At least 50% of the people reading these words have a vitamin D deficiency. That's even true if you live in Florida! Given the benefits of vitamin D, it's a pretty good idea you know what your vitamin D level is because a tremendous amount of research is showing not only are most people deficient but lack of vitamin D increases our risk of several diseases. Because it's a critical nutrient, here are 49 BIG vitamin D facts, you probably don't know. After this list, you will be a vitamin D expert!
1 It's More Hormone Than Vitamin
If you look at the chemical structure of vitamin D, it looks more like a hormone than a vitamin. It also acts more like a hormone than a vitamin too, having a variety of effects in the body. Because of this, if it were discovered today, I'd bet it would be called hormone D.
2 Every Cell Has Receptors
Most don't know every cell in your body has receptors for vitamin D. This fact goes to how important this vitamin is and how far reaching it's effects are in the human body.
3 Your Liver And Kidneys Activate It
Whether we make it from the sun or take it as a supplement, our liver and kidneys are critical for turning vitamin D into its active form – “s 1,25-dihydroxyvitamin D.” While this is true, many other cells can activate vitamin D also. This includes cells in the brain, prostate, breast and lungs to name a few.
4 You Can Take It An Empty Stomach
We've all heard vitamin D is fat soluble, but it turns out we don't need fat to absorb it. This surprising revelation came up as I was reading the Vitamin D Solution book, by Dr. Michael Holick. As a D researcher, Dr. Holick is a one of America's expert on this topic.
5 Overweight People May Need More
Because it's fat soluble, vitamin D is stored in fat cells. As such, overweight people have a greater ability to lock in vitamin D, preventing it from getting into the blood where it can help us. Some estimate those who are overweight with a BMI over 30 may need twice the vitamin D as a more normal weight individual.
6 Bone Pain May Be Deficiency Sign
Osteomalicia – or soft bones – is basically the childhood disease, rickets in adults. One sign of osteomalacia is constant pain the bones. The pain gets worse when you press on the bone. The pain can be anywhere such as legs, arms, chest or even spinal pain. If not taken care of, osteomalacia can lead to osteoporosis.
7 It May Lower Blood Pressure
Vitamin D can cause blood vessels to relax and open up. The result, a drop in blood pressure. Conversely, lack of the vitamin may cause calcium to build up in blood vessels, causing them to stiffen up. This can not only raise blood pressure but also contribute to to heart disease and stroke.
8 Deficiency May Make You Hungry
Being deficient in vit D interferes with the appetite reducing hormone, leptin. Leptin is made in our fat cells. As leptin levels rise, we don’t feel hungry. As leptin levels fall, we get hungry.
By preventing a rise in leptin, lack of vitamin D may cause increased hunger and weight gain. Is it a coincidence vitamin D levels fall while weight goes up during the winter months?
9 Most Foods Don't Have It
Unless it's fortified, most foods don't contain vit D. Those which do include fish like tuna and salmon, mushrooms and fortified foods like milk, orange juice and some breakfast cereals.
10 D2 and D3 Are Equally Effective
Vitamin D comes in two forms – D2 (ergocalciferol) and D3 (cholecalciferol). D3 is what we make when we go out in the sun while D2 comes from yeast. While many assume D3 is more potent, this is debatable. Many studies have shown the benefits of vitamin D2. I believe they are equally effective. See the next fact for proof.
11 It Reduces Falls In Older Folks
One of the sexiest things about vitamin D is the finding it can significantly help reduce falls in older adults. One study showed as much as a 22% decrease in falls. In another study, a 72% reduction in falls was seen. Many anti-fall studies use 800 IU per day.
I'm rather proud I was one of the first in the US to call attention to this research in my book on supplements. Many studies on this topic have used D2 to reduce falls. Vitamin D3 also works.
12 Taking 1000 to 2000 Is Usually Fine
For most people, getting 1000 IU to 2000 IU through food and supplements is usually enough to get most of the benefits of this vitamin although those who are deficient will need more to bring their blood levels up into the normal range.
13 Fish Is a Good Source
A typical 3 oz serving of Salmon can provide 600-1000 IU. Because it's not in many foods, it's difficult to get enough with diet alone. That’s why vitamins are often used.
14 The Sun Last Longer
Vitamin D made from being in the sun remains in the body about 4-8 weeks. When taken as a supplement, it's only around 2-4 weeks.
15 It Can Help Psoriasis
Some research suggests vit D can help return cells with psoriasis to their normal state of growth.
16 Only UV B Rays Work
Sunlight is often divided into UVA and UVB rays. It's only the UVB rays the skin uses to convert cholesterol into vitamin D.
17 It’s Other Names
three other names for vitamin D are cholecalciferol, ergocalciferol and calcidiol.
18 Ask For This Blood Test
When you get your D levels checked, ask your doctor to do a “Serum 25 (OH) D” Test. This is also called the 25-Hydroxy vitamin D test or “25 Vitamin D test.” That is the test you should get.
19 The Type Used In Fortification
Fortified foods contain vitamin D2. D2 and D3 are equally effective.
20 These Groups Might Also Be Deficient
Muslims, astronauts on long space voyages, submariners and those confined to nursing homes may also be low in this vitamin.
21 Vegans Take This Form
Vitamin D2 does not come from animals and is ideal for vegans.
22 How Much Do My Levels Go Up?
As a rule, every 1000 IU of vitamin D will raise blood levels by 10 nanograms per milliliter of blood. So if the blood test said your level was 20 ng/ml, then taking 1000 IU would bring you up to 30 ng/ml.
23 It's Hard To Get Too Much
In his book, The Vitamin D Solution, Dr. Hollick states people could take 10,000 IU for 6 months before they’d have to start wondering if they are taking too much.
