Vitamin D – Essential Nutrient for Overall Health

July 27th, 2020

Often referred to as the ‘sunshine vitamin,’ vitamin D is one of the most important nutrients for overall health.


A, B, C, D, E, K… these are not your typical ABCs – they are just a few of the 13 vitamins that your body needs to grow, develop, and work properly. Vitamins are a group of compounds that allow you to function normally and to stay healthy and strong. Each vitamin has one or more important jobs: from helping the bone marrow form red blood cells, to being a vital ingredient for making one of the most important molecules for life – DNA, and more.

Depending on how the body absorbs them, vitamins are classified into two categories: fat-soluble and water-soluble. Fat-soluble vitamins, as the name suggests, dissolve in fat. They are similar to oil in that they don’t dissolve in water, and your body absorbs fat-soluble vitamins better when you eat them with fat. There are four fat-soluble vitamins in the human diet: vitamin A, D, E, and K.

The rest of the vitamins are water-soluble, meaning that they dissolve in water. Contrary to fat-soluble vitamins, which stay in the body for up to six months, water-soluble vitamins are generally not stored in the body. Instead, they pass through the bloodstream before the kidneys eliminate any excess vitamins that aren’t needed.

It is no secret that vitamin C is one of the most popular essential nutrients. Celebrated for potentially treating and preventing the common cold, approximately half of adults in the U.S. take nutritional supplements that typically contain vitamin C.

But another vitamin has slowly been claiming vitamin C’s spot as one of the most beneficial vitamins you could take. Vitamin D is both a vitamin and a hormone. Among other things, it promotes calcium absorption and maintains appropriate phosphate levels, two nutrients that work in tandem to keep your bones strong. Read on to find out about the roles and benefits of vitamin D in more detail.


Vitamin D is a fat-soluble vitamin that’s naturally present in many natural and fortified foods. The human body also makes vitamin D when the skin is directly exposed to the sun. Recent research has shown that taking vitamin D supplements reduces the risk of developing certain respiratory infections, like the influenza virus. Other studies have shown that vitamin D may protect against some types of cancer, including colon and breast cancer.

Here are three more benefits of vitamin D.

1.  Healthy bones

You probably already know that calcium is essential for bone health. It helps form and maintain bones, and adequate levels of this mineral can protect you against osteoporosis later in life. But what many people don’t know is that without vitamin D, your body can’t absorb the calcium that you ingest.

A vitamin D deficiency in adults can increase the risk of developing osteoporosis, fractures, and can also present as osteomalacia, a softening of the bones that can lead to serious health complications. In children, vitamin D deficiencies can cause rickets, a rare condition that results in weak bones, stunted growth, and muscle weakness.

2.  Immunity

Supplementing with vitamin D3 may protect against acute respiratory tract infections, according to a 2015 systematic review and analysis of previous studies. Published by the British Medical Journal, the reviewers looked at 25 clinical trials with over 11,000 participants in total to see if vitamin D supplements could potentially prevent respiratory infections.

The results showed that vitamin D supplementation reduced the risk of getting at least one respiratory infection, and was particularly effective at preventing respiratory infections among those who already had a vitamin D deficiency.

Other reviews of existing evidence have found similar results, like this 2018 meta-analysis, which concluded that vitamin D supplements may have a protective effect against the influenza virus, though some of the studies that they analyzed had no relevant results.

Based on these findings, a number of recent studies have started looking at the potential role of vitamin D in the novel coronavirus (COVID-19), from helping prevent the virus by making its symptoms less severe. So far, the results have been mixed. There hasn’t been enough time to conduct in-depth studies that could establish a strong causal relationship, and many of the reports are preliminary and have not been thoroughly reviewed.

One study led by researchers from Northwestern University compared COVID-19 data from 10 countries to each country’s average vitamin D deficiency rates. They found that countries with more vitamin D deficiency had higher mortality rates, whereas countries with higher vitamin D levels were not affected as severely by the virus. However, a review by U.K.’s National Institute for Health Care and Excellence concluded that there is not sufficient evidence to determine whether vitamin D can prevent or treat COVID-19.

