A Shocking 1 In 3 Deficient In Vitamin D & At Risk for Cancer—Are You One of Them?

Wednesday May 22 | BY |
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Vitamin D

If you’re not getting enough sun exposure, you could be deficient in vitamin D,
which can increase your risk of cancer and heart disease.

We’ve heard a lot about how vitamin D is good for us, but the studies on how much we’re getting have been mixed. Now, new research published in PLOS One indicates that about one in three of us are deficient in the nutrient—and that’s using the newer guidelines which say we need 20 ng/mL (nanograms per milileter of blood) a day. Older guidelines, preferred by many doctors, set that limit at 30/ng/ML a day. If we go by those standards, about 70 percent of us are deficient.

This is not good news, especially considering a vitamin D deficiency can lead to a number of health problems, including cancer. Could you be one of those at risk?

What is Vitamin D?

Vitamin D is one of the fat-soluble vitamins that encourages the absorption and metabolism of calcium and phosporous. The body makes the vitamin when the skin is exposed directly to the sun, which has given the nutrient the name “the sunshine vitamin.” Few foods contain vitamin D, but you can find it in:

  • Dairy products (cheese, cream, butter, fortified milk)
  • Oysters
  • Fatty fish (tuna, salmon, mackerel)
  • Other fortified foods, like breakfast cereals and soy milk

According to the National Institutes of Health, older children and adults age 9 to 70 years old should be getting 600 IUs (15 mcg) a day, while adults over 70 years old should be getting 800 IUs (20 mcg/day) a day.

We’re Not Getting Enough

This recent study isn’t the only one to show that many Americans are not getting enough vitamin D. In fact, there are a number of studies raising warning flags. Here are just a few:

  • Data collected from the National Health and Nutrition Examination Survey (NHANES) found that 9 percent (7.6 million) of children across the U.S. were vitamin D deficient (defined as less than 15 ng/mL of blood). Another 61 percent (50.8 million) were vitamin D “insufficient” (defined as 15 to 29 ng/mL). “We expected the prevalence of vitamin D deficiency would be high, but the magnitude of the problem nationwide was shocking,” said lead author Juhi Kumar.
  • A 2013 study published in PLOS Medicine found that a 10 percent rise in Body Mass Index (BMI) was linked to a four percent drop in concentrations of vitamin D in the body. Overall, findings suggested that a higher BMI leads to a lower level of vitamin D.
  • According to the Harvard School of Public Health, if you live north of the line connecting San Francisco to Philadelphia, odds are that you don’t get enough vitamin D. The same holds true if you don’t get outside for at least 15 minutes a day—without sunscreen.
  • A 2010 study found that vitamin D deficiency and insufficiency are globally still very common especially in risk groups such as young children, pregnant women, the elderly, and immigrants.
  • A 2009 study published in the Archives of Internal Medicine reported that three-quarters of U.S. teens and adults are deficient in vitamin D (defined as less than 30 ng/mL), marking a dramatic increase in the amount of vitamin D deficiency in the U.S. between 1994 and 2004. “We were anticipating that there would be some decline in overall vitamin D levels,” said study co-author Adit Ginde, “but the magnitude of the decline in a relatively short time period was surprising.”

There is some debate about these studies. The Institute of Medicine (IOM), for instance, defined insufficiency as less than 11 ng/mL, rather than 30 ng/mL. (Though a later table distributed by the IOM in 2010 noted that levels less than 20 ng/mL were generally considered inadequate for bone and overall health.)

But even at that low level (below 12 ng/mL), which many doctors now believe is not enough for good health, 10 percent of Americans would still be deficient.

In 2012, after the IOM stated that 20 ng/mL were sufficient (rather than the older 30 ng/mL), the study published in PLOS One stated that 70 percent of Americans would be considered as sufficient, but still a third of us would have insufficient vitamin D levels.

What Are the Dangers?

