Vitamin D blood tests are practically a necessity for determining if you’re getting adequate vitamin D as I’ll explain shortly. Normally these tests cost about $50 or more from most blood testing labs, sometimes much more. But through January 3, 2011, for $45 most people in the US can get not only a vitamin D blood test but also a CBC (Complete Blood Chemistry) test which helps identify the presence of many common illnesses such as diabetes, kidney and liver dysfunction, unbalanced common minerals such as calcium, and quite a bit more.
CBC is probably the single most commonly run medical test. It is used widely for screening for many common medical conditions and is often run for annual checkups. Your doctor (if you have one) has probably run this test on you many times in the past. Unfortunately, many doctors are still not running vitamin D tests on their patients as they should be because of outdated education and concerns about HMO or insurance companies not approving reimbursement for the vitamin D tests. So this blood test offer is a great way to get around issues with a lack of a cooperative doctor or insurance company at a low price as you do not need a doctor to prescribe these tests for you.
This time of year in the northern hemisphere is a great time for a vitamin D test because in the winter to early spring, most people reach their annual low levels of vitamin D because of the shorter daylight hours and more time spent indoors.
Click on through to add the Vitamin D and CBC test combo to your Life Extension shopping cart. If for some reason this link doesn’t work (such as Life Extension changes its site), the coupon code for this Life Extension offer is WSM002W.
Most Americans Suffer from Inadequate Vitamin D
Most Americans and others who live away from the equator do not get anywhere near enough vitamin D because the amount of sun exposure they get is inadequate to cause the skin to generate sufficient vitamin D for optimal health. If you’re outside in the bright sun for several hours every day, you may be one of the few who does get enough vitamin D from sun exposure. But few people are in this group.
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You get some vitamin D in your diet. Milk and some dairy products in many nations such as the US and Canada are fortified with it, for instance. But the amounts in even fortified foods are inadequate for nearly all adults and most children — even a glass of such fortified milk is not likely to have more than about 100 IU of vitamin D. So you may think as the recently updated Institute of Medicine (IOM) vitamin D RDA (Recommended Daily Allowance) for most adults is 600 IU per day, you could simply drink a glass of milk with each meal and get 400 IU from your daily multivitamin and get enough vitamin D. But for most people, that’s not the case.
IOM focused essentially only on bone health, ignoring vast evidence of vitamin D’s impact on many other health conditions. Their revised guidelines are being heavily criticized by many scientists and doctors as misleading and inaccurate.
Virtually every biomedical and health researcher who has spent any time looking at the issues surrounding the chronically insufficient levels of vitamin D in the American population knows that even the updated RDA is vastly too low. Many think the US RDA should be raised to 2000 IU or more per day for adults and perhaps 1000 IU per day or more for kids beyond toddlerhood. A significant number are recommending 4000 IU per day for most teens and adults, some even 5000 IU per day. That’s because the cost and risks of higher dosages are both minimal and the evidence of higher vitamin D levels helping to avoid many bad health outcomes continue to mount.
Health Risks Associated with Low Vitamin D Levels
Traditionally it was assumed that vitamin D mostly had to do with bone health and low vitamin D would increase the risk of related diseases such as osteoporosis. But research in recent years has tied low vitamin D levels to significantly elevated risks of death or serious illness from cardiovascular disease, stroke, flu infections, cancer, diabetes, obesity, asthma, autoimmune conditions (multiple sclerosis, for instance), autism, depression, and many other health conditions.
It may be that many of these correlations are connected to how vitamin D affects body weight. In particular, cardiovascular diseases, diabetes, excess weight, and obesity are all often shown to be interrelated to a high degree. Recent research suggests that increasing vitamin D levels may help some people lose weight, and this might be connected to how getting sufficient vitamin D can help your overall health.
Pregnant women and children in particular are at high risk for health complications related to deficient vitamin D levels. A study released in 2009 suggests that about 70% of American kids ages 1 to 21 have inadequate levels of vitamin D. Other studies have shown that premature births and bacterial infections during pregnancy correlate with low vitamin D levels, particularly among African-American mothers whose dark skin impedes the absorption of sunlight that can trigger the body’s own vitamin D synthesis.
Optimum Vitamin D Dosing is Highly Variable
Even if the US RDA for vitamin D was raised by a factor of 5 as some believe would be prudent, it still would not be enough for many people. That’s because the variability in diet, genetics, and the effects of excess weight and obesity all contribute to making it effectively impossible for a one-size-fits-all daily dose of vitamin D to be determined. Everybody is different and this is particularly true for vitamin D and how it is absorbed and distributed in the body.
