Vitamin B Complex: Its Benefits, Uses and Risks

Vitamin B complex refers to a class of water-soluble vitamins that play an important role in cell metabolism. They help in utilizing the energy obtained from fats, proteins, and carbohydrates. However, they cannot provide the body with energy on its own. 

Read on to know more about vitamin B complex deficiency, its benefits, and side effects!

What does Vitamin B Complex do?

The vitamin B complex functions as coenzymes for other enzymes required in metabolic processes. An enzyme cannot function without its coenzyme. Hence, vitamin B complex deficiency leads to metabolic disorders in our body.

The vitamin B complex contains eight vitamins, namely thiamine (B1), riboflavin (B2), niacin (B3), pantothenic acid (B5), vitamin B6, biotin (B7), folate (B9), and vitamin B12. These vitamins have chemically different structures and are often found in the same foods.

Thiamine (B1)

• Thiamine acts as a coenzyme for enzymes involved in the metabolism of carbohydrates and amino acids.
• All plant and animal tissues contain thiamine; hence, it is present in natural, unprocessed foods. Some thiamine-rich vitamin B complex foods are oatmeal, whole-grain cereals, pulses, nuts, lean pork, heart, kidney, and liver.
• The recommended daily allowance (RDA) of thiamine is 1.2 mg/day for men and 1.1 mg/day for women. Excess consumption of thiamine has no adverse side effects. Hence, no upper limit for consumption is defined.
• Thiamine deficiency severely affects malnourished and alcoholic individuals. Prolonged deficiency of thiamine can cause the disease beriberi. Common symptoms of beriberi include loss of appetite, pain in the limbs, weakness, and damage to the nervous system as well as the heart.

Riboflavin (B2)

• Riboflavin also functions as a coenzyme in different biochemical reactions. The coenzymes participate in numerous oxidation-reduction reactions and energy metabolisms in the body.
• Riboflavin is stable under heat, and cooking does not destroy it easily. Some sources of riboflavin-rich vitamin B-complex foods include dark green leafy vegetables, milk and milk products, liver, fortified grain products, whole grains, and cereals.
• The RDA of riboflavin is 1.3 mg/day for men and 1.1 mg/day for women. Similar to thiamin, there is no defined upper limit for riboflavin consumption. Excess consumption is, therefore, not harmful.
• Riboflavin deficiency can occur due to nutrient deficiencies, kidney problems, and liver disorders. Ariboflavinosis is a riboflavin deficiency causing sore throats, chapped lips, and scaly skin, among a few other symptoms. Riboflavin deficiency can also cause symptoms such as inflammation of the mouth, eyes, skin, and GI tract.

Niacin (B3)

• Nicotinamide is the major form of niacin in our blood. The coenzyme forms of niacin participate in several metabolic reactions and play a critical role in the metabolism of glucose, fat, and alcohol in our body.
• The RDA for niacin is given in niacin equivalents (NE). This is because dietary tryptophan (an amino acid) also helps fulfill our daily niacin requirements. The RDA for men is 16mg NE/day, and for women, it is 14mg NE/day.
• Some niacin-rich vitamin B complex foods are poultry, tomatoes, potatoes, mushrooms, legumes, and whole grains. Dietary tryptophan can provide half the daily niacin requirement. Large doses of supplements containing niacin can have adverse effects such as flushing (redness, itching, or tingling sensation), pain, rash, vomiting, nausea, headache, and diarrhea.
• Niacin deficiency can occur due to malnutrition, alcoholism, and hereditary disorders. Severe niacin deficiency can cause the disease pellagra. Common symptoms of this disease are dementia, dermatitis, diarrhea, inflammation, hyperpigmentation, and eventually death if left untreated.

Pantothenic Acid (B5)

• Pantothenic acid plays an important role in several metabolic processes and helps in the metabolism of carbohydrates, fats, and amino acids. It also has a significant role in the synthesis of lipids, neurotransmitters, steroid hormones, and hemoglobin.
• The adequate intake (AI) for pantothenic acid for adults is 5 mg/day. Vitamin B complex foods rich in pantothenic acid include chicken, beef, potatoes, oat cereals, tomato products, liver, kidney, yeast, egg yolk, broccoli, and whole grains.
• Pantothenic acid deficiency is rare. The symptoms of pantothenic acid deficiency include vomiting, muscle cramps, hypoglycemia, nausea, depression, and increased sensitivity to insulin.
• Supplementation of pantothenic acid has no severe side effects. The supplemental form of pantothenic acid is calcium pantothenate which is used as dietary supplements.

