Vitamins

Vitamin A

Vitamin A is a fat-soluble and essential nutrient crucial for your child's overall health and growth. It is vital for vision, immune function, and cellular development.

Vitamin A is a powerful micronutrient that supports many critical processes in the body. It belongs to a group of compounds called retinoids. Since the body cannot produce it on its own, children must obtain it through their diet.

There are two main types of Vitamin A found in food. Preformed Vitamin A (Retinol) comes from animal sources (like liver, dairy, and eggs). This form is immediately ready-to-use by the body. The second type is Provitamin A (Beta-Carotene), which comes from plant sources (like carrots and sweet potatoes). This is a precursor that the body converts into Retinol only when needed, making it the safest form to consume in large quantities.

For Preformed Vitamin A (Retinol), good sources include liver (in small amounts), eggs, milk, and cheese. For Provitamin A (Beta-Carotene), focus on brightly colored foods like carrots, sweet potatoes, spinach, squash, kale and fruits such as mango. These orange, yellow, and dark green foods are easily converted by the body.

1. Visión

Vitamin A is famously essential for vision. It is crucial for visual perception, particularly in the rods of the eye, which are what allow us to see in low light or at night.

2.Barrier protection

Vitamin A is the guardian of your body's surfaces. It maintains the functional and structural integrity of epithelial tissues, acting like a continuous maintenance crew for the linings of your skin, eyes, and the internal tracts of your respiratory and gastrointestinal systems. This also includes supporting the production of protective substances like mucins in the gut.

3. Immunity

Vitamin A is a critical factor in the body's defense forces, particularly the adaptative immune system—the part that learns to fight specific threats. It is necessary for the proper proliferation and differentiation of regulatory T cells, which manage the immune response.

4. Metabolism

Vitamin A plays a background but vital role in metabolism, influencing how the body handles fats and helping to maintain healthy insulin sensitivity.

The EFSA recommends different daily values depending on the children's age. However, in kids supplements many European countries do not allow more than 200 ug RE/day. Take in consideration that RE have been introduced and defined as 1 μg RE = 1 μg of retinol = 6 μg of β-carotene = 12 μg of other carotenoids with provitamin A activity.

Vitamin A deficiency is more prevalent worldwide than retinoid intoxication.

The most characteristic consequence of vitamin A deficiency is impaired vision. Early sight impairment is significant, especially under conditions of reduced light.

A sudden excessive consumption of vitamin A leads to acute poisoning. The main symptoms observed in acute toxicity are nausea, irritability, reduced appetite, vomiting, blurry vision, headaches, hair loss, muscle pain, papilledema, hemorrhage, weakness, drowsiness and altered mental status.

Retinol
Retinyl acetate
Retinyl palmitate
β-carotene

- Carazo, A., Macáková, K., Matoušová, K., Krčmová, L. K., Protti, M., & Mladěnka, P. (2021). Vitamin A Update: Forms, Sources, Kinetics, Detection, Function, Deficiency, Therapeutic Use and Toxicity. Nutrients, 13(5), 1703. https://doi.org/10.3390/nu13051703

- von Lintig, J. Metabolism of carotenoids and retinoids related to vision. J. Biol. Chem. 2012, 287, 1627–1634.

- Zhong, M.; Kawaguchi, R.; Kassai, M.; Sun, H. Retina, retinol, retinal and the natural history of vitamin A as a light sensor. Nutrients 2012, 4, 2069–2096.

- Pino-Lagos K, Benson MJ, Noelle RJ. Retinoic acid in the immune system. Ann N Y Acad Sci. 2008 Nov;1143:170-87. doi: 10.1196/annals.1443.017. PMID: 19076350; PMCID: PMC3826166.

- Iwata, M.; Hirakiyama, A.; Eshima, Y.; Kagechika, H.; Kato, C.; Song, S.Y. Retinoic acid imprints gut-homing specificity on T cells. Immunity 2004, 21, 527–538.

Vitamin C

Vitamin C, or ascorbic acid, is an essential, water-soluble vitamin that, while popular for its antioxidant function, has a much wider physiological role in the body.

Unlike most mammals, humans lack the enzyme needed to synthesize it, so we rely entirely on dietary intake.

Vitamin C is found in cells in millimolar concentrations, much higher than in blood circulation.

1. Antioxidant

Vitamin C's primary function is to neutralize free radicals to combat oxidative stress and prevent cellular damage.

