Vitamin D - The Sunshine Vitamin
- Haley Singer
- May 11
- 5 min read
What your bones, mood, immune system, and hormones all have in common — and why the sunshine vitamin matters more than you think.
"Sunlight is medicine for the body, mind, and spirit.”
Vitamin D is a fat-soluble vitamin your body makes when sunlight hits your skin. It plays a key role in immune health, mood, muscle function, bone strength, and — especially for women — hormonal balance across every stage of life.
At Wild Witch Wellness, we believe that understanding why a nutrient matters is just as important as knowing it exists. So let's go deeper.
What Vitamin A does for your body
Vitamin D is far more than a bone health vitamin. It acts more like a hormone in the body, helping regulate gene expression across hundreds of pathways involved in immune function, mood, muscle health, hormones, and cellular communication. Here’s where it shows up most:
🦴Bone Strength
Vitamin D helps your body absorb calcium and phosphorus, two key minerals needed to build and maintain strong bones and teeth. Adequate levels may help reduce the risk of bone loss, fractures, and conditions like osteoporosis over time.
🛡️Immune Defense
Vitamin D plays an important role in regulating the immune system and supporting your body’s natural defense mechanisms. It helps immune cells communicate properly, which may support resilience against illness while also helping prevent excessive inflammation.
☀️Mood & Energy
Low vitamin D levels have been associated with fatigue, low energy, brain fog, and seasonal mood changes. Because vitamin D receptors are found in areas of the brain involved in mood regulation, maintaining healthy levels may support overall emotional well-being.
💪Muscle Function
Vitamin D supports muscle contraction, coordination, balance, and recovery. Adequate levels are especially important for maintaining strength, preventing muscle weakness, and supporting healthy movement as we age.
⚖️Hormone Balance
Vitamin D acts more like a hormone than a traditional vitamin and influences many hormonal pathways in the body. It may support thyroid function, reproductive health, insulin sensitivity, and overall endocrine balance.
Where to find it in food
Vitamin D is naturally found in only a few foods, with fatty fish like salmon, trout, tuna, and mackerel being some of the best sources. Smaller amounts are found in foods like egg yolks, cheese, beef liver, and UV-exposed mushrooms, but most vitamin D in the American diet comes from fortified foods such as milk, plant milks, cereal, yogurt, and orange juice.
Food | Serving | Amount | % Daily Value | Source |
Cod Liver Oil | 1 tbsp | 1360 IU | 170 | Animal |
Salmon | 3 oz | 570 IU | 156 | Animal |
Mushrooms (white, raw, exposed to UV) | ½ cup | 366 IU | 46 | Plant |
Fortified Milk | 1 cup | 120 IU | 15 | Animal |
Fortified Cereal | 1 Serving | 80 IU | 10 | Plant |
Egg | 1 whole | 44 IU | 6 | Animal |
Other Sources:
☀️Sun Exposure
Your body can naturally produce vitamin D when your skin is exposed to sunlight, though factors like season, skin tone, cloud cover, and time spent outdoors can affect how much is made.
💊Dietary Supplements
Vitamin D supplements come in two forms: D2 and D3. Both help raise vitamin D levels, but vitamin D3 is generally more effective at increasing and maintaining levels long term. However, Vitamin D3 is not vegetarian as it is sourced from lanolin (sheep's wool). Take Vitamin D with a fat-containing meal for best absorption — and consider pairing it with Vitamin K2, which helps direct calcium to your bones rather than your arteries.
How much do you actually need?
Vitamin A is measured in micrograms of Retinol Activity Equivalents (mcg RAE) — a unit that accounts for the fact that your body uses retinol and beta-carotene very differently.
Here are the official daily recommendations:
Adults (19–50 years) - 15 mcg or 600 IU / day
Adults (51-70 years) - 15 mcg or 600 IU / day
Adults (>71 years) - 20 mcg or 800 IU / day
Signs you might be running low
The best way to know your levels is a simple blood test (25-OH Vitamin D), but you can also keep an eye out for these signs.
Bone or muscle aches
Irregular cycles
Frequent illness
Low mood
Vitamin D & the female body
*Not so fun, fun fact: Women were largely excluded from medical research until the late 20th century, with most studies conducted on men. In 1993, the NIH Revitalization Act of 1993 officially required women to be included in federally funded clinical research. Therefore, on this page, we will ALWAYS talk about women's bodies.
Despite being called a vitamin, Vitamin D functions more like a hormone — and it directly influences estrogen, one of women's most important hormones. Low vitamin D levels are linked to menstrual irregularities, fertility challenges, mood shifts, and accelerated bone loss during menopause. Research shows women are disproportionately affected by deficiency, yet their need for it changes throughout life.
Cycle Support
Vitamin D helps regulate the hormones behind your cycle. Low levels are linked to painful periods, PMS, and irregular cycles.
Fertility & Conception
Adequate levels support healthy ovarian function and egg quality. Deficiency is more common in women experiencing fertility challenges.
Pregnancy
Supports fetal bone and immune development. Low levels are associated with a higher risk of gestational diabetes and preeclampsia.
Perimenopause
As estrogen declines, bones lose their natural protection. Vitamin D helps slow that loss and eases muscle aches and fatigue.
Post-Menopause
Women over 65 benefit most from higher intake — studies show it reduces non-spinal fracture risk and supports muscle balanc
🌿 The Wild Witch approach
Aim for about 10–30 minutes of morning or midday sun on your face, arms, and legs a few times a week.
Nourish yourself with vitamin D-rich foods like salmon, sardines, egg yolks, fortified dairy-free milks, and UV-exposed mushrooms.
Pair vitamin D with healthy fats (like olive oil, avocado, nuts, or salmon) to help improve absorption.
Support balance with key cofactors like magnesium and vitamin K2, which work alongside vitamin D in the body.
Consider a high-quality vitamin D3 supplement during winter months, limited sun exposure, or if lab levels are low.
Prioritize restorative sleep, movement, and stress management — your hormones, immune system, and nutrient status are all deeply connected.
Get your vitamin D levels tested periodically, especially if you experience fatigue, low mood, frequent illness, or spend most of your time indoors.
As always, the most powerful thing you can do is pay attention to your own body. These are patterns and guidelines — not prescriptions. If you suspect you're running low or want to understand your levels more precisely, a simple blood panel and a conversation with an integrative health practitioner can tell you a great deal.
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