{"id":22883,"date":"2020-11-27T10:00:00","date_gmt":"2020-11-27T18:00:00","guid":{"rendered":"https:\/\/foodrevolution.org\/?p=22883"},"modified":"2026-09-15T00:34:43","modified_gmt":"2026-09-15T07:34:43","slug":"health-benefits-of-vitamin-d","status":"publish","type":"post","link":"https:\/\/foodrevolution.org\/blog\/health-benefits-of-vitamin-d\/","title":{"rendered":"Vitamin D Guidelines: What Is It, How Much Do You Need?"},"content":{"rendered":"

Ella Fitzgerald and Frank Sinatra agreed that \u201cLife is sweet on the sunny side of the street.\u201d Other singers have advised us to \u201cKeep to the sunny side of life.\u201d And The Beatles reminded us that \u201cIt\u2019s all right,\u201d because \u201cHere comes the sun.\u201d<\/p>\n

We instinctively feel better on sunny days. And despite fears of melanoma, the fact is that being out in the sun, in moderation, is good for you. One of the coolest tricks your body can pull off is done by your skin, which converts sunlight into a hormone essential for human health. The hormone in question, known as calcitriol<\/a>, is incorrectly referred to as vitamin D. Incorrectly because the definition of a vitamin is an essential nutrient that cannot be synthesized<\/a> by the body in sufficient quantities to maintain health. With that bit of nitpicking out of the way, I\u2019m going to conform to the prevailing norms, and call it vitamin D for the rest of this article.<\/p>\n

Vitamin D, also known, for obvious reasons, as \u201cthe sunshine vitamin,\u201d has a number of health benefits, most famously when it comes to your bone health. And it has come into the spotlight recently, in the context of COVID-19, as a potential immunity booster<\/a>. (More about that later.)<\/p>\n

But even though the evidence is clear that having enough vitamin D is critically important, 61% of the elderly population in the United States (and 96% in India) have some degree of vitamin D deficiency<\/a>. Checking for vitamin D deficiency isn\u2019t usually a part of standard blood tests in every physician\u2019s office, so it’s often missed. And if you are deficient, you might not know it.<\/p>\n

So what exactly is vitamin D? How much do you need? And do you need to supplement it?<\/p>\n

What Is Vitamin D?<\/h2>\n
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Vitamin D<\/a> is called calcitriol, or sometimes cholecalciferol<\/a> (vitamin D3), because it is calciferous (\u201ccarrying calcium around\u201d) and a sterol (a type of steroid hormone).<\/p>\n

Vitamin D is primarily obtained from your body\u2019s response to the sun\u2019s UV rays when they penetrate your skin. In addition to direct sun exposure, you can also get vitamin D from a few foods, as well as dietary supplements. It\u2019s a fat-soluble vitamin, which means that if you take it orally, you\u2019ll need to accompany it with at least some fat for the best absorption. Furthermore, while water-soluble vitamins are excreted and not stored in the body, vitamin D and other fat-soluble vitamins (like A, E, and K) accumulate in fatty tissues throughout your body.<\/p>\n

Vitamin D promotes calcium absorption in your gut and helps your body to maintain adequate serum calcium and phosphate concentrations.<\/b> Vitamin D also works together with vitamin K to regulate calcium metabolism<\/a>, which is essential for heart health. And it also plays a key role in skeletal health and bone strength. Plus, it controls the reduction of inflammation, as well as modulation of processes like cell growth, neuromuscular and immune function, and glucose metabolism.<\/p>\n

7 Health Benefits of Optimal Vitamin D<\/h2>\n
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Your body needs vitamin D \u2014 and enough of it \u2014 to run properly. In fact, vitamin D offers a number of health benefits both on its own and through working together with other compounds in the body. Here are seven great reasons to \u201cLet the sunshine in\u201d on a regular basis.<\/p>\n

1. It\u2019s good for your muscles and bones.<\/h3>\n

You need vitamin D in order to absorb calcium, which is necessary to grow and maintain strong bones. Research shows that when people are vitamin D deficient, they have worsened skeletal integrity. For example, in a 2017 study<\/a> published in Nutrients<\/i>, researchers found that supplementation of vitamin D2 over the course of six months reduced oxidative protein damage, decreased self-reported pain, improved quality of life, and improved grip strength and physical performance in osteoarthritis patients. Let\u2019s recap: less damage, less pain, stronger, and happier. Sounds good to me!<\/p>\n

In addition to bone health, vitamin D is also needed for the normal development and growth<\/a> of muscle fibers \u2014 the thousands of muscle cells that are tightly wrapped together to form your muscles. As such, having inadequate levels of vitamin D in the body can lead to muscle weakness and pain.<\/p>\n