Vitamin (B6)

• Vitamin B6 occurs in several different forms, all of which convert into the coenzyme pyridoxal phosphate (PLP), which helps in amino acid metabolism. The ability of PLP to add and remove amino groups also makes it useful in protein and urea metabolism. Vitamin B6 is also crucial for normal growth, homeostasis, development, and maintenance of the immune system.
• The Recommended Dietary Allowances (RDA) for vitamin B6 is 1.3 mg/day for adults. We can lose Vitamin B6 from foods due to processing, freezing, cooking, and drying. Vitamin B-complex foods rich in vitamin B6 are fortified breakfast cereals, chickpeas, potatoes, bananas, and pork.
• A person suffering from vitamin B6 deficiency will also have other vitamin B inadequacies. Vitamin B deficiency can lead to poor synthesis of neurotransmitters, depression, ulceration, scaly dermatitis, and confusion. People suffering from liver disease, type 1 diabetes, systemic inflammation, and rheumatoid arthritis, as well as alcoholics and the elderly, are at increased risk of vitamin B6 deficiency.
• The upper-level intake of vitamin B6 is 100 mg/day. Higher consumption can be dangerous because it can cause neurological damage in people. Common symptoms of overconsumption include depression, headaches, skin lesions, irritability, and muscle weakness.

Biotin (B7)

• Biotin plays an important role as a coenzyme and supports various metabolic pathways in our body. Some researchers also suggest that biotin is useful for healthy skin and better nail and hair growth.
• The Adequate Intake (AI) of biotin for adults is 30 µg/day. Some food sources rich in biotin include liver, egg yolks, soybeans, fish, and whole grains. Some bacteria present in our gastrointestinal tract also produce biotin.
• Biotin deficiency is rare if you maintain a healthy and balanced diet. Deficiency symptoms include depression, lethargy, hallucinations, tingling sensations in the arms and legs, hair loss, and a scaly rash around the eyes, mouth, and nose.
• Excess consumption has no known side effects. Hence, there is no upper limit for biotin consumption.

Folate (B9)

• The primary coenzyme form of folate is THF (tetrahydrofolate). THF plays a part in the synthesis of purines and pyrimidines, the base constituents of DNA. Thus, folic acid is crucial for proper brain function and plays an important role in mental and emotional well-being. It works with vitamins B6 and B12 and other nutrients to control blood levels of the amino acid homocysteine.
• It is common to have low levels of folic acid. Alcoholism, inflammatory bowel disease, and celiac disease can cause folic acid deficiency. Common symptoms include poor growth, tongue inflammation, gingivitis, loss of appetite, shortness of breath, diarrhea, and irritability.
• The folate derived from supplements can be used by the body more effectively than the folate derived from foods. Thus, folate intakes and requirements are often expressed as dietary folate equivalents (DFE).
• The RDA of folate for adults over 19 years old is 400 µg DFE/day. Some folate-rich foods are leafy greens, asparagus, Brussels sprouts, citrus fruits, and beets.
• The folate requirement for women increases during pregnancy. However, excess folate from fortified foods and supplements can delay the diagnosis of this vitamin B complex deficiency, which can lead to neurological damage.

Cobalamin (B12)

• Cobalamin plays an important role in the synthesis of DNA and RNA and in the regeneration of the amino acid methionine with the help of the trace element cobalt. Vitamin B12 helps in the growth and protection of nerve fibers. Bone growth also depends on vitamin B12 at a cellular level.
• The RDA of vitamin B12 for adults is only 2.4 µg/day. Anyone who consumes reasonable amounts of animal products is virtually guaranteed adequate amounts of vitamin B. Vegans can, however, consume fortified soy milk or even resort to artificial supplements.
• Like all water-soluble vitamins, vitamin B12 is susceptible to degradation while cooking. Microwave cooking reduces these losses significantly.
• Cobalamin deficiency can cause pernicious anemia, neurological symptoms, impaired cognitive performance, fatigue, constipation, and even advanced neurological symptoms.
• Excess consumption has no reported side effects. Hence, no upper limit for cobalamin consumption has been determined.

Thus, a balanced diet rich in macronutrients and other micronutrients is essential to leading a healthy lifestyle and living a disease-free life! The use of vitamin B complex supplements should be discussed with your doctors to avoid serious side effects and treat the deficiency promptly.