Vitamins are nutrients, a group of biomolecules, that cannot be produced by the body, except two. The word ‘vitamin’ has been derived from ‘Vita’, which means life, and ‘amin’, which means nitrogen. These are organic compounds that enable energy generation from carbohydrates and fats and absorption of the required minerals. Though vitamins are required in minuscule quantities, their inadequate consumption can result in deficiencies. A few major sources of vitamins are meat, fruits, grains and leafy greens.
Did you know plants are capable of synthesising all vitamins but animals only a few?
Why Are Vitamins Important?
Vitamins are important and irreplaceable in our diet. Vitamins perform hundreds of different functions in the body – from promoting growth to blood clotting and catalysing enzymatic reactions.
Here are a few reasons why vitamins are important to us:
- Keep our body functioning normally.
- Protect body cells from environmental stressors, thereby supporting healthy ageing.
- Support and boost immunity.
- Maintain a healthy metabolism and gut health.
- Keep your bones strong.
- Meet your other nutritional needs.
Classification of Vitamins
There are over 20 types of vitamins that have been discovered so far, categorised as:
- Water-soluble vitamins
Vitamins B and C are called water-soluble vitamins as they dissolve in water. Due to this property, these vitamins are easily absorbed by the body and carried to different tissues. However, the body cannot store these vitamins. Some rich sources of water-soluble vitamins are cereals, meat, fish, egg, legumes and fresh vegetables.
- Fat-soluble vitamins
Vitamins A, D, E and K dissolve in fats and oils and do not dissolve in water. These are termed fat-soluble vitamins. When consumed with dietary fats, they are absorbed better and get stored in fat tissues in the body. Since they are stored in fatty tissues in the body, fat-soluble vitamins can become toxic when they accumulate in the body.
Functions and Sources of Vitamins
Each vitamin has a role to play in the body. Let’s understand more about the functions and sources of each of these vitamins:
- Vitamin B1
This vitamin is also called thiamine or antineuritic vitamin. It forms a part of an enzyme that is needed for energy metabolism. It also plays a role in nerve function. Vitamin B1 is insoluble in fats and oils and can be destroyed when heated above 313 K.
Vitamin B1 is found in pulses, nuts, whole cereals, rice, yeast, egg yolk, green vegetables and fruits. A deficiency of vitamin B1 causes a disease called Beriberi, which is characterised by loss of appetite, pain and weakness in limbs, shortness of breath, swelling in the feet and legs, and sometimes, even paralysis of the legs.
- Vitamin B2
Also called riboflavin and lactoflavin, vitamin B2 is needed for energy metabolism and plays a vital role in maintaining normal skin and eye health. This vitamin is found abundantly in milk and its products, leafy greens, whole grains, fortified bread and cereals, meat, liver and kidney.
A deficiency of vitamin B2 causes ariboflavinosis, which is characterised by skin disorders, hyperemia, oedema of the mouth and throat, lesions at the corner of the mouth (angular stomatitis), hair loss, reproductive problems, dermatitis and generalised body inflammation.
- Vitamin B3 (Niacin)
Niacin forms a part of enzymes that –
- Convert food into glucose to produce energy
- Maintains normal functioning of the nervous system
- Reduces tiredness and fatigue
It also plays an important role in skin health.
You can find abundant niacin in meat, fish, whole grains, fortified cereals, leafy greens, cruciferous vegetables, peanut butter, and poultry.
A severe deficiency of vitamin B3 or niacin causes a condition called pellagra. This disease affects the digestive and nervous systems and the skin.
Some symptoms of this disease include:
- Swollen, bright red tongue
- A thick, scaly pigmented rash on the skin
- Loss of memory and disorientation
Pellagra requires immediate treatment and reversal with niacin supplementation to avoid serious complications and death.
- Vitamin B5 (Pantothenic Acid)
Pantothenic acid plays a role in the synthesis of coenzyme A, which is essential for the synthesis and degradation of fatty acids in the body. Apart from its role in fatty acid synthesis and metabolism, vitamin B5 participates in different metabolic reactions in the body.
One can get around 85% of their pantothenic acid requirement from a variety of plant and animal sources such as fortified cereals, beef, mushrooms, potatoes, eggs, sunflower seeds, oats, broccoli, tomatoes and apples.
A deficiency of pantothenic acid is usually rare because many foods contain small amounts of the vitamin required by the body. It is usually accompanied by a deficiency of other nutrients, often making it difficult to diagnose. Some symptoms of pantothenic acid deficiency are:
- Cramps in the stomach
- Muscle cramps
- Disturbed sleep
- Numbness in feet
Also called vitamin H, biotin forms a part of the vitamin B complex and participates in converting food into energy. This vitamin keeps your nervous system, skin, hair, eyes and liver healthy. It is also a vital nutrient to take during pregnancy as it helps in embryonic growth. 30 to 100mcg of biotin are recommended to be taken every day. While people do take biotin supplements, some people may experience side effects like digestive trouble and nausea.
