamin D2.
To find out more about the crucial importance of sunlight and vitamin D for your health, my forthcoming book Dark Deception will explore this topic in detail, and expose why the conventional wisdom on the subject, which encourages you to stay out of the sun, is dead wrong.
Russ, while your statement can not be disputed (and I look forward to your posts when I read these post article comments BTW), it is of questionable value unless a person resides in a location further south of where most of us live. It would make more sense to inform us of sources of quality Kosher brands of supplementation. Agree?
The summer of '06 gave me more sun than I had been exposed to in the previous 15 years combined. No, supplementation was not a major concern last summer. However, as I live in Wisconsin, that source of vit D was short lived. Agree? As readers of this site, we know it requires a lack of suncreen to take advantage of the UVB (vitamin D) rays. Last summer I spent hours in the sun at a time with no shirt and shielded with NO sunscreen. At no time did I show evidence of any skin burning. That may amaze some, unless they have read info that has been available on this site. Last summer, I learned a little more about me and my reaction/benefit to what I consume for a diet.
Yes, my previous post should be read '07 in lieu of '06. I could have also added that any summers previous to '07 found me to be no stranger to peeling of burnt skin, with minor permanent color scarring to show for it. With the extent of my skin peeling, I could have been considered part reptilian. Yes, it also could have been considered carelessness on my part.
So what was different about my sun exposure of '07? In addition to being more deliberate with a couple of initial half hour exposure sessions to establish a base, instituting of full time, prominent intake of Omega 3s and essential fatty acids in general. My diet is VERY strict and regimented, so I am comfortable stating that I believe the above reasons are valid.
Yes, sunshine amazing! It is unfortunate that so many people walk around with pale skin, slathering on sunscreens and avoiding the sun.
Many people are not aware that in addition to helping to prevent many health problems, including high blood pressure, and cancer, vitamin D stimulates your immune system to help protect against infections such as the flu.
www.naturalpureorganics.com/sunshine.htm
After reading Dr.M's newsletters for a few years I decided to go to the doctor to have a bunch of bloodwork done. I had them run tests that Dr.M often suggests having done (hydrox-D 25, homocysteine, ferritin, C-Reactive Protiens, ect....). I had not been to a doctor in 2.5 years and my dr. was anxious to get me in. Especially bc I have 3 children and I had my last one I had at home with only my midwife and no dr. visits. 2 of my 3 children are also unvaccinated so they like to get me in to try to convince me to posion them.
Well first off, I had to get online and find the right CPU codes for all my lab I wanted done bc the nurse seemed unfamiliar with most of them except cholestrol and she couldn't seem to find the EXACT ones I was wanting. Then, I had to spend much time trying to convince my doctor why I wanted all the tests done since they weren't routine for someone my age (25 years old) just so she would order them.
She was especially rude to me about getting the vit. D lab bc only "old ladies and the institutionalized need vit. D levels checked." When I said I wanted to know if mine was low so I could get it up higher she asked "how do you suppose you're going to do that??" OMFG...."HOW"?!?!? I had to tell her sunlight and cod liver oil. Well, she was pretty confident I was wasting my money getting the test done. THEN, AH HA! She called me in bc my level WAS 22!!! WAY TOO LOW! She acted like it was just a fluke and I was just a rare case....WHATEVER DOCTOR!
I drink raw milk and eat grass-fed meat but, I was also nursing a 9 month old at the time who was still solely nursing and on no solids. Also, I knew I wasn't getting enough sun bc I wasn't outside enough. She said there was no way I wasn't getting enough sun bc "even in the winter Kansas is still a sunny place." I told her it might be sunny but, when it's only 20 degrees outside how much skin are you willing to expose for longer than 5 minutes outside!!
So, now I take cod liver oil (1 Tbsp/ a day).
I dont understand why intelligent, well informed persons wait for official confirmation on ANY supplementation, prior to suppplementing at the full optimum health amounts. These confirmations are given with reluctance, cautions, and always at lower than optimum amounts. Why? Not to protect your health, but in this sad, upside-down world, to allow more profit for the MS quacks and drug companies. I daily take 4500iu D3, as I cannot take any sun on my skin, damaged by previous extreme high altitude sun exposure, keratosis.