Unfortunately, this isn’t a deficiency we can take lightly. Many studies have linked an insufficiency of vitamin D with an increased risk for disease. Here are a few of them:

  • More Colds and Flu: A 2009 study found that people with low levels of vitamin D were more likely to catch cold and flu than those with adequate amounts. People with the worst deficiencies were 36 percent more likely to suffer respiratory infections. Asthmatics with vitamin D deficiency were five times more likely to get sick. More than half the people in the study were below the 30 ng/mL level.
  • Suicide: A study of active duty military personnel found that overall, low vitamin D status was common in service embers, and that the lowest levels were associated with an increased risk for suicide.
  • Heart Attack: A 2012 study found that low levels of vitamin D may increase the risk of heart attack and early death. Researchers studied over 10,000 individuals, and found the lowest levels were linked with a 64 percent higher risk of heart attack, and a 57 percent higher risk of death.
  • Colon Cancer: Several studies have indicated that a lower level of vitamin D is associated with a higher risk of colon cancer. The VITAL trial (Vitamin D and Omega-3 Trial) is currently underway to determine if higher doses of vitamin D can lower risk for cancer, heart disease, stroke, and other chronic illnesses.
  • Multiple Sclerosis (MS): A 2006 study found that among white men and women, those with the highest vitamin D blood levels had a 62 percent lower risk of developing MS than those with the lowest levels.
  • Asthma: Children with low levels of vitamin D were significantly more likely to have been hospitalized for asthma is the previous year, and were more likely to have several markers of allergy, including dust-mite sensitivity.
  • Type 1 Diabetes: A 30-year study following more than 10,000 children from birth, found that children who regularly received vitamin D supplements during infancy had a nearly 90 percent lower risk of developing type 1 diabetes than those who didn’t.
  • Rheumatoid Arthritis: A 2004 study found that women with the highest levels of vitamin D were 30 percent less likely to develop rheumatoid arthritis than those with the lowest levels of the vitamin. Dietary intake of the vitamin reduced risk by 28 percent, while supplemental intake reduced risk by 34 percent.
  • Premature Death: A report in the Archives of Internal Medicine suggests that taking vitamin D supplements (between 400 and 800 IU a day) may reduce overall mortality rates.

How Much Should You Take?

As to making a choice for your own intake of vitamin D, your best bet is to get a blood test to see where you are today. What is called the “25-hydroxy vitamin D” test is considered the most accurate way to measure your vitamin D levels. All that is required is a simple blood test. You can request this from your doctor, or even get one online. Try Direct Labs or Personalabs.com.

The following may be more at risk for low vitamin D levels:

  • Those living in northern climates or who are exposed to the sun less often, particularly during the winter months.
  • Those on a vegetarian or vegan diet, who consume fewer eggs, fatty fish, fortified milk, soy, or other food sources of vitamin D.
  • Women with arthritis, diabetes, and other chronic conditions are more susceptible to drops in vitamin D levels during the winter months.
  • People with osteoarthritis or conditions like celiac disease or Crohn’s disease, which impairs the ability to absorb vitamin D, may need supplements.
  • Those who are dark-skinned, overweight, or middle-aged or older are at an increased risk of deficiency.

Beyond the IOM’s recommendations (listed at the beginning of this article), other experts recommend more, up to 2,000–4,000 IUs per day. Our own Dr. Williams recommends 39 to 70 ng/mL for overall healthy blood levels. (Read his recommendations on a former post.) He also talks about the difference between Vitamin D2 and D3, in that D2 is considered a vegetarian source of the nutrient, but may not be absorbed as well as D3. Kevin’s interview with Brenda Davis also covers this topic.

The National Institutes of Health states that the safe upper limits are:

  • 1,000 to 1,500 IU/day for infants
  • 2,500 to 3,000 IU/day for children 1-8 years
  • 4,000 IU/day for children 9 years and older, adults, and pregnant and breastfeeding teens and women

Do you have a vitamin D deficiency? Please share your story.

* * *

“Wellness Facts,” University of California, Berkeley, Wellness Letter, March 2013.

“What is Vitamin D? What Are the Benefits of Vitamin D?” August 24, 2009, http://www.medicalnewstoday.com/articles/161618.php.

University College London (2013, February 5). Obesity leads to vitamin D deficiency, study suggests. ScienceDaily. Retrieved April 19, 2013, from http://www.sciencedaily.com­ /releases/2013/02/130205173724.htm.

“Vitamin D Deficiency: A Global Concern,” Harvard School of Public Health, http://www.hsph.harvard.edu/nutritionsource/vitamin-d/.

