Dr. Sarah Livelo 03 Aug 2021

Humans need nutrition for energy production, growth, and development. Our diet usually contains macronutrients, such as carbohydrates, proteins and fats, to provide energy for daily activities. On the other hand, micronutrients, such as vitamins and minerals, are necessary for normal physiologic functions.

The Different Vitamins and Signs of Deficiencies

Vitamin A

Vitamin A, also known as retinol, is a fat-soluble vitamin necessary for the proper development of vision and immunity. Normal embryonic development requires sufficient amounts of this vitamin. For newborns, vitamin A helps in the production of different types of cells in the body, especially the components of blood (called hematopoiesis).

Vitamin A is easily obtained from a regular diet. Foods rich in Vitamin A include organ meats (especially the liver), milk, cheese, eggs, yellow-orange vegetables, and leafy green vegetables. The recommended nutrient intake of Vitamin A for infants 0-12 months old is 350 micrograms per day. Children 1-3 years old should be given 400 micrograms per day.

Deficiencies in Vitamin A are common in developing countries. One of the more common signs are disturbances in vision. Children may present with difficulties adapting to low amounts of light (delayed dark adaptation), which may lead to night blindness and photophobia. Other eye conditions include drying and scaling of some layers of the cornea (called xerophthalmia) and keratin production of the conjunctiva (called Bitôt spots). In severe cases, there may be ulceration of the cornea, which leads to irreversible blindness. Other signs and symptoms include diarrhea, anemia, tea-colored urine, dry and scaly patches on the extremities and buttocks, increased risk of infections, and poor growth.

Vitamin B1 (Thiamine)

There are many subtypes of the water-soluble Vitamin B, forming what is commonly known as the Vitamin B complex. Because each has its own set of functions in the body, symptoms may not be similar across all types of Vitamin B.

Vitamin B1 is also known as thiamine. This is a cofactor for enzymes involved in carbohydrate metabolism and nerve conduction. When the body uses up additional energy in situations such as fever, pregnancy and muscular activity, a higher intake of Vitamin B1 is needed.

Thiamine may be acquired from fish, poultry, lean meat, rice, fortified cereals and in human milk. The recommended nutrient intake of thiamine in children 0-12 months old is 0.2 mg per day. For children 1-3 years old, around 0.5 mg should be given daily.

Vitamin B1 deficiency may occur when the diet is mostly composed of polished, repeatedly washed rice or highly refined wheat flour. Alcoholism decreases the available amount of the vitamin in the body. Patients with critical illnesses or post-surgery may develop thiamine deficiency as well.

Some genetic disorders may predispose a child to thiamine-related medical conditions. The thiamine-responsive megaloblastic anemia (TRMA) syndrome is due to a mutation in the SLC19A2 gene, while the biotin and thiamine-responsive basal ganglia disease is due to a mutation in the SLC19A3 gene.

Vitamin B1 deficiency, called beriberi, develops after a few months. Children may have nonspecific signs and symptoms at the onset of the condition, such as drowsiness, fatigue, apathy, irritability, nausea, abdominal discomfort and anorexia. As the disease progresses, they may present with painful leg muscles, tingling or burning pain in the toes or feet (called peripheral neuritis), difficulty coordinating movement, decreased sensation, edema, drooping eyelids (called ptosis), and a hoarse voice. In severe cases, death may occur from cardiac complications, such as heart enlargement and heart failure.

Vitamin B2 (Riboflavin)

Vitamin B2 is also known as riboflavin. It is a component of some coenzymes that play a role in metabolism and generation of energy.

This vitamin is found in organ meats, milk, eggs, fortified cereals and breads, legumes and mushrooms. In children 0-12 months old, the required amount of riboflavin per day is 0.4 mg. For those 1-3 years old, a daily dose of 0.6 mg is needed.

Most cases of riboflavin deficiency are due to malabsorption or malnourishment. The use of certain medications, such as oral contraceptives and probenecid, can cause Vitamin B2 deficiency. Some signs and symptoms include poor growth, photophobia, increased tearing of the eyes (called lacrimation), inflammation of the conjunctivae (called conjunctivitis), cracks in the corner of the mouth (cheilosis), smoothening of the surface of the tongue (called glossitis) and anemia.

Vitamin B3 (Niacin)

Vitamin B3, also referred to as niacin, is a water-soluble B vitamin essential in DNA processing, the production of energy, and the synthesis of natural fatty acids and steroids. This vitamin can also be produced from tryptophan, which in turn can also be obtained from one’s diet.

Niacin comes from meat, poultry, fish, legumes, green leafy vegetables and fortified cereals. Tryptophan is readily available from milk and eggs. The recommended daily intake of niacin is 3mg for 0-6 months old, 4-5mg for 7-12 months old, and 8mg for those 1-3 years of age.

