What is vitamin D and how does our body get it?

Would you believe vitamin D isn’t actually labeled as a vitamin any longer but rather, is described as a prohormone? A prohormone is a substance that your body converts into a hormone, in this case, calcitriol. This hormone is produced in the liver and kidneys and helps to regulate calcium in the bloodstream for bone development, along with supporting optimal functioning in many other areas of the body, such as the immune system. 

Vitamin D is one of the most chronically deficient vitamins in the population. New studies have shown that around 60% of the population is insufficient when vitamin D levels are tested. One of the main reasons for this is that most people eating the standard American diet don’t consume enough of the foods that naturally supply the body with vitamin D. Additionally, sun exposure, the main source of vitamin D, is hard to get in sufficient quantities in certain parts of the world. There is also some confusion about how much is enough or too much – there is a fine line with sun exposure: the “more is better” philosophy does NOT apply here. 

Let’s unpack this…

Vitamin D-rich foods

About 10% of vitamin D comes from diet and is in the forms of D2 or D3. These are absorbed in the beginning of digestion in the small intestine. Some good food sources of vitamin D would be things like fatty wild caught fish, cod liver oil, red meats, liver, mushrooms and eggs. In order for us to absorb vitamin D more quickly and efficiently, it needs to be consumed with a form of fat, which most of these foods already contain. However, this is important to remember if you are using vitamin D supplements also. Opt for healthy fats to accompany your supplementation, like avocado, nuts, or something with grass-fed butter or olive oil. 

Aim to eat wild and sustainably caught fish 1-2 times per week to maintain optimal vitamin D levels.

Vitamin D from sunlight

We get the majority of our vitamin D from sunlight on our skin. As we are exposed to sunlight, UV rays are absorbed through the skin and begin the synthesis of vitamin D. It then travels to two major organs to be hydroxylated. The first stop for this vitamin is the liver, where it is converted to 25-hydroxyvitamin D, calcidiol. The second stop is the kidneys, where it becomes the active form called 1,25-hydroxyvitamin D, aka calcitriol. In this form, it is able to carry out the majority of its functions and is the major form we would be looking for in lab work.

Safe sun exposure and vitamin D

How much sun do you need? What time of day is best?  How do you get sun exposure safely and not too much?

Get vitamin D naturally by exposing skin to unfiltered sunlight for 10-20 minutes a few times per week.

Getting adequate sunlight to create sufficient vitamin D levels can be difficult, especially in the winter months or in the northern parts of North America and Europe. Aging skin and darker pigmentation of skin can also play a role in diminished absorption. In Florida, we often saw surfers who, even with all-day sun exposure, would test deficient in vitamin D because their skin was tanned so dark. This is where education on safe sun exposure is crucial. 

About 300-600 IUs of vitamin D is the recommended daily amount. Optimal levels can be dependent on the individual but there are optimal ranges which would fall between 50-80 ng/mL in blood markers. If we look at our exposure to sunlight, we get about 15,000-25,000 IUs of vitamin D just from the amount of sun it takes to turn our skin slightly red in color. One thing to note is that you can’t overdose on vitamin D from sunlight, as our body knows exactly what to do with it to regulate the levels.

The amount of sun exposure recommended is between 10-20 minutes of sunlight during non-peak hours of the day (before 10:30 am and after 3:30 pm) but each individual differs based on skin darkness, absorption issues, and liver and kidney function. (During peak hours of sunlight, the sun is more intense so it requires less time to get your dose of vitamin D, however, it is much easier to get burned and cause skin damage.) To reap the largest benefit, make sure the arms and legs are uncovered. More than 20 minutes in the sun does not equate to more vitamin D production, and can have harmful effects on the skin. Avoid burning the skin by using a high-quality and clean sunscreen, hat, and UV protective clothing if you are out in the middle of the day or if you are in the sun for extended periods of time. Also use common sense: if you have fair skin or you find yourself getting sunburned easily, cover up and opt for vitamin D supplementation instead. 

Why having your vitamin D levels checked is important

Getting your vitamin D levels tested is an easy and affordable way to proactively monitor your health and identify health risks.

It is only now being realized the critical role that vitamin D plays in so many systems of the body. For example, we already talked a little about the importance of vitamin D in bone health. It minimizes the risk of osteopenia and osteoporosis because it is essential in the absorption of calcium and mineralization of bone. Research has also shown that adequate levels of vitamin D reduce the risk of autoimmune disease and diabetes in patients by more than 60%. In children low in vitamin D, the deficiency can lead to rickets, a disease which causes bones to not mineralize properly and can cause bone deformities. Patients with intestinal and gut conditions who have an issue absorbing fats, can also show greater risk for vitamin D deficiencies. Low vitamin D levels can also lead to greater risk of excess inflammation, depression, allergies, and even certain types of cancers. 

For these reasons, it is important to look at optimal levels of vitamin D in the blood to make sure you are keeping these risks low and taking proactive measures to supplement with high-quality vitamin D, if deficiency is detected.  

We encourage all patients to take an informed and proactive approach to their health by talking with their practitioner about routine blood work that can test some basic markers of health and risk. When it comes to testing for vitamin D levels, everyone should be tested to know their base level. We monitor levels closely in pregnant women and those with compromised immune systems. 

Why quality matters when in comes to vitamin D supplementation

In our office, we use and recommend Bio D Mulsion Forte from Biotics Research to help optimize vitamin D levels in our patients. The microemulsion helps enhance the body’s absorption, especially with conditions of malabsorption, such as digestive issues. Clinical studies have shown that this form can significantly increase blood levels in as little as 6 weeks. Sublingually, the body is able to more efficiently absorb vitamin D, as opposed to taking it orally in capsules and having to allow time for the intestinal tract to break it down. Taking the correct form of vitamin D, cholecalciferol, along with vitamin K2, can play a major role in keeping those levels optimal. Monitoring the vitamin D levels along with parathyroid hormone, calcium and phosphorus, provides a more holistic view of overall health and whether/how much supplementation is needed. Dosage is based on your blood levels and should always be monitored by your practitioner to make sure you are hitting those healthy levels of vitamin D, and thus keeping your bones, immune system, and mental health at their peak.

The bottom line: increase delicious, vitamin-D rich foods like fatty fish and mushrooms; get adequate but safe sunlight exposure several times each week; use quality vitamin D supplementation; know your vitamin D level by having it tested.

Talk with your practitioner about your vitamin D levels and what role it is playing in your health. Call our office to learn how to get easy and affordable lab testing (even if you aren’t currently a patient) through our Direct Labs. (970) 532-2755.

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