Some powerful natural sources of biotin include:
- Egg yolk
- Nuts and nut butter
Though biotin deficiency is rare, like pantothenic acid deficiency, it can occur due to some medications, intestinal problems, excessive dieting, and IV feeding.
Some symptoms of biotin deficiency are:
- Rashes on the skin, especially the face
- Dry, scaly skin
- Dryness in the eyes
- Brittle nails
- Hair loss
- Loss of appetite
- Burning or pricking sensation in the extremities
- Frequent digestive trouble
- Difficulty in sleeping
- Difficulty in walking
- Vitamin B6 (Pyridoxine)
Pyridoxine is required for a part of an enzyme that participates in protein metabolism. This vitamin also plays an important role in the production of red blood cells in the bone marrow. Foods like rice bran, molasses, fish, meat and poultry are excellent sources of this vitamin.
Vitamin B6 deficiency rarely occurs alone and is often accompanied by deficiency of other B vitamins. Though a mild vitamin B6 deficiency may not cause symptoms, a chronic or severe deficiency may cause the following symptoms:
- Fatigue due to microcytic anaemia
- Anorexia and gastrointestinal trouble
- Itchy rashes on the skin, cracks at the corner of the mouth
- Swollen tongue
- Lowered immunity
Some conditions may interfere with vitamin B6 absorption and result in its deficiency:
- Celiac disease
- Ulcerative colitis
- Crohn’s disease
- Kidney disease
- Vitamin B9 (Folic acid)
Folic acid or folate is a very important B vitamin and is vital for the formation of red blood cells. We need folic acid for DNA production. A woman who is planning a pregnancy or is pregnant is advised to take folic acid supplements as low levels of this vitamin can cause birth defects like spina bifida and spinal irregularities in babies.
Many foods are rich in folic acid, and these include leafy greens, fortified cereals, liver, orange juice, nuts and seeds.
When you do not consume enough folic acid, your body will become deficient in the vitamin and lead to a condition called megaloblastic anaemia.
Some symptoms of folic acid deficiency include:
- Difficulty in concentrating
- Palpitations in the heart
- Tongue and mouth sores
- Change in colour of the skin, hair and nails
- Shortness of breath
It is important to note that some groups of people are prone to folic acid deficiency:
- Pregnant women
- Women of childbearing age
- People with issues related to nutrient absorption like IBD, celiac disease, etc.
- People having a specific variant of the MTHFR gene
- Vitamin B12 (Cobalamin)
Vitamin B12, or cobalamin, is an essential water-soluble vitamin found abundantly in meat, poultry, fish and dairy. Vitamin B12 is required for the development and growth of many parts of the body, such as the brain, nerves and blood cells.
Vitamin B12 supplements are prescribed for deficiency of the vitamin, cyanide poisoning, canker sores, Alzheimer’s disease, fatigue, osteoporosis and many other conditions.
Some symptoms of vitamin B12 deficiency are:
- Extreme tiredness
- Feeling of pins and needles on the extremities
- Red, sore tongue
- Ulcers in the mouth
- Muscle weakness
- Disturbed vision
- Depression and confusion
- Memory problems
Vitamin C, also called ascorbic acid, helps in the formation of proteins like collagen and elastin, both of which are found in skin, tendons, ligaments and blood vessels. Vitamin C also plays a role in the growth and repair of tissues in all parts of the body. It also helps in wound healing and the formation of scar tissue. Vitamin C is a powerful antioxidant, supports immunity and also helps in iron absorption.
Vitamin C is abundantly found in citrus fruits, cruciferous vegetables, cantaloupe, strawberries, peppers, tomatoes, papayas, lettuce, kiwi, and mangoes, among others.
Deficiency of vitamin C causes a disease called scurvy, the symptoms of which include:
- Muscle pain
- Oedema (fluid accumulation)
- Small red spots on the skin due to bleeding under the skin ( a condition called petechiae)
- Shortness of breath
- Gum inflammation and loss of teeth
- Poor wound healing
Vitamin A, also called retinol or bright eye vitamin, is a fat-soluble vitamin that is required for healthy skin, proper vision, healthy mucous membranes, bone formation, strong teeth and immune system. Some foods that are rich sources of vitamin A include fortified milk, cheese, butter, cream, eggs and liver.
You can also get vitamin A from foods that are rich in beta-carotene as carotenoids are a precursor of vitamin A. Rich sources of beta carotene include dark orange foods, vegetables like carrots, winter squash, sweet potatoes, and pumpkin.
A deficiency of vitamin A causes a condition called xerophthalmia which is characterised by the following symptoms:
- Dry skin and eyes
- Night blindness
- Infertility and difficulty in conception
- Delayed growth
- Poor wound healing
- Susceptibility to throat and chest infections
- Skin problems like acne
Also called the antirachitic vitamin or the sunshine vitamin, vitamin D is important to the body as it controls calcium and phosphorus metabolism. This is one vitamin that our body can synthesise on exposure to sunlight. However, you can also get vitamin D from food sources like butter, fish liver oil, liver, milk, and eggs. You must take about 0.025 mg of vitamin D every day.
insufficient consumption of synthesis of vitamin D results in a deficiency in the vitamin, causing symptoms like:
- Hair fall.
- Bone pain.
- Muscle weakness, cramps, and aches.
- Mood changes and depression.
- Reduced calcium levels in the body that affects your bones, teeth, gums, nerves, and muscles.
Also called tocopherol, vitamin E is a powerful antioxidant and a fat-soluble vitamin. Its primary goal is to keep your immune system healthy and robust. We need a small amount of vitamin E in our diet every day, and a large number of foods are rich in this vitamin. Due to these reasons, the chances of developing vitamin E deficiency are usually rare.
However, if you experience any of the following symptoms, you must visit your doctor for getting your vitamin E levels checked:
- Difficult in walking
- Problems with coordination
- Visual disturbances
- A general feeling of malaise
- Muscle pain
Vitamin E deficiency is characterised by increased fragility of red blood cells and sterility as well.
Some foods abundant in vitamin E include plant oils, leafy greens, wheat germ, whole grain products, liver, egg yolks, nuts, and seeds.
Vitamin K is vital for blood clotting and plays an irreplaceable role in the process. It is also called phylloquinone or antihemorrhagic vitamin. It is a mixture of two vitamins– K1 and K2.
Some rich sources of vitamin K include green vegetables like kale, collard greens, spinach, cruciferous vegetables like broccoli, Brussel’s sprouts, and asparagus. Some amount of vitamin K is also synthesised by the bacteria in your gut.
A deficiency of vitamin K results in haemorrhage and lengthens the time for blood clotting.
Can We Intake Excess Vitamins?
Now that we know vitamins are healthy and should be a part of our daily routine, can we ever take ‘excess’ vitamins? Well, you surely can! Though most vitamin supplements advise you to take a specified amount per day, it is common practice to take more than that amount.
Before we learn how excess vitamin consumption can harm us, we must understand that water-soluble vitamins are easily expelled from the body, whereas fat-soluble vitamins accumulate in the body tissues. For this reason, fat-soluble vitamins may cause toxicity.
The side-effects of excess vitamin consumption are more likely with supplements than with foods, as supplements contain vitamins in a more concentrated form.
Adverse effects of consuming excessive water-soluble vitamins are:
- Vitamin C: Consuming excessive amounts of vitamin C can cause gastrointestinal issues like diarrhoea, cramps in the abdomen, nausea, and sometimes, vomiting. If you consume vitamin C in doses over 6 g per day, you may experience symptoms of migraine.
- Niacin: Consumption of 1-3 gms of niacin in the form of nicotinic acid causes hypertension, pain in the abdomen, liver damage and vision impairment.
- Pyridoxine: Chronic excessive consumption (1-6 g per day) of pyridoxine or vitamin B6 can lead to severe neurological symptoms, lesions on the skin, nausea, heartburn, among others.
- Folate: Despite its many benefits, consuming folate in excess can negatively affect your mental function, your immune system and disguise deficiency of vitamin B12.
Adverse effects of consuming excessive amounts of fat-soluble vitamins can cause:
- Vitamin A: Excess vitamin A in the body is termed hypervitaminosis A. This condition can occur from consuming vitamin A-rich foods but is mostly observed with vitamin A supplements. The most common symptoms of hypervitaminosis A are nausea, increased intracranial pressure, coma and sometimes, even death.
Vitamin A toxicity can occur when one consumes over 200 mg of the vitamin, or their chronic intake of the vitamin is over ten times the RDI (recommended dietary intake).
- Vitamin D: Just like a deficiency of vitamin D is fatal for the body, an excess of the vitamin (more than 50,000 IU daily) can also cause symptoms like increased hair fall and harmful symptoms, like weight loss, appetite loss, and irregular heartbeat. Increased vitamin D levels are directly linked to an increase in calcium levels, which can damage organs.
- Vitamin E: Vitamin E, as we now know, is a powerful antioxidant. However, excessive consumption of this vitamin interferes with blood clotting. This can cause haemorrhages and may lead to hemorrhagic stroke.
Vitamin K, unlike the other three fat-soluble vitamins, has a low potential for toxicity even when consumed in high doses. However, when taken in excess, it interacts with other medications, especially antibiotics and warfarin.
Wrapping it Up!
Compared to other nutrients in food, vitamins may seem small but are essential for our well-being.
Armed with all this information about vitamins, their types and their functions, you are all set to ace your test on them! Find more such interesting topics for your upcoming exams on our blog! Happy learning!