Vitamin D and fertility. Will it improve your egg quality?

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Vitamin D is a double-edged sword.

Too much and too little will both harm your fertility. It is proven that people and mice with vitamin D deficiency reduces their ability to breed. Same goes if you have an excess of Vitamin D. How to know if you are doing it right?

Vitamin D and fertility

Vitamin D is very popular. It should be. We get 80% of what we need from the sun. 20% from our diet.

It is suggested 1 billion people worldwide have Vitamin D deficiency.

How could this happen?

Science suggests that depending on your skin pigmentation that you can get your daily dose in 5 – 20 minutes. That’s all.

So why are 1 billion people Vitamin D deficient?

Not getting enough sun on their skin apparently.

We have done such a good job on window tinting, staying indoors and using sunscreen. It prevents those nasty UV rays getting to us, but it is now affecting our health.

What is the best thing to do for vitamin D?

Get outdoors, take you shoes off, roll your sleeves up and take a 15 minute stroll at lunch-time. Not only is it good for your physical health, it is good for your mental health too.

What about Vitamin D and feRtility?
Have you heard it can improve egg quality?

It is proven that making mice vitamin D deficient reduces their ability to breed. In female mice it interferes with egg implantation. In male mice it interferes with their ability to produce quality sperm.

These same studies also found too much Vitamin D is no good either.

Very high vitamin D levels can reduce the corpus luteum, progesterone, and oestrogen. In mice anyway.

Winter in cold areas affects your fertility. It’s proven.

Ovulation rates and endometrial receptivity are reduced during long dark winters in northern countries.

One study says that women with correct Vitamin D levels and 4 times more likely to fall pregnant using IVF. Another study done exactly the same way found no differences at all.

To date, there is insufficient data to accurately evaluate the effects of vitamin D in women undergoing IVF.

If you don’t need it, don’t take it.

Studies done on healthy women taking Vitamin D supplements show a decrease in estradoil and progesterone. These hormones are very important for fertility.

What about the guys?

Science says Vitamin D is important for sperm production in men. Yet, no trial has ever tested vitamin D to see if and how much it can improve sperm quality in mice or men.

Sperm motility is lower in men with vitamin D deficiency.

Men with less than 10 ng/ml of vitamin D in their blood stream have problems with sperm motility, morphology and count.

Men with too much vitamin D also had the same problem.

When these studies also included the seasons, smoking and drinking, the conclusions failed.

Does taking Vitamin D improve sperm quality in any way?

Who has got the evidence?

Nobody has done any testing and nobody knows anybody who has done the testing, and it seems, nobody is looking either.

So where did the idea that Vitamin D improved sperm quality come from?

It came from knowing that vitamin D deficient men often also had bad sperm.

Until someone actually does the testing, we will not know if it helps or not. We saw that it helped some women in one trail, but did nothing for others in a repeat of the trial.

But it is enough to create a belief that Vitamin D3 can help with male infertility and sperm quality. Which is completely untested, we now know.

We do know that maintaining vitamin D levels while pregnant is very good for you and your baby.

One study done with 350 women in 2011 showed that vitamin D had no adverse effects. In fact it reduced miscarriages and pre-eclampsia. You should know that the women stated taking it after 12 weeks of pregnancy. The first 12 weeks are the most probable times for a miscarriage. Rates drop significantly after the first trimester. No pre-eclampsia is a real win for pregnant women everywhere.


What we know.

Vitamin D and fertility go hand in hand.

Vitamin D is essential for good health and fertility.

1 billion people do not get outdoors enough during the day.

Trials on mice show that not enough vitamin D will reduce their ability to breed.

Men need Vitamin D for sperm production.

The evidence it helps men’s sperm in any way has never been tested, not even on mice.

We know that maintaining your levels is a smart thing to do.

We also know that taking too much will interfere with your fertility.

You don’t want that.

What we don’t know.

We don’t know if Vitamin D improves pregnancy outcomes with IVF. There is conflicting evidence and nobody is testing it any more.

There is no evidence that Vitamin D3 improves egg quality or pregnancy rates in any women. All we know is that it play a role in the production of maturing eggs.

Next time you get a blood test have your Vitamin D levels checked.Don’t take it blindly. Go for a walk at lunch-time and avoid the problem entirely.

Vitamin D and fertility

Check the science for yourself using the links in the text or the links below.

Halhali A AG, Garabédian M. 1,25-Dihydroxyvitamin D3 induces in vivo the decidualization of rat endometrial cells. J Reprod Fertil 1991 91 59-64.

Kwiecinski GG, Petrie GI, DeLuca HF. Vitamin D is necessary for reproductive functions of the male rat. J Nutr 1989 119 741-744.

Horii I, Takizawa S, Fujii T. Effect of 1,25-dihydroxyvitamin D3 on the female reproductive system in rats. J Toxicol Sci 1992 17 91-10.

Rojansky N, Benshushan A, Meirsdorf S, Lewin A, Laufer N, Safran A. Seasonal variability in fertilization and embryo quality rates in women undergoing IVF. Fertil Steril 2000 74 476-481.

Ozkan S, Jindal S, Greenseid K, Shu J, Zeitlian G, Hickmon C, Pal L. Replete vitamin D stores predict reproductive success following in vitro fertilization. Fertil Steril 2009 in press.

Aleyasin A, Hosseini MA, Mahdavi A, Safdarian L, Fallahi P, Mohajeri MR, Abbasi M, Esfahani F. Predictive value of the level of vitamin D in follicular fluid on the outcome of assisted reproductive technology. Eur J Obstet Gynecol Reprod Biol 2011 159 132-7.

E Lerchbaum, BR Obermayer-Pietsch. Vitamin D and fertility – a systematic review. European Journal of Endocrinology, 2012 – EFES

Knight JA, Wong J, Blackmore KM, Raboud JM, Vieth R. Vitamin D association with estradiol and progesterone in young women. Cancer Causes Control 2010 21 479-483.

Blomberg Jensen M, Bjerrum PJ, Jessen TE, Nielsen JE, Joensen UN, Olesen IA, Petersen JH, Juul A, Dissing S, Jørgensen N. Vitamin D is positively associated with sperm motility and increases intracellular calcium in human spermatozoa. Hum Reprod 2011 26 1307-1317.

Ramlau-Hansen CH, Moeller UK, Bonde JP, Olsen J, Thulstrup AM. Are serum levels of vitamin D associated with semen quality? Results from a cross-sectional study in young healthy men. Fertil Steril 2011 95 1000-1004.

Hollis BW. Randomized controlled trials to determine the safety of vitamin D supplementation during pregnancy and lactation. In Fourteenth Workshop on Vitamin D Brugge, Belgium, 2009.

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