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How to Improve your Vitamin D levels to Support Fertility by Sarah Trimble

By May 6, 2022May 10th, 2022No Comments
Vitamin D

Making improvements to our lifestyle and eating better is an essential step in preparation for trying to conceive. However, there is one specific fertility enhancing nutrient that we can’t get enough of from our diet, vitamin D. While certain foods contain small amounts of vitamin D, it is impossible to meet our requirements for vitamin D from diet alone and, as a result, deficiency is very common. Testing for and then treating vitamin D deficiency is a relatively straightforward way to improve both male and female fertility and improve the chances of conceiving. 

Vitamin D: why it’s difficult to get enough 

Vitamin D is essential for healthy reproductive function for both men and women. It acts more like a hormone in our bodies because it controls several important bodily functions – some of which are key reproductive functions. It is almost impossible to know if you are getting enough vitamin D because our main source is sunlight. When UVB rays hit our skin they stimulate a chemical reaction in the body that results in vitamin D production and we rely on the action of sunlight for around 80-90% of our vitamin D stores. As mentioned above, you can find small amounts of vitamin D in foods such as eggs, liver, oily fish, and mushrooms, however, we can’t get adequate vitamin D levels from diet alone.

Because we rely on sunlight to produce vitamin D, it is estimated that around 50% of the UK population is vitamin D deficient. In the UK we don’t get enough strong sunshine throughout the year, in fact from October to March the sun’s rays are not strong enough to stimulate vitamin D production. Spending time in the sun during the spring and summer months can build vitamin D stores, however, the body can quickly use up these stores over the autumn and winter months. 

Because we don’t know how much vitamin D our body is producing from sunlight exposure, it can be difficult to predict vitamin D levels and there are many risk factors for developing a vitamin D deficiency. 

Risk factors for vitamin D deficiency

  • Inadequate sunlight exposure: we should be exposing our skin to sunlight between 12-3 pm when most of us are at work. 
  • Dark skin colour: individuals with darker skin need more sunlight to stimulate vitamin D production and can find it difficult to get enough in the UK climate. 
  • Obesity: fat tissue absorbs and retains vitamin D, making it inactive
  • Poor absorption: digestive issues that affect the absorption of dietary vitamin D include gallbladder removal and coeliac disease

 Vitamin D and Female Fertility

Having optimal vitamin D levels can have a real positive impact on female fertility. In some studies, women with better vitamin D levels were 3 times more likely to get pregnant than those women who were vitamin D deficient, and having healthy vitamin D levels improves the chances of having a healthy pregnancy. Vitamin D deficiency is considered a risk factor for miscarriage. Having higher blood levels of vitamin D can also improve symptoms of PCOS and endometriosis – the two most common conditions that reduce women’s chances of conceiving. 

Immune system imbalances can negatively impact a woman’s chances of conceiving and increase the risk of miscarriage. Improving vitamin D stores is an important and straightforward way to rebalance the immune system. Vitamin D acts as an immune system modulator, balancing an immune system that might be underactive or overactive. The research shows that women with better vitamin D levels in the pre-conceptual period have a reduced risk of miscarriage and better rates of conception during IVF. It is recommended that all women who are trying to conceive, either naturally or through IVF should test their vitamin D status so that appropriate steps can be taken to achieve and maintain healthy vitamin D stores. 

Vitamin D and Male Fertility

Vitamin D can help to improve sperm health and the research shows a very clear and direct relationship between better blood levels of vitamin D and better semen quality. Men who had good levels of vitamin D had better sperm, quality, concentration, and motility compared to men who were vitamin D deficient. Vitamin D is linked to testosterone production and men with low testosterone levels saw these levels improve after spending more time in the summer sun and naturally increasing their vitamin D. In one study infertile men who were treated for vitamin D deficiency saw their testosterone levels and sperm quality improve in line with improved vitamin D levels. 

How to optimise vitamin D levels to support fertility

An important first step is to test vitamin D levels either with your GP or using a private testing kit. When preparing the body for conception and pregnancy achieving vitamin D levels of 100nmol/L (or 45ng/ml) is recommended. If your vitamin D levels are well below this it is recommended to supplement with vitamin D for a few months to increase vitamin D stores. 