2.Mineral absorption

As a consequence of its antioxidant properties, Vitamin C contributes to the reduction of iron, thereby facilitating its absorption. For example, consuming Vitamin C sources with ferric vegetable sources is a good strategy to prevent anemia.

3. Enzymatic Function and Synthesis

Vitamin C is an essential cofactor for many enzymes. It is fundamental for the synthesis of hormones and carnitine, and crucial for the correct formation of connective tissue (e.g., collagen).

4. Cellular Regulation

Vitamin C plays a critical role in epigenetic processes by acting as a cofactor for enzymes that regulate gene expression.

Daily intake recommendations vary substantially by age. In children the recommended dose varies from 30 to 100 mg/day.

Deficiency

Vitamin C deficiency is rare. However, the chronic deficit of vitamin C is responsible for scurvy. Typical symptoms of scurvy are muscle weakness, swollen and bleeding gums, loss of teeth, petechial hemorrhaging, spontaneous ecchymoses, anemia, impaired wound healing, hyperkeratosis, weakness, myalgia, arthralgia,and weight loss (there can also be a paradoxical weight increase due to swelling) while the early manifestations encompass lethargy, lassitude, and irritability.

Overdose

Vitamin C is generally considered relatively safe. However, the administration of very high doses should be done with caution, as it can cause side effects in susceptible patients, such as the formation of kidney stones.

L-ascorbic acid
sodium-L-ascorbate
calcium-L-ascorbate
potassium-L-ascorbate
magnesium L-ascorbate
zinc L-ascorbate
L-ascorbyl 6-palmitate

Doseděl, M., Jirkovský, E., Macáková, K., Krčmová, L. K., Javorská, L., Pourová, J., Mercolini, L., Remião, F., Nováková, L., Mladěnka, P., & on behalf of The OEMONOM. (2021). Vitamin C—Sources, physiological role, kinetics, deficiency, use, toxicity, and determination. Nutrients, 13(2), 615.

Carr, A. C., & Maggini, S. (2017). Vitamin C and immune function. Nutrients, 9(11), 1211.

Manning, J., Mitchell, B., Appadurai, D. A., Shakya, A., Pierce, L. J., Wang, H., & Spangrude, G. J. (2013). Vitamin C promotes maturation of T-cells. Antioxidants & Redox Signaling, 19(17), 2054–2067.

Vitamin D

Vitamin D, often called the "sunshine vitamin" , is an essential, fat-soluble nutrient crucial for numerous biological and physiological human processes.

The body gets Vitamin D in two main ways. Vitamin D (Cholecalciferol) is produced in the skin from a precursor molecule under the influence of sunlight (UV). Both Vitamin D2 and D3 can be present in the diet. Once absorbed or produced, Vitamin D2 and D3 is first converted in the liver to 25-hydroxyvitamin D, which is the accepted biomarker of vitamin D status.

The main source of Vitamin D for humans is non-enzymatic production in the skin via exposure to sunlight.

Dietary sources include foods that contain:

Vitamin D3 (Cholecalciferol): Often found in animal products and fortified foods
Vitamin D2 (Ergocalciferol): Often found in plant source

1. Skeletal Health

Vitamin D is essential for calcium homeostasis; deficiency reduces intestinal calcium absorption. Supplementation with Vitamin D and calcium together has been shown to decrease hip and other fractures in older adults.

2. Gene Regulation

The active form acts as a hormone, regulating gene expression to support fundamental processes like cell growth and differentiation.

3. Immunity

It is vital for the immune system, major trials suggesting benefits in reducing the incidence of autoimmune diseases. Deficiency increases the risks of both autoimmune and infectious diseases.

4. Cardiovascular and Metabolic Health

Observational studies suggest potential benefits in reducing cardiovascular events and risks associated with the development of Type 2 Diabetes Mellitus (T2D).

5. Extra-Skeletal Development

It is vital for numerous extra-renal tissues , including support for prenatal health, brain function, and positive effects on pregnancy and birth outcomes.

Vitamin D daily intake for kids triplicates the dose recommended for adults. The dose is 15 µg per day.

Deficiency

Vitamin D deficiency remains a significant global public health issue, it is estimated that 42 % of healthy children. The lack of Vitamin D results in impaired calcium absorption and increases susceptibility to and the severity of infectious diseases.

Overdose

Vitamin D overdose is rare as its deficiency prevalence is higher than poisoning. It mainly causes hypercalcemia. It includes difficulty in concentration, confusion, apathy, drowsiness, depression, psychosis, and in extreme cases, a stupor and coma. Additionally vomiting, abdominal pain, polydipsia, anorexia, constipation, peptic ulcers, and pancreatitis could happen.

Cholecalciferol
Ergocalciferol

Cui, A., Zhang, T., Xiao, P., Fan, Z., Wang, H., & Zhuang, Y. (2023). Global and regional prevalence of vitamin D deficiency in population-based studies from 2000 to 2022: A pooled analysis of 7.9 million participants. Frontiers in Nutrition, 10, 1070808.

Wimalawansa, S. J. (2023). Physiological basis for using vitamin D to improve health. Biomedicines, 11(6), 1542.

Disphanurat, W., Viarasilpa, W., Chakkavittumrong, P., & Pongcharoen, P. (2019). The clinical effect of oral vitamin D2 supplementation on psoriasis: A double-blind, randomized, placebo-controlled study. Dermatology Research and Practice, 2019(1), 5237642.

Giustina, A., Bilezikian, J. P., Adler, R. A., Banfi, G., Bikle, D. D., Binkley, N. C., … Virtanen, J. K. (2024). Consensus statement on vitamin D status assessment and supplementation: Whys, whens, and hows. Endocrine Reviews, 45(5), 625–654.

Vitamin B1

Vitamin B1, or Thiamine, is an essential, water-soluble B-complex vitamin necessary for proper cell function, actively participates in the metabolism of carbohydrates, fats, and proteins.

Thiamine exists in the body in various forms (free thiamine, mono-, di-, or triphosphate), with thiamine pyrophosphate (TPP) being the major active coenzyme form. The need for Thiamine increases when the diet contains a high proportion of carbohydrates, reflecting its critical role in glucose processing.

Thiamine cannot be produced by the body, it must be acquired by diet. It is found naturally in a wide variety of plant and animal foods. Since grain processing often removes much of the vitamin content, many flours, cereals, and infant formulas in developed countries are fortified with Thiamine.

Animal Sources: Pork (lean cuts and products), trout, salmon, mussels, and organ meats (like liver).

Plant Sources:Whole grains (brown rice, whole wheat bread), legumes (black beans, lentils, peas, soybeans), nuts (pecans, macadamia), seeds (especially sunflower seeds), and yeast (including nutritional yeast and yeast extract spreads).

1. Energy and Cellular Metabolism

Thiamine is required for the proper functioning of enzymes involved in glucose metabolism, making it critical for providing energy to all cells. It participates in cellular respiration, the oxidation of fatty acids, and the overall process of energy production.

2. Nervous System Function

It is vital for ensuring the proper functioning of both the central and peripheral nervous systems. It is involved in the synthesis of important neurotransmitters, and its absence directly affects nerve and brain health.

3. Cellular Integrity and DNA Repair

Thiamine is a prerequisite for the functioning of key enzymes involved in the biosynthesis of pentose sugars, which are essential for the synthesis of nucleic acids (DNA/RNA). Additionally, Thiamine has antioxidant properties that help reduce oxidative stress, indirectly supporting the maintenance of DNA integrity and repair mechanisms.

The European Food Safety Authority (EFSA) recommends that children receive 0.1 mg of thiamin per Megajoule (MJ) of energy consumed. This value is used because thiamin's requirement is closely linked to the body's energy metabolism. To find your child's specific daily need in milligrams (mg/day), you must multiply the 0.1 mg/MJ value by their total daily energy intake in MJ. For example, a moderately active child aged 4-6 with an average energy need of about 6 MJ would require approximately 0.6 mg of thiamin per day.

Thiamine deficiency, known as Beriberi, remains a risk in populations with limited diets (e.g., those relying heavily on polished white rice) and in specific risk groups like individuals with disease-related malnutrition and malabsorption predisposition.

Since Vitamin B1 is water-soluble, excess amounts are readily excreted in the urine. For this reason, oral Thiamine intake is considered relatively safe, and there is no established Tolerable Upper Intake Level B1.

Thiamin mononitrate
Thiamin hydrochloride
Thiamine monophosphate chloride
Thiamine pyrophosphate chloride

Mrowicka, M., Mrowicki, J., Dragan, G., & Majsterek, I. (2023). The importance of thiamine (vitamin B1) in humans. Bioscience Reports, 43(10), BSR20230374.

Kaźmierczak-Barańska, J., Halczuk, K., & Karwowski, B. T. (2025). Thiamine (vitamin B1)—An essential health regulator. Nutrients, 17(13), 2206.

Nga, N. T. T., & Quang, D. D. (2019). Unraveling the antioxidant potential of thiamine: Thermochemical and kinetics studies in aqueous phase using DFT. Vietnam Journal of Chemistry, 57(4), 485–490.

Vitamin B2

Riboflavin

Vitamin B2, or Riboflavin (RF), is an essential, water-soluble B-complex vitamin. It is a fundamental component of the human diet, necessary for key metabolic functions and cellular protection. The body cannot synthesize it and must obtain it from dietary sources.

Riboflavin is relatively stable to heat but is highly photosensitive (easily destroyed by exposure to light, which is why milk is often sold in opaque containers).

Riboflavin is widely available in both plant and animal foods:

Animal sources: milk and dairy products (cheese)

Plant sources: green leafy vegetables, mushrooms, almonds, nuts, rice, and legumes.

1. Energy and Cellular Metabolism

Vitamin B2 is an essential cofactor for many metabolism reactions in the body . These reactions are the base of the metabolism of carbohydrates, proteins, and fats, and are critical for the cellular respiration and overall energy production.

2. Antioxidant and Protective Function

Riboflavin protects the body against oxidative stress, particularly lipid peroxidation and reperfusion oxidative injury (damage caused by the restoration of blood flow after a period of ischemia).

3. Other clinical benefits

Vitamin B2 also contributes to eye health and cognitive function.

Daily intake recommendations vary substantially by age. In children the recommended dose varies from 0.6 to 1.1mg/day.

Deficiency

Riboflavin deficiency is linked to an increased risk of anemia due to impaired iron absorption, metabolism of tryptophan, mitochondrial function, brain and the metabolism of other vitamins.

Overdose

Riboflavin has no known toxicity, even at very high doses, because the body's absorption capacity is limited, and the excess is rapidly excreted in the urine. For this reason, no Tolerable Upper Intake Level has been established.

riboflavin
riboflavin 5’-phosphate, sodium

Suwannasom, N., Kao, I., Pruß, A., Georgieva, R., & Bäumler, H. (2020). Riboflavin: The health benefits of a forgotten natural vitamin. International Journal of Molecular Sciences, 21(3), 950.

Ashoori, M., & Saedisomeolia, A. (2014). Riboflavin (vitamin B2) and oxidative stress: A review. British Journal of Nutrition, 111(11), 1985–1991.

Cheung, I. M., McGhee, C. N., & Sherwin, T. (2014). Beneficial effect of the antioxidant riboflavin on gene expression of extracellular matrix elements, antioxidants and oxidases in keratoconic stromal cells. Clinical and Experimental Optometry, 97(4), 303–309.

Vitamin B3

Vitamin B3, or Niacin, is an essential, water-soluble B-complex vitamin that encompasses two primary forms found in food and supplements: Nicotinic Acid and Nicotinamide (Niacinamide).

Unlike most vitamins, Niacin can be partially synthesized by the body from the amino acid Tryptophan (found in protein-rich foods). Despite this, adequate dietary intake of Niacin itself is essential to meet the body's needs.

Animal sources: red meats, poultry and fish

Plant sources: brown rice, nuts, legumes (e.g., peanuts), and seeds.

Niacin functions as a coenzyme in over 400 reactions, more than any other vitamin-derived coenzyme.

1. Energy and Cellular Metabolism

Niacin’s primarly function is as a precursor of two essential coenzymes: Nicotinamide Adenine Dinucleotide (NAD) and Nicotinamide Adenine Dinucleotide Phosphate (NADP). Both molecules are involved in the metabolism and energy production of the body.

2. DNA Repair and Cellular Integrity

NAD is required for enzymes involved in critical cellular functions, including the maintenance of genome integrity and DNA repair mechanisms.A sufficient supply of Niacin is essential for healthy cell function and regeneration.

3. Nervous and Digestive System Function

Niacin is necessary to maintain a healthy nervous system, contributing to normal psychological function and the formation of neurotransmitters. It is also vital for the normal function of the digestive system and mucous membranes.

The recommended daily intake is expressed in Niacin Equivalents (NE)/ megajoule (MJ), where 1NE = 1 mg of Niacin or 60 mg of Tryptophan. a moderately active child aged 4-6 with an average energy need of about 6 MJ would require approximately 8 mg of niacin per day.

Deficiency

Severe niacin and/or Trp deficiency leads to a variety of clinical symptoms, including diarrhea, dermatitis and dementia, collectively known as “pellagra” or “the three D disease”. Niacin is present in many foods, making deficiency rare in developed countries.

Overdose

Niacin overdose (around 3 grams per day) can cause serious hepatotoxicity that ranges from a mild elevation of liver enzymes to acute liver failure. Clinical manifestations are fatigue, nausea, and vomiting.

Nicotinamide
Nicotinic acid
inositol hexanicotinate

Hrubša, M., Siatka, T., Nejmanová, I., Vopršalová, M., Kujovská Krčmová, L., Matoušová, K.,Oemonom. (2022). Biological properties of vitamins of the B-complex, part 1: Vitamins B1, B2, B3, and B5. Nutrients, 14(3), 484.

Gasperi, V., Sibilano, M., Savini, I., & Catani, M. V. (2019). Niacin in the central nervous system: An update of biological aspects and clinical applications. International Journal of Molecular Sciences, 20(4), 974.

Vitamin B5

Vitamin B5, or Pantothenic Acid, is a water-soluble vitamin essential for metabolism.

The name comes from the Greek word "panthos," meaning "everywhere," which reflects its ubiquitous presence in food. It is widespread in food, making deficiency rare. Rich sources include:

Animal sources: meat, eggs, milk, cheese and royal jelly (one of the richest natural sources)
Plant sources: Whole grain cereals, legumes, nuts, yeast, mushrooms, avocado, potatoes, and cruciferous vegetables (broccoli, cauliflower).

Note on Processing:Milling of cereals can reduce content by 50-88%. While pantothenic acid is stable to heat at optimal pH levels, significant losses (15-50% in meat/fish) can occur through leaching into cooking liquids, particularly during boiling.

Vitamin B5 actively participates in numerous catabolic (energy-releasing) and anabolic (biosynthesis) reactions. Being crucial in the synthesis of fatty acids, cholesterol, steroid hormones, acetylcholine (a key neurotransmitter), and bile acids.

In children the daily recommended dose is 4-5 mg.

Deficiency

Vitamin B5 deficiency is generally rare and usually occurs alongside multiple nutrient deficiencies in cases of severe malnutrition. The common symptoms include fatigue, irritability, sleep disturbances and gastrointestinal health.

Overdose

No Tolerable Upper Intake Level has been established for pantothenic acid because there are no reports of adverse effects from food or supplements at normal levels. Very high doses may cause mild gastrointestinal upset and diarrhea.

D-pantothenate, calcium
D-pantothenate, sodium
dexpanthenol
pantethine

Yoshii, K., Hosomi, K., Sawane, K., & Kunisawa, J. (2019). Metabolism of dietary and microbial vitamin B family in the regulation of host immunity. Frontiers in Nutrition, 6, 434971.

Hrubša, M., Siatka, T., Nejmanová, I., Vopršalová, M., Kujovská Krčmová, L., Matoušová, K., Javorská, L., Macáková, K., Mercolini, L., Remião, F., Máťuš, M., Mladěnka, P., & on behalf of the OEMONOM. (2022). Biological properties of vitamins of the B-complex, part 1: Vitamins B1, B2, B3, and B5. Nutrients, 14(3), 484.

Vitamin B6

Vitamin B6 is a water-soluble B-vitamin, also known as Pyridoxine. As a water-soluble vitamin, the body does not store large amounts, so a regular dietary intake is necessary.

Key sources of Vitamin B6 include:

Animal Sources: Beef liver, tuna, salmon, and poultry.
Plant Sources: Chickpeas, potatoes (and other starchy vegetables), fortified cereals, and bananas.

Vitamin B6 is heat stable, and processing steps such as cooking or frying do not affect its content.

Vitamin B6 is essential for over 100 enzyme reactions, primarily involved in protein metabolism. Its main roles include:

1. Metabolism

Vitamin B6 participates in the body breakdown protein, as well as fats and carbohydrates, turning them into usable energy.

2. Brain and nerve function

Pyridoxine is crucial for brain development and function, including the production of neurotransmitters like serotonin (which regulates mood) and norepinephrine (which helps the body respond to stress)

3.Red Blood Cell Formation

Vitamin B6 is necessary for the creation of red blood cells and for maintaining normal levels of the amino acid homocysteine, which, when elevated, is linked to an increased risk of heart disease.

For children the EFSA recommended dose is between 0.6 mg 0.9 mg per day.

Deficit

Vitamin B6 deficiency is uncommon but can occur alongside deficiencies in other B-vitamins. The symptoms can include microcytic anemia, seborrheic dermatitis, confusion and weakened immune function.

Overdose

Vitamin B6 overdose can affect the nervous system causing burning and tingling sensations, which may lead to peripheral neuropathy.

pirydoxine hydrochloride
pirydoxine 5’-phosphate
pyridoxal 5’-phosphate

Stach, K., Stach, W., & Augoff, K. (2021). Vitamin B6 in health and disease. Nutrients, 13(9), 3229.

Mooney, S., Leuendorf, J.-E., Hendrickson, C., & Hellmann, H. (2009). Vitamin B6: A long known compound of surprising complexity. Molecules, 14(1), 329–351.

Parra, M., Stahl, S., & Hellmann, H. (2018). Vitamin B₆ and its role in cell metabolism and physiology. Cells, 7(7), 84.

Vitamin B12

Vitamin B12, also known as Cobalamin, is a water-soluble vitamin essential for human health. A healthy gut normally absorbs 50 % of the total intake of vitamin B12.

It is naturally found almost exclusively in animal-source foods, however many foods are fortified with added vitamin B12 to reduce the risk of deficit of vegan and vegetarian population.

Food processing techniques that can contribute to dietary B12 degradation are pasteurization, heating, canning, and irradiation.

Vitamin B12 plays several crucial roles, primarily as a cofactor:

Nervous System Health: It is a critical cofactor for synthesizing myelin (the protective sheath around nerve fibers) and neurotransmitters, ensuring the proper functioning of the central and peripheral nervous systems.

Metabolism: It participates in cellular metabolism and is essential for regulating homocysteine levels. Low B12 levels are associated with elevated homocysteine, which is a risk factor for cognitive impairment and depression.

The EFSA recommendations of vitamin B12 daily intake for kids is 1.5-2.5 µg per day.

B12 deficiencies feel tired or weak. These are symptoms of megaloblastic anemia, which is a hallmark of vitamin B12 deficiency.

Tolerable Upper Intake Level has not been established for Vitamin B12, as there is low risk of adverse effects from food or supplements in healthy individuals. The body's absorption capacity is limited, and the excess is rapidly excreted in the urine

methylcobalamin
cyanocobalamin
hydroxocobalamin
5’-deoxyadenosylcobalamin

Abuyaman, O., Abdelfattah, A., Shehadeh-Tout, F., Deeb, A. A., & Hatmal, M. M. (2023). Vitamin B12 insufficiency and deficiency: A review of nondisease risk factors. Scandinavian Journal of Clinical and Laboratory Investigation, 83(8), 533–539.

Markun, S., Gravestock, I., Jäger, L., Rosemann, T., Pichierri, G., & Burgstaller, J. M. (2021). Effects of vitamin B12 supplementation on cognitive function, depressive symptoms, and fatigue: A systematic review, meta-analysis, and meta-regression. Nutrients, 13(3), 923.

Folic Acid

Folic acid is the synthetic (human-made) form of the naturally occurring vitamin, Folate (also known as Vitamin B9). It is a water-soluble B-vitamin that plays a fundamental role in cell division and growth.

The body cannot produce Folate on its own, so children and adults must obtain it through their diet. Folic acid, the synthetic form, is better absorbed by the body than the natural Folate found in food (up to 85% absorption vs. approximately 50%, respectively). This high bioavailability is why many countries require Folic Acid fortification in staple grain products like enriched breads, flours, cereals, pastas, and rice.

Folic acid is found in plant and animal sources:

Plant sources: Spinach, kale, and collard greens, citrus fruits, peas, lentils.
Animal sources: liver.

1. Growth and cell division

Folate is critical during periods of rapid growth and cell division, making it especially vital for infants and children. It functions as a coenzyme in single-carbon transfers, which are essential for the body's internal chemistry.

One of its most crucial functions is the synthesis and repair of genetic material, which is necessary for all cell creation and replication:

2. DNA