And if you ever get achy bones, infections, headaches, migraines, forgetfulness or head sweating - please get this checked.
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. However, 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.
Definition of Vitamin D Deficiency
According to research published in June 2018, an estimated 40% 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% 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%, 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% 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.
“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 told me. “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.”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 tipoff that your immune function is subpar, which likely means you’re low on vitamin D.
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.
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.
Top 5 Risk Factors for Vitamin D Deficiency
Several factors will influence your risk for vitamin D deficiency, including the following:- Rarely spending time outdoors and/or always wearing sunscreen — Researchers have noted that vitamin D deficiency is prevalent in adults of all ages who always wear sun protection (which blocks vitamin D production) or limit their outdoor activities. The ideal time for sun exposure is between 10 a.m. and 2 p.m., when the UVB rays are present.
- Darker skin — Your skin pigment acts as a natural sunscreen, so the more pigment you have, the more time you'll need to spend in the sun to make adequate amounts of vitamin D. If you have dark skin, you may need as much as 10 times more sun exposure to produce the same amount of vitamin D as a person with pale skin.
- Being 50 or older — As you get older, your skin doesn’t make as much vitamin D in response to sun exposure. At the same time, your kidneys become less efficient at converting vitamin D into its active form. Older adults also tend to spend more time indoors (i.e., getting even less sun exposure and therefore vitamin D).
- Obesity — Because vitamin D is fat-soluble, body fat acts as a “sink” by collecting it. If you’re overweight or obese, you’re therefore likely going to need more vitamin D than a slimmer person. In one recent study, vitamin D deficiency was three times more prevalent in obese individuals.
- Gastrointestinal problems — Since vitamin D is fat-soluble, which means if you have a gastrointestinal condition that affects your ability to absorb fat, you may have lower absorption of fat-soluble vitamins like vitamin D as well. This includes gut conditions like Crohn’s, celiac and nonceliac gluten sensitivity and inflammatory bowel disease.
Health Benefits of Vitamin D Optimization
Optimizing your vitamin D levels has been shown to have a powerful effect on health, helping protect against a wide variety of diseases. Among them:- Dry eye syndromes
- Macular degeneration, which is the No. 1 cause of blindness in the elderly.
- Autoimmune diseases — Vitamin D is a potent immune modulator, making it very important for the prevention of autoimmune diseases such as multiple sclerosis, inflammatory bowel disease and psoriasis, just to name a few.
- Gastrointestinal diseases — Dysbiosis of your gut microbiome, inflammatory bowel disease and colitis are all disorders connected to vitamin D deficiency.
- Infectious diseases, including influenza and HIV
- Inflammatory rheumatic diseases such as rheumatoid arthritis — A 2020 study showed that “vitamin D supplementation seemed to be an effective intervention for patients with rheumatoid arthritis. Different doses of vitamin D and durations of intervention produce different effects.”
- Osteoporosis and hip fractures
- Cardiovascular disease — Vitamin D is very important for reducing hypertension, atherosclerotic heart disease, heart attack and stroke, as it plays a vital role in protecting and repairing damage to your endothelium.It also helps trigger production of nitric oxide — which improves blood flow and prevents blood clot formation — and significantly reduces oxidative stress in your vascular system, all of which are important to help prevent the development and/or progression of cardiovascular disease.According to Holick, vitamin D deficiency increases your risk of heart attack by 50%, and if you have a heart attack and you’re vitamin D deficient, your risk of dying from that heart attack is virtually guaranteed.Indeed, a Norwegian study published in The Journal of Clinical Endocrinology and Metabolism found “a normal intake of vitamin D” significantly reduces your risk of death if you have cardiovascular disease.
- Neurological diseases such as Alzheimer’s disease and epilepsy — In one study, epileptics given a one-time megadose of vitamin D3, ranging from 40,000 IUs all the way up to 200,000 IUs, followed by a daily dose of 2,000 to 2,600 IUs a day for three months to bring each individual’s vitamin D status to at least 30 ng/mL, resulted in significant improvements.Ten out of 13 had a decrease in the number of seizures, five of whom experienced more than a 50% reduction. Overall, the group had a 40% reduction in the number of seizures.
- Lupus — According to researchers in Cairo, most patients with systemic lupus erythematosus have some level of vitamin D deficiency, defined as a level of 10 ng/mL or less, or insufficiency, a level between 10 and 30 ng/mL.
- Obstructive sleep apnea — In one study, 98% of patients with sleep apnea had vitamin D deficiency, and the more severe the sleep apnea, the more severe the deficiency.
- Bone health, falls and fractures — A 2006 review looking at vitamin D intakes and health outcomes such as bone mineral density, dental health, risk of falls, fractures and colorectal cancer, found “the most advantageous serum concentrations of 25(OH)D begin at 30 ng/mL, and the best are between 36 to 40 ng/mL.”
- Obesity and diabetes — Research has shown vitamin D supplementation (4,000 IUs/day) combined with resistance training helps decrease your waist-to-hip ratio, a measurement that is far better at determining your risk for Type 2 diabetes and heart disease than body mass index.
- Type 1 diabetes — Data from GrassrootsHealth’s D*Action project to prevent Type 1 diabetes suggests maintaining a vitamin D level between 40 and 60 ng/mL (100 to 150 nmol/L) may prevent Type 1 diabetes, and stop the progression of the disease, which is a growing problem.
- Neurodegenerative diseases, including Alzheimer’s, Parkinson’s and multiple sclerosis (MS) — Research shows MS patients with higher levels of vitamin D tend to experience less disabling symptoms. Vitamin D deficiency is also common among patients with Parkinson’s and seniors with severe vitamin D deficiency may raise their risk for dementia by 125%.
- DNA repair and metabolic processes — One of Holick’s studies showed healthy volunteers taking 2,000 IUs of vitamin D per day for a few months upregulated 291 different genes that control up to 80 different metabolic processes, including DNA repair and autoxidation (oxidation that occurs in the presence of oxygen and/or UV radiation, which has implications for aging and cancer).
- Preterm birth — A level of 40 ng/mL has also been shown to offer powerful protection against preterm birth if you’re pregnant. Women with a vitamin D level of at least 40 ng/mL may lower their risk of preterm birth by as much as 62%, compared to having a level of just 20 ng/mL. Women with a history of preterm birth gain even greater protection — an 80% reduction — when raising their vitamin D level above 40 ng/mL.
- Pregnancy complications — Having a vitamin D level above 40 ng/mL also protects the mother by reducing her risk of preeclampsia, gestational diabetes and prenatal infections by approximately 50%.
- All-cause mortality — Studies have also linked higher vitamin D levels with lowered mortality from all causes.