Vitamin B isn't one vitamin -- it's 8. This group of water-soluble vitamins is involved in key metabolic processes in the body, such as the breakdown of carbohydrates, proteins and fats for energy production, growth and development.
Why do we need B vitamins?
Each B vitamin has a specific function. Here’s a quick rundown of their roles:
How easy is it to get enough?
It is usually very easy to get sufficient B vitamins from your diet as long as you are not following a restrictive diet.
Whole grains are a good source of B vitamins. Processing grains usually removes most of the B vitamin content, but manufacturers often add the vitamins back. This is especially true for breakfast cereals, bread and flour, which are almost always fortified with B vitamins.
B vitamins are also found abundantly in meat, pulses, beans, nuts, potatoes, bananas, yeast, eggs, dairy products, molasses, dark green leafy vegetables, asparagus and avocados.
Is it possible to get excessive levels of B vitamins?
B vitamins are water-soluble and excess vitamins are eliminated in the urine. Taking large doses of certain B vitamins usually only produces transient side effects, such as restlessness, nausea and insomnia. These side effects are almost always a result of excessive dietary supplements and not from foods containing B vitamins.
But an excessive intake of certain B vitamins can cause more long-term issues:
With a tolerable upper level of just 1mg (250% of the recommended daily intake) for folic acid and many foods now fortified with this nutrient, it is not impossible to exceed this value regularly.
Is it possible to be deficient in B vitamins?
If you are eating a healthy, well-balanced diet containing good sources of B vitamins, such as meat, eggs, dairy products, legumes, fruit and vegetables, it is very rare to suffer from a B-vitamin deficiency. However, you will probably be deficient in vitamin B12 if you are vegetarian and almost certainly if you are vegan because vitamin B12 is not adequately integrated from plant foods.
If you are pregnant, it is vital to ensure that you are getting enough vitamin B9 (folic acid), especially in the early weeks of pregnancy, to prevent birth defects. A supplement may be useful to cover this increased need.
So, in summary, unless you are on a restrictive diet or pregnant, it is probably unnecessary to take a daily supplement containing B vitamins.