Vitamin B12 and unexplained infertility: an often overlooked link
Doctors tend to prescribe a wide range of tests for couples who are having difficulty conceiving naturally. However, some essential factors — such as vitamin B12 and folic acid — are often not taken into account.
Studies have revealed a clear link between diet and fertility, suggesting that couples trying to conceive should pay attention to several vitamins — including folic acid and vitamin B12 — to avoid deficiencies.
Studies on vitamin B12 have shown that low levels can affect fertility in both men and women. About 15% of the population suffers from a vitamin B12 deficiency, with some estimates reaching nearly 40%. Levels considered “normal” are often insufficient compared to the optimal levels needed for fertility.
In a study on IVF conducted at Massachusetts General Hospital, women who achieved the highest pregnancy rates had serum vitamin B12 levels above 700 pg/mL.
This indicates that simply measuring vitamin B12 in the blood is not enough, as it does not assess the B12 available within our cells. One can have a normal or even above-normal blood level of vitamin B12, yet still have a functional deficiency.
The Importance of Vitamin B12 in Fertility
Checking vitamin B12 levels in cases of unexplained infertility is very important, as metabolic toxins can affect the quality of oocytes and sperm, thereby increasing the risk of miscarriage in women or causing complications during pregnancy.
How to Test Your Vitamin B12 Levels?
To determine if our body has a sufficient amount of vitamin B12, we need to measure the level of a toxin produced during normal metabolism that should normally be broken down with the help of B12. This toxin is called methylmalonic acid (MMA). If its level is higher than normal, it indicates a vitamin B12 deficiency. Another similar test is homocysteine, which can reflect a deficiency in vitamin B12, but also in folic acid or other medical conditions.
Causes of Vitamin B12 Deficiency
There are several reasons that can cause a vitamin B12 deficiency. Sometimes, its absorption in its active form requires multiple steps in our body, and these steps can be disrupted by various factors such as MTHFR genes, medications like metformin, autoimmune conditions, celiac disease, or Crohn’s disease.
How to Correct a Vitamin B12 Deficiency?
The standard form of this vitamin is cyanocobalamin, which is not biologically active. For the reasons mentioned above, some people may have difficulty converting it into its active form. It is recommended to choose a prenatal vitamin containing hydroxocobalamin, adenosylcobalamin, or methylcobalamin. If you take a higher dose than your body needs, the excess will be excreted, and the remainder will be used to replenish long-term B12 stores in the liver. You can later discuss with your doctor about reducing the dose during pregnancy.
