The Water-Soluble Vitamins


Dr Noureen Ahmad

General Practitioner, Belgium

The water-soluble vitamins can be divided in two groups: one group contains all forms of vitamin B whilst the other water-soluble vitamin is vitamin C. 

In this article the main focus lies on the B complex vitamins. These consist of the following vitamins: vitamin B1 (thiamine), vitamin B2 (riboflavin), vitamin B3 (niacin), vitamin B5 (pantothenic acid), vitamin B6 (pyridoxine), vitamin B7 (biotin), vitamin B9 (folate), vitamin B12 (cobalamin). Some of the vitamin B deficiencies are rare, like vitamins B2, B5, B6 and B7. Due to this reason, these vitamins won’t be discussed further. 

Deficiencies of vitamin B complex occur in specific circumstances, usually in population groups that are displaced, for example refugees. 

Vitamin B1 (thiamine) is usually found in good sources such as brown rice and whole grains. It is believed that this vitamin is important in starting an impulse for the conduction in nerves and its levels can be measured in the blood. Deficiency of thiamine can lead to neurological conditions such as “beriberi” or a syndrome known as “Wernicke-Korsakoff syndrome”. Beriberi is more common in Asia whilst Wernicke-Korsakoff syndrome is familiar in resource-rich countries. Beriberi can present itself as a dry form, which is an impairment of sensory and motor systems in the arms and legs (nerves dysfunction). The wet form of beriberi involves cardiovascular problems affecting the heart rate and potentially leading to heart failure. Wernicke-Korsakoff syndrome is commonly seen in resource-rich countries and especially in individuals who suffer from chronic alcoholism. This condition results in a loss of muscle coordination, short-term memory loss and impairment of the normal reasoning and perception. If these individuals don’t receive vitamin B1 on time, their situation can deteriorate progressing to a coma and eventually leading to death. 

Vitamin B3 (niacin) can be found in lentils, chicken and tuna. This vitamin plays a big role in cellular metabolism. Deficiencies can result in a condition called “pellagra”, which causes symptoms such as skin lesions, diarrhoea, and dementia. In severe situations and if left untreated this condition can be fatal. This deficiency is common in resource-poor countries like Africa, India and China. In resource-rich countries like the UK, this is usually seen due to chronic alcoholism.

The following vitamin is very well known; vitamin B12. This vitamin is present in sources such as chicken, meats, fish, liver and dairy products. During the digestion of food in the stomach, vitamin B12 becomes free and binds to a protein called IF (Intrinsic Factor) synthesised by the cells in the stomach and this complex is then absorbed in the intestine. Vitamin B12 cannot be properly absorbed from the diet if it is not bound to IF. Deficiencies can be caused due to inadequate intake of it through a diet (i.e. in cases of vegans). 

Another cause is malabsorption, and this can be due to the condition of the stomach (surgery or lack of IF usually due to pernicious anaemia) or the condition of the intestines (surgery of the bowel or bowel diseases). 

Deficiency of vitamin B12 can result in symptoms of anaemia (tiredness, fatigue, pallor, chest pain and shortness of breath), nerves dysfunction and psychiatric problems (memory loss and psychosis). A specific cause of vitamin B12 deficiency is pernicious anaemia, which is an autoimmune disorder. This is where the body makes antibodies against the stomach cells and the protein IF resulting in damage of these cells and thus causing less uptake of vitamin B12. This form of anaemia is usually present in individuals with other autoimmune diseases. Individuals with pernicious anaemia also have a high risk of stomach cancer, especially for the two years after diagnosis, therefore they must be followed up properly. 

Treatment of vitamin B12 deficiency can be done with vitamin B12 tablets or with intramuscular injections of vitamin B12 ampoules. The tablets can be given if the cause is only due to dietary deficiency. 

For children, the dose is 100 micrograms (mcg) once per week and when the deficiency is corrected, it can be given once every month. For adults, the effective dose is 1000 mcg daily. The guidelines for the injections of vitamin B12 are slightly variable, but usually it is advised to start with 1000 mcg 3 times a week for two weeks and then every 2-3 months. After eight weeks, a follow up of the blood cells and vitamin B12 status is needed to check the efficiency of the supplementation.

Vitamin B9, better known as folate, is a vitamin usually found in yeast, liver, nuts and green vegetables such as spinach. The supplementation of this vitamin is essential during pregnancy, because a deficiency of folate can lead to permanent neural tube defects (spinal cord and brain) in the unborn baby. Subsequently, these defects can lead to spina bifida (incomplete development of the spinal column causing a gap in the spine) and anencephaly (undeveloped brain and skull resulting in death). The risk factors for developing folate deficiency are an increased demand (pregnancy), poor diet (elderly, alcoholics), medication (methotrexate) and malabsorption. Usually a folate deficiency co-exists with vitamin B12 deficiency and so this needs to be checked in the blood as well.

Supplementation of folate deficiency exists of 15 milligrams (mg) of folic acid (synthetically form of folate) daily for four months. It is advised that all women start with 0.4 mg/daily of folic acid from the day they start planning pregnancy till the time when they are 12 weeks pregnant. This is because in this period the development of the nerve system of the unborn baby takes place. Higher dose such as 4 mg/daily is recommended if there is a history of neural tube defects in the family.

(Always discuss with your doctor what supplements you want to take or are taking so your health and wellbeing can be properly looked after.)

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