Still, many experts believe that the new and growing evidence linking vitamin D deficiencies to COVID-19 is compelling. Observational studies conducted at South Asian hospitals show that the prevalence of vitamin D deficiency was significantly higher among patients with severe coronavirus cases. And an investigation – which has not been peer-reviewed yet – from researchers at the University of Chicago found that people who had vitamin D deficiencies before the pandemic were 77 percent more likely to get COVID-19 than people with normal levels.

3.  Depression

There may be some association between vitamin D and certain mood disorders, including depression and seasonal affective disorder (SAD) – a type of depression that typically occurs during the fall and winter and ends in spring or early summer. A 2018 meta-analysis published in the British Journal of Psychiatry, investigators found that low vitamin D levels are associated with depression.

On the other hand, another study led by Danish researchers looked at vitamin D levels in relation to SAD. The research team looked at 34 healthcare workers with symptoms of SAD that took either a vitamin D supplement or a placebo for three months. Unfortunately, the investigators didn’t find any significant associations between supplementing with vitamin D and reducing the symptoms of SAD.

Vitamin D3 benefits are far more extensive and in fact decrease the risk of all cause mortality (death regardless of the cause).  Although vitamin D is made by the body when skin is exposed to sunlight, the majority of people have below optimal levels of D3.  In fact a study showed below optimal levels of vitamin D3 in many people from a group of outdoor workers.  Also, sunscreen, protective clothing, limited exposure to sunlight, dark skin, and age may prevent getting enough vitamin D from the sun.  So even if you are in the sun a lot, that is no guarantee your vitamin D3 levels are sufficient.  Almost everyone should be supplementing with vitamin D3 for the following reasons:

Vitamin D3 supports

  • Supports a Healthy Nervous System
  • Supports Immune System
  • Healthy Teeth
  • Healthy Bones
  • Healthy Lung Function
  • Cardiovascular Health
  • Improves Brain Function
  • Regulates Insulin Levels
  • Aides in Diabetes Management

Vitamin D3 Lowers risk of 

  • Flu
  • Diabetes (Type 1 & 2)
  • Macular Degeneration
  • Eczema & Psoriasis
  • Bone Fractures
  • Heart Disease
  • Hypertension
  • Colorectal Cancer
  • Dementia
  • Alzheimer’s
  • All Cause Mortality

Optimal levels of Vitamin D3 range between 60 – 90 nanograms/ml. 

If you fall below this range, consider supplementing with 2,500 -5,000. If you fall below 30 ng/ml, consider taking 10,000 I.U. daily.  Some people, even with additional daily D-3 supplementation, do not easily increase their vitamin D-3 levels, so you may need to double your daily intake.  If  your vitamin D-3 levels did not increase much upon having them  tested a second time,  (despite having doubled your daily dose), discuss this with your doctor.  You may have to take as much as 50,000 IU of vitamin D-3 a day (or more) to get up to 60-90 ng/ml. I know that going to your doctor’s office or a lab can be inconvenient but it is extremely worth it to decrease your risk of death from all causes as well as specifically from heart disease and cancer!

Vitamin D Deficiency

Vitamin D deficiency is fairly common. About 1 billion people have vitamin D deficiency worldwide, and nearly 50 percent of the entire world’s population has vitamin D insufficiency. In the United States, it is estimated that almost 40 percent of Americans are vitamin D deficient.

Vitamin D deficiencies can happen for several reasons, including not getting enough sunlight, being lactose intolerant, eating a limited diet, or having a medical condition like kidney disease or cystic fibrosis. Symptoms of a vitamin D deficiency might include fatigue, mood changes, bone pain, and muscle aches.

Sources of Vitamin D

You can get vitamin D in different ways, including:

  • Ultraviolet B rays (aka sunshine)
  • Fatty fish and seafood, like:
    • Tuna
    • Salmon
    • Oysters
    • Shrimp
  • Mushrooms
  • Egg yolk
  • Fortified foods, including:
    • Cow’s and plant-based milk
    • Tofu
    • Boxed cereal
    • Orange juice
  • Nutritional supplements