Experts use the following equation to determine the dosage of vitamin D required to increase vitamin D levels over 2 months: 

(Target level – Current vitamin D level in ng/ml) x (Bodyweight in kg/70) x 10,000 

An example for someone aiming for levels of 45ng/ml: 

Target level = 45ng/ml Current vitamin D level = 25ng/ml Body weight = 75kg

(45-25) x (75/70) x 10,000 = 214,285 

A dosage of around 3,500 i.u. daily is required to reach vitamin D levels of 45ng/ml over 60 days.

Nuabiome For Women and Men provides 400 i.u. of vitamin D, which will maintain an already healthy vitamin D status, and can safely be used together with an additional vitamin D supplement for a few months if vitamin D deficiency is discovered. 

Always seek the advice of your GP, a qualified medical or nutritional professional before introducing any nutritional supplementation. 


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Cito G, Cocci A, Micelli E, Gabutti A, Russo GI, Coccia ME, Franco G, Serni S, Carini M, Natali A. Vitamin D and Male Fertility: An Updated Review. World J Mens Health. 2020 Apr;38(2):164-177. 

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Amy Martin

Marketing Director

Amy is a high achieving individual with a number of marketing awards under her belt, including Young Digital Business Person of the Year 2019. She is a big believer in digital marketing and an expert in executing personalised targeted campaigns. Amy strives to learn from data and campaigns that show return on investment.

Robert Gordon

Managing Director, Gordons Chemists


Robert Gordon, director at Gordons Chemist's. Gordons Chemists is a chain of more than 60 pharmacies, located in NI and Scotland. Gordons Chemists is Northern Ireland's largest independent pharmacy chain.

Dr. Debbie Collins



Dr. Debbie Collins MBBchBAO MRCGP, a practicing GP and partner in Belfast. She has a passion for patient education and advocacy. Her special interests are Women's Health and Fertility

Sarah Trimble

Nutritional Therapist


Sarah Trimble - a nutritional therapist with a passion for good food instead of fad diets. Sarah has a particular Interest in using the power of nutrition to support hormonal imbalances and reproductive health.

Barbara Scott

Director, Seren Natural Fertility
Chair, Association of Reproductive Reflexologists


Barbara Scott is Chair of The Association of Reproductive Reflexologists, founder of Seren Natural Fertility and author of Reflexology for Fertility. In 2017, she was awarded ‘Complementary Therapist of the Year’ by the Federation of Holistic Therapists and has been nominated for several awards within the field of complementary therapy. In 2019 she was awarded the Innovation in Reflexology Award by the Association of Reflexologists.

Barbara speaks and lectures globally on her integrative approach to supporting couples having difficulties conceiving. She has spoken at many of the Fertility Shows and Fertility Fest. Alongside her own busy clinics, she also trains practitioners in providing this integrative, approach to fertility and reproductive healthcare and well-being. The ARR (Association of Reproductive Reflexologists) has trained practitioners globally, from Australia, New Zealand, Canada, Europe, and most areas of the UK.

Her expertise and passion is in advocating a patient-centred and integrative approach to supporting both men and women on their journey to parenthood.

Cindy Charles

Fertility coach and Founder of Fertilelife


Cindy Charles- Fertility coach and Founder of Fertilelife. Cindy is a committed advocate of social and personal development. Her own life experiences inspired her fertility support services. Cindy has worked with the Fertility Network UK, and has had the privilege to work as a resident Fertility Coach for the London Women's Clinic on Harley Street. Cindy believes in the importance of nurturing our own fertility.

Dr. Lyuda Shkrobot

MD, MSc Gynecologist, Fertility specialist at unq.life fertility clinic


Dr Lyuda has a special interest in reproductive immunology. Dr Shkrobot assisted in establishing the first European Donor Egg programme at Sims, coordinating and liaising with Intersono Clinic in Ukraine Advisors. She is passionate about patient-centred, results-driven care.

Lisa Corcoran

Business Development Executive


Lisa has 15 years of commercial business experience. She has proven her capabilities in Investment Property Sales and, Management & Business Development for Technology companies that have provided her with an understanding of different customer needs across several sectors. Lisa appreciates the value of customer education and relationship building in long-lasting partnerships.