One person may attain optimal vitamin D levels with 2000 IU per day of supplements, another may need 20,000 IU per day which is double the 10,000 IU per day level generally considered to be safe for long-term supplementation. The only way to know is to test, adjust your supplements, and after a few months retest. Repeat until you get the dosage right for you as shown by your blood tests.
Expect to need at least two to four tests over the course of one to two years before you have a good handle on how much vitamin D your body needs. At that point, you don’t need to retest very often (perhaps every two years) unless there’s a big change in your weight, diet, nutritional supplements, or sun exposure.
Variations in nutritional supplements can have a huge effect on vitamin D levels even if you think you’re taking the same amount of vitamin D. That’s why it is important to pay close attention to the vitamin D ingredient used and also to the amount of preformed vitamin A you are getting in your supplements.
For starters, different vitamin D supplements are not uniformly effective because of differences in ingredients. A supplement that says it has 400 IU of vitamin D may be significantly inferior to another that says it has 400 IU of vitamin D. Why? It’s because the former uses the less potent form of vitamin D known as ergocalciferol (vitamin D2) rather than the better form cholecalciferol (vitamin D3). Cholecalciferol is about 2 to 3 times more potent than ergocalciferol.
Moreover, other nutrients can vastly change the way vitamin D is absorbed and used in the body. A common problem for people who take mass-market multivitamins is that they get way too much pre-formed vitamin A (rather than its precursor beta carotene) and this impedes vitamin D function significantly. It’s better to pick supplements that mostly use the beta carotene vitamin A precursor and include only very small amounts (less than 1000 IU) of pre-formed vitamin A.
Excess Vitamin A Can Thwart Vitamin D
Most aging people take a multi-vitamin supplement. In some cases, these commercial supplements may be doing more harm than good.
Preformed vitamin A is active retinol as opposed to beta-carotene that can convert to retinol in the body. We reviewed 14 popular multivitamin formulas and found the average amount of preformed vitamin A to be 4,395 IU, while the average vitamin D content was only 407 IU.
The problem with this potency ratio is that in the presence of excess preformed vitamin A, the beneficial effects of vitamin D can be neutralized.73
The first hint of this problem occurred when a group of doctors reviewed historical medical records on the use of cod liver oil to prevent respiratory infections. In the 1930s, two large controlled studies showed that cod liver oil reduced incidence of common colds by 50% and respiratory infections by 30% in adults.74-77
A study published in year 2004 showed that cod liver oil and a multivitamin slightly reduced mean number of respiratory infections in children, but the total number of doctor visits for these infections was slightly higher in the cod liver oil/multivitamin group (68 versus 61).78 The 1930s study demonstrated far superior benefits with cod liver oil.74-77
One difference between these studies is that cod liver oil in the 1930s study had more vitamin D. The other issue is that children in the 2004 study received 3,500 IU of preformed vitamin A (not beta-carotene) and only 700 IU of vitamin D.
Given what we now know, a more appropriate dose should have been 500-1,000 IU of vitamin A (instead of 3,500 IU used in the 2004 study) and 2,000-3,000 IU of vitamin D3 (as opposed to 700 IU used in the 2004 study).
Vitamins A and D compete for each other’s function in the body. Preformed vitamin A, found in excess amount in many commercial supplements, can thwart vitamin D’s protective effects.73 This is not an issue with beta-carotene, as it converts to vitamin A in the body only on demand.
What is an Optimal Vitamin D Level?
There is some debate about exactly what is the optimal level for vitamin D in the blood. Most recent recommendations have varied from around 40 to 60 ng/ml to 50 to 80 ng/ml. A good target for most people is probably 60 mg/ml as it fits into both ranges and it is still far from toxic levels. Vitamin D toxicity is very rare, especially as risks for this don’t appear to be significant until 200 ng/ml or higher levels are reached.
GrassrootsHealth, a public health awareness organization composed of many doctors and biomedical researchers, has been running their D*Action campaign for vitamin D sufficiency for a couple of years now. They have collected vitamin D test results and supplementation information for over 1000 participants and have found that there is such high variability in response to vitamin D supplements that there is no way to know if you have adequate vitamin D without blood tests. Some particularly interesting points:
- At 1000 IU per day of vitamin D supplementation, blood tests show ranges from about 15 ng/ml to 85 ng/ml — varying both well below and above their recommended range of 40 to 60 ng/ml for optimal health.
- 6000 IU per day of vitamin D would be enough to get 98% of people to above 40 ng/ml, where the group considers them to be in optimal health range
- Even 10,000 IU per day of vitamin D was not enough to get anybody into the vitamin D toxicity risk range of above 200 ng/ml
Adjusting Vitamin D to Optimal Levels
In most areas of the US, Life Extension blood tests can be used up to six months after their purchase through any LabCorp blood draw facility. So during this sale, you could buy a couple of these tests for each person in your family, do the initial tests, adjust your supplements as I’ve previously discussed in my article Adjusting Your Vitamin D Intake to Optimal Levels, and then after three or four months retest to see how you are doing.
