Vitamin D can play an essential role in our health – including immune health, various diseases, skin health, thyroid disorders, inflammation and even some cancers. Although many of us know the importance of this vitamin, many don’t know where to start, how much to take or are aware of the dangers of taking too much (yes, overdoses are possible!).
What is Vitamin D?
Vitamin D is a fat-soluble vitamin. That means it can dissolve in fats and oils. It’s needed for bone growth and development. It also helps cell growth and nerve, muscle, and immune function. Vitamin D is called the “sunshine vitamin” because it is produced by the body in response to sun exposure.
What does Vitamin D do for the body?
Vitamin D helps control calcium balance in the body. It maintains normal calcium levels and bone density. Vitamin D you get from the sun or in your diet increases the absorption of calcium and phosphorus from your intestines. It also aids in the reabsorption of phosphorus from the kidneys.
Vitamin D is needed for normal bone growth. It’s also needed for healing bones after a fracture. It’s very important for babies, children, and teens.
Adults can meet the recommended dietary allowance for Vitamin D without supplements. You can do this by exposing your face, hands, arms, or back, without sunscreen, to the sun for 10 to 15 minutes at least 2 times a week.
You can also get vitamin D from your diet. These foods contain vitamin D:
- Egg yolks
- Canned tuna
- Oily fish – such as sardines, herring and mackerel
- Cod liver oil
- Fortified foods – like milk, orange juice, and some cereals or oatmeal
How do you know if you have low Vitamin D levels?
Although exact levels have not been identified, experts believe that levels of 20 nanograms per milliliter (ng/mL) is enough for good bone and overall health. Recommended daily amounts range from 400 to 800 international units (IU) per day based on your age.
Older adults are at increased risk for vitamin D insufficiency. This is because older skin can't make vitamin D as well. Older adults also spend more time indoors, away from sunlight. And they may have diets low in vitamin D.
To determine if you have low levels of Vitamin D your doctor may want to do a blood test. A needle is used to draw blood from a vein in your arm or hand.
Levels lower than normal can mean you are:
- Not making enough vitamin D on your own
- Not getting enough vitamin D in your diet
- Not absorbing vitamin D from your food as you should
Lower levels may also mean that your body is not converting the vitamin as it should. Low levels of vitamin D in an adult can lead to loss of calcium and the softening of bones (osteomalacia). It can also lead to thinning of the bones (osteoporosis).
Above-normal levels may be a sign that you're taking too much in supplement form.
What is the recommended supplement level for Vitamin D?
People who are found to be deficient in vitamin D or have low levels of vitamin D (vitamin D insufficiency) should take higher doses of vitamin D. If you are found to have vitamin D insufficiency or deficiency, your healthcare provider will determine the correct supplement and dosage for you.
Because vitamin D is fat soluble, it's best to take vitamin D supplements with food that has some fat in it for enhanced absorption.
Is it possible to get too much Vitamin D?
It is possible to overdose on vitamin D, so that is why you should consult your healthcare provider before taking supplements to get the correct dosage for you.
Symptoms of vitamin D overconsumption in children and adults often occur after several months of heavy use. They include:
- Decreased muscle tone (hypotonia)
- Joint pain
- Being thirstier than normal
- Making more urine than normal
- Loss of appetite
- High blood pressure (hypertension)
Too much vitamin D can also damage the valves in the heart and the kidneys. This is due to calcium building up in these organs. When taking vitamin D supplements, don't use magnesium, phosphorus, or calcium unless your healthcare provider says to.
If you believe you have a vitamin D deficiency consult with your primary care physician to schedule a blood test.
Need to find a Primary Care physician? Visit touro.com/primarycare.
About Dr. Schuyler Williams
Dr. Williams specializes in Internal Medicine at Touro. She attended Meharry Medical Coll School of Medicine and completed her residency at Tulane University and is board-certified by the American Board of Internal Medicine.