You may have heard that many people are deficient in vitamin D. But did you know that over 40% of Americans are vitamin D deficient? This deficiency is significant as low levels of this vitamin are also linked with cardiovascular disease (CVD), and CVD is the number one cause of death in the U.S. This statistic may be alarming. Fortunately, there are ways to improve Vitamin D levels and, at the same time, reduce your risk of CVD. There are multiple methods to attain sufficient vitamin D levels, but let's take it even further for you and describe how to optimize these levels so you can receive all the benefits of this sunshine vitamin. 

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What is Vitamin D?

Vitamin D is a well-known essential micronutrient with critical physiological roles in musculoskeletal health, gene expression, hormone regulation, metabolism, immune balancing,  and many other body functions. There are multiple forms of this vitamin that determine its availability and function.

Vitamin D is mainly created from sunlight and the skin, which is why it's commonly called the sunshine vitamin. This process creates the vitamin D3 form, a form that isn't very active in the body at this point. Another form of this vitamin is D2, which can come from food sources such as mushrooms or supplements. However, you will need more amounts of D2 versus its D3 counterpart to increase your levels. It's important to note that you can also attain D3 from supplements or in small and insufficient amounts from animal proteins.

Two other organs, besides the skin, are essential for converting this vitamin. They are the liver and the kidneys. The liver will convert D2 and D3 into calcidiol. Calcidiol is the form that is tested most often by practitioners, and you may see calcidiol as 25(OH)D (25-hydroxy vitamin D) or 25-hydroxycholecalciferol in your labs. This form, however, is still not the most active form as it still needs further conversion from your kidneys to convert it to its most active form of calcitriol. Vitamin D in this form is what stimulates the physiological processes.

Vitamin D and Cardiovascular Risk Factors

There are multiple cardiovascular risk factors, and approximately half of Americans have the top three risk factors, which are high cholesterol, high blood pressure, and smoking. The other risk factors for CVD are considered lifestyle factors or conditions that are modifiable and include diabetes, being overweight, unhealthy nutritional choices, lack of exercise or movement, and excessive alcohol consumption. Genetics and family history can also play a role in increasing cardiovascular risk.

Beyond being essential for many physiological processes, sufficient vitamin D levels are also needed to reduce the risk of CVD. Research indicates that low levels of vitamin D are a predicting factor in CVD and mortality. Therefore, vitamin D status should be evaluated and addressed if the tests indicate deficient or insufficient levels to support heart health and reduce the burden of CVD.

Factors Affecting Vitamin D Levels

We now know that vitamin D levels are vital for many body functions and for reducing the risk of CVD, but what factors affect vitamin D levels in us? Sunlight and vitamin D synthesis are important to consider, as sunlight exposure is crucial for us to attain this essential nutrient. 

Lifestyle factors and vitamin D deficiency risk also include dietary sources of vitamin D. What you consume and how you live can impact your nutrient levels. These lifestyle factors include avoiding sunlight and staying indoors or not consuming enough vitamin D through food sources and supplementation. These factors can create deficiencies of this necessary vitamin.

The Role of Vitamin D Testing

Vitamin D testing for individuals is essential because deficient levels of this nutrient can have detrimental effects, such as causing an increased risk of CVD. So, how do you test for Vitamin D, and what lab values are you looking to attain? 

As previously mentioned, the lab test that is most commonly used is a 25(OH)D to assess your levels. This test is typically completed through a serum sample, as this is what practitioners use to determine if you have sufficient circulating levels. Vitamin D levels can also be assessed through saliva samples as a less invasive way to attain these measurements. 

Saliva testing isn't commonly used as of right now but may offer an alternative to serum testing. Testing will allow your healthcare provider to target dosing protocols to attain optimal levels to reduce your risk of disease progression, so your body is getting everything it needs from this nutrient. 

