Vitamin D: Where to get it and why it’s important

In my practice, I routinely screen Vitamin D levels. Some practitioners or other providers would maybe question this practice. However, it is KEY. This essential vitamin is just that; essential. Patient’s come to me asking why they are tired, fatigued, depressed, thyroid or other hormone levels are “off”, and many other complaints. Unfortunately, insurance does not always pay for this lab. Of course not, right? Insurance corporations are making a load off their ill patients. Remember that.

According to the National Institutes of Health (NIH), “Vitamin D obtained from sun exposure, foods, and supplements is biologically inert and must undergo two hydroxylation's in the body for activation”. What does all that mean? Our liver and kidneys have to convert the vitamin to the bioavailable version. So imagine if patient A has liver disease, or liver AND kidney disease. Versus patient B, who has no liver or kidney disease, it would be assumed that patient B would have a higher level in their serum (blood). Not always true, but hopefully it is.

Myth #1: “I get Vitamin D from the sun and that is good enough”.

Truth: Vitamin D is from several food sources, in exogenous supplements, and also from UV light (endogenous).

Myth #2: “I eat a healthy diet, I shouldn’t have to take a vitamin supplement”.

Truth: The Standard American Diet (abbreviated, SAD :() is full of highly processed, refined carbohydrates, and sugars. Please take a moment to think about what you consume over a week, a month. Do you visit Chik-fil-A* for breakfast/lunch/dinner? Eat pizza out? Always get chips and cookies for the kids? Refined carbohydrates and sugar. Unless you are consuming oily, cold-water fishes (like salmon, mackerel, sardines, etc.), red meat, egg yolks, mushrooms, and/or fortified cereals, you could have a deficiency. It is wise to ask your provider for a blood test annually.

Myth #3 “I drink milk everyday. I get enough Vitamin D, right?

Truth: According to Dr. Gregory Miller, PhD, FACN, an 8 ounce serving of milk that is Vitamin D fortified has approximately 100–150 IU (international units). It is highly recommended to get 2000–4000 IU daily*, and sometimes higher depending on medical and mental health comorbidities. Pregnancy increases the need for Vitamin D, too.

Symptoms of low Vitamin D can include: joint pain, fatigue, hypoactive thyroid, anxiety, poor or low mood, and more frequent illnesses. These are the complaints I get in office. But they are vague and can be symptoms of many diagnoses. I rarely see high or upper levels of Vitamin D; I typically see levels of less than 30 ng/mL, and quite frequently critical levels of less than 20 ng/mL. Some experts recommend levels of more than 50 ng/mL. I am this expert, too; I recommend this level as well. Also, be advised there is such a thing as Vitamin D toxicity, so it is very important to have this level checked, especially if supplementing. Talk with your provider about possible drug interactions, for those on medicinal medications.

One item I think is fascinating is that Vitamin D is responsible for glucose metabolism. Hello, Diabetes! The CDC reports 34 million Americans have Diabetes and 90+% of those have Type 2 Diabetes. I am very passionate about diabetes and try to encourage and mentally strengthen my patients who have this disease process, as it can be a very depressing disease process. I cannot say it better than the NIH, “It stimulates insulin secretion via the vitamin D receptor on pancreatic beta cells and reduces peripheral insulin resistance through vitamin D receptors in the muscles and liver”. Unfortunately, clinical trials have not concluded that this vitamin helps manage the disease well. More studies should be performed.

I encourage you to create a relationship with your provider to discuss your symptoms that are bothersome and find a path to discover wellness. Also, the rest of the article from the NIH has a lot of details about why it’s important to consume Vitamin D. Excited for more research in this area for the benefit of patient’s everywhere!

Please ask me questions, leave comments


Aly Johnston, FNP-BC

Well by AM, LLC

Note: I feel Chik-fil-A is an excellent corporation, and is faith based, which I am definitely for. Replace Chik-fil-A with Taco Bell, McDonald’s, etc.

Note: According to the NIH, it is recommended to have a minimum of 600 IU for men and women 18–70 and 800 IU for those 70 years and older. Some studies recommend higher, as I mentioned above.




I am a Board Certified Family Medicine Nurse Practitioner. I have over 18 years of experience in various modalities in nursing.

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Alyssa Johnston

I am a Board Certified Family Medicine Nurse Practitioner. I have over 18 years of experience in various modalities in nursing.