If you live somewhere that morphs into an arctic tundra for a chunk of the year, you’ve probably been told you’re missing out on some valuable vitamin D. In fact, low vitamin D is quite common. But it can be hard to know whether you’re getting enough, and the signs are tricky to spot. So, we had experts break down signs of low vitamin D and solutions for getting more of it all year long.

What is vitamin D

Vitamin D, is a fat-soluble nutrient, according to the National Institutes of Health Office of Dietary Supplements (ODS). This means that it is stored in fat cells via absorption from your diet or generated via sunlight on your skin, according to the ODS. Fat cells house the vitamin D you absorb from your diet until it’s time to send them to the liver and kidney to turn it into the usable hormone that the body sends around the body for important processes, the ODS says. When you absorb sunlight on your skin, cholesterol compounds in your skin chemically react on a molecular level to create a usable form of vitamin D, which is then sent elsewhere, Keeley Berry, BS, molecular biologist, biomedical scientist, and nutritional supplement chemist for Better You says. 

But what does it do? The answer is a lot. Remember those got milk posters from the ’90s? (OK, maybe I am dating myself a bit) they always encouraged you to drink milk for calcium and strong bones. Well, the thing that really ensures strong bones is vitamin D. This is because your body can only absorb calcium properly if vitamin D is present, according to the Mayo Clinic. It also plays an essential role in many other bodily functions, including cardiovascular health, neurological, and immune function, Betsy Fears RDN, CD, a registered dietitian at the medical nutrition and physical therapy practice RET Physical Therapy Group says. 

Everybody is different, and your vitamin D needs change based on your age and body size. The daily amount of vitamin D, according to the ODS, is 400 international units (IU) for children up to age 12 months, 600 IU for people ages 1 to 70 years, and 800 IU for people over 70 years. Fears recommends that individuals get approximately 10-30 minutes of sun exposure to the face, legs, and arms at midday to help their body synthesize vitamin D. 

Signs you’re not getting enough vitamin D

Signs of vitamin D deficiency include tiredness, low mood, poor bone and teeth health, hair loss, low immunity, frequent colds, and infections, according to Fears and Berry. The thing is, these are also signs of common health conditions. They’re not exclusive to a vitamin D deficiency, Berry says, so it’s easy to be unaware of any shortage.

Still, if other areas of your health needs are met, you should chat with your doctor about your concerns, Fears says. However, there’s no need to panic. Signs like low mood, fatigue, colds, and bone brittleness can indicate that adding more vitamin D to your diet could help your overall health. These symptoms are not a guarantee that you’re moments from developing serious osteoporosis, Fears says. 

So how can you get more 

There are three ways to get more vitamin D, according to the ODS: through your diet, sunlight, or supplementation. Great food sources include animal products like salmon, sardines, mackerel, red meat, liver, egg yolks, and foods like milk and breakfast cereals that say they are fortified with vitamin D,” Berry explains. “The number of people choosing to remove animal products from their diet is increasing, and this can limit the amount of vitamin D you can get from food.” 

Supplementation is also an option, but you should have your vitamin D levels tested by a healthcare provider first, Fears says. Why? There is such a thing as having too much vitamin D, and because it is fat-soluble, you don’t pee out extra amounts of the nutrient the way you expel extra vitamin C via your urine.

The good news is that the amount of vitamin D you get from food and sunlight are unlikely to reach a toxic level, according to the Harvard School of Public Health. They go on to say that you shouldn’t take more than 4,000 IU unless monitored under the supervision of your doctor. Symptoms of too much vitamin D include weight loss, anorexia, irregular heartbeat, excess calcium levels that can damage kidneys, blood vessels, and the heart. 

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