Vitamin D deficiency. What are the risks? How can you determine if you’re deficient? And what are the benefits of raising your vitamin D level?
Vitamin D deficiency is incredibly common around the world, but many mistakenly believe they aren’t at risk because they consume vitamin D-fortified foods, such as milk. Few foods have therapeutic levels of vitamin D naturally, and even fortified foods do not contain enough vitamin D to support your health needs.
Despite its name, vitamin D is actually a steroid hormone that you obtain primarily through sun exposure, not via your diet. Since most dermatologists and other doctors recommend avoiding the sun and using sunscreen before venturing outdoors, vitamin D deficiency has reached truly epidemic proportions around the world.
Unfortunately, while the justification for sun avoidance is that it may reduce your risk of skin cancer, by avoiding sun exposure you risk vitamin D deficiency, which in turn raises your risk for many cancers — not only internal ones but also skin cancer, as well as a whole host of chronic diseases.
Considering the importance of vitamin D for disease prevention, strict sun avoidance is likely doing far more harm than good. The major problem with sun exposure is burning, not overall exposure. And, the easily treatable forms of skin cancer — squamous and basal cell carcinomas — are the ones most likely to form.
Definition of Vitamin D Deficiency
According to research published in June 2018, an estimated 40 percent of Americans are profoundly vitamin D deficient, defined as having a serum (blood) level of vitamin D below 20 ng/mL (50 nmol/L). Sufficiency is defined as having a level of 20 ng/mL or higher.
Calling someone with a vitamin D level of less than 20 ng/ml vitamin D deficient is like calling someone over 400 pounds simply overweight; in both cases a grossly serious understatement.
Seventy-five percent of American adults and teens are deficient in vitamin D when a sufficiency level of 30 ng/mL is used. If the sufficiency cutoff were to be moved to 40 to 60 ng/mL, sufficiency rates in the U.S. would likely be in the high 90 percent bracket.
It’s important to realize that 20 ng/mL has repeatedly been shown to be grossly insufficient for good health and disease prevention and, really, anything below 40 ng/mL (100 nmol/L) should be suspect. For example, research has shown that once you reach a minimum serum vitamin D level of 40 ng/mL, your risk for cancer diminishes by 67 percent, compared to having a level of 20 ng/mL or less.
Most cancers occur in people with a vitamin D blood level between 10 and 40 ng/mL (25 to 100 nmol/L), and the optimal level for cancer protection now appears to be between 60 and 80 ng/mL (150 to 200 nmol/L).
Several studies also show that these higher vitamin D levels are protective against breast cancer specifically. Importantly, a 2005 study showed women with vitamin D levels above 60 ng/mL have an 83 percent lower risk of breast cancer than those below 20 ng/mL! I cannot think of any other strategy that can offer that kind of risk reduction.
More recently, a pooled analysis published in June 2018 of two randomized trials and a prospective cohort study came to a near-identical conclusion. The objective was to assess whether there are any benefits to having a vitamin D level above 40 ng/mL, as most studies do not venture into these higher levels.
Indeed, mirroring the 2005 findings, women with vitamin D levels at or above 60 ng/mL had an 82 percent lower incidence rate of breast cancer than those with levels of 20 ng/mL or less. Published research by GrassrootsHealth reveals as much as 80 percent of all breast cancer incidence could be prevented simply by optimizing vitamin D and nothing else.
Top 5 Signs of Vitamin D Deficiency
The only way to definitively identify vitamin D deficiency is via blood testing. However, there are some general signs and symptoms to be aware of as well. If any of the following apply to you, you should get your vitamin D levels tested sooner rather than later, and take proactive steps to boost your level into the 60 to 80 ng/mL range:
1. Ongoing musculoskeletal pain and achy bones — According to vitamin D researcher Dr. Michael Holick, many who see their doctor for aches and pains, especially in combination with fatigue, end up being misdiagnosed as having fibromyalgia or chronic fatigue syndrome.
“Many of these symptoms are classic signs of vitamin D deficiency osteomalacia, which is different from the vitamin D deficiency that causes osteoporosis in adults,” Holick says. “What’s happening is that the vitamin D deficiency causes a defect in putting calcium into the collagen matrix into your skeleton. As a result, you have throbbing, aching bone pain.”7
2. Frequent illness/infections — Vitamin D regulates the expression of genes that influence your immune system to attack and destroy bacteria and viruses, so frequent illness and infections of all kinds, including colds and flu, is a tip off that your immune function is subpar, which likely means you’re low on vitamin D.
3. Neurological symptoms — This includes depression, “feeling blue, cognitive impairment, headaches, and migraines. In 2006, scientists evaluated the effects of vitamin D on the mental health of 80 elderly patients and found those with the lowest levels of vitamin D were 11 times more prone to be depressed than those who received healthy doses.
The same study also found low vitamin D was linked to poor cognitive performance. Several other studies have also linked vitamin D deficiency with poor mental function, confusion, forgetfulness, and difficulty concentrating. Headaches and migraines are also associated with low vitamin D.
4. Fatigue and daytime sleepiness — Studies have linked low vitamin D to persistent fatigue. In one case, a woman struggling with chronic fatigue, daytime sleepiness (hypersomnia), low back pain and daily headaches were found to have a vitamin D level below 6 ng/mL.
Her symptoms resolved once she raised it to 39 ng/mL. Another study found women with vitamin D levels below 29 ng/mL were more likely to complain of fatigue than those with levels above 30 ng/mL.
5. Head sweating — According to Holick, a classic sign of vitamin D deficiency is a sweaty head. In fact, physicians used to ask new mothers about head sweating in their newborns for this very reason. Excessive sweating in newborns due to neuromuscular irritability is still described as a common, early symptom of vitamin D deficiency.