Niacin deficiency is commonly known as pellagra. This condition is commonly seen in people whose diet consists mainly of corn, patients diagnosed with anorexia nervosa, and patients with issues in tryptophan metabolism, such as carcinoid syndrome. Pellagra has a classic triad of symptoms: dermatitis (including prominent demarcations around the hands, feet, or neck), diarrhea, and dementia. Some accompanying symptoms are vomiting, constipation, anemia, glossitis, irritability, anxiety and insomnia.

Vitamin B6 (Pyridoxine)

Vitamin B6 is also known as pyridoxine. This vitamin serves as a coenzyme for amino acid and glycogen metabolism, and also contributes to neurotransmitter synthesis. When there is an increased intake of protein, a higher amount of Vitamin B6 is needed. Some medications, such as corticosteroids, phenytoin, isoniazid and progesterone-estrogen oral contraceptives, may decrease Vitamin B6 activity.

Pyridoxine is found in meat and liver, poultry, fish, rice, bananas, vegetables, fortified cereals, human milk and infant formulas. The recommended daily reference nutrient intake for Vitamin B6 is 0.2 mg for 0-6 months old, 0.3-0.4 mg for 7-12 months old, and 0.7 mg for 1-3 years of age.

Pyridoxine deficiency largely affects the nervous system. Symptoms include irritability, vomiting, seizures, peripheral neuritis, glossitis, cheilosis, anemia, and infections. Bladder stones may also develop.

Vitamin B7/H (Biotin)

Vitamin B7 is more commonly known as biotin; Vitamin H is another term. Like other B complex vitamins, biotin is a cofactor for enzymes central to amino acid, fatty acid and glucose metabolism. Deficiency may occur in patients prescribed with valproic acid. Interestingly, there have been cases of biotin deficiency which involves ingesting large amounts of raw egg whites.

Sources of biotin include beef liver, pork, salmon, cooked eggs, sweet potato, nuts, seeds and avocados. Because biotin in general is widely available in the typical modern diet, there is no recommended dietary allowance for this vitamin.

Biotin deficiency usually affects the skin and the nervous system. Signs and symptoms include inflammation of the skin and eyes (dermatitis and conjunctivitis, respectively). There may be thinning or loss of hair (called alopecia). Affected individuals may present with decreased muscle tone, abnormal muscle movements and seizures.

Vitamin B9 (Folate)

Vitamin B9, commonly referred to as folate, plays a significant role in growth and metabolism during the childhood years, especially in neurological development during infancy. Like biotin, deficiency may be due to certain medications, such as anticonvulsants and anti-inflammatory drugs. Other causes are intestinal malabsorption and hereditary conditions. When the body uses up additional energy in cases such as sickle cell anemia and malignancy, a higher intake of folate is needed.

Some foods are usually fortified with folic acid, a synthetic form of folate. Most foods contain folate: liver, seafood, eggs, beans, peanuts, sunflower seeds, dark green leafy vegetables and fruits. The recommended intake for this vitamin is 50 micrograms per day for 0-12 months old, and 70 micrograms per day for 1-3 years old.

The most common consequence of folate deficiency are neural tube defects. These are malformations in the brain or spinal cord of a fetus or a newborn. Other manifestations are megaloblastic anemia, glossitis, and growth problems.

Vitamin B12 (Cobalamin)

Vitamin B12 is also known as cobalamin. It is an essential cofactor in hematopoiesis, carbohydrate and lipid metabolism, and synthesis of proteins and nucleic acids. In the small intestine, it is bound to intrinsic factor before absorption.

Cobalamin may be found in muscle and organ meats, poultry, seafood, egg yolk and fortified cereals. The recommended daily intake is 0.3 micrograms for 0-6 months old, 0.4 micrograms for 7-12 months old, and 0.5 micrograms for 1-3 years old.

Vitamin B12 deficiency may be due to a strict lactovegetarian, vegetarian or vegan diet. Use of proton pump inhibitors, malabsorption diseases, and certain inborn errors of metabolism can lead to decreased cobalamin levels. Affected individuals may have developmental delays or regression, irritability, hypotonia, peripheral neuritis, or tremors. Some children may have impaired growth.

Vitamin C

Vitamin C is also known as ascorbic acid, a water-soluble vitamin essential for collagen synthesis, cholesterol metabolism, and neurotransmitter metabolism. It is also famously known as the body’s natural antioxidant.

This vitamin is frequently found in citrus fruits, berries, tomatoes, peppers, melons, guava and green leafy vegetables. Children 0-12 months old should receive 25 mg of Vitamin C daily, while for those 1-3 years of age, the value is increased to 30 mg per day.

Vitamin C deficiency is commonly known as scurvy. This may develop in children who consume an inadequate amount of fruits and vegetables. Patients develop fragile bones, connective tissues and even blood vessels. Initial symptoms include nonspecific signs such as fever, muscle pains and irritability. Children may complain of painful or tender lower extremities, which may have also be swollen. The sternum may be depressed, and there are bead-like, prominent bones along the ribcage. Other symptoms include bluish gums, anemia, and bleeding.