Aoibheann Murphy

Chief Financial Officer


Having trained with PWC, Aoibheann qualified as a Chartered Accountant in 1997. She subsequently spent eight years working in industry, gaining invaluable experience in many areas In 2005 Aoibheann became MD of Pangur Consulting, providing professional expertise to a broad client base. She is looking forward to the new challenge of Nua Fertility.

Share a little about yourself—the things we wouldn’t learn from simply reading your professional bio.


What was your journey to parenthood like?

Right craic!

Do you prefer podcasts or books? And of the one that you prefer, what is a show or title that you recommend?

I love sport…any sport…and the outdoors. Living in the Barrow valley I get to enjoy swimming and kayaking in the Barrow and exploring the Blackstairs mountains. Since I hung up my soccer boots (the body just couldn’t take it anymore!), I’ve been cycling with my lovely friends in Mount Leinster Wheelers and was chuffed to have completed the Ironman 70.3 triathlon event in Dublin in 2019!
I’m an avid reader…books beat podcasts hands down!...although recently I’ve dabbled with audio books through the library app Borrow Box. “A Little Life” left its mark on me. A harrowing story, definitely not for the faint hearted.

If there was just one thing you could impart on women on their journey to parenthood, what would it be?

Don’t be consumed by the roles in your life – parent, partner, employee etc. Parenthood, be it getting there or going through it, will have its tough times. Cherishing yourself as an individual and making time for yourself can help you through those times….it’s good to be a bit selfish!!

Mark Mullins

Director of Sales


What was your journey to parenthood like?

To be honest it was very difficult. At the beginning we thought that when we decided that we wanted to start a family Deborah would fall pregnant shortly afterwards like many of her friends. As time went by, we started to suspect something was wrong. After initial tests we found out that I had a low sperm count which meant that we would have to go down the assisted pregnancy route. This took me several months to get my head around as I blamed myself for this. All I wanted was my wife to be able to go through the pregnancy journey. We couldn’t wait to become parents. There were many long and painful nights where I thought this would never happen for us. After several failed attempts we decided to look at further ways of improving our chances. This led us to look at fertility supplements, our diet, exercise. I will never forget when that morning during our Two Week Wait when Deborah woke me up at 5 a.m. to show me those two lines, we had both been yearning for! We are blessed to now have our beautiful daughter.

On challenging days, what kept you going? Where did you find inspiration?

My wife was my inspiration. She kept me going through those challenging months and years. She was there to help me deal with everything. The guilt I felt when I saw her having to go through everything.

What is your ideal was to relax and unwind?

My latest passion is cooking on my BBQ. I find it so peaceful and I just switch off. It just gives me a bit of alone time which everyone needs.

If there was just one thing you could impart on men as they begin trying to become parents, what would it be?

I would highly recommend communicating with friends and family. A problem shared is a problem halved. Failing that there are some really good private Facebook groups for men suffering from infertility. I found this great support through the good and especially the bad times.

Deborah Brock

Founder & CEO of Nua Fertility


Deborah has a personal passion for fertility health, supporting people and communities. With over 15 years experience of working in the Non profit and Education sector, I have had the honour of working together with people and communities focusing on their strengths, capacities and assets. With extensive senior management, project management and creative programme development experience.

How did your experience with fertility inspire you to help start Nua Fertility?

My own personal fertility journey opened my eyes to the world of fertility health. Trying for a baby is one of the most exciting yet vulnerable times in your life. It took myself and my husband over three years and the helping hand of science to become a mum.  I have always worked with people and communities and felt my vision for Nua Fertility could genuinely support others who have fertility challenges.

Share a little about yourself—the things we wouldn’t learn from simply reading your professional bio.

I'm am curious person and love all things research. My ideal evening would be reading and exploring scientific journals! I like to think I am a little bit creative and I LOVE paint by numbers! Its probably the only time I slow down, I become immersed in the painting and think of nothing else.

What do you want to tell someone trying to conceive or already pregnant?

Educate yourself! Knowledge is power. The more you inform yourself about your fertility health the more you are empowering yourself with knowledge. Own your journey and take control over your own fertility health.

What’s something you wish someone told you while trying to conceive?

Open up and talk with friends and family. I was surrounded by amazing friends and family but I never opened up. When your struggling to conceive, a non-judgemental ear to listen or a shoulder to cry on is so powerful.