Should You Keep Taking Vitamin D Supplements in the Summer?

Summer sunshine isn’t always enough to meet your body’s vitamin D needs. That’s why many experts recommend continuing vitamin D supplements during the summer to help maintain adequate levels year-round.

Why You Should Continue Taking Vitamin D In the Summer

You May Not Produce Enough

• You may not produce enough vitamin D from sunlight alone, even in the summer, since your body’s ability to make vitamin D depends on several factors, like skin tone and geographic location.
• Maintaining healthy vitamin D levels is important year-round because the vitamin helps your body absorb calcium to keep bones strong, supports muscle strength, contributes to mood regulation, and keeps your immune system strong.

Taking It In The Summer Helps Build a Reserve for Darker Months

• Since vitamin D is stored in fat tissue and the liver, getting enough during the summer can help build up your body’s reserves for darker months with less sunlight.
• Taking a vitamin D supplement in the summer helps keep your vitamin D levels steady and supports your long-term bone, immune, and mental health, no matter the season.

How Much Vitamin D Do You Need?

Most adults require 600 to 800 international units (IU) of vitamin D daily. However, people at risk of deficiency, such as older adults or those with low sun exposure, may require higher doses. The National Institutes of Health recommends 600 IU for adults under 70, and 800 IU for those over 70.

However, experts in clinical practice may suggest higher dosages, especially for those with risk factors for vitamin D deficiency.

How Skin Tone Impacts Vitamin D Production

Your skin makes vitamin D when it absorbs ultraviolet B (UVB) rays from sunlight. The amount of sun you need to produce enough vitamin D depends on several factors, including skin tone.

• People with darker skin tones may need 30 to 60 minutes of sun exposure because melanin, the pigment that gives skin its color, naturally blocks some UVB rays, so more sunlight is required to produce enough vitamin D.
• People with lighter skin tones typically require 10 to 15 minutes of midday sun on areas such as the arms, legs, back, or abdomen, two to three times a week.

The best time to make vitamin D from sunlight is between 10 a.m. and 4 p.m., when UVB rays are strongest.

Other Factors Affecting Vitamin D Production

While skin tone is one factor affecting vitamin D production, several factors affect how much vitamin D your body makes from sunlight, including:

• Age: Older adults (65 and older) don’t make vitamin D as efficiently as younger people. They may need more frequent sun exposure to meet their needs.
• Air pollution and cloud cover: Air pollution, such as smog, and overcast skies can block UVB rays from reaching your skin, reducing your body’s ability to produce vitamin D, even when you’re outside.
• Body weight: While extra body weight doesn’t affect vitamin D production, it does affect how the body uses vitamin D. Vitamin D is stored in fat tissue, so having excess body fat can make it less available for use throughout the body.
• Clothing coverage: Wearing clothing that covers most of your skin reduces UVB exposure and slows vitamin D production.
• Geographic location: People who live farther from the equator, such as in the northern parts of the United States, Canada, or northern Europe, receive less direct sunlight and UVB rays, especially during the fall and winter.
• Sunscreen use: Sunscreens with a sun protection factor (SPF) of 30 or higher can block up to 97% of UVB rays, which reduces vitamin D production. While it’s still important to protect your skin, you can spend 10 to 30 minutes in the sun before applying sunscreen to help your body make vitamin D safely.
• Time of day: The sun’s UVB rays are strongest between 10 a.m. and 4 p.m.
• Time of year: People typically have less sun exposure in winter, producing less vitamin D than in summer.
• UV Index: The UV Index predicts the sun’s strength on a scale of 1-11+. The higher the UV Index in your location, the more vitamin D you absorb. (However, increased UV exposure increases the likelihood of sunburn and skin damage, so proceed with caution.)

How Do You Know If You Need More Vitamin D?

A blood test is the only reliable way to know your vitamin D level. You can ask a healthcare provider for this test if you have symptoms of low vitamin D or are at risk for a deficiency.

You may need to consider a vitamin D supplement if you:

• Are over age 65
• Have a condition that affects vitamin D absorption, such as celiac disease or inflammatory bowel disease (IBD)
• Have darker skin
• Have overweight or obesity
• Live in a northern climate with limited sunlight
• Spend most of your time indoors
• Take medications that interfere with vitamin D absorption or use, such as corticosteroids, weight-loss medicines, or anti-seizure drugs
• Wear sunscreen daily or keep most of your skin covered when outdoors

Consult a healthcare provider before starting any new supplements to ensure a new supplement is appropriate for you, you take the proper dosage, and it doesn’t interact with your health conditions or other medications and supplements you may be taking.

How to Fill Vitamin D Gaps

Some foods contain or are fortified with vitamin D, but it can be challenging to get enough solely from food. Vitamin D supplements can help you meet your body’s needs. The two main types of supplements are vitamin D2 and vitamin D3. Your body can absorb both vitamin D2 and D3,  but research shows that D3 is more effective at increasing and maintaining healthy vitamin D levels in your body.

Key Takeaways