2. It might have protective effects against cancer.<\/h3>\n

Research has shown that having higher serum levels of vitamin D is associated with a lower cancer incidence. In fact, a 2019 meta-analysis<\/a> of prospective cohort studies published in Nutrients<\/i> looked at 16 studies involving 101,794 participants to determine the relationship between serum vitamin D levels and risk of cancer diagnosis and mortality. The researchers concluded that with each 20 nmol\/L (that\u2019s pronounced \u201cnanomoles per liter,\u201d in case you\u2019re reading this article out loud as a bedtime story) increment increase of 25-hydroxyvitamin D (another name for calcidiol) concentration, the risk of developing cancer dropped by seven percent.<\/p>\n

This relationship remains when looking at specific types of cancer, too. Another 2019 study<\/a> found that higher serum vitamin D levels were associated with statistically significant, substantially lower risk of colorectal cancer among women. While not as significant, the same association was also seen among men. And in a 2020 review<\/a>, researchers concluded that epidemiological evidence suggests there is a link between higher vitamin D levels and a lower risk for ovarian cancer as well.<\/p>\n

3. It offers cardiovascular benefits.<\/h3>\n

Another health benefit of having adequate vitamin D levels in your body is heart health protection. A 2017 meta-analysis<\/a> of 32 studies published in the American Journal of Clinical Nutrition <\/i>found that higher serum vitamin D levels were inversely associated with total cardiovascular disease events, like heart attacks and strokes, and, ultimately, mortality from them.<\/p>\n

A 2018 review<\/a> and meta-analysis published in Nutrients<\/i> also examined the relationship between vitamin D levels and ischemic stroke risk. The authors found that having lower vitamin D status was associated with a higher risk for ischemic stroke.<\/p>\n

4. It may be protective against autoimmune diseases.<\/h3>\n

An autoimmune disease is a condition in which your immune system mistakenly attacks your body. A 2017 study<\/a> published in Neurology <\/i>found that vitamin D deficiency is a risk factor for multiple sclerosis, a physically and mentally progressive autoimmune disease in which the insulating covers of nerve cells in the brain and spinal cord are damaged. In a broader review from 2018<\/a>, researchers concluded that vitamin D deficiency is prevalent in a number of autoimmune diseases. As such, vitamin D supplementation has been linked to the prevention of autoimmune diseases.<\/p>\n

5. It may help prevent and manage type 2 diabetes.<\/h3>\n

Having adequate vitamin D levels appears to be helpful in the management of type 2 diabetes as well. In a 2018 review<\/a> published in Nutrients<\/i>, researchers found that when serum vitamin D levels among people with type 2 diabetes were increased, their insulin resistance was reduced.<\/p>\n

In another 2018 meta-analysis<\/a>, researchers found that low vitamin D levels were associated with an increased risk for hyperglycemia \u2014 or uncontrolled high blood sugar \u2014 in both people who did and did not have diabetes.<\/p>\n\n \n

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6. It may protect your body against viral infections.<\/h3>\n

Vitamin D has recently been highlighted as a key player in the strength of our immune systems, especially when it comes to fighting off viral infections. <\/span><\/p>\n

In a <\/span>2020 study<\/span><\/a>, researchers examined the mean vitamin D levels among populations from 20 European countries as well as the documented cases of COVID-19 and the subsequent mortality rates from the virus. They found a potential correlation between lower vitamin D levels and higher incidence of COVID-19 risk and mortality. <\/span><\/p>\n

An additional Spanish study on COVID-19 outcomes <\/span>used vitamin D<\/span><\/a> to treat patients already hospitalized for the disease. A total of 76 patients in the study were given the immunosuppressant hydroxychloroquine and the antibiotic azithromycin. Fifty of them were also given oral calcifediol (a vitamin D3 analog) daily, while 26 were not.<\/span><\/p>\n

Of the 50 patients treated with calcifediol, only one required admission to the ICU (2%), while of 26 untreated patients, 13 required ICU admission (50%), and two died (8%). Although this was a small sampling of participants, the results were statistically significant when it came to reducing the severity of the disease.<\/span><\/p>\n

These studies suggest that both screening for vitamin D deficiency and possibly using it as a supplementary treatment could play an important role in pandemic-related public health. <\/span><\/p>\n

Other studies tell us that addressing vitamin D deficiency could also help protect against other viral illnesses, like <\/span>seasonal influenza<\/span><\/a>. <\/span><\/p>\n

7. It may help prevent or treat depression and anxiety.<\/strong><\/h3>\n

Vitamin D deficiency, or low vitamin D status, has been linked to depression and other mood disorders. Various parts of the brain, including the <\/span>hippocampus<\/span><\/a> (an alteration which has been <\/span>linked to depression<\/span><\/a>), have vitamin D receptors in neurons and glial cells (which are important parts of the nervous system).<\/span><\/p>\n

One <\/span>2017 study<\/span><\/a> on women with depression, anxiety, and type 2 diabetes found that there was a significant increase in mental health status after vitamin D supplementation. The women all had vitamin D levels below the recommended amount of 32 ng\/ml and were given 50,000 IU of vitamin D2 once a week for six months. In some cases, perceived depression was halved from the beginning to the end of the study.<\/span><\/p>\n

