Did you know vitamin D is more like a hormone than a vitamin? Many people have borderline low levels of this vitamin/hormone and don’t even know it. A low vitamin D level can cause vague symptoms like fatigue and vague joint pains and muscle aches. Unfortunately, if you go to visit a doctor with these symptoms, they’ll probably run some blood tests, including a thyroid function test, but may not check a vitamin D level. If you have a low vitamin D level, you can go for years with vague symptoms of “just not feeling right” and not know why you don’t feel well.
Low Vitamin D Symptoms: How Common is Vitamin D Deficiency?
Did you know as many as one out of three people have sub-optimal levels of vitamin D? The problem is it’s not entirely clear what the ideal level is. Some studies suggest that a higher vitamin D level offers protection against certain autoimmune problems, particularly multiple sclerosis. Some studies also suggest it may reduce the risk of heart disease and certain types of cancer but there isn’t enough supportive research to recommend supplementing with vitamin D for these purposes since results are conflicting.
There are still so many unanswered questions about vitamin D – how high your level should be to maximize health and what health benefits vitamin D offers. What is clear is vitamin D increases calcium absorption from your intestinal tract and helps to preserve bone health. Deficiency of vitamin D in adults causes a bone disease called osteomalacia and a bone disorder called rickets in children. It’s also clear that vitamin D can cause vague symptoms like muscle fatigue and joint aches and pains. Simply put, if your vitamin D level is sub-par, you may not feel your best.
Why Is Vitamin D Deficiency So Prevalent?
One reason why low vitamin D levels are relatively common is there aren’t a lot of good food sources of D. The best natural source of vitamin D is sunlight. Yes, sunlight. There are vitamin D precursors on the surface of your skin. When you expose your skin to sunlight, these precursors are converted to the active form of vitamin D your body can use. Your liver and kidneys participate in this conversion.
So how much sun do you need? It takes about 10 minutes of sun exposure a day to meet vitamin D requirements for most people. If you’re not getting that, you’re at higher risk for deficiency. Some areas of the country don’t get much direct sunlight during certain times of the year. As a result, you see more cases of diseases associated with low vitamin D levels like multiple sclerosis in these areas.
People with dark skin need even more sun exposure than lighter skinned people to meet their requirements. That’s because they have higher levels of melanin in their skin, and melanin blocks absorption of sunlight. The elderly are also at high risk for vitamin D deficiency since they usually have limited sun exposure and don’t make the conversion to active vitamin D as easily as younger people.
What about Food Sources of Vitamin D?
If you’re counting on diet to meet your vitamin D requirements, prepare to be disappointed. There aren’t lots of foods that are naturally high in vitamin D, although some foods like breakfast cereal and milk are fortified with it. Here are some of the best natural sources of vitamin D:
Food Source and Amount of Vitamin D
Salmon (3 ounces) 447 I.U.
Canned Tuna (3 ounces) 150 I.U.
Fortified milk ( 1 cup) 130 I.U.
Fortified orange juice (1 cup) 110 I.U.
Fortified cereal (1 cup) 50 I.U.
Egg 35 I.U. (must eat the yolk)
Cheese (1 ounce) 7 I.U.
Considering adults need between 600 to 800 I.U. a day, and many experts think we need more – it’s challenging to meet your vitamin D requirements through diet. How much dietary vitamin D are you getting daily based on this chart? Unless you’re eating a salmon-rich diet and drinking lots of milk or spending time in the sun, you may be falling short.
Should You Take a Vitamin D Supplement?
People who have low vitamin D levels need a supplement to raise their level. It’s very difficult to raise a low vitamin D level through diet and sun exposure alone. Vitamin D levels come up very slowly. That being said – don’t go blindly take a vitamin D supplement “just in case” you’re low. It’s better to get a vitamin D level checked and see where you stand.
There is some emerging evidence that vitamin D levels above a certain level may have other health risks. One study showed that higher vitamin D levels are associated with elevated CRP levels. CRP is a marker for inflammation – not something you want. Since vitamin D increases calcium absorption, there’s concern that calcium may build up inside blood vessels and contribute to atherosclerosis in people who have high vitamin D levels. Plus, high vitamin D levels increase your risk for kidney stones.
Don’t be too quick to jump on the supplement bandwagon when it comes to vitamin D. It’s tempting to think that more might be better based on how “hot” vitamin D is right now – but there are risks to over-supplementing with vitamin D.
Testing for Low Vitamin D
The best way to check your vitamin D level is to ask your doctor for a 25(OH) D test. This is a simple blood test that measures your vitamin D level. There’s also a home test kit for testing your vitamin D level at home through a finger stick but you have to send it to a lab to be analyzed.
If your vitamin D level is low, talk to your doctor about supplementing. There are two types of vitamin D called vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). The D3 form is the recommended form.
The take-home message? Know your vitamin D level. Even if it’s normal, take steps to expose your skin to sunlight for 10 minutes daily and add some fatty fish to your diet to prevent future deficiency. If it’s low, talk to your doctor about how much vitamin D3 to take to gradually bring your levels up. You might find you feel a whole lot better once your vitamin D level rises.
National Institute of Health. “Vitamin D”
John Hopkin’s Medicine. “Vitamin D: More May Not Be Better”
Medscape Family Medicine. “Prevalence and Predictors of Vitamin D Deficiency in Healthy Adults”