B vitamins are a group of water-soluble nutrients that play important roles in energy metabolism, nervous system function, and overall wellbeing. Each B vitamin contributes to different physiological processes:
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B1 (Thiamine): Supports energy metabolism and nerve function.
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B2 (Riboflavin): Involved in energy production and acts as an antioxidant.
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B3 (Niacin): Supports metabolism and contributes to skin health.
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B5 (Pantothenic Acid): Helps the body metabolise fats, carbohydrates, and proteins.
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B6 (Pyridoxine / P-5-P): Supports brain function, neurotransmitter synthesis, and red blood cell formation.
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B7 (Biotin): Contributes to metabolism and the health of hair, skin, and nails.
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B9 (Folate): Important for DNA synthesis, red blood cells, and cognitive function.
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B12 (Cobalamin): Supports nervous system function, brain health, and red blood cell formation.
B vitamins are found in a wide range of foods, including whole grains, legumes, nuts, seeds, green leafy vegetables, eggs, and dairy products. They help the body convert food into energy and contribute to general metabolic processes.
Active Forms of B Vitamins
Some B vitamins are available in “active” forms that the body can use directly. These include:
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Folate → 5-MTHF (methyl folate)
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B12 → methylcobalamin or adenosylcobalamin
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B6 → P-5-P
Certain genetic variations, such as MTHFR variants, can affect how efficiently the body converts standard vitamins into these active forms. In these cases, active forms may be more suitable.
B12 Absorption Considerations
Some individuals may have conditions that affect B12 absorption, such as pernicious anaemia, gut surgery, or certain gastrointestinal disorders. Options for supporting B12 intake can include:
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Sublingual B12
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Higher-dose oral B12 under professional guidance
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B12 injections administered by a qualified healthcare professional
Deficiency Risk Factors and Considerations
| B Vitamin | Why Levels May Be Low | Common Effects of Deficiency |
| B1 Thiamine | Low dietary intake, alcohol use | Fatigue, nerve issues |
| B2 Riboflavin | Poor intake, absorption issues | Low energy, mouth sores, |
| B3 Niacin | Poor diet, absorption problems | Pellagra, skin changes, diarrhoea, cognitive decline |
| B6 | Poor intake, certain medications, conversion issues | Low mood, irritability, nerve symptoms, anaemia |
| B7 Biotin | Rare, genetic factors, long term gut issues | Hair loss, skin rashes, brittle nails |
| B9 Folate | Poor diet, pregnancy, malabsorption, | Fatigue, anaemia, |
| B12 Cobalamin | Pernicious anaemia, gut disorders, vegan diet | Fatigue, neuropathy, memory issues, anaemia |
How to choose supplements!
For most healthy adults, a balanced B complex supplement that provides recommended daily amounts is generally sufficient. Active forms of B vitamins may be considered for individuals with genetic variations, absorption issues, or increased physiological requirements. It is recommended to consult a healthcare professional before starting high-dose supplementation.
Simple guidelines include:
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Confirming potential deficiencies with appropriate lab tests where possible.
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Considering active forms of vitamins for genetic or absorption concerns.
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Selecting a balanced B complex for general daily support rather than assuming one size fits all.
References
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Lyon P, Strippoli V, Fang B, Cimmino L. B Vitamins and One-Carbon Metabolism: Implications in Human Health and Disease. Nutrients. 2020;12(9):2867. doi:10.3390/nu12092867
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Giammarco S, et al. MTHFR polymorphisms and vitamin B12 deficiency: correlation between MTHFR polymorphisms and clinical and laboratory findings. Ann Hematol. 2024;103(10):3973-3977.
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Caffrey A, et al. Epigenetic effects of folate and related B vitamins on brain health throughout life: Scientific substantiation and translation of the evidence for health improvement strategies. Nutr Bull. 2023;48(2):267-277. doi:10.1111/nbu.12611
