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Vitamins and their functions

Vitamins and their functions


Vitamins are compounds that are essential for the health of humans and other vertebrates but cannot be self-synthesized by these animals and must therefore be obtained in the diet. 

Vitamins are classified into two categories:

  1. Fat-soluble Vitamins 
  2. Water-soluble Vitamins

The fat-soluble group of vitamins is Vitamin A, D, E, K

The water-soluble group of vitamins is Vitamins C, and B

Vitamin B is further divided into B1, B2, B3, B6, B12, and Biotin, folate, and Pantothenic acid

Let's see their uses and effects when they are deficient in the human body.

  • Fat-soluble Vitamins

Vitamin-A (Vit A) They are otherwise called retinoids that include retinol, retinal, retinoic acid, and carotenoids. 

Sources: The sources of vitamin A are spinach, carrots, sweet potatoes, eggs, dairy, animal liver, cheddar cheese, cod liver oil, etc.,

Functions: Vitamin A in its various forms functions as a hormone and as the visual pigment of the vertebrate eye. Vitamin A helps bolster immune function, supports cell growth, and aids in fetal development and vision. The best-known functions of Vitamin A are its role in vision and eye health. Vit A derivative retinal is the pigment that initiates the response of rod and cone cells of the retina to light, producing a neuronal signal to the brain.

Deficiency: Deficiency of Vit A leads to a variety of symptoms including dryness of skin, eyes, and mucous membranes, retarded development and growth, and night blindness.

Vitamin D 

Vit D3 or cholecalciferol is normally formed in the skin from 7-dehdrocholesterol in a photochemical reaction driven by the UV component of sunlight. Vit D3 is not biologically active but is converted by enzymes in the liver and kidney to form an active component which is a hormone that regulates calcium uptake in the intestine and calcium levels in the kidney and bone.  Vit D is therefore an important component in bone and teeth health. Vit D has a crucial role in the process of cell division.

Though Vit D is formed in our body, with the help of the sun, deficiency is common in people who live in cold parts of the world where there is less sunlight. 

Sources: Sources of Vitamin D are eggs, butter, oily fish, dairy, mushrooms, oatmeal, soya, and almond milk.

Deficiency: Deficiency of Vit D leads to defective bone formation and the disease rickets.

Vitamin E

Vit E is the collective name for a group of closely related lipids called tocopherols.

Since they are hydrophobic, tocopherols are associated with the cell membranes, lipid deposits, and lipoproteins in the blood. Tocopherols are biological antioxidants, therefore capturing loose electrons (free radicals) that are formed during cellular metabolic processes, which can damage the cells. Therefore, they are one of the primary components of all skin products. 

Sources: The sources of Vit E are spinach, almonds, sunflower seeds, broccoli, hazelnuts, peanuts, mangoes, kiwis, etc.,

Deficiency: Deficiency of Vit E leads to scaly skin, muscular weakness and wasting and sterility, fragile erythrocytes, etc.,

Vitamin K

Vitamin K1 (phylloquinone) is found in green plant and leaves, Vitamin K2 (menaquinone) is formed by bacteria residing in the vertebrate intestine.

Vitamin K plays a critical role in helping the blood clot thus preventing excessive bleeding.

Vitamin K molecule has an aromatic ring that undergoes a cycle of oxidation and reduction during the formation of active prothrombin, a blood plasma protein essential in blood clot formation. Prothrombin is a proteolytic enzyme that splits peptide bonds in the blood protein fibrinogen to convert it to fibrin, the insoluble fibrous protein that holds blood clots together.

Sources: The sources of vitamin K are eggs, kiwi, and green leafy vegetables including collard, turnip, greens, kale, and spinach, etc.,

Deficiency: A deficiency of Vit K leads to slow blood clotting which could be fatal.

  • Water soluble Vitamins

Vitamin C

Vitamin C or ascorbic acid is a small carbohydrate molecule essential for humans and other animals. Some animals can biosynthesize their own vitamin C, but humans cannot. 

Functions of Vitamin C

Vitamin C is an antioxidant, that scavenges free radicals from the body reducing damage from inflammation and oxidation, playing an important role in fighting pathological conditions and infections.

It also helps in wound healing and collagen synthesis. Vitamin C acts as a co-substrate of a large class of enzymes performing crucial biochemical reactions in the body.

They also regulate gene expression by interacting with an important transcription factor.

