The biological consequences of malnutrition are an important public health problem; Vinicus et al. stated that undernutrition is ‘affecting more 900 million individuals around the world.’1 Folate and vitamin B12 are important in the diet of growing and matured individuals; as they regulate levels of homocysteine, which can be converted to methionine, an amino acid, and latter can be used in the formation of proteins in the body. These natural molecules are significant for the development and maintenance of biological functions in the human body.
Folate is a salt of folic acid, it is a B vitamin that is a vital factor in the synthesis of DNA and RNA in the making of nucleic acid.2 It is naturally present in an abundance of food such as citrus fruits, bread, and leafy green vegetable, making it an easily accessible nutrient for many individuals. The British Dietetics Association states the importance of folate in the body is linked to the production and repair of DNA and RNA, aiding in the cell cycle and replacement of cells, such as red blood cells. Folate has been implicated in memory improvement and further evidence has seen that it can also protect heart health.3 Due to being a water-soluble vitamin, folate cannot be stored in fat cells, this means that an individual must maintain an intake of folate in their diet.4 Causes of folate deficiency include dietary neglect, blood disorders (such as sickle cell anaemia and chronic myelosclerosis), and excessive urinary excretion from conditions such as acute liver damage and chronic dialysis. Genetic factors may also play a factor; as a mutation in the SLC46A1 gene leads to folate transporter deficiency.5 The impact on the body from folate deficiency can lead to anaemia- a condition described as the number of functional red blood cells is below normal in the blood6 – where an individual can experience tiredness, feeling faint, and becoming easily breathless; which are common symptoms associated with the deficiency. Less common effects on the body include headaches, heart palpitations, and suffering from tinnitus.7 Long term effects can lead to complications of the nervous system, infertility development, and serious hearing conditions.8
Vitamin B12 is a nutrient that aids also in the production of nucleic acids; B12 helps in the formation and maintenance of blood cells and nerve tissues.9 Dr Group states in an article focusing on the functions of vitamin B12, as vitamin B12 has also been described to be essential for the production of energy, as it provides energy for cells, ensuring there is an adequate balance for the day.10 The vitamin has also been associated with the formation of neurotransmitter, serotonin, which plays an important role in the regulation of mood, and therefore lack of B12 can lead to depression as found in a study of diabetic patients.11 Vitamin B12 interactions with folate play an important role in the regulation of homocysteine levels and protection against heart disease.12 Pernicious anaemia, an autoimmune disease that cause the immune system to attack the cells in the stomach-that produces a factor called intrinsic factor that aids in the absorption of vitamin B12-is known as a common cause of vitamin B12 deficiency; other causes such as Crohn’s disease also affects the lining of the intestines from absorbing vitamin B12 due inflammation.13 A deficiency of B12 is linked to anaemia and psychological problems more common in older individuals. Cognitive and behavioural changes from disorders such dementia, paranoia, and depression are common with vitamin B12 deficiency. Neurological changes may occur with patients feeling weakness and extreme fatigue, and tingling in the feet and hands. 14 These changes result in permanent alterations that cannot be easily reversed. Skin lesions and hyperpigmentation have been related to decreased levels of B12. Mori and Ando (2001) investigated the case of a forty-nine-year-old man, where histology had shown an increase of melanin in the basal layer; that was later corrected with vitamin B12 supplementation.15 Long term effects of this deficiency ensure a permanent interference of nerve activity and destruction of the myelin sheath, this damage would still present even after treatment of vitamin B12 deficiency, as supplementation with B12 cannot repair the damage of the myelin sheath.16
Homocysteine is an amino acid present in the blood plasma, produced as a by-product from the consumption of meat.17 Homocysteine is broken down and converted into cysteine, that can be used as an amino acid during protein synthesis. Cysteine is used as an anti-oxidant and involved in the folding and shape maintenance of proteins; it also plays a part in metabolic reactions of different metals in the body such as iron, zinc, and copper.18 Folate and vitamin B12 work together to ensure the levels of homocysteine are regulated in the blood, high levels of homocysteine are associated with decreased levels of folate and B12; as these levels are controlled in an individual’s diet, it has commonly been linked to malnutrition. A genetic MTHFR (methylenetetrahydrofolate reductase) mutation could also be a cause of high homocysteine levels, this affects folate and vitamin B12 interaction pathway required to lower the homocysteine levels, as the genes change the way individuals are able to metabolize and convert the needed nutrients and vitamins in their diet. Other causes of these elevated levels of this amino acid are renal diseases and thyroid hormones. Major heart diseases, including coronary heart disease and high blood pressure, are linked to high homocysteine levels, due to the hyperhomocysteinemia causing blood clotting, increased inflammation, and blockage of arteries.19 Cognitive disorders, especially in older patients, are symptoms of the elevated levels, including Alzheimer’s disease and dementia. Children with high homocysteine levels have a greater risk for skeletal and anatomical development abnormalities; behavioural and learning disabilities may also occur, such as ADHD and autism.20
Both folate and vitamin B12 play important role in several biological functions and one of these functions is maintaining a low level of homocysteine as high levels of latter have been linked to several diseases such as diabetes, rheumatoid arthritis, and high blood pressure.21 Though they work together to maintain a healthy body, they all have different functions to make certain those multiple diseases and disorders previously mentioned are at a lower risk of developing. This keeps the human body a healthy functioning system without serious biological consequences occurring.