When looking at your lab results, there are standard lab ranges and optimal lab ranges of Vitamin D levels. Standard ranges are used to diagnose disease, whereas optimal ranges are often used in functional medicine for early disease detection. With that stated, the standard lab ranges of Vitamin D are between 20 and 40 ng/mL, and the optimal range is 40-70 ng/mL. 

Practical Steps to Optimize Vitamin D for Heart Health

The following are some integrative approaches to optimize vitamin D levels to help reduce your risk of CVD and improve your heart and overall health:

Dietary Recommendations for Vitamin D

Before discussing the dietary recommendation for vitamin D, let's discuss where this recommendation comes from. Many people are aware of Recommended Dietary Allowance (RDA), as this recommendation is what's typically seen on product and supplement labels. This dietary recommendation is one of multiple dietary recommendations that fall under the umbrella of Dietary Reference Intakes (DRIs). DRI's were developed by the National Academies of Sciences, Engineering, and Medicine and their experts. These recommendations vary by age and gender.

For vitamin D, the RDA can be listed as two different units, micrograms (mcg) and international units (IU), where 40 IU equals one mcg. The RDAs for vitamin D vary by age and are based on the daily amount required to maintain bone health. For 0-12 months, it's ten mcg (400 IU). For 1–70 years, it's 15 mcg (600 IU), and for ages 70 and above, it's 20 mcg (800 IU). Vitamin D can be found in multiple food sources, where animal food sources such as cod liver oil will contain higher amounts. You can also attain vitamin D from plant sources such as mushrooms or from fortified foods such as milk.

Sun Exposure Guidelines for Vitamin D

We produce most of our vitamin D from the sun, hence the sunshine vitamin. The amount we need will vary, depending on skin tone. The darker the skin tone, the more time you will need in the sun due to melanin. Melanin is amazing at protecting us against the damage of UV rays, sunburn, and skin cancers. However, if you have more melanin, you will need more time in the sun to produce adequate amounts of vitamin D. Experts suggest that people with lighter skin tone people will need about 10-30 minutes in the sun at least three times per week while people with more melanin and with darker skin tones will need 30 mins to three hours.

Here are some tips to help you get adequate amounts of vitamin D while reducing the harmful effects it may have: 

• Expose at least ⅓ of your skin to the sun - this can be accomplished through wearing a tank top and shorts.
• Wear a hat and sunglasses to safeguard your eyes and face.
• Apply sunscreen after you get the amount of sun you need, which is usually right before you start burning.

Vitamin D Supplements and Heart Health

If you can't get your vitamin D from the sun or through food, another option is through supplementation such as vitamin D2 or vitamin D3. Supplements can be an excellent and easy source to achieve sufficient levels of this nutrient. It's important to note that taking vitamin D with calcium can increase your risk for hypercalcemia or gastrointestinal issues. They can also cause adverse effects in amounts higher than 500,000 IUs. Therefore, it is recommended to talk to your doctor before taking supplements. Based on your lab results, they can target the correct and safe dosing for you.

Here are some recommended dosages for heart health:

Blood pressure- Take approximately 800 IU per day (as D3) for six months to healthy patients older than the age of 50

CVD- 60,000 IU (as D3) monthly for four months is recommended for African-American adults with CVD

Heart failure- 2000-4,000 IU (as D3) with or without 500 mg calcium daily for 6 to 36 months is recommended for adults with vitamin D deficiency

Heart failure prevention- 800 IU (as D3) daily with 1,000 mg of calcium continuously for one to 17 years is suggested for older adults

High cholesterol- 2,000 IU (as D3) daily for six months in conjunction with statins for people with high cholesterol

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Summary

CVD is the primary cause of death for people in the U.S., and low vitamin D levels can increase the risk of CVD. Therefore, optimizing the levels of vitamin D for people with low levels should be prioritized to reduce CVD and support heart health. Eradicating D deficiency can help decrease the burden of CVD. Attaining sufficient levels of vitamin D can be accomplished through food, sunlight, and supplementation. Testing can ensure that levels are optimized, and supplement dosing can be tailored to each person.