Boise's Sun: No Sidewalks Crashing Summer D?

By Franklin Everett Shaw

November 10, 2025

The air in Boise, Idaho, is crisp, clean, and often filled with sunshine. You’d think vitamin D deficiency would be the last thing on anyone’s mind. Yet, despite the abundant sunshine, many Boise residents might be surprisingly low on this crucial nutrient. It’s not about the availability of sunshine, but rather how effectively our bodies utilize it.

Boise’s latitude, nestled in the high desert, means that even on sunny days, the angle of the sun during certain months (especially winter) isn’t optimal for vitamin D production. The sun’s UVB rays, which trigger vitamin D synthesis in our skin, are weaker and less effective during the colder months. This is a problem that many northern states face.

Sunscreen, while essential for protecting against skin cancer, significantly blocks UVB rays. A sunscreen with an SPF of 30, for example, can reduce vitamin D production by as much as 95%. Boiseans, known for their active outdoor lifestyles, are often diligent about sunscreen use, inadvertently hindering their vitamin D synthesis.

Indoor lifestyles are another major contributor. Many Boise residents spend a significant portion of their day indoors, whether at work, school, or home. Even on sunny days, if you’re primarily indoors, you’re missing out on the opportunity to produce vitamin D naturally. This is especially true for those working in downtown Boise office buildings.

Skin pigmentation plays a crucial role. Melanin, the pigment that gives skin its color, acts as a natural sunscreen. Individuals with darker skin require significantly more sun exposure to produce the same amount of vitamin D as those with lighter skin. Boise’s diverse population includes individuals with varying skin tones, and those with darker skin may be at a higher risk of deficiency.

Age is also a factor. As we age, our skin’s ability to produce vitamin D declines. Older adults in Boise, particularly those in assisted living facilities or with limited mobility, may be especially vulnerable to deficiency.

So, what can Boiseans do to optimize their vitamin D levels safely? It’s a balancing act between getting enough sun exposure and protecting against skin cancer.

Here’s a practical approach:

• Know your skin type: Lighter skin requires less sun exposure than darker skin.
• Time of day matters: Aim for sun exposure during peak hours (typically between 10 am and 3 pm) when UVB rays are strongest.
• Expose more skin: Short periods of sun exposure with more skin exposed (arms, legs, back) are more effective than longer periods with limited skin exposed.
• Consider supplementation: Vitamin D supplements are a safe and effective way to boost your levels, especially during winter months. Look for Vitamin D3 (cholecalciferol), which is more effective than Vitamin D2.
• Get tested: A simple blood test can determine your vitamin D levels. Talk to your doctor about getting tested, especially if you have risk factors for deficiency.

Specific Challenges and Pitfalls:

• Over-reliance on sunshine: Don’t assume you’re getting enough vitamin D just because it’s sunny. Factors like sunscreen use and skin pigmentation can significantly impact production.
• Incorrect supplementation: Taking the wrong type or dosage of vitamin D can be ineffective or even harmful. Consult with a healthcare professional to determine the appropriate dosage for you.
• Ignoring symptoms: Vitamin D deficiency can manifest in various ways, including fatigue, bone pain, muscle weakness, and mood changes. Don’t dismiss these symptoms; get checked by a doctor.
• Assuming all sunscreens are equal: Mineral sunscreens (zinc oxide and titanium dioxide) tend to block UVB rays more effectively than chemical sunscreens. Be mindful of the type of sunscreen you’re using.

Local Resources in Boise, Idaho:

• Primary Care Physicians: Your primary care physician can order a vitamin D blood test and recommend appropriate supplementation. Many practices in the Boise area, such as Saint Alphonsus Medical Group and St. Luke’s Health System, offer vitamin D testing.
• Specialty Clinics: Some clinics specialize in vitamin deficiencies and hormone imbalances. These clinics can provide more in-depth testing and personalized treatment plans.
• Pharmacies: Local pharmacies like Albertsons and Walgreens carry a wide range of vitamin D supplements. Consult with a pharmacist to choose the right product for you.
• Health Food Stores: Stores like Boise Co-op and Natural Grocers offer high-quality vitamin D supplements and can provide expert advice on dosage and brands.
• Online Retailers: Online retailers like Amazon and iHerb offer a vast selection of vitamin D supplements at competitive prices. However, be sure to choose reputable brands and read reviews carefully.

Case Study:

Consider Sarah, a 35-year-old Boise resident with fair skin. She enjoys hiking in the foothills but always wears sunscreen with an SPF of 50. She works indoors during the day and rarely spends time outside without sunscreen. Despite living in a sunny climate, Sarah was experiencing fatigue and muscle aches. Her doctor ordered a vitamin D blood test, which revealed a significant deficiency. Sarah started taking a daily vitamin D3 supplement and made an effort to spend 15 minutes outside without sunscreen (during peak hours) a few times a week. Within a few months, her vitamin D levels improved, and her symptoms resolved.

Actionable Insights:

• Track your sun exposure: Use a sun tracking app to monitor your daily sun exposure and ensure you’re getting enough UVB rays.
• Optimize your diet: Include vitamin D-rich foods in your diet, such as fatty fish (salmon, tuna, mackerel), egg yolks, and fortified foods (milk, cereal).
• Consider a UV lamp: During winter months, a UV lamp can provide a source of UVB rays to stimulate vitamin D production.
• Re-evaluate your sunscreen habits: Consider using sunscreen only when necessary (e.g., during prolonged sun exposure) and choose a lower SPF when possible.

Vitamin D deficiency is a real concern, even in sunny Boise. By understanding the factors that influence vitamin D production and taking proactive steps to optimize your levels, you can ensure you’re getting enough of this essential nutrient for optimal health. Don’t just assume you’re getting enough; take control of your vitamin D levels and enjoy the Boise sunshine to its fullest.