Why Do We Need Vitamins?

Lucy Bell-Young

by Lucy Bell-Young

3rd February 2021

We need vitamins because many of our metabolic processes wouldn’t be possible without them. Vitamins act as coenzymes that facilitate various biochemical reactions in our cells, such as protein synthesis. For instance, vitamin C is crucial in the synthesis of collagen, which is a structural component of the skin, bones, and muscles. Deficiency in one or more vitamins can lead to certain debilitating conditions such as osteoporosis (vitamin D deficiency) or chronic illnesses.

Pills and capsules in wooden spoon with fresh fruits

What Type Of Vitamins Are There?

Vitamins are classified into two categories: water soluble vitamins and fat soluble vitamins. Overdose or poisoning is virtually impossible with water soluble vitamins because they’re easily excreted. Fat soluble vitamins, on the other hand, can be dangerous and may reach toxic levels if you overdose on them because they accumulate in the fat cells of the body.

Fat-soluble Vitamins

  • Vitamin A: From its other name, retinoid, you can glean something about vitamin A’s main function in the human body: it’s essential for good eyesight. It also helps maintain a healthy immune system and aids in cell division. It’s particularly beneficial to the cone cells of the retina, which are photoreceptors responsible for colour vision. Vitamin A has two types: the retinoids, which are the active form and come from animal products; and those that come from plants, including beta-carotene.
  • Vitamin D: Also known as calciferol, which can be naturally produced by the skin when certain types of cholesterol in the skin are exposed to direct sunlight or ultraviolet rays. Vitamin D is essential in the absorption of calcium in the bones and teeth. It similarly helps balance the calcium and phosphate in the blood.
  • Vitamin E: This is actually a group of eight fat-soluble compounds with the same chemical formula and different molecular structures. Vitamin E includes four tocopherols and four tocotrienols. As an antioxidant that helps protect the cells from damage, it’s commonly used as an ingredient for skin rejuvenation products. It can be naturally found in many food items like eggs, cereals, meat, poultry, and vegetables.
  • Vitamin K: This vitamin exists in two forms. The first one is known as phylloquinone, which occurs naturally in green leafy vegetables like spinach. The second form is known as menaquinones, which is commonly found in fermented foods like kimchi and sauerkraut. Symbiotic bacteria in the intestines also produce vitamin K. 

This vitamin is essential in synthesising various types of proteins that are necessary in the clotting mechanisms of the blood and the building of bones. Prothrombin is a protein that is directly involved in blood clotting – but it cannot function without vitamin K. Osteocalcin is another type of vitamin K-dependent protein that’s involved in the production of healthy bone tissues. Vitamin K is present throughout the body, including the brain, heart, liver, and pancreas. It rarely reaches toxic levels in the body because unlike other fat soluble vitamins, it can be easily broken down and excreted.

Water-soluble Vitamins

There are two main groups of water-soluble vitamins: vitamin C and vitamin B-complex. The latter has several types and sub-types. The human body needs eight dietary B vitamins.

  • Vitamin C: Otherwise known as ascorbic acid, this vitamin has to be derived from food because the human body cannot synthesise it. It’s commonly found in high abundance in citrus fruits, like oranges and lemons, and is an essential antioxidant that helps protect the cell from free radicals and oxidation processes. Vitamin C is also good at boosting the immune system and preventing many chronic diseases, like high blood pressure and heart disease.
  • Vitamin B1: Also known as thiamine, this has an important role as a coenzyme in the catabolism or breakdown of sugars and amino acids.
  • Vitamin B2: Otherwise known as riboflavin, this vitamin is a precursor of two coenzymes that are needed for enzyme reactions of flavoprotein, which includes the activation of other vitamins.
  • Vitamin B3: This vitamin is known by many several names such as niacin (nicotinic acid), nicotinamide, and nicotinamide riboside. This is because of its several molecular forms and variations. Vitamin B3 is important in the respiration process, as well as in other metabolic processes, as a precursor of two coenzymes known as NAD and NADP.
  • Vitamin B5: Also known as pantothenic acid, vitamin B5 is a precursor of coenzyme A (CoA, SHCoA, CoASH). CoA, in particular, has a crucial role in the synthesis and oxidation of fatty acids, as well as in the oxidation of pyruvate in the citric acid cycle, a.k.a. the Krebs cycle.
  • Vitamin B6: Vitamin B6 has three forms: pyridoxine, pyridoxal, and pyridoxamine. They all serve as coenzymes in many metabolic processes that predate oxygen-dependent or aerobic respiration. 
  • Vitamin B7: Also known as biotin, this vitamin acts as a coenzyme for carboxylase enzymes that are necessary for synthesising fatty acids. It’s also needed in producing glucose from non-carbohydrate precursors.
  • Vitamin B9: Otherwise known as folate, this is a coenzyme that’s involved in the transfer of single-carbon units in the metabolism of nucleic acids and amino acids, making it essential in protein synthesis and DNA integrity. In tetrahydrofolate or THF form, this vitamin is important in the synthesis of purine and pyrimidine nucleotide synthesis during cell division. Folate is very important during pregnancy, especially during the rapid cell growth stage of the embryo.
  • Vitamin B12: The other name for this vitamin is cobalamin. It has important roles in the metabolism of carbohydrates, proteins, and lipids. Blood cells in bone marrow and nerve sheaths will not properly form without this vitamin.
Vector showing health benefits of different vitamins

Why Are Vitamins Important?

As coenzymes, vitamins have a wide range of involvement in many metabolic processes, both catabolic and anabolic. The synthesis of many biochemicals and the formation of healthy tissues wouldn’t be possible without vitamins. Although many essential vitamins can be synthesised by the body, most of our daily vitamin needs have to be derived from food.

Vitamin deficiency can cause several health problems like scurvy, anaemia, and nerve malfunctions. People who are not getting enough vitamins from their diet may benefit from vitamin supplements. You must consult your physician if you need to take supplements. Be careful on the dosage, especially when taking fat-soluble vitamins.

Do All Vitamins Have A Different Chemical Formula?

While some vitamins have the same chemical formula, they will have different molecular forms or structures. For instance, vitamin E has the chemical formula C29H50O2. However, vitamin E has eight variants, and each one has a slightly different structure.

Chemical formulae simply tell the proportions of elements in each molecular compound – it doesn’t indicate the molecular structures or isomers. So, technically, all vitamins of different categories or groups have different chemical formulas, but not all within the same categories have different formulas.

On the other hand, some vitamin categories like vitamin B complex vitamins have radically different chemical formulas and structures. For instance, the chemical formula for riboflavin is C₁₇H₂₀N₄O₆, while the formula for thiamine is C1217N4OS+.


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