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:
- Vitamin B1, also known as thiamine, is required to generate cellular energy. It assists in the metabolism of carbohydrates and supports nerve and muscle function.
- Vitamin B2, known as riboflavin, is essential for normal growth and development, for healthy cellular energy production and to support antioxidant activity in the body.
- Vitamin B3, or niacin, plays a role in more than 200 different metabolic reactions in the body, including cellular energy production and the metabolism of carbohydrates, lipids and proteins. It is also important for circulation, supporting the nervous system and producing hormones such as estrogen, progesterone and testosterone.
- Vitamin B5, also called pantothenic acid, like niacin, supports cellular energy levels and the metabolism of carbohydrates and fats. It is also involved in the production of fatty acids, ketones, cholesterol and neurotransmitters. It is known as the anti-stress vitamin due to its adrenal support function
- Vitamin B6, known as pyridoxine, is involved in over 100 cellular reactions throughout the body. It helps metabolise amino acids and glycogen (the body’s storage form of glucose), is necessary for the production of neurotransmitters, such as serotonin, and supports the body’s nervous system.
- Vitamin B7, or biotin, supports healthy carbohydrate, protein and fat metabolism, energy production, healthy growth and development, and healthy hair, skin and nails.
- Vitamin B9, known as folic acid, is needed for DNA synthesis, the formation of red blood cells and for the metabolism of amino acids. Folic acid is most commonly known for its role in foetal health – it is critical for the development of a baby’s spinal cord and nervous system.
- Vitamin B12, or cobalamin, plays a critical role in cellular energy production, the metabolism of carbohydrates, proteins and lipids. It is also needed for DNA synthesis, red blood cell formation and for a healthy nervous system.
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:
- Too much niacin can cause jaundice and liver problems
- Excess vitamin B6 impairs nerve function and can cause numbness
- Folic acid is essential for preventing birth defects, but excess amounts interfere with the absorption of vitamin B12
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.