Vitamin D

Vitamin D, also known as 3-cholecalciferol, is another fat-soluble vitamin. It affects calcium and phosphate absorption, as well as normal bone growth.

Sources of cholecalciferol are fatty fish, egg yolks, fish oil, bread, cereals and fortified infant formula. This vitamin may be synthesized in the skin with the help of sunlight exposure. Children aged 0-6 months old need to take 8.5 micrograms of cholecalciferol every day, while for those aged 7 months up to 3 years old, the dose is decreased to 7 micrograms per day.

Vitamin D deficiency is known for causing rickets. Signs and symptoms of this condition include muscle weakness, an increased predisposition to bone fractures and elevated intracranial pressure, delayed closure of fontanels and eruption of teeth, rachitic rosary, back problems, enlarged wrists or ankles, stridor, and seizures.

Vitamin E

Vitamin E is a fat-soluble vitamin primarily aiding the body as an antioxidant. Like biotin, this vitamin is seen in most foods. Children are recommended to take 0.4 mg of vitamin E once a day.

Deficiencies are common in premature infants, children in severe malnourished states, and in patients diagnosed with abetalipoproteinemia. They present with predominantly neurologic symptoms, such as tremors, ataxia, slurring, unsteady gait, and blindness.

Vitamin K

Vitamin K is a fat-soluble vitamin that functions as a component of blood coagulation. Insufficient amounts of Vitamin K in the body may lead to bleeding. This is common in newborns who were not given Vitamin K at birth.

Sources of vitamin K include liver, legumes and green leafy vegetables. The recommended daily intake is 10 micrograms for infants up to children 3 years of age.

The usual sign of Vitamin K deficiency is bleeding. This may be seen in the brain, gastrointestinal tract and umbilical stump for newborns.

Prevention of vitamin deficiencies

There are various ways to prevent vitamin deficiencies from developing.

1. Adequate maternal diet (pregnant and breastfeeding)
Both pregnant and breastfeeding mothers should have a balanced diet that can sufficiently provide their daily nutritional requirements, including all macronutrients and micronutrients. Supplements containing vitamin C and folate may also be taken.

2. Balanced meals for a healthy diet
For newborns and infants, the best source of nutrition is human milk. Good quality infant formula may be given when human milk is unavailable or cannot be given. For children, include fortified foods in their diet, such as cereals and bread.

Supplements are highly encouraged for those with a vegetarian or vegan diet. For hospitalized patients who rely on parenteral nutrition, supplementation may also be done as necessary.

3. Cooking techniques
In certain populations, frequently washing rice or using polished rice as a daily diet staple can wash away vitamins. Parboiling may ensure that less amounts of thiamine, pyridoxine and other vitamins will be removed from the rice.

4. Routine Vitamin K for newborns
It is highly recommended to give vitamin K to all newborns. They are prone to bleeding due to naturally decreased Vitamin K levels at this age.

5. Be mindful of your current medications
Some medicines may inhibit the functions of certain vitamins. Examples include:

  • Vitamin B6: isoniazid, penicillamine, corticosteroids, carbamazepine, phenytoin, progesterone-estrogen oral contraceptives
  • Vitamin B12: proton pump inhibitors, metformin, H2-receptor antagonists
  • Vitamin D: phenobarbital, phenytoin

A healthcare provider can help decide which vitamin supplements are needed for patients who take these medications on a long-term or maintenance basis.

6. Sunlight exposure
Vitamin D may be synthesized through sunlight. Daily sunlight exposure is a simple way to ensure that one has enough vitamin D levels.

7. Past and family medical history
Take note of any significant medical conditions or illnesses in the family, such as genetic and renal disorders. Early detection and treatment of vitamin deficiencies may help prevent the progression of the disease or any severe complications.


Insufficient amounts of any vitamin can cause mild to severe illnesses and can halt natural growth and development. Overall, a holistic and adequate diet is an important contributor to our daily required intake of vitamins.

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About the Author:
Dr. Sarah Livelo is a licensed physician with specialty training in Pediatrics. When she isn't seeing patients, she delves into healthcare and medical writing. She is also interested in advancements on nutrition and fitness. She graduated with a medical degree from the De La Salle Health Sciences Institute in Cavite, Philippines and had further medical training in Makati Medical Center for three years.


  • Kliegman, R.M. et al. (2020). Part V Nutrition. Nelson Textbook of Pediatrics 21st edition. Elsevier.
  • Leaf, AA; RCPCH Standing Committee on Nutrition (2007). Vitamins for babies and young children. Arch Dis Child. 2007 Feb; 92(2): 160–164.
  • Biotin – Vitamin B7. The Nutrition Source. Harvard T.H. Chan School of Public Health. Taken from:
  • Folate (Folic Acid) – Vitamin B9. The Nutrition Source. Harvard T.H. Chan School of Public Health. Taken from:

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