Vitamin D Benefits for Women: What You Need to Know

Do you feel tired, low in mood, or constantly fighting off colds — even when you’re doing your best to stay healthy?
It might be time to look at something surprisingly simple: your vitamin D levels.

Often called the “sunshine vitamin,” vitamin D plays a key role in immune function, bone strength, mood balance, and long-term wellbeing — especially for women.

In this post, we’ll cover:

• ✅ What vitamin D actually does in your body

• ✅ Signs of vitamin D deficiency

• ✅ The best food and supplement sources

• ✅ How much you really need

• ✅ Why vitamin D3 (with K2) is so important for women’s health 

Looking for the video version? – Watch my full breakdown here!

Vitamin D is a fat-soluble vitamin that acts more like a hormone in the body. Your skin makes it when exposed to sunlight, specifically UVB rays. It then gets activated by the liver and kidneys into a form your cells can use.

Once active, vitamin D helps:

• Support a resilient immune system

• Regulate inflammation

• Strengthen bones and teeth by helping absorb calcium

• Balance mood and cognitive function

• Improve blood sugar control and insulin sensitivity

Here’s a simplified look at how vitamin D is made, where it’s activated, and what can get in the way of proper absorption.

(ref https://pmc.ncbi.nlm.nih.gov/articles/PMC6631968/)

Vitamin D deficiency is incredibly common — especially in the UK and Northern Europe, or among those who work indoors, wear sunscreen daily, or have darker skin.

Common symptoms include:

• Low mood or mild depression

• Fatigue and poor recovery

• Frequent illness or infections

• Bone or joint pain

• Muscle weakness

• Brain fog or low motivation

For women, deficiency can also contribute to:

• Bone thinning or early signs of osteoporosis

• Hormonal imbalance

• Increased belly fat after menopause

• Higher risk of cardiovascular issues

While sunlight is the most effective source, you can also get vitamin D from:

• Oily fish like sardines, mackerel, and salmon

• Cod liver oil (rich in D3 and A)

• Pasture-raised eggs (especially the yolks)

• UV-exposed mushrooms (especially for vegans)

• Fortified foods like milk or cereals (often contain D2, a less effective form)

If you’ve ever wondered what supplements do I need in my 40s, vitamin D is a key place to start — especially for women in the UK.

If you’re low in vitamin D or not getting enough sunlight, supplements can help — but not all vitamin D is created equal.

The best form to take is:

✅ Vitamin D3 (cholecalciferol)

This is the same type your body makes from the sun, and it’s more effective than D2 (ergocalciferol).

🌿 D3 with Vitamin K2

K2 helps direct calcium into your bones and away from soft tissues like arteries. This is especially important if you’re also taking calcium or worried about bone health and cardiovascular risk.

💡 Formats That Absorb Well:

• Oil-based softgels or capsules

• Sublingual sprays or drops (great if you have digestive issues or fat malabsorption)

• Always take it with a meal that contains fat for best absorption

While NHS guidelines suggest 400 IU per day for maintenance, many experts now recommend 2,000–4,000 IU daily for general wellbeing — and even more if you’re deficient, have higher body fat, or take medications that impair absorption.

You can ask your practitioner for a 25(OH)D blood test to check your levels. Ideally, you want to be between:

• 40–60 ng/mL (100–150 nmol/L) for optimal health

• Anything below 30 ng/mL (75 nmol/L) is considered insufficient

Some women have genetic variations (called SNPs) that affect how well they absorb, convert, or use vitamin D.

These include:

• VDR gene variants (affect receptor sensitivity)

• CYP2R1 (impacts liver conversion)

• GC/DBP (impacts how vitamin D is carried in your blood)

If you have these, you may need higher doses or specific supplement forms to reach your target range — this is where nutrigenomic testing can be really helpful.

I’ve even seen this in my own genetics. My nutrigenomic test showed that I have a “good transporter” gene (GC rs2282679), meaning vitamin D circulates well through my body.

But I also carry two low-sensitivity VDR gene variants (rs1544410 TT and rs731236 GG) — which reduce the activity of vitamin D receptors. This means I may not respond as effectively to typical vitamin D levels and might need slightly higher doses or longer periods of supplementation to feel the full benefit.

This is why testing — both blood levels and genetics — can make a big difference in knowing what your body really needs.

• It’s vital for immune health, mood, energy, hormones, and bone strength

• Many women are unknowingly deficient, especially in winter

• D3 with K2 is the most effective and protective form

• Testing your levels is the best way to personalise your intake

Other posts you might like: 

Nutrigenomic Testing – click HERE

Creatine for Women: Benefits, How It Works & Why It Matters – Click HERE 

Apple Cider Vinegar Before Bed – Does It Really Work? The Science-Backed Benefits You Should Know – Click HERE

Magnesium: The Essential Mineral for Energy, Sleep, and Overall Health – Click HERE

Signs of Low B12 in Older Adults (And What You Can Do About It) – Click HERE

How often should you weigh yourself – Click HERE

References 

https://pubmed.ncbi.nlm.nih.gov/22552031/ Comparison of vitamin D2 and vitamin D3 supplementation in raising serum 25-hydroxyvitamin D status: a systematic review and meta-analysis 

https://pubmed.ncbi.nlm.nih.gov/18722618/ High dietary menaquinone intake is associated with reduced coronary calcification 

https://pmc.ncbi.nlm.nih.gov/articles/PMC5613455/   The Synergistic Interplay between Vitamins D and K for Bone and Cardiovascular Health: A Narrative Review

https://pubmed.ncbi.nlm.nih.gov/16825677/ Estimation of optimal serum concentrations of 25-hydroxyvitamin D for multiple health outcomes 

https://www.sciencedirect.com/science/article/pii/S0002916523277722?via%3Dihub Estimation of optimal serum concentrations of 25-hydroxyvitamin D for multiple health outcomes 

https://pmc.ncbi.nlm.nih.gov/articles/PMC2912737/ Vitamin D Deficiency in Adults: When to Test and How to Treat 

https://www.ncbi.nlm.nih.gov/books/NBK557876/  

 https://pmc.ncbi.nlm.nih.gov/articles/PMC3349454/  Comparison of vitamin D2 and vitamin D3 supplementation in raising serum 25-hydroxyvitamin D status: a systematic review and meta-analysis

https://pmc.ncbi.nlm.nih.gov/articles/PMC6631968  Bioavailability of Different Vitamin D Oral Supplements in Laboratory Animal Model 

https://pmc.ncbi.nlm.nih.gov/articles/PMC11314300/ Daily and Weekly “High Doses” of Cholecalciferol for the Prevention and Treatment of Vitamin D Deficiency for Obese or Multi-Morbidity and Multi-Treatment Patients Requiring Multi-Drugs—A Narrative Review