Typically Life Extension also runs an annual blood sale test in late spring to early summer, so if it turns out you still have not manage to optimize your vitamin D levels, you could order another vitamin D test at that time.
If you’re not already a Life Extension member, memberships are available for as little as $45 per year. Members can order supplements and tests for themselves and their family members. Life Extension’s website makes it easy to set up testing profiles for each family member by gender and age so that the test requisitions will be coded appropriately for each person. That’s important because on many tests, particularly hormone tests, the results must be interpreted differently based upon gender and age.
Vitamin D supplementation can be very inexpensive, but please realize you are unlikely to get enough vitamin D from the typical multivitamins that usually contain 400 IU or less of the nutrient. You don’t want to be popping many typical multivitamin tablets each day as you could easily overdose on pre-formed vitamin A, iron, and selenium long before you get enough vitamin D. So consider adding a vitamin D supplement to your daily multivitamin.
Most people should be looking to vitamin D3 supplements of between 2000 IU and 5000 IU per day as a starting point until they can refine their dosages based upon retesting. Initially, if you have not supplemented with vitamin D3 beyond 1000 IU per day in the last couple of years, then it’s a reasonable idea to take 50,000 to 100,000 IU of vitamin D3 on a one-time basis to get a head start on loading up on it. But aside from this one-time loading dose, something that many hospitals are doing with patients who come in with heart attack symptoms, don’t exceed 10,000 IU per day without getting blood tests to look at both your vitamin D and calcium levels.
John Cannell, MD, is the president of The Vitamin D Council, a non-profit group that advocates higher vitamin D intake. According to a letter written to us by Dr. Cannell, adults need to take 5,000 IU a day of vitamin D to put the vast majority of them (97.5%) above the 50 ng/mL level.
Dr. Cannell supplied us with published papers arguing that optimal doses for adults are between 4,600 and 10,000 IU, with persuasive evidence that 10,000 IU a day of supplemental vitamin D is not toxic.62-68
To answer the question as to exactly how much vitamin D3 an individual needs requires a blood test. Members can obtain this test for $47 by calling 1-800-208-3444.
Since our analysis uncovered 85% of blood test results are far below 50 ng/mL, it appears that virtually all members should supplement with 5,000 to 8,000 IU of vitamin D3 each day—especially in winter months!
Fears of vitamin D toxicity have caused health-conscious people to limit their vitamin D3 intake to only a few thousand IU (international units) a day. This amount is clearly inadequate to optimally protect against disease, based on recently published studies.52,64,69-72
Those with a rare disorder called sarcoidosis, severe renal impairment, primary hyperparathyroidism, or any condition resulting in an elevated calcium level in the blood should consult with their physician before taking vitamin D supplements. A low-cost blood chemistry test easily rules out elevated blood calcium. The member price for a comprehensive CBC/chemistry test is only $35.
The test prices in that quote reinforce what a great deal the $45 vitamin D plus CBC test is compared to the normal pricing around $82 for the same two tests.
Life Extension has a number of very good vitamin D supplement products. The combo versions that include other nutrients such as iodine, vitamin K, and gamma tocopherol (one of the forms of vitamin E) of which most people are not getting enough (even if they are taking multivitamins and eat a healthy diet) may be particularly good choices if you don’t want to be swallowing a large number of pills each day. Two examples are:
But if you’re focused mainly on vitamin D, get sufficient iodine, vitamin K, and gamma tocopherol from other supplements, and don’t mind taking yet another tiny little softgel, then the least expensive high concentration vitamin D product I’ve found (and which I use personally) is NOW Foods 5000 IU Vitamin D3 softgels. One these tiny softgels per day has the 5000 IU of vitamin D3 that Dr. John Cannell mentioned is likely adequate for most people to reach optimal blood levels of vitamin D after several months of using the supplements. A year’s supply of that dosage is about $20 per person. The cost is kept low in part because Amazon.com provides free shipping on orders of $25 or more.
I believe that vitamin D supplementation is so important to health for most people. It would be terrific to help as many people benefit from it as inexpensively as possible. If you find another vitamin D supplement that is even less expensive after considering shipping and taxes, please leave a comment mentioning your source.
These statements have not been evaluated by the Food and Drug Administration. The products mentioned in this post and on this website are not intended to diagnose, treat, cure or prevent any disease. The information presented here is for educational purposes and does not constitute medical advice. Please obtain medical advice from qualified healthcare providers. Pursuant to FTC regulations, please be aware some of the links herein may be affiliate iinks. If you click on them and complete a purchase, this website may earn a commission.