With summer in full swing, you may be enjoying more vitamin D-producing sunlight than in the previous months. But are you getting enough to put your daily vitamin D regimen on hold for the summer?
Most experts say no—you should still keep taking the “sunshine vitamin.”
There are several reasons why you may not be getting enough vitamin D despite the sunny weather. These include living in a more northern region of the country, using sunscreen, working inside most of the day, being over 65, and having darker skin.
Your body naturally produces vitamin D when exposed to direct sunlight, but it still may not be enough to make up for the deficit from the winter months, Hedva Barenholtz Levy, PharmD, a pharmacist specializing in geriatrics, told Health.
Factors that affect the amount of vitamin D your skin can synthesize from the sun alone include:
- Skin pigmentation
- Age
- Time of day when you are outside
- A diet low in or lacking vitamin D-rich foods
- Medications that decrease your production of vitamin D
The only way to know definitively whether you need a vitamin D supplement in the summer is through a blood test.
To get enough vitamin D, you need around 10 to 30 minutes of direct sunlight on your face, arms, or legs several times a week, according to Brynna Connor, MD, board-certified family medicine physician specializing in anti-aging and regenerative medicine.
If you’re in northern climates and/or have darker skin, you may need more time in direct sunlight.
“However, prolonged sun exposure carries health risks, such as sunburn and an increased risk of skin cancer,” added Connor.
UV light (UV-B) is transformed in the skin to vitamin D3, the active form of vitamin D. Exposure to sunlight several times a week could potentially provide about 80% of the vitamin D your body needs, said Levy.
However, if you’re over 65, have darker skin, or use sunscreen, your ability to produce vitamin D naturally is diminished.
According to Jen Hernandez, RDN, a registered dietitian and founder of Plant-Powered Kidneys, the recommended dietary allowance (RDA) for vitamin D is:
- 15 micrograms (600 international units (IU)) per day for adults aged 19 to 70
- 20 micrograms (800 IU) per day for those older than 70 years old,
A healthcare provider should adjust the dose and frequency of your vitamin D supplements based on your vitamin D levels from blood test results.
Not many foods contain vitamin D naturally.
Some fatty fish, like trout and salmon, have vitamin D, along with some UV-treated mushrooms. Fortified foods like milk, juices, and ready-to-eat cereals can also contain vitamin D.
Here are some foods to consider:
- Cod liver oil
- Trout
- Salmon
- Mushrooms (UV treated)
- Milk
- Fortified soy, almond, and oat milk
- Ready-to-eat cereal
- Sardines
- Eggs
- Beef liver
- Tuna (canned in water)
- Cheddar cheese
It is possible to take too much vitamin D through supplements. Though rare, vitamin D toxicity can occur because your body stores it rather than getting rid of any excess.
Too much vitamin D in your blood may cause problems like high calcium levels, kidney failure, heart arrhythmias, and even death, according to Hernandez.
Vitamin D toxicity is usually accompanied by:
- Loss of appetite
- Nausea
- Vomiting
- Muscle weakness
- Pain
- Dehydration
- Kidney stones
- Mood disorders
Your body can produce enough vitamin D from the sun during the warmer months, but you may often come into the season deficient, especially if you are older than 65, have darker skin, live in a northern climate, and practice good sun protection.
To determine how much vitamin D you should be taking during the summer, talk with a healthcare provider. They can check your vitamin D levels and make recommendations on how much you should take daily.
