Want to stay limber throughout your life? Make sure you’re getting enough vitamin D. The nutrient helps regulate the amount of calcium and phosphate in your body—two things that are crucial for bone and muscle health.
Also known as the “sunshine vitamin,” vitamin D is naturally produced by your body when you’re exposed to sunlight. It can also be found in certain foods and in supplement form.
Unfortunately, it can be difficult to get enough of it. Vitamin D deficiency is common, especially with so many of us stuck indoors these days. In Australia around 30% of adults have a mild, moderate or severe deficiency of vitamin D, putting them at risk for various health problems like brittle bone and heart disease.
Before you run off to the pharmacy to pick up a vitamin D supplement, check out our guide to vitamin D below. Learn about the health benefits of vitamin D and how much you actually need.
What are the benefits of vitamin D?
Vitamin D helps your body function in multiple ways. It’s important for...
✔️ Bone health
Vitamin D assists your body in absorbing calcium, which is one of the main building blocks of your bones. When your body gets enough calcium and is able to process it properly, you’re less likely to develop osteoporosis, a disease that makes bones brittle and more susceptible to fractures, according to the Cleveland Clinic.
✔️ Muscle health
Research shows that 30% of phosphate absorption in the gut is dependent on vitamin D (phosphate allows you to contract your muscles). If it’s out of whack, you may experience muscle cramping, weakness, and pain.
✔️ Cognitive function
Several studies have shown that vitamin D helps with brain function by strengthening neural circuits. Low vitamin D levels have been found in those living with Alzheimer’s, multiple sclerosis (MS), and Parkinson’s, but it is currently unclear whether or not vitamin D can help treat or prevent these neurological diseases.
✔️ Mental health
Low vitamin D levels have been linked to increased incidences of depression, according to recent research. This doesn’t necessarily mean that vitamin D deficiency causes depression but it’s clear that vitamin D supports brain health, in general.
✔️ Immune system function
Vitamin D helps your immune system fend off viruses and bacteria. A 2017 analysis found that vitamin D reduced the risk of acute respiratory infection when taken daily or weekly in supplement form. Researchers are now studying how vitamin D impacts COVID-19 outcomes.
✔️ Heart health
According to a 2019 review, vitamin D deficiency may raise blood pressure and damage your heart. Researchers hypothesize that supplementing with vitamin D could help treat hypertension.
What are the best sources of vitamin D?
According to the Cancer Council, the best source of vitamin D is UVB radiation from the sun. UV radiation levels vary depending on location, time of year, time of day, cloud coverage and the environment.
"For most people, adequate vitamin D levels are reached through regular incidental exposure to the sun," the Cancer Council notes. "When the UV Index is 3 or above (such as during summer), most people maintain adequate vitamin D levels just by spending a few minutes outdoors on most days of the week.
"In late autumn and winter in some southern parts of Australia, when the UV Index falls below 3, spend time outdoors in the middle of the day with some skin uncovered. Being physically active (e.g. gardening or going for a brisk walk) also helps boost vitamin D levels."
Sun protection is recommended when the UV Index is 3 or above, or when spending extended periods of time outdoors. Sunscreen should be incorporated into your daily morning routine on these days.
To check UV levels and the times sun protection is required, visit the Bureau of Meteorology website or download Cancer Council's free SunSmart app to your mobile device.
Several studies have shown that sunscreen use has minimal impact on Vitamin D levels over time.
You can also get plenty of vitamin D from certain foods such as:
- Oily fish (salmon, sardines, herring, mackerel, trout, tuna)
- Red meat
- Cheese
- Egg yolks
- Fortified foods (such as milk and breakfast cereals)
- Mushrooms that have been exposed to UV light
Should you take a vitamin D supplement?
According to Health Direct, most people don’t need vitamin D supplements.
"There can be side effects if you have too much vitamin D in your body," the website states. Vitamin D toxicity is rare but when it occurs it can cause kidney stones, bone pain, muscle weakness, nausea, and vomiting.
"If you have been found to have vitamin D deficiency, talk to your doctor about whether you need supplements," Health Direct advises.
High-risk groups for vitamin D deficiency include:
- Breast-feeding infants. Breastmilk and formula often don’t have enough vitamin D for newborns.
- People who have celiac disease, cystic fibrosis or any disorder that hinders nutrient absorption from fat.
- People who can’t or don’t often go outdoors to get sun exposure.
- People who have darker skin. It’s harder for their bodies (compared to people with lighter skin) to synthesize vitamin D from UVB rays.
- People who are malnourished or who don’t eat enough vitamin D rich foods.
- People who follow a vegan or plant-based diet and don’t consume enough vitamin D fortified foods or supplements.
- Elderly adults. As you age, your ability to make vitamin D from the sun decreases.
Vitamin D supplements are available over the counter and in different forms, including capsules, tablets, soluble tablets, chewable tablets, powder and liquids. Your doctor or pharmacist can advise you on the best one for you based on the strength of the medicine, the number and type of active ingredients it contains and your reason for taking it.
What’s the difference between vitamin D2 and vitamin D3?
There are two forms of vitamin D: Vitamin D3 (cholecalciferol) is the type your skin produces when you get sunlight. It’s also found in animal products like the oily fish mentioned above.
Vitamin D2 (ergocalciferol) comes from plant sources like mushrooms and yeast. They, too, produce their own vitamin D when they are exposed to UVB rays. This is the type you’ll find in most fortified foods.
Some doctors suggest that D3 is the better choice when it comes to supplementation. This is partially because research has shown that D3 increases the vitamin D in your blood more efficiently than D2.
Overall, the studies comparing D2 and D3’s efficacy and shelf stability are mixed so “we can’t say with 100% certainty which one would be better,” says Dr Sabith Rajan. “If you find a supplement that you like that can help you meet the daily recommendation, that would be fine. There is no hard and fast rule.”
When navigating the vitamin aisle at the store, though, you want to make sure you’re grabbing a quality product. Many supplements are not regulated by the FDA so you may want to ask your physician for a recommendation, suggests Dr Rajan.
The bottom line: Vitamin D is a crucial nutrient for maintaining your health.
While diet and sunlight can usually provide enough vitamin D, some people may need to take a supplement. Vitamin D2 and vitamin D3 are both great options—particularly since science hasn’t proven if one is better than the other. But of course, always talk to your doctor before adding a new supplement to your health regimen.
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