All vitamins and minerals should generally be obtained from a healthy, balanced diet. The more diverse the diet, the more exposure to a vast range of nutrients. Although some people swear by taking daily supplements, there is conflicting research as to whether taking supplements are actually significantly beneficial to health and prevention of disease.

General overview of important vitamins: 

Vitamin A – Chemical names: retinol, retinal and carotenoids.

Found in carrots, liver, fruits and vegetables, milk, leafy greens etc. Deficiency disease is night blindness and hyperkeratosis – the thickening of the outmost layer of skin.

Vitamin C – Chemical name: ascorbic acid.

When deficient, this can cause Scurvy, a common disease for pirates. Vitamin C is found in citrus fruits (such as oranges and lemons), leafy greens (broccoli and kale), and peppers. Symptoms of Vitamin C deficiency include spots on the tongue, bleeding gums, and pale or yellow skin.

Vitamin D – Chemical names: Cholecalciferol (D3) and Ergocalciferol (D2).

Vitamin D can also be made in the skin when exposed to sunlight. The main deficiency disease is rickets, a common childhood disease in developing countries. In rickets, the bones become mineralised or calcified, leading to risk of fractures and deformities.

At London Doctors Clinic, we offer blood tests to measure levels of all of these vitamins, if required.


We could spend a lifetime telling you all about every single dietary nutrient, however today we're focusing more on:

Vitamins B12 and B9.

Vitamin B12’s chemical name is Conalamin, which is essential in maintaining a healthy nervous system, brain, and the formation of red blood cells (erythrocytes).

Additionally, Vitamin B9, otherwise known as Folate or Folic acid, is also essential for red blood cell formation. It's also essential during early pregnancy, to avoid neural tube defects in the unborn baby, such as spina bifida and anencephaloces. Deficiency disease in adults presents as megaloblastic anaemia.

A lack of either vitamin B12 or B9 can lead to the formation of malfunctioning red blood cells. This can in turn lead to a type of anaemia (fewer than normal red blood cells, or a low haemoglobin count). This is different to the more common ‘iron deficiency anaemia’, which is caused by lack of iron required for healthy erythrocytes

Symptoms of Vitamin B12, or Folate deficiency anaemias are:

  • Tiredness
  • Muscle weakness
  • Pins and needles (paraesthesia)
  • Sore, red tongue
  • Vision disturbances
  • Cognitive function problems: memory loss, change in judgement and understanding

Vitamin B12 levels can be measured with a simple blood test, costing just £78.40 and results usually available next-day.

Alternatively, both Vitamins B12 and red blood cell Folate can be measured in another test costing just £127.70, with results available in just 2 days.

Vitamin B12/B9 Deficiency: Causes

There are a few different causes for B12 or Folate deficiency anaemias. The first, like other vitamin deficiencies, is a lack of the vitamin in the diet. In this situation, dietary advice on how to increase vitamins B12 or B9 uptake would be given.

Another potential cause for these Vitamin B-associated anaemias is an interaction between vitamin absorption mechanisms and certain medications. For example, some anticonvulsant medications, and drugs that are proton pump inhibitors (PPIs) may affect vitamin uptake, leading to low vitamins B9 and B12 levels, and risk of B12 or folate deficiency anaemia. Other diseases such as coeliac disease can cause reduced nutrient absorption.

The most common cause for a deficiency in Vitamin B12 uptake is also inhibited in the case of pernicious anaemia, an autoimmune condition whereby the body’s immune system mistakenly attacks health stomach cells. This then prevents the absorption of vitamin B12 from the diet. 


Some causes of Vitamin B12 deficiency.



As usual, the best way to treat a deficiency, is to replace or replenish the missing nutrient. If this can’t be done sufficiently through diet, good levels of Vitamin B12 can be achieved through injections or tablets. If the cause is pernicious anaemia, life-long treatment is required.

It’s important that patients with Vitamin B12 or Folate deficiency anaemia monitor their condition, as to avoid any potential serious complications, such as:

  • Nervous system problems
  • Infertility (although this is usually temporary)
  • Heart conditions
  • Pregnancy complications and birth defects

So you’re experiencing any anaemia-like symptoms, such as tiredness and paraesthesia, it’s a good idea to see a GP to discuss this. During a 15-minute GP consultation, costing just from £89, the doctor can discuss and assess your symptoms, and recommend any necessary investigative blood tests. From there, one of our doctors will get back to you as soon as possible with your blood test results, and advise what necessary steps should be taken.