It’s not uncommon to feel a bit depressed in winter; it’s cold and the days are darker. This may be seasonal affective disorder caused by reduced light or it could be caused by a low blood level of vitamin B12.

As you get older your ability to absorb vitamin B12 often reduces. This is due to your body’s declining production of a protein called Intrinsic Factor. Intrinsic Factor helps your body absorb vitamin B12.

Metformin is a medication often used as a first line medication treatment for insulin resistance in type 2 diabetes. Sometimes it is used in gestational diabetes and people living with type 1 diabetes who are insulin resistant. Metformin reduces the absorption of vitamin B12.

Deficiency of vitamin B12 may also occur at times of rapid growth – childhood, adolescence, and pregnancy, in pernicious anaemia, with excess alcohol intake, some inherited conditions, or due to a diet lacking in it, such as a vegan diet.

What does vitamin B12 do in your body?

Vitamin B12 is a group of compounds which contain biologically active cyanocobalamin, a water-soluble vitamin, which acts as an essential co-enzyme in red blood cell formation, brain and nerve function, and DNA synthesis. Deficiency may cause:

• changes in personality
• feeling irritable and depressed
• memory loss
• lack of energy
• impaired taste
• glossitis – a swollen and inflamed tongue
• a range of nerve related issues including neuropathy or loss of proprioception – the ability to feel where your body is in space
• heart issues including an increase in homocysteine, a recognised cardiovascular risk factor
• blood problems which can result in looking pale, shortness of breath and palpitations (rapid heart beat)

A low level of vitamin B12 is not a good thing.

What food contains vitamin B12?

Animal products are the main source of vitamin B12 in our diet: meat, poultry, fish, eggs, milk, and dairy products.

Some of our foods are fortified with vitamin B12, including meat replacements and some plant-based milks.

The recommended daily intake for vitamin B12 is 2.4ug (microgram)/day for men and women 19-over 70 years old, 2.6ug/day for pregnant women and 2.8ug/day for breastfeeding women.

When to see your doctor

People living with diabetes who have neuropathy or are taking Metformin should have their vitamin B12 levels measured regularly by their general practitioner. If you follow a vegan diet or if you are feeling a bit low, see your doctor for a check-up and some blood tests.

If vitamin B12 is present in your diet but your blood level is low, it may be due to a lack of absorption and your doctor will give you an injection of vitamin B12 every three months. If your diet is lacking in vitamin B12, see an accredited practising dietitian for a diet check-up; you may have to take a vitamin B12 supplement in the short term to get your levels back to normal.

You’ll be feeling better in no time!

By Dale Cooke, Accredited Practising Dietitian