A 2020 review of 61 articles on <\/span>vitamin D and depression<\/span><\/a> also concluded that there is a biological link between the two. The review attributed this connection to ways in which vitamin D works with the body\u2019s biological functions, especially the immune system and brain. And the best improvements are seen in clinical cases of depression where multiple symptoms are present.<\/span><\/p>\n

Vitamin D Deficiency<\/h2>\n
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Vitamin D deficiency \u2014 or not having enough vitamin D circulating in your blood \u2014 is a very common condition. Subclinical vitamin D deficiency is <\/b>widely prevalent<\/b><\/a> in almost every nation, impacting up to a billion people worldwide.<\/b><\/p>\n

With chronic and\/or severe vitamin D deficiency, a decline in intestinal absorption<\/a> of calcium and phosphorus leads to hypocalcemia or a deficiency of calcium in the blood. Inadequate calcium can lead to secondary hyperparathyroidism, a condition in which your parathyroid glands make too much parathyroid hormone. This can result in accelerated bone demineralization, which can eventually turn into osteomalacia (softened bones) and osteoporosis (porous bones) in adults as well as rickets (softened and weakened bones) in children. Whew \u2014 a lot of hard words there. If you\u2019re still reading this, you deserve a medal!<\/p>\n

Vitamin D deficiency is diagnosed when the amount of vitamin D circulating in your bloodstream is lower than recommended levels for optimal health. So what should your levels be? That\u2019s where the controversy begins! And it turns out there are many credible researchers coming to very different conclusions.<\/p>\n

Guidelines for Vitamin D Levels<\/h3>\n

In 2011, the widely respected Endocrine Society issued a report which concluded<\/a>: \u201cBased on all the evidence, at a minimum, we recommend vitamin D levels of 30 ng\/mL, and because of the vagaries of some of the assays, to guarantee sufficiency, we recommend between 40 and 60 ng\/mL for both children and adults.\u201d <\/i>(That one is pronounced \u201cnanograms per milliliter.\u201d)<\/p>\n

However, writing for the New England Journal of Medicine<\/i> in 2016, several leading epidemiologists and endocrinologists stated<\/a> that in their opinion, we are over-screening for vitamin D deficiency and unnecessarily treating individuals who are actually fine. Based on their analysis, a more appropriate cutoff for vitamin D deficiency would be much lower \u2014 12.5 ng\/mL.<\/p>\n

This leads to another question, which is maybe what we should have been asking all along. What is optimal? Apparently, most people can survive with blood levels as low as 12.5 ng\/mL. But is that what\u2019s best?<\/p>\n

Here too, there is controversy. But a growing body of research is <\/b>finding<\/b><\/a> that the optimal blood levels of vitamin D are above 30 ng\/mL, while other studies <\/b>conclude<\/b><\/a> that 40-60 ng\/mL is the preferred range. <\/b><\/p>\n

Can You Get Too Much Vitamin D?<\/h2>\n
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The short answer is, yes. Remember that vitamin D is a fat-soluble vitamin, which means that it accumulates in your body and is stored over time \u2014 unlike water-soluble vitamins that are just peed away if you consume more than you need. So vitamin D can build up in your body, and side effects and toxicity are possible if your blood levels get too high.<\/p>\n

Vitamin D helps your body absorb calcium from the food you eat. But too much of it<\/a> can cause your body to store up excess calcium in your blood. Symptoms of hypercalcemia, or high blood calcium levels, include digestive distress, fatigue, and bone loss. And a 2019 study concluded<\/a> that excessive use of vitamin D could cause kidney damage in people who are not deficient in the vitamin.<\/p>\n

It\u2019s important to clarify that excess vitamin D levels result from oral intake only; you can\u2019t overdose on the vitamin D your body makes from sunlight. Your body is remarkably good at regulating how much naturally produced vitamin D is made and stored.<\/p>\n

Vitamin D Toxicity?<\/h3>\n

Blood levels of 100 ng\/mL are considered<\/a> to be the upper limit of a normal or healthy range by the Institute of Medicine, the Endocrine Society, and many reference laboratories. But it turns out, it\u2019s not easy to get your vitamin D levels that high. In one major study involving more than 17,000 healthy adult volunteers, vitamin D supplements as high as 20,000 international units (IU) per day didn\u2019t get participant\u2019s blood levels above 100 ng\/mL and also didn\u2019t lead to any evident toxic effects.<\/p>\n

A 2015 study looked at data<\/a> from more than 20,000 people over the course of 10 years. The researchers found that only 37 people had levels above 100 ng\/ml.<\/p>\n

However, while 100 ng\/mL might be a rarely reached upper limit, there are studies that have shown<\/a> a small level of increased mortality with blood levels of 50 ng\/mL or higher. While the evidence is a bit murky, it does seem that vitamin D toxicity is rare, and that somewhere in the 30-60 ng\/mL range could be the \u201csweet spot\u201d for most people.<\/p>\n

Getting Your Levels Checked<\/h2>\n

There are certain individual factors<\/a> that can increase your risk of being vitamin D deficient. Some of these include:<\/p>\n