Lips P, “Worldwide status of vitamin D nutrition,” J Steroid Biochem Mol Biol. 2010 Jul; 121(1-2):297-300, http://www.ncbi.nlm.nih.gov/pubmed/20197091.

Jordan Lite, “Vitamin D deficiency soars in the U.S., study says,” Scientific American, March 23, 2009, http://www.scientificamerican.com/article.cfm?id=vitamin-d-deficiency-united-states.

“Vitamin D Fact Sheet,” Office of Dietary Supplements, National Institutes of Health, June 24, 2011, http://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/.

Loyola University Health System (2012, October 24). Nearly 80 million Americans won’t need vitamin D supplements under new guidelines. ScienceDaily. Retrieved April 19, 2013, from http://www.sciencedaily.com­ /releases/2012/10/121024175229.htm.

Jordan Lite, “Vitamin D deficiency linked to more colds and flu,” Scientific American, February 23, 2009, http://www.scientificamerican.com/blog/post.cfm?id=vitamin-d-deficiency-linked-to-more-2009-02-23.

John C. Umhau, et al., “Low Vitamin D Status and Suicide: A Case-Control Study of Active Duty Military Service Members,” PLOS ONE, January 4, 2013, http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0051543.

Glynn, Sarah. “Low Levels of Vitamin D Linked To Heart Disease.” Medical News Today. MediLexicon, Intl., 24 Sep. 2012. Web. 19 Apr. 2013. http://www.medicalnewstoday.com/articles/250628.php

“Vitamin D and Health,” Harvard School of Public Health, http://www.hsph.harvard.edu/nutritionsource/vitamin-d/.

Yin L., et al., “Meta-analysis: longitudinal studies of serum vitamin D and colorectal cancer risk,” Ailment Pharmacol Ther. 2009 Jul 1; 30(2): 113-25, http://www.ncbi.nlm.nih.gov/pubmed/19392870?dopt=Citation.

Munger KL, Levin LI, Hollis BW, Howard NS, Ascherio A. Serum 25-hydroxyvitamin D levels and risk of multiple sclerosis. JAMA. 2006; 296:2832-8.

Gillespie KM. Type 1 diabetes: pathogenesis and prevention. CMAJ. 2006; 175:165-70. http://www.ncbi.nlm.nih.gov/pubmed/16847277?dopt=Citation.

“Vitamin D Levels Linked To Asthma Severity.” Medical News Today. MediLexicon, Intl., 24 Apr. 2009. Web. 19 Apr. 2013. http://www.medicalnewstoday.com/releases/147265.php

“High vitamin D intake linked to reduced risk of rheumatoid arthritis.” Medical News Today. MediLexicon, Intl., 12 Jan. 2004. Web. 19 Apr. 2013.

Colleen M. Story

Colleen M. Story

Colleen M. Story, a northwest-based writer, editor, and ghostwriter, has been creating non-fiction materials for individuals, corporations, and commercial magazines for over 17 years. She specializes in the health and wellness field, where she writes and ghostwrites books, e-books, blogs, magazine articles, and more.

Colleen is the founder of Writing and Wellness. Her fantasy novel, “Rise of the Sidenah,” was released with Jupiter Gardens Press in September 2015. Her literary novel, “Loreena’s Gift,” is forthcoming in spring 2016 from Dzanc Books. She lives in Idaho. www.colleenmstory.com


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  1. Deane Alban says:

    I live in southern Arizona where we get 350 days of sunshine per year. The sun here is intense and I walk, hike, or bike ride daily. Imagine my shock when I had blood work done and turned out to be extremely low in vitamin D! If you spend time outdoors with sunscreen, it basically doesn’t count – you won’t manufacture vitamin D. Now I take a supplement and get 20 minutes of sun on a large area of my body – usually my legs – a few times a week and my levels are fine.

    A cool rule of thumb I’ve heard is that if you stand in the sun and your shadow is longer than you are tall, the sun is not strong enough to make vitamin D!

    I write about brain health, so if I may add a few more benefits of vitamin D: studies have shown it can lift your mood, banish depression, improve memory, and increase problem-solving ability. Inadequate levels may contribute to the depression many people feel in the winter.

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