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The not-so-complex guide of the Vitamin B Complex

By: Mint Suetrong, Contributing Writer

Edited by: Elias Azizi, Editor in Chief

Food and nutrition have been taught to students worldwide: a healthy diet comprises the 'right' portions of five major food groups consisting of carbohydrates, proteins, fats, dairy, and fruits and vegetables. Then there are vitamins and minerals. What are they and why do we need them?

Vitamins are coenzymes which catalyze reactions to maintain healthy cell function, growth and development. Although they are required in small quantities, they are in fact essential in regulating your body’s internal chemical reactions such as your metabolism and converting the food you eat into energy. Vitamins can be categorized into two distinct categories, fat-soluble vitamins and water-soluble vitamins. Some examples of fat-soluble vitamins are A, D, E, and K. Water-soluble vitamins include all 8 Vitamin B’s and Vitamin C. As fat-soluble vitamins cannot be excreted through urine like water-soluble vitamins, overconsumption of fat-soluble vitamins can cause harmful build-ups in the fat stores around our body. It should be noted, however, that both types of vitamins should be consumed in moderation, as recommended by guidelines, such as the NHS, or modified for you by healthcare professionals.

In this article, we will take a more in-depth study of Vitamin B, particularly B3, B9, and B12. Collectively known as the Vitamin B Complex, there are eight variations of vitamin B in total: B1, 2, 3, 5, 6, 7, 9, and 12. They are central to cell metabolism and brain function thus it is crucial to consume a sufficient amount of foods rich in these vitamins as deficiency can result in complications in many body systems.

Vitamin B3, also known as niacin, holds a crucial role in the body. It cannot be synthesized by the body and must be obtained through the consumption of dairy products, meat, or legumes. These foods contain the amino acid tryptophan which, in addition to being a precursor molecule of serotonin and melatonin, can also be converted to niacin by the liver. Taken as a supplement, niacin can help lower cholesterol levels and improve metabolism by synthesizing the coenzymes nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP) which are both involved in respiration to release energy.

B3 deficiency can be due to behavioral, socioeconomic, and genetic risk factors. Behavioral risk factors may include alcohol abuse and self-imposed dietary restrictions. Socioeconomic factors may include food insecurity. Genetic risk factors such as the Hartnup disorder could be responsible for malabsorption as well. Certain medications, such as phenobarbital and chloramphenicol can also inhibit the conversion of tryptophan to niacin or result in accelerated depletion, such as the prolonged use of isoniazid. One complication of niacin deficiency is Pellagra; patients with pellagra may present symptoms of diarrhea, dementia, and dermatitis which can be fatal if left untreated.

Vitamin B9, folate or pteroylglutamic acid, is largely responsible for forming blood components such as erythrocytes, or red blood cells. Like niacin, folate cannot be synthesized and is generally stored in low amounts to use in short periods of insufficient consumption. Folate deficiency, however, is the result of a deficit over several weeks which can be caused by a regular diet that does not contain sufficient leafy greens, animal products especially the liver, or vitamin C, which is a cofactor for folate metabolism.

Deficiency can also be due to other factors. Certain medications can interfere with metabolism, such as methotrexate, which is a folate antagonist. There are inherited conditions such as the rare, autosomal recessive disorder called hereditary folate malabsorption (HFM), or the infantile cerebral folate deficiency, which is where the body produces an autoantibody, an antibody generated against the person’s own body, against folate receptors in the choroid plexus, preventing transportation across the blood-brain barrier. Other patients who fulfill their regular dietary requirements but are pregnant, lactating, or have malignancy are recommended to increase their uptake.

Complications concerning folate deficiency stem from ineffective hematopoiesis, or the formation of blood components, reducing the lifespan of red blood cells and resulting in anaemia if left untreated. Specific complications can include megaloblastic anaemia, a form of macrocytic anaemia, where the bone marrow produces stem cells that release abnormally large red blood cells. Infantile cerebral folate deficiency may result in developmental delay, particularly in neurological developments that manifest at the ages of 4-6 months and can present as reduced sensorineural hearing, seizures or sleep disturbance and vision loss.

The final vitamin of the vitamin B complex is Vitamin B12, also known as cobalamin. There are two active forms including methylcobalamin and 5-deoxyadenosylcobalamin. Cobalamin is essential for metabolic reactions involving protein, DNA, RNA and myelin synthesis, processes in hematopoiesis, and maintaining the mucosa membrane of the gastrointestinal tract. Methylcobalamin catalyses the formation of methionine (Met), an essential amino acid for tissue growth and repair and protein synthesis, while 5-deoxyadenosylcobalamin is involved in the metabolism of lipid and protein to release energy.

Risk factors for cobalamin deficiency are similar to ones for folate deficiency. Others may include fish tapeworm Diphyllobothrium latum infestation which competes for absorption in the ileum or the autosomal recessive disorder Imerslund-Gräsbeck syndrome which is a defect in the receptors. Complications due to B12 deficiency are, again, similar to B9, including macrocytic anaemia and neurodegenerative disorder.

If you are interested in modifying your diet, this hyperlink is an article from Healthline that quotes recommendations of the National Institutes of Health (NIH) on the daily recommendations for Vitamin B and foods that contain them.

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