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.
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
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.
It's important to realise 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.
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 chronic fatigue syndrome.
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.
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, low back pain and daily headaches was 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.16
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 — 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 Optimisation
Optimising 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. |
Infectious diseases, including influenza and HIV. |
Inflammatory rheumatic diseases such as rheumatoid arthritis. |
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. 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 which experienced more than a 50 percent reduction. Overall, the group had a 40 percent 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. |
Check Your Vitamin D Level Twice a Year
Regular, sensible sun exposure is the best way to optimise your vitamin D status, but many will need to take an oral vitamin D3 supplement, especially during winter months.
The only way to gauge whether you might need to supplement, and how much, is to get your level tested, ideally twice a year, in the early spring, after the winter, and early fall when you level is at its peak and low point. This is particularly important if you're pregnant or planning a pregnancy, or if you have cancer.
Again, the level you're aiming for is between 60 and 80 ng/mL, with 40 ng/mL being the low cutoff point for sufficiency to prevent a wide range of diseases, including cancer.