Sources of Vitamin C:

Citrus fruits (Oranges, kiwi, lemon, grapefruit), strawberries, capsicum, tomatoes, cruciferous vegetables (broccoli, brussels sprouts, cabbage, cauliflower)

Deficiency of Vitamin C

The major disease that occurs in people who are deficient of Vit C is Scurvy.

Scurvy can cause severe anemia, excessing bleeding, exhaustion, pain in the limbs, swelling, ulceration of the gums, and loss of teeth.

Vitamin B

  • Vitamin B1 – Thiamine

Functions: They have a variety of functions in many different biochemical reactions in our body. One important function is that they act as co-enzymes and catalyze the conversion of carbohydrates into sugar, thereby playing a key role in carbohydrate metabolism and energy production. Energy production is a vital part of all cellular functioning. Therefore, they are needed for the functioning of major organs such as the brain and heart in the body.

Sources: Sources of Vit B1 are fish, beans, lentils, green peas, fortified breakfast cereals, yogurt, sunflower seeds, legumes, leafy greens, seafood, poultry, and dairy products, etc.,

Deficiency: Symptoms of Vit B deficiency include headache, weakness, mental disorder, etc., Beriberi- is a disease caused due to Vit B1 deficiency.

  • Vitamin B2 – riboflavin

Vit B2 is essential for the formation of 2 major coenzymes, flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD). These 2 coenzymes play a major role in cellular respiration, energy metabolism, antibody production, and metabolism of carbohydrates, proteins, fats, etc., FMN and FAD are also involved in many other crucial biochemical reactions in the body.


Dairy, eggs, lean beef, chicken, salmon, almonds, spinach, etc.,


Deficiency causes severe anemia, eye disorders, hair loss, cracked lips, swelling, glossitis, skin problems, etc.,

  • Vitamin B3 – Niacin

There are 3 forms of this Vitamin - Nicotinic acid, nicotinamide, nicotinamide riboside.

These 3 forms of VItamins play a major role in the formation of NAD (Nicotinamide Adenine Dinucleotide). This NAD is a pyridine nucleotide that serves as an essential cofactor and substrate for innumerable cellular processes such as oxidative phosphorylation, ATP production, DNA repair, etc.,


Poultry, nuts, seeds, legumes, bananas, brown rice, meat, etc.,


Pellagra- The deficiency of Niacin causes a disease called Pellagra. 

The symptoms of pellagra include dementia, skin inflammation, diarrhea, mouth sores, etc. When left untreated, it may lead to death.

  • Vitamin B6 – Pyridoxine

The pyridoxal 5 phosphate which is the active coenzyme form of pyridoxine is a coenzyme that plays a major role in the breakdown of proteins, carbohydrates, and fats.

They play a major role in maintaining healthy levels of homocysteine (an amino acid, whose high level in the blood causes heart problems, and brain damage) Vit B6 breakdown Homocysteine into other chemicals that the body needs. 

They also support the immune system in various functions.

Sources: Chickpeas, poultry, salmon, dark leafy greens, bananas, papayas, oranges, cantaloupe, etc.,

Deficiency: Deficiency of Vit B6 causes anemia, depression, confusion, lowered immunity, heart and brain damage, etc.


All in all, it is important to eat a healthy and balanced diet so that our body is nourished with all the necessary vitamins and minerals. Towards this end, Let’sLive is introducing a lineup of products that are natural and healthy. 

To try our products, order them here

About Let’sLive

Let’sLive is a social empowerment enterprise committed to enhancing and improving the livelihoods of tribal and farming communities. We work directly with small-scale farmers so that our customers can get access to products that are natural, pristine, and picked from the lap of nature. We encourage and provide advice for practicing ethical farming and eco-friendly methods to all those who partner with us.

At Let'sLive we are passionate about bringing 100% all-natural and healthy products directly from the farming and tribal communities to your doorstep like Pure Raw Honey, Traditional varieties of rice, etc. We want our consumers to enjoy and have direct access to the products that are pristine and picked directly from the lap of nature. The mandates by which we operate are:
* Value every life around us by encouraging ethical farming
* Leverage local knowledge and promote legacy harvesting practices with high hygienic standards
* No preservatives or artificial processing on any of our products
* Each product can be traced to its origins and the people involved in its making
* Educate consumers on the importance of consuming rich and natural local produce

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