We have been facing very hot weather recently. The weather is expected to worsen, and I cannot imagine how hot it will get.
The scorching sunshine burns through our skin, and many of us tend to stay indoors.
Apart from plants, humans also need sunshine to keep healthy.
Vitamin D, otherwise known as the “sunshine vitamin”, is a group of fat-soluble steroid hormones synthesized mainly by the skin on exposure to sunshine.
Less than 10-20% of vitamin D is obtained from diet – the synthesis of vitamin D in the skin is the major natural source of this vitamin.
When our skin is exposed to ultraviolet light from sunshine, it makes the inactive form of vitamin D, D3.
This inactive vitamin D then enters the bloodstream and continues its journey to the liver.
In the liver, through an enzymatic reaction, it is converted to 25-hydroxyvitamin D [25(OH)D].
However, this form of vitamin D is still not physiologically active. It undergoes another enzymatic transformation, mainly in the kidneys, to become 1,25-dihydroxyvitamin D [1-25 (OH)2 D].
This final form is active, and it is now ready to carry out its duties.
Vitamin D is responsible for the absorption of minerals from the gut, namely, calcium, phosphate, iron, magnesium and zinc.
Calcium and phosphate absorption from the gut maintains adequate levels of these minerals in the body, which in turn maintains the normal health of our bones.
Vitamin D exerts its actions via a “vehicle” called vitamin D receptors.
This “vehicle” is not only present in the gut and bones, but also in a woman’s reproductive organs, such as the ovary and uterus (womb).
The expression of this “vehicle” in a woman’s reproductive organs clearly suggests that there is a role for vitamin D in female reproduction.
Vitamin D and female fertility
Generally, vitamin D deficiency is defined as a serum level of less than 20 ng/ml. Values more than 30 ng/ml is considered normal, and a value between 20-30 ng/ml is considered insufficiency.
Vitamin D affects a woman’s fertility by:
• Affecting a woman’s ovarian reserve test
• Affecting “egg” growth
• Affecting factors related to problems with ovulation in a woman with Polycystic Ovarian Syndrome (PCOS).
• Affecting treatment outcome of In-Vitro Fertilisation (IVF).
Lets take a deeper look at these factors.
Couples who have gone through fertility assessment might be familiar with the term “ovarian reserve test”.
If you are a woman, you may have had people telling you to get pregnant and complete your family before you reach your late 30s, as it will be difficult to do so later.
Essentially, they are talking about a woman’s ovarian reserve.
Ovarian reserve is a fertility term that indicates the number of eggs a woman has left. So, an ovarian reserve test indirectly measures how many eggs a woman has.
Currently, the best ovarian reserve test in the market measures the level of Anti-Mullerian Hor-mone (AMH).
A woman with a low AMH value has less eggs left in her ovaries, compared to a woman with a normal AMH level.
This test has less month-to-month variation, compared to other tests such as the Follicle-Stimulating Hormone (FSH) test.
However, research has shown that AMH levels are altered by vitamin D deficiency. A woman with vitamin D deficiency has lower levels of AMH.
This means that this group of women will have a lower AMH value, which indirectly indicates that they have lower fertility (when in fact their ovarian reserve is better than what the AMH shows).
This would then affect the advice and treatment given by the fertility specialist.
Every month during a woman’s menstrual cycle, a few eggs are “chosen” to mature, but only one will eventually grow.
AMH actually protects the pool of eggs in a woman’s ovary. This means AMH prevents too many eggs from growing all at once.
This is where vitamin D plays an important role. Vitamin D has been shown to counteract the repressive effect of AMH on growing eggs.
This action of Vitamin D helps more eggs to grow and reach their maturation and ovulation, thus, optimising the chances of obtaining healthy eggs for couples undergoing fertility treatment.
Polycystic Ovarian Syndrome
PCOS is one of the common causes of infertility. Women with PCOS not only suffer from infertility, but also have menstrual irregularities and obesity.
While a woman with PCOS has many eggs, they are resistant to growth and ovulation. Medications need to be given to boost egg growth.
A woman with PCOS produces a substance that harms the growth of her eggs. This pro-inflammatory substance is called “Advanced Glycation End Products” (AGE).
On the other hand, a woman’s body also produces a protective substance called “soluble receptor sRAGE”. sRage binds to AGE and prevents harmful effects on egg growth.
So, where is vitamin D is this equation?
Vitamin D causes significant increase in sRAGE levels in a woman with PCOS.
This means a woman with PCOS and normal levels of vitamin D is more likely to have egg growth and ovulation than a woman with low levels of vitamin D.
Furthermore, scientific evidence points to the fact that a woman with PCOS is more likely to have low vitamin D, and this phenomenon also contributes to insulin resistance and obesity, which is common in PCOS.
Every couple going through IVF will do everything possible to maximise their success rate. There are many ways to improve success rate, such as weight maintenance, acupuncture and good nutrients.
Vitamin D has been shown to improve IVF success rates. Higher vitamin D levels are associated with higher clinical pregnancy rates.
This again emphasises the importance of testing a women’s vitamin D level prior to IVF treatment.
Since vitamin D has many positive influences in a woman’s journey to motherhood, how can a woman get enough of this vitamin?
Here are a few ways you can achieve this:
Sunlight: I know, I know… we have spoken about it already. This is just to emphasise the point.
About 20-25 minutes of sunlight exposure daily is helpful. If you are dark-skinned, you get less vitamin D from sunlight because your skin pigment blocks sunlight.
Eat fatty fish such as salmon and tuna: These are rich sources of omega-3-fatty acids, which are also very good for fertility.
Mushrooms: Certain mushrooms are grown in ultraviolet light to produce vitamin D. So, the next time you buy mushrooms, check if they are ‘vitamin D mushrooms’.
Drink fortified milk: Fortified milk contains vitamin D.
Eat egg yolk: Yes, eat egg yolk as it contains vitamin D. Of course, do not eat too many as it also contains cholesterol.
Vitamin D supplements: This is probably the easiest way to get vitamin D into your system.
Ultraviolet lights and bulbs: This is similar to tanning beds. This method is usually required for someone who is at high risk of vitamin D deficiency. For the majority, the other six methods will suffice.
Keep in mind that you can re- duce the fear factor in infertility by having the “D” factor taken care of.
Dr A. Agilan is a fertility specialist and gynaecologist. For further information, e-mail firstname.lastname@example.org. The information provided is for educational and communication purposes only and it should not be construed as personal medical advice. Information published in this article is not intended to replace, supplant or augment a consultation with a health professional regarding the reader’s own medical care. The Star disclaims all responsibility for any losses, damage to property or personal injury suffered directly or indirectly from reliance on such information.