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:
Heart disease
Diabetes
Inflammatory bowel disease
Rheumatoid arthritis
Multiple sclerosis and osteoporosis
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.
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