Vitamins – Deficiency & Excess

Overview

Vitamins are essential ingredients for a healthy life. Deficiency of these elements can lead to numerous diseases within the human body which are at times incurable. Excess quantity of vitamins also proves to be detrimental, but complications associated with them can be controlled through the reduced intake. At present, the low and middle-income countries, as well as the developing or underdeveloped countries of the world, are suffering from vitamin deficiency. A large percentage of the population in those countries suffer from malnutrition, which is directly impacting the life expectancy. According to the recent epidemiological studies by the United Nations World Food Program (WFP), about 12.9% of the current global population is malnourished.

What are vitamins?

Vitamins are a category of organic nutrients (medically termed as micronutrients) which are necessary for a healthy life. These vitamins need to be present in adequate quantities in the regular diet because the human body is incapable of synthesizing them naturally. They play a vital role in metabolism and growth.

All total there are 13 different types of vitamins and each of them has important roles in the growth and development of the body. Proper intake of all these vitamins is necessary especially in the growing years of a child, to ensure healthy development and proper build up of immunity. It is to be noted that all the 13 vitamins cannot be obtained from a single source of food. Hence the daily diet should consist of different types of foods, each having a definite value (in terms of vitamins and essential nutrients).

According to statistics of the World Health Organization, in industrialized countries, the daily food intake by an average adult is about 600 g (dry-weight basis), of which vitamins constitute about less than 1 g.

Different types of vitamins

Vitamins are divided into two main classes according to their medium of solubility. These are as follows-

Fat-soluble vitamins: Fat-soluble vitamins are those vitamins which are primarily dissolved in fat before they are carried by the circulating blood to different organs of the body. Surplus quantities of fat-soluble vitamins are stored in the liver and fat tissues and utilized by the body whenever needed. There are four fat-soluble vitamins namely- Vitamins A, D, E and K.

 Characteristics of fat-soluble vitamins

 Following are the unique characteristics-

• Storage: These vitamins are stored in liver and fat tissues and utilized whenever necessary.
• Longevity: They last for a long time since the body does not need them on a daily basis.
• Absorption and excretion: They are absorbed along with dietary fat through the small intestine and excreted at a slow rate.
• Toxicity: Fat soluble vitamins stored within the body for a prolonged period can cause toxicity.

Water-soluble vitamins: Water-soluble vitamins are necessary on a regular basis via a balanced diet. They dissolve easily in water and are carried to the body tissues which perform several essential functions. The main water-soluble vitamins are- Vitamin B complex group and Vitamin C. 

Characteristics of water-soluble vitamins

 Following are the unique characteristics-

• Storage: These vitamins are not stored in the body for a long time.
• Longevity: They do not last for a long period within the body tissues and are easily excreted on a regular basis.
• Toxicity: Since these vitamins do not stay within the body for a very long period, hence the chances of toxicity are nil.

Different sources of vitamins

Vitamins of any category are consumed via daily diet (preferably a balanced diet). There are two primary sources of vitamins – plant source and animal source. The different sources of all varieties of vitamins are discussed below-

• Vitamin A: Fruits (green or ripened), green leafy vegetables (contain beta carotene and carotenoids), dairy products, cereals, fish oil, liver
• Vitamin D: Egg yolk, organ meat, fortified milk, fish (cod liver oil), sunlight
• Vitamin E: Whole wheat, cereals, egg yolk, nuts, avocado, peanut butter
• Vitamin K: Soybeans, broccoli, spinach, sprouts, turnip
• Vitamin B1: Yeast, whole grains, wheat germ, organ meat, pork, dried beans, seeds
• Vitamin B2: Dairy products, green leafy vegetables, organ meat, nuts, whole grain, mushrooms, poultry
• Vitamin B3: Fish, poultry, whole grains, peanut butter, mushrooms
• Vitamin B5 (Pantothenic acid): Beef, corn, meat, orange juice
• Vitamin B6: Yeast, poultry, wheat germ, whole grains, meat, potato, banana, beans
• Vitamin B12: Fish, poultry, liver, meat, dairy products (cheese, yogurt)
• Vitamin C: Citrus fruits (lemon, orange), green leafy vegetables, green pepper, black currant, tomato, cooked egg, non-fat yogurt, low-fat milk

What are the main functions of vitamins?