24 Vitamin D Helps Bones
When people don’t get enough D, they don’t absorb as much calcium to keep their bones strong. Normal bone loss is about 0.3 to 0.5 % per year. At the start of menopause, women can lose 3%-4% of bone mass per year. After menopause, it drops to about 2% per year.
25 The Prostate Cancer Connection
Low vitamin D levels in the blood appear to increase the odds of getting prostate caner. Higher D levels are reduce the odds of prostate cancer.
26 The Colon Cancer Connection
One study noted elevated vitamin D levels appear to increase the odds of surviving colon cancer by 48%.
27 It May Help Diabetes
Studies tend to show when we are deficient in D, insulin resistance – one of the hallmarks of metabolic syndrome (pre-diabetes) goes up. Increasing vitamin D may decrease metabolic syndrome and and diabetes risk.
28 It May Help Autoimmuity Diseases
Autoimmune diseases are those where our immune system attack us by mistake. Evidence suggests vitamin D may help keep the immune system healthy and reduce auto immune diseases. Auto immune diseases are less likely in areas that get a lot of sunlight.
29 It May Reduce MS
Multiple Sclerosis is an autoimmune disease where the immune system attacks the fatty covering (myelin) surrounding nerves. It’s more likely to occur in areas where people get less sunlight. Lack of vitamin D during our younger years, puts us at greater risk of getting MS in the future.
30 Makes Older Adults Stronger
Studies show vit D supplements increase strength in older adults. Who knew?
31 Vitamin D Helps Rheumatoid Arthritis
People with rheumatoid arthritis (RA) tend to be low in vitamin D and have more pain than those with higher levels.
32 It May Reduce Cavities
People with more cavities tend to have lower levels of vitamin D. This may be related to D’s ability to reduce inflammation.
33 Alters Gut Bacteria
34 It May Help Depression
Well done studies suggest a link between low D levels and depression and improvement of depression when the vitamin is supplemented. One review stated improvement in depression was significant when people took at least 800 IU per day.
35 It May Help Asthma
While research is needed there seems to be a link between asthma and low vitamin D levels. Some research noted vitamin D as effective as medications. It’s a bit controversial so stay tuned.
36 You’re Clinically Deficient When…
When your blood levels are 20 ng/ml or less you are classified as “vitamin D deficient.” I’ve known people whose D levels were only 12 ng/ml.
37 Optimal Levels Not Known
Most experts agree people should be somewhere between 30 ng/mg and 100 ng/ml. Some advocate 40ng/ml – 50 ng/ml. The optimal amount would likely differ between medical issues. It's probably best to talk about an optimal range. For more specific than this is something best discussed with your doctor.
38 The Highest Risk Of Deficiencies Are In…
One review of 4,495 people noted that overall 42% of people were deficient. The highest rates of deficiencies were in blacks (82.1%) and Hispanics (69.2%).
39 Factors Related to Low D Include
The following tend to be associated with deficiency:
- no college education
- being overweight/obese
- being in poor health
- having high blood pressure
- not consuming milk
- having low HDL (good) cholesterol levels
Mind you, this doesn't necessarily mean they are related. They might just be a coincidence.
40 Remember the Different UV Rays
UVA rays “age” and cause wrinkles (A for ageing) while UVB rays cause sunburn (B for burn) Vitamin D is only made from UVB rays.
41 Look for Broad Spectrum Sunscreen
Sunscreens which block both UVA and UVB rays are “broad spectrum.” If your sunscreen doesn’t say it's broad spectrum, it probably only blocks UVB rays.
42 Vitamin D Drug Interactions
Talk to a pharmacist about your intake if you take medications. Possible interactions include cholesterol lowering statin meds, ulcer meds and high blood pressure meds.
43 Does Window Light Count?
Generally, windows will filter out UVB rays, which are the rays which make this vitamin. So, don’t rely on your desk window sunshine to provide your vitamin D. Windows do not filter out aging, UVA rays.
44 Do Lightbulbs Produce Vitamin D?
As a rule, the light bulbs in your house/apartment do not produce vitamin D. You can purchase special sun lamps which will do this. Some light bulbs may list they produce UVB rays. Investigate those claims before you buy.
45 Can We Absorb D In Orange Juice?
Orange juice has no fat but it turns out we can still absorb it in orange juice.
46 Is Any Brand Best To Take?
All quality made vitamin D supplements would be expected to be the same. A supplement from company A and company B should be identical if they contain the same amount (say 1000 IU for example). More expensive brands are not better. While it's often recommended to look for the “USP” ( United States Pharmacopeia) label as a way to check for quality, I believe brands which have been around a long time- Walmart, Costco, Vitamin Shoppe or GNC brands – should be just fine to use.
47 Can Vitamin D Become Toxic?
It's unlikely for most people taking a typical 1000 to 2000 IU supplement per day. Even taking 10,000 IU per day would take months of daily use before it would become toxic. A blood test would show elevated calcium (hypercalcemia). This can lead to kidney stones. Other vague signs of vit D overdose can be constipation, increased thirst, confusion and depression. The best way to know for sure is to get a blood test.
48 Fish vs. Fish Oil Supplements?
Fish like salmon will have some vit D but fish oil supplements generally have none.
49 Why Is Vitamin D Measured In IUs?
Because it's the convention used. It’s a measure of biologic potency. IU stands for international units. It’s the convention used for things like vitamin A and D. 1 IU of vitamin D = 0.025 micrograms (mcg). So, if you take 1000 IU, this equals 25 micrograms. If you take 2000 IU of vitamin D, this equals 50 micrograms.
I hope this helped open your eyes to the importance of this vitamin. A good amount of this review came from the Vitamin D Solution, a book I highly recommend.