Vitamin B12

Why do you need it?

All B vitamins help the body produce energy from food. Vitamin B12 also keeps your nerve cells healthy and helps make DNA – your body’s genetic material. It works closely with folate, to make red blood cells and to help iron work better in the body and can also affect your immune system and mood. This essential vitamin is only needed in small amounts, but that amount is vital for good health! 

Vegans need a B12 supplement

Traditionally, people, as well as farmed animals, got B12 from eating food from the ground because B12 is made by bacteria found in soil. However, now many food production systems are so sanitised, we all need to take a supplement. Some animal products (eg meat and dairy) contain vitamin B12 because animals are given supplements too to make up for poor quality soil or the lack of B12 in their diet, which is no longer natural. This makes the recommendation to eat animal products to obtain B12 somewhat invalid. Cut out the middleman and get it straight from the source by taking a supplement yourself. 


In Uganda, B12 deficiency is not uncommon but is not widely tested for. Some studies looking at it in specific groups found deficiency in one in ten people with diabetes (this may be because the diabetes medication metformin lowers B12 absorption) and almost one-third of HIV-infected children under five years. 

The following symptoms can be a sign of B12 deficiency; extreme tiredness, lack of energy, pins and needles sensation, muscle weakness, depression and problems such as impaired memory, understanding and judgement. A lack of B12 can lead to a raised level of the amino acid homocysteine in the blood which has been linked to heart disease. B12 levels can be checked by a doctor and deficiency can be treated with supplements or a course of injections.

How much do you need?

The World Health Organisation recommends 2.4 micrograms (μg) of vitamin B12 a day for adults aged 19 and over. Their recommended intakes for infants, children, adolescents and pregnant and lactating women are given below.

Recommended nutrient intakes for vitamin B12. Click to read more…
Age groupRecommended nutrient intake
Viva! Uganda recommend
Infants and children
0-6 months0.4
7-12 months0.76 months-3 years
1-3 years0.9
4-6 years1.24-10 years
7-9 years1.8
10-182.411 years onwards
Females, 19+2.4
Males, 19+2.4
Pregnant women2.6
Lactating women2.8
Source: WHO, FAO. 2004. Vitamin and mineral requirements in human nutrition. 2nd ed. Geneva: WHO.

Scientists suggest that official recommendations may be too low and that four to 20 micrograms a day is more appropriate to prevent B12 deficiency. Viva! Uganda recommends taking a daily vitamin B12 supplement providing at least 50 micrograms per day, or weekly supplements once or twice a week that add up to 2,000 micrograms. 

The reason we advise this is because as the dose of B12 you take increases, the amount your body absorbs drops. Vitamin B12 is a water-soluble vitamin, so excess amounts leave the body in the urine and taking 2,000 micrograms of B12 or less a day is unlikely to cause harm.

Where to find vitamin B12

Vitamin B12 supplements can help you meet your daily requirements for this important nutrient. They are available in pharmacies, health food stores and online retailers.

While the best source is a reliable B12 supplement, B12-fortified foods, such as plant-based milks (soya, almond or oat), breakfast cereals and yeast extract, can provide a useful top-up. Nutritional yeast is a popular ingredient in vegan cooking and is often fortified with vitamin B12. It provides a cheesy flavour to dishes and can be sprinkled on salads and pasta or used in sauces to boost your B12 intake.

Find out about the different types of B12 below. Click here to read more.

There are different forms of B12 – the main two are cyanocobalamin and methylcobalamin. Cyanocobalamin is a cheap and stable form of B12 used in most enriched foods and supplements – as long as you’re healthy, it’s perfectly suitable. Methylcobalamin is an ‘active’ form of vitamin B12. It costs more as it is not so stable and is recommended for smokers and people with kidney problems.