Different vitamins have different roles in the growth and nutritional development of the body. These are discussed below-

Vitamin A

• Hair, skin and nail growth
• Bone and teeth development
• Healthy maintenance of respiratory and intestinal tract
• Protection and regeneration of mucous membrane
• Eye health

Vitamin D

• Healthy maintenance of bone, teeth, brain
• Regulation of blood calcium level

Vitamin E

• Maintenance of healthy cell, skin and tissue
• Protection and development of red blood cells
• Antioxidation
• Immunity enhancement

Vitamin K

• Assists in blood coagulation
• Prevents excess bleeding
• Maintenance of liver health

Vitamin B1 (Thiamin)

• Enables carbohydrate and protein metabolism
• Maintenance of normal functioning of heart, muscles and digestive system
• Growth and development

Vitamin B2 (Riboflabin)

• Carbohydrate, protein and fat metabolism
• Maintenance of health of eyes and oral health
• Skin, hair and nail growth

Vitamin B3 (Niacin)

• Carbohydrate and fat metabolism
• Regulation of cholesterol level
• Maintenance of oral health

Vitamin B6

• Protein metabolism
• Production of red blood cells, hormones, enzymes, antibodies
• Proper transmission of nerve impulse

Vitamin B12

• Maintenance of nervous system health
• Production of red blood cells
• Improves protein metabolism
• Enhances appetite

Vitamin C

• Maintenance of oral health
• Collagen synthesis
• Healing after surgery or injury
• Facilitates calcium and iron absorption
• Improves immunity

What are the deficiency symptoms of vitamins?

A regular intake of all forms of vitamins is important for the proper growth and development of the human body. A balanced diet is essential to achieve the same. Shortage of any type of vitamin in the body can give rise to several deficiency symptoms which are discussed below-

Vitamin A deficiency symptoms

• Night-blindness
• Dry and reddish eyes
• A weakness of bone and teeth
• Stomach discomfort

Vitamin D deficiency symptoms

• General bone deformities
• Rickets (in children)
• Osteoporosis (in adults)

Vitamin E deficiency symptoms

• General body weakness (in adults)
• Hemolytic anemia (in children)

Vitamin K deficiency symptoms

• Blood coagulation problems
• Excessive, uncontrolled bleeding after an injury

Vitamin B1 deficiency symptoms

• Beriberi
• Insomnia
• Vomiting
• Impaired growth (in children)
• Complications of the nervous system

Vitamin B2 deficiency symptoms

• General weakness
• Inflammation and swelling of the inner linings of the mouth, oral cavity, and tongue
• Reddened eyes with constant itching
• Dry skin

Vitamin B3 deficiency symptoms

• Digestion problems (dyspepsia)
• Drying up and inflammation of the skin
• Listlessness

Vitamin B6 deficiency symptoms

• Anemia
• Anxiety and depression
• Insomnia
• Muscle cramps

Vitamin B12 deficiency symptoms

• Pernicious anemia
• Loss of memory
• Mental instability
• Cognitive impairments
• General weakness

Vitamin C deficiency

• Scurvy
• Gum inflammation and bleeding
• Loss of teeth
• Bleeding through the skin (due to rupture of capillary vessels)
• Pain in bones and joints
• Swelling and inflammation of joints
• Extreme fatigue
• General weakness

What are the symptoms of hypervitaminosis?

Excess intake of any kind of vitamin (hypervitaminosis) is as bad as vitamin deficiency. The complications associated with hypervitaminosis are discussed below-

Vitamin A hypervitaminosis symptoms

• Dry, itchy skin with rashes
• Peeled off scales
• Hair loss
• Loss of appetite
• Nausea and vomiting
• Stomach discomfort
• Liver dysfunctions
• Headache
• Anxiety and nervousness
• Extreme fatigue

Vitamin D hypervitaminosis symptoms

• Excess calcium salt depostion in body tissues and cartilages (calcification)
• Arrhythmia due to the presence of excess calcium ions in the blood
• Kidney damage (due to inability to filter larger calcium molecules)
• Nausea and vomiting
• Diarrhoea
• Sore eyes
• Itchy skin

Vitamin E hypervitaminosis symptoms

• Drop in thyroxine level
• Headache and dizziness
• Fatigue
• Loss of appetite
• Stomach discomfort

Vitamin K hypervitaminosis symptoms

• Blood clots within arteries
• Liver damage

Vitamin B3 hypervitaminosis symptoms

• Nausea and vomiting
• Stomach discomfort
• Fatigue
• Listlessness
• Headache

Vitamin B6 hypervitaminosis symptoms

• Numbness of limbs leading to difficulty in walking
• Temporary loss of sensation

Vitamin C hypervitaminosis symptoms

• Kidney stone
• Diarrhea
• Abdominal pain

How to manage and prevent nutritional deficiencies?

• A majority of the population is deficient in vitamin D. The daily requirement of vitamin D is 2000 IU. Vitamin D2 comes from plants while D3 comes from animal products. D3 is also produced in our bodies when we expose ourselves to sunlight. Thus a balanced diet rich in fish, eggs, liver, and milk can help prevent vitamin D deficiency.
• Cruciferous vegetables such as broccoli, kale, cabbage, bok choy, and cauliflower are rich in essential nutrients and also help your body Detox.
• It is important to address the major reasons behind nutritional deficiencies among low and middle-income countries. These mainly include – maternal nutritional anemia, protein-energy malnutrition, lactation failure, and vitamin A deficiency.
• Include healthier eating habits – consume whole grains instead of refined, fruits in place of sweet desserts, and water in place of artificially sweetened beverages.

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