Vitamin D: The Hidden Link Between Menopause, Mood and Immunity
- urbanwellnessuk
- 7 days ago
- 5 min read
Updated: 4 days ago
You're a high-functioning woman in your 40s or 50s—holding down a demanding career, managing family or empty-nest transitions, and keeping it together on the outside. But privately, the flat mood, shorter fuse, and nagging anxiety feel relentless. You've tried the "right things"—exercise, mindfulness, even antidepressants—but nothing fully explains why you still don't feel like yourself.
What if the missing piece is something as simple as vitamin D? As a registered nutritional therapist specialising in midlife women's mood, I've seen how this overlooked nutrient bridges menopause changes, immune health, and emotional resilience. Here's what you need to know—and how to act.
Vitamin D: More Than a Sunshine Vitamin
Vitamin D isn't just for bones. It functions like a hormone messenger. In the UK, we can only reliably sythesise vitamin D from sunlight during late Spring and Summer months. Your liver and kidneys then activate it into calcitriol, its active form, which binds to vitamin D receptors (known as VDRs) throughout your body—in your heart, bones, lungs, brain, and immune cells.
Once activated, VDRs regulate hundreds of genes, influencing everything from inflammation to mood stability—much like oestrogen or cortisol, but with broader reach.
The Midlife Connection: Why It Matters Now
In your 40s-60s, vitamin D becomes critical for three reasons:
Menopause shifts absorption: Oestrogen decline reduces vitamin D synthesis in the skin (not dietary or supplemental forms) – a particular problem in the UK where winter sun is too weak. Deficiency rates hit 40% in midlife women—directly linking to low mood and fatigue.[1}
Mood and brain health: VDRs in the brain calm neuroinflammation—a key driver of anxiety and flatness. Low vitamin D correlates with higher depression risk, especially when combined with stress or antidepressants.
Immune resilience: Activated VDRs boost antimicrobial proteins (like cathelicidin) that help fight infections. Vitamin D also optimises macrophages—immune cells that tackle viruses—and reduces inflammation that drags down energy during colds.
This is why Vitamin D matters now at this life stage: Hormones stabilise, mood lifts, and you’re not derailed by every winter cold or virus.
The Evidence: What Human Studies Show
Mood support - RCTs (Random Controlled Trials) show low-dose vitamin D (1000 IU daily) reduces depression symptoms in deficient women. For you, this means lifting the "flatness" without requiring major lifestyle overhaul.[2]
Infection prevention - Meta-analyses of 25+ RCTs confirm a 12% lower respiratory infection risk with daily low doses. Fewer winter bugs derailing your week or leaving you depleted for months. [3]
Anti-inflammatory action - Vitamin D reduces inflammatory cytokines (IL-6, TNF-α) in 14 out of 16 immune cell trials. This calms gut-brain inflammation—the kind triggered by stress, hormones, or poor digestion—without medication side effects. [4]
Menopause synergy - Studies show vitamin D improves sleep and steady energy in perimenopausal women. Instead of waking at 3 AM or dragging through afternoons, you get the baseline stability that makes everything else possible. [5]
Real-world protection - Recent UK Biobank data on 36,000+ adults links severe vitamin D deficiency to 33% higher hospitalisation risk for flu and chest infections. This matters when you're juggling work, health, and don't have weeks to recover from illness. [6]
Why You're Likely Deficient (And Tests Miss It)
UK sun scarcity: October-March, your skin barely makes vitamin D. This is why the NHS recommends every adult in the UK supplements with Vitamin D over the winter months
Midlife factors: Body composition changes in midlife mean Vitamin D distributes differently in tissue – so you may need slightly higher doses to maintain optimal levels.
Antidepressant use – certain antidepressants (such as SSRIs) reduce vitamin D absorption or increase its breakdown in the body. This means you may need higher supplemental doses to reach optimal levels, especially if you’ve been on medication for years.
GP tests often "normal": NHS guidelines to define vitamin D sufficiency as 30 nmol/L or above for bone health. However, for mood support an immune function, functional medicine evidence suggest 75 to 100 nmol/L is more optimal. Vitamin D testing is also not run as standard by the NHS.
Skin tone and genetic factors – if you have darker skin, your body produces less vitamin D from sunlight – a physiological reality, not a deficiency in you. Certain populations and ethnic necessities naturally require high sun exposure of supplement of doses to reach the same blood levels. Testing your baseline is especially important if this applies to you, rather than assuming standard recommendations fit your needs.
My Practical Plan: Test, Dose, Track
Step 1: Test properly
Request a 25 (OH) D blood test from your GP as they do not offer it as standard. Alternatively, home testing kits (like Medichecks) are convenient and affordable, especially with a discount. Use code NICOLASHUBROOK for 10% off.* Either way, you want to be aiming for at least 75 to 100 nmol/L.
Step 2: Dose smart
Daily low-dose: Take a daily vitamin D supplement (all formats—pills, drops, sprays—absorb equally well) [7]
With food: Pair with eggs, avocado, or nuts for 50-80% uptake - natural fats in the diet help improve absorption
Consider taking a vitamin D with K2: vitamin K2 works synergistically with vitamin D to direct House into your bones and away from soft tissues like arteries. This is particularly important for cardiovascular and bone health in midlife. If you’re concerned about either, I combine D3 plus K2 supplement is convenient, otherwise K2 rich foods (fermented dairy, NATO, leafy greens) support the same function. [8]
Step 3: Retest in 3 months
Keep track of your Vitamin D levels. If you have a test that showed a deficiency re-test in 3 months.Â
Step 4: Food boosters (not replacements)
Certain foods are good sources of vitamin D which are good to include all year round whether you are taking a supplement or not:
·      Oily fish: salmon, mackerel, tuna and sardines
·      Mushrooms – put them on the windowsill for extra vitamin D
·      Fortified cereals
·      Fortified non-dairy milks such as soy, almond and oat – this is brand specific so please check labels.
The Transformation
Imagine waking with steady energy, fewer mood dips, and resilience against winter bugs. Not from willpower or another prescription, but from addressing a root cause your standard tests overlooked.
Vitamin D won't "cure" everything, but testing your actual levels rather than guessing is the essential first step.
If you would like more help with your mood & menopause, then please book a clarity call with me today to see how I can help
* Please note I do earn a small commission from any tests purchased from Medichecks using my discount code
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