Updated 31 October 2016

What's sapping your vitamin B levels?

Be aware that some medications and medical conditions are linked to vitamin B deficiencies.

Most health conscious people are quite clued up about the roles that vitamins play in keeping us healthy. However, just because you eat a lot of vitamin B-rich foods like wholegrain bread, leafy green vegetables, meat, cheese and eggs doesn’t mean you can’t develop a deficiency.

A medical condition or chronic medicine could seriously deplete B vitamins in your body.

The B vitamins comprise a group of eight water-soluble vitamins that are crucial for a wide range of different metabolic processes in the body. The body is unable to store most of them, so make sure you get enough in your diet.

Read: B-Vitamins Help Protect Against Stroke, Heart Disease

Conditions that cause vitamin B deficiencies

B9 (folic acid), B6 and B12 appear to be linked more often to conditions and medicines that cause serious deficiencies.

Vitamin B12 deficiency may occur with:

  • Digestive disorders – can decrease the amount of Vitamin B12 your body is able to absorb
  • Pernicious anaemia – a condition in which your immune system attacks healthy cells in your stomach, preventing your body from absorbing B12 from the food you eat

Symptoms of a B12 deficiency include fatigue, poor appetite, depression and numbness/tingling in the hands and/or feet. A B12 deficiency can cause progressive nervous system damage, so speak to your doctor promptly about treatment.

Read: To B12 or not B12?

Vitamin B6 and/or B9 deficiency may occur with:

  • Kidney disease – end-stage renal diseases and chronic renal insufficiency
  • Inflammatory bowel diseases – Crohn's disease and ulcerative colitis
  • Digestive disorders – coeliac disease
  • Rheumatoid arthritis – associated with vitamin B6 deficiency, tending to worsen as the disease becomes more severe
  • Cancer or chronic inflammation – can cause an increase in your body's demand for B9 (folate) and enhance vitamin B6 degradation

Several of the B-vitamins (B2, B6, B9 and B12) affect brain metabolism and contribute to psychiatric illnesses like depression and behavioural disorders.

Deficiencies of B6, B9 and B12 seldom arise on their own. They usually occur with low concentrations of other B-vitamins like B2 (riboflavin).

Medicines that can interfere with the body’s absorption or use of B12 include:

  • Antibiotics (e.g. tetracycline) – used to treat certain infections         
  • Proton pump inhibiters (PPIs) – for peptic ulcer disease and acid reflux
  • H2 receptor antagonists (Tagamet and Zantac) –  to treat stomach ulcers (peptic ulcer) and gastroesophageal reflux disease (GORD)
  • Metformin (Glucophage) – for diabetes

Medicines that affect Vitamin B6 absorption:

  • Anti-convulsant drugs (carbamazepine [Carbatrol, Epitol, Tegretol], valproic acid [Depakene, Stavzor] and phenytoin [Dilantin] – used to treat epilepsy
  • Cycloserine (Seromycin) – a broad-spectrum antibiotic used to treat tuberculosis
  • Oral contraceptives, especially those with high doses of oestrogen
  • Theophylline (Aquaphyllin, Elixophyllin, Theolair) – used to prevent or treat wheezing, shortness of breath and other respiratory problems caused by certain lung conditions such as asthma, chronic bronchitis and emphysema.

Read: How much vitamin B6 you need

Medicines affecting B9 (folate):

  • Nonsteroidal anti-inflammatory drugs (NSAIDs) (e.g. aspirin or ibuprofen) – may interfere with folate metabolism in high doses
  • Cholesterol-lowering drugs (e.g. cholestyramine [QuestranLite] and colestipol [Colestid]) – may decrease the absorption of folic acid
  • Oral contraceptives, especially those with high doses of oestrogen.

Advice on B vitamins

  • Always tell your doctor or pharmacist about any dietary supplements and prescription or over-the-counter (OTC) medicines you take regularly. They’ll assess whether any might interfere with how your body absorbs, uses or breaks down B-vitamins.
  • Avoid unnecessary long-term use of antibiotics – they can lower levels of B2, B9, and B12.
  • If you suspect a vitamin B deficiency, see your doctor or dietitian for advice. Avoid deficiency self-diagnosis – some vitamins can be toxic if taken incorrectly.

Read more:

Getting smarter about vitamin B deficiency

Why vitamin B is so important for a healthy nervous system

Take the vitamin B quiz and win!









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