Five Important Vitamin D Benefits

You’ve undoubtedly heard by now that vitamin D is beneficial to your health, and you may have even considered taking a vitamin D supplement in the hopes of optimizing your vitamin D advantages. As a matter of fact, according to a study published in the journal Nutrients, vitamin D is one of the most Googled nutritional supplements. Although vitamin D has long been recognized for its capacity to build bones, new research has also shown that it may provide a number of other health advantages, particularly in the COVID-19 period. However, there are instances when these myths regarding vitamin D’s health advantages are incorrect. When it comes to vitamins and your health, it may be difficult to tell what is genuine and what is not.

You’ve probably heard that vitamin D is good for you, and maybe you’ve even considered taking a supplement to get the most out of it. (According to a Nutrients study, vitamin D is one of the most Googled dietary supplements.)

Aside from its ability to strengthen bones, vitamin D has recently been linked to several other health benefits, particularly in the COVID-19 era. But these vitamin D benefits rumors aren’t always true. You never know what’s true when it comes to vitamins and your health.

We asked experts to cut through the hype and explain what we know about vitamin D benefits.

What is it?

First, a quick definition of what this stuff is. Vitamin D is a unique nutrient whose name is a misnomer. It’s not just a vitamin, “says Sue Shapses, Ph.D., R.D., of Rutgers University. “As a hormone, it affects many organs.” Although we can get vitamin D from food, our bodies make it and it has a molecular structure similar to other hormones, making it more like a hormone than a true vitamin. This article will refer to it as a vitamin throughout to avoid confusion—but it is an interesting fact.

Vitamin D is ingested or produced by the body. Vitamin D is a fat-soluble nutrient found in foods like milk and salmon, as well as in dietary supplements (NIH). Vitamin D is also made by our bodies from sunlight, hence the name. Dr. Shapses says that as soon as you step outside, your skin starts producing previtamin D3. Then it goes through your blood, liver, and kidneys to be converted to active vitamin D, says Dr. Shapses. This D3 is the same as the vitamin D you eat.

Then vitamin D is distributed throughout the body to do its job. “It can activate vitamin D receptors in the pancreas, brain, muscles, cardiac tissue, you name it,” Dr. Shapses explains. It has vitamin D receptors. They help vitamin D do things like reducing inflammation and affecting cell growth.

Vitamin D benefits

Now let’s look at vitamin D’s health benefits. While vitamin D’s potential benefits have been much discussed, especially during the pandemic, Dr. Shapses says its reputation as a bone builder is its most well-studied and proven benefit. Based on strong cell and animal studies and encouraging human studies, other potential benefits are promising but not proven.

Studies link low vitamin D to an increased risk of heart disease, obesity, and depression. It’s difficult to establish a causal relationship between adequate intake of a specific nutrient, like vitamin D, and better health outcomes. And when researchers give people vitamin D supplements to see if the intervention works, the results are often disappointing.

Nonetheless, adequate vitamin D intake is linked to a number of positive health outcomes, some of which are well-documented. Keeping that in mind, here are some key vitamin D health benefits:

1. Vitamin D promotes bone health.

Vitamin D is essential for a strong, healthy skeleton. Vitamin D aids in calcium absorption. The ODS says it also promotes bone health by promoting muscle growth around the bones.

According to the National Institute of Arthritis and Musculoskeletal and Skin Diseases, a lack of vitamin D can cause bone weakening and prevent the growth of strong bones. That’s why the ODS says a lack of vitamin D can lead to osteoporosis. The ODS states that a lack of vitamin D can cause osteomalacia, or bone weakness.

2.Vitamin D helps the immune system.

Dr. Shana Minei Spence, a registered dietitian nutritionist in New York City, saids that vitamin D supports important immune cells and regulates immune health. Scientists believe that vitamin D may increase the production of cathelicidin, an immune system protein that fights invading pathogens like viruses and bacteria. Vitamin D may also regulate the immune system’s production of substances and cells that cause inflammation.

During the COVID-19 pandemic, vitamin D was clearly a hot topic. While the NIH’s COVID-19 Treatment Guidelines mention vitamin D’s immune system effects, they state that there isn’t enough data to say if it works as a COVID-19 prevention or treatment.

