Dark Skin, Winter D: Chicago's UV Lie?

By Franklin Everett Shaw

August 9, 2025

The biting wind whips off Lake Michigan, a constant reminder that winter in Chicago isn’t just a season, it’s a lifestyle. But beyond the inconvenience of scraping ice off your windshield, there’s a more insidious threat lurking: Vitamin D deficiency. And for Chicagoans with darker skin, the risk is significantly amplified.

The reason is melanin. Melanin, the pigment that gives skin its color, acts like a natural sunscreen. While this is great for protecting against skin cancer, it also reduces the skin’s ability to produce Vitamin D from sunlight. This is especially problematic in northern latitudes like Chicago (around 41°N), where the sun’s UVB rays, necessary for Vitamin D synthesis, are weak or nonexistent for a significant portion of the year (roughly October to April).

So, how can Chicago residents with darker skin navigate this seasonal challenge and maintain optimal Vitamin D levels? It’s not about chasing fleeting sunshine; it’s about a strategic, multi-pronged approach.

First, understand the science. Vitamin D isn’t just one thing; it’s a group of fat-soluble secosteroids responsible for increasing intestinal absorption of calcium, magnesium, and phosphate, and many other biological effects. The two major forms are Vitamin D2 (ergocalciferol) and Vitamin D3 (cholecalciferol). D3 is generally considered more effective at raising blood levels of Vitamin D.

Next, get tested. Don’t guess; know your baseline. Ask your doctor for a 25-hydroxyvitamin D blood test (25(OH)D). This test measures the amount of Vitamin D in your blood and is the most accurate way to determine your Vitamin D status. Aim for a level between 30-50 ng/mL. Anything below 20 ng/mL is generally considered deficient. Given Chicago’s latitude, testing in late winter (March/April) is crucial to assess the impact of the season.

Now, let’s talk supplementation. This is where things get specific. The Recommended Dietary Allowance (RDA) for Vitamin D is 600 IU (International Units) per day for adults under 70. However, this is often insufficient, especially for individuals with darker skin living in northern climates. Many experts recommend a higher daily intake, often ranging from 1000-2000 IU, or even higher based on individual blood test results.

Choose D3: Opt for Vitamin D3 supplements, as they are more effective at raising blood levels.
Consider Liquid or Softgels: These forms may be better absorbed than tablets, especially if you have digestive issues.
Take with Fat: Vitamin D is fat-soluble, so take your supplement with a meal containing healthy fats to improve absorption. A handful of almonds or a spoonful of olive oil will do the trick.
Monitor Your Levels: Re-test your Vitamin D levels after a few months of supplementation to ensure you’re reaching your target range.

But supplementation isn’t the only answer. Let’s explore dietary sources. While few foods naturally contain high levels of Vitamin D, some are fortified, and others are naturally good sources.

Fatty Fish: Salmon, tuna, and mackerel are excellent sources of Vitamin D. Incorporate these into your diet a few times a week.
Fortified Foods: Milk, yogurt, orange juice, and breakfast cereals are often fortified with Vitamin D. Check the labels to see how much Vitamin D they contain.
Egg Yolks: Egg yolks contain a small amount of Vitamin D.
Mushrooms: Certain types of mushrooms, especially those exposed to UV light, can be a good source of Vitamin D.

Now, let’s get culturally relevant. Many cultures have traditional foods that can be adapted to boost Vitamin D intake. For example, consider incorporating these into your diet:

African Diaspora: Many Caribbean and African dishes use fatty fish like mackerel and herring. Explore recipes that feature these ingredients.
South Asian Cuisine: Ghee (clarified butter) is often used in South Asian cooking and can be a source of fat to aid Vitamin D absorption. Pair it with Vitamin D-rich foods.
Latin American Cuisine: Many Latin American dishes include eggs. Experiment with egg-based dishes that incorporate other Vitamin D-rich ingredients.

Another often-overlooked factor is indoor lighting. While it’s not a replacement for sunlight or supplementation, optimizing your indoor lighting can help.

Full-Spectrum Bulbs: Consider using full-spectrum light bulbs in your home and office. These bulbs mimic natural sunlight and can help regulate your circadian rhythm, which can indirectly impact Vitamin D levels.
Light Therapy Lamps: Light therapy lamps, also known as SAD (Seasonal Affective Disorder) lamps, emit bright light that can help boost mood and energy levels during the winter months. While they don’t directly produce Vitamin D, they can improve overall well-being.

Common Pitfalls and How to Avoid Them:

Assuming You’re Getting Enough: Don’t assume you’re getting enough Vitamin D, even if you spend time outdoors. Chicago’s winter sun is often too weak to produce sufficient Vitamin D, especially for those with darker skin.
Inconsistent Supplementation: Taking Vitamin D supplements sporadically won’t cut it. Consistency is key. Set a reminder to take your supplements daily.
Ignoring Blood Test Results: Don’t just get tested and forget about it. Work with your doctor to interpret your results and adjust your supplementation accordingly.
Relying Solely on Fortified Foods: While fortified foods can contribute to your Vitamin D intake, they’re often not enough to meet your needs, especially if you’re deficient.
Not Considering Other Factors: Certain medical conditions, such as Crohn’s disease and celiac disease, can interfere with Vitamin D absorption. Talk to your doctor if you have any underlying health issues.

Real-World Scenario:

Imagine a 35-year-old Black woman living in Bronzeville, Chicago. She works indoors and rarely spends time outside during the winter. She’s been feeling fatigued and experiencing muscle aches. She gets a 25(OH)D blood test in March, and her level comes back at 15 ng/mL, indicating a significant deficiency.

Her doctor recommends 2000 IU of Vitamin D3 daily, taken with a meal containing healthy fats. She also starts incorporating more salmon and fortified yogurt into her diet. After three months, she re-tests her Vitamin D levels, and they’ve increased to 35 ng/mL. Her fatigue and muscle aches have also improved significantly.

The Chicago Advantage:

Chicago, despite its harsh winters, offers resources to combat Vitamin D deficiency. Many local health food stores and pharmacies carry a wide range of Vitamin D supplements. Community health centers often offer affordable blood testing. And the city’s diverse culinary scene provides ample opportunities to incorporate Vitamin D-rich foods into your diet.

Actionable Insights:

Schedule a Vitamin D blood test with your doctor, especially if you have darker skin and live in Chicago.
Start taking a Vitamin D3 supplement daily, preferably with a meal containing healthy fats.
Incorporate more fatty fish, fortified foods, and eggs into your diet.
Consider using full-spectrum light bulbs or a light therapy lamp in your home and office.
Monitor your Vitamin D levels regularly and adjust your supplementation as needed.

Don’t let Chicago’s winter blues get you down. By taking a proactive approach to Vitamin D, you can maintain your health and well-being throughout the year. It’s about understanding your body, leveraging available resources, and making informed choices to thrive, even when the sun is hiding behind those infamous Chicago clouds.