Use of the popular insulin-sensitising drug, Metformin, has grown in recent years.

Large numbers of women who have been diagnosed with Polycystic Ovarian Syndrome (PCOS) report Metformin helps significantly with overall symptoms, as well as with reproduction.

New research, however, is cause for a serious warning to Metformin users: they should ensure they’re not becoming deficient in vitamin B12.

This vitamin is essential for our health – particularly nerve and blood cell health – and it also helps to make DNA.

But the body does not produce vitamin B12.

If enough vitamin B12 isn’t consumed, and properly absorbed by the body, a vitamin deficiency occurs.

What Is Metformin?

Metformin is an insulin-sensitising drug. This means the drug increases the sensitivity of your fat, liver, and muscle to the insulin your body produces. It also suppresses the liver’s release of glucose, and it slows down the absorption of the carbohydrates you consume.

For people with Type 2 diabetes and insulin resistance, the medication helps to maintain healthy levels of blood glucose.

Why Do Women With PCOS Take Metformin?

PCOS is a common endocrine disorder that affects women of reproductive age.

Women with PCOS have enlarged polycystic ovaries (the ovaries are covered with small, fluid filled cysts), as well as higher levels of male hormones, irregular ovulation, and insulin resistance.

While health professionals aren’t 100% sure of the cause, they know insulin resistance is a large component of the condition.

Like the luteinising hormone (LH), estrogen, and progesterone, insulin is a hormone that plays a role in reproductive health. Insulin resistance, which results in higher blood sugar levels, affects reproductive health, fertility and overall wellness.

People with Type 2 diabetes take Metformin to control blood glucose levels. Women with PCOS use it for the same reason. When blood glucose levels are controlled, the endocrine system and hormones are positively affected, which helps with symptoms of PCOS.

While taking Metformin, many also experience significant weight loss, because the body is better able to process carbohydrates, and maintain healthy insulin and glucose levels.

What Does The Research Show About B12 Deficiency?

PCOS is a common reproductive health issue but, unfortunately, it is not thoroughly studied and understood.

Because Metformin is used for Type 2 diabetes, however, many studies have been done with regard to its use, and its potential side effects or complications.

The Diabetes Prevention Program Outcomes Study (DPPOS) compared the B12 levels of Metformin users with those taking a placebo, over a 5-year period. Those on Metformin took 850mg/day.

The study found:

Of those on Metformin, 4.3% had low levels of B12 (<203 pg/ml) compared with 2.3% on a placebo
Of those on Metformin, 19% had borderline low B12 levels (204–298 pg/ml) compared with 9.5% on a placebo

This information suggests that those on Metformin would probably need to consume more vitamin B12 – most likely a regular supplement.

It’s also very important to note that women who take Metformin for PCOS typically take a much larger dose than those who take it for Type 2 diabetes.

The average dose for a woman with PCOS is 1500-2000mg/day. This might mean that women who have PCOS and take Metformin might be at an even higher risk for vitamin B12 deficiency.

What Are The Symptoms Of Vitamin B12 Deficiency?

Vitamin B12 plays a very important role in the body – it’s involved in the creation of DNA and red blood cells.

According to WebMD, a mild deficiency may have no symptoms, but if left untreated, symptoms can develop.

Some of the symptoms experienced by those low in vitamin B12 include:

Heart palpitations
Shortness of breath
Weakness, fatigue and lightheadedness
Depression, memory loss and other behavioural issues
Pale skin
Gastrointestinal upsets, like gas, constipation, diahorrea
Muscle weakness, numbness or tingling

A deficiency can also lead to anaemia as well as nerve damage. Unfortunately, nerve damage can be permanent.

What Does This Mean For Women With PCOS?

The treatment and control of PCOS will depend upon a woman’s symptoms, her reproductive goals, and her overall health. Different healthcare providers offer a variety of PCOS treatment suggestions and options.

What this study suggests, however, is that if you’re on Metformin, you’ll probably need a vitamin B12 supplement. Of course, make sure you speak to your doctor first, before taking any new medicines or supplements.

Metformin is an effective medical treatment for PCOS. However, other options are available, and some women find them helpful in place of, or in addition to, Metformin.

Some of these treatment and lifestyle options are:

Overall dietary and lifestyle changes – the World Health Organization’s number one recommendation for treatment of PCOS
Maintaining a diabetes friendly diet, which includes a limited amount of low-glycemic carbohydrates, adequate intake of healthy proteins throughout the day, and the consumption of healthy fats, such as nuts, avocado and fish
Regular exercise, and some activity following meals. A simple walk after dinner can help maintain healthy blood sugar levels
Drastically reducing or eliminating processed sugars and carbohydrates, such as refined sugar, white bread products, and juices
Increased intake of essential fatty acids
Going on the pill – this can help ease symptoms, but doesn’t treat the actual cause of PCOS and its symptoms and may mask other problems
Acupuncture and other Traditional Chinese Medicine treatments
Giving up smoking

You can read more about Polycystic Ovarian Syndrome in BellyBelly’s article Polycystic Ovarian Syndrome (PCOS), written by women’s health and reproductive medicine specialist, Dr. Andrew Orr.