However, vitamin D has long been touted as a cold and flu fighter. A 2013 review in Inflammation & Allergy—Drug Targets cites large studies showing adequate vitamin D levels reduce the risk and severity of respiratory infections, while vitamin D deficiency increases the risk and severity of respiratory infections. Vitamin D supplements may also help prevent these illnesses, according to some research. A 2017 British Medical Journal review of 25 studies found that vitamin D supplementation reduced the risk of acute respiratory tract infections by 14% in people with vitamin D levels in the deficiency or low normal range. The benefits of supplements increase with deficiency. (Fun fact: vitamin D-rich sun lamps and cod liver oil were used to treat tuberculosis in the 19th and early 20th centuries.)

Vitamin D deficiency has also been linked to autoimmune diseases, Spence adds. A review published in Nutrients in 2020 found a link between low vitamin D and autoimmune diseases like psoriasis, MS, and RA. (However, taking more vitamin D does not prevent these diseases.)

3. Vitamin D can help regulate blood sugar.

Vitamin D is essential for metabolizing glucose from food. To put it simply, it stimulates your pancreas to secrete insulin, which helps you convert food into energy and regulate your blood sugar levels. According to the ODS, it also reduces insulin resistance (when your body stops responding to insulin) and may help prevent type 2 diabetes.

There is “little evidence” that taking extra vitamin D supplements reduces diabetes risk or improves blood sugar control in people who already have diabetes, according to the ODS.

4. Vitamin D can help a pregnant woman.

Take a prenatal vitamin for this reason. Pregnant women need enough vitamin D. A 2019 Cochrane review suggests that pregnant women taking vitamin D supplements may reduce their risk of preeclampsia, gestational diabetes, low birth weight, and severe postpartum hemorrhage. Some of these benefits may be due to vitamin D’s positive effects on the immune system, inflammation, and blood vessel function.

5. Vitamin D may help prevent cancer.

The ODS says that while research in humans is mixed, lab and animal studies show that vitamin D can inhibit cancer formation and tumor growth.

Some studies and clinical trials link low vitamin D levels to cancer development or death, including breast, prostate, and colorectal cancer, while others do not.

The ODS cites two large meta-analyses that found higher vitamin D levels linked to lower cancer incidence and death (but not in every study or demographic). Also, promising clinical data. A 2019 meta-analysis in Annals of Oncology found that vitamin D supplementation reduced cancer mortality by 13%. Experts say more research is needed before claiming that “vitamin D can help prevent cancer.”

How to Get Enough D?

So, how much vitamin D do you need to stay healthy? Vitamin D benefits come from consuming enough of it—not too little or too much.

Dr. Shapses advises avoiding vitamin D deficiency to reap its benefits. The ODS defines vitamin D deficiency as a blood level of 20 nanograms per milliliter (ng/ml) or less. Low 12 ng/ml or less. According to Dr. Shapses, low vitamin D levels cause negative health outcomes when levels fall below 20, especially 12. The ODS warns that too much vitamin D can cause symptoms like confusion, nausea, and vomiting (or even kidney failure at extremely high levels).

Sunlight is a great source of vitamin D. According to the ODS, five to 30 minutes of sun exposure per day, or twice weekly, is enough to make enough vitamin D. (And, according to the ODS, most people don’t apply enough sunscreen to prevent vitamin D-producing rays from reaching their skin.) While darker skin produces less vitamin D than lighter skin due to the presence of melanin, the ODS says it is unclear if the lower levels of vitamin D more common in black people have negative health effects.

Although vitamin D is known as the “sunshine vitamin,” Spence advises getting it from a variety of foods. The ODS recommends 600 IU of vitamin D per day for women aged 19 to 70. Nutritional powerhouses like mushrooms and egg yolks, Spence says. While processed and packaged foods are often portrayed as unhealthy, Spence says they are a great source of vitamin D. Dairy products such as yogurt and juice are fortified with vitamin D.

Some people do not get enough vitamin D from food or sunlight. The prevalence of vitamin D deficiency varies, but data from the National Health and Nutrition Examination Survey from 2011 to 2014 showed that 18% of people over 1 were at risk of inadequate levels, and 5% were at risk of deficiency.

If you don’t eat enough vitamin D–rich foods or are otherwise vitamin D deficient, you may benefit from a vitamin D supplement. “Many of my clients have trouble eating a variety of foods,” Spence says. My advice is to take a supplement, whether it’s a standalone vitamin D supplement or a multivitamin.

As with any dietary supplement, talk to your doctor about taking vitamin D. Make an appointment if you’re unsure if you’re getting enough vitamin D. Your doctor may suggest a simple blood test for vitamin D. If your levels are low, they will likely recommend or prescribe a vitamin D supplement to raise your levels and ensure you are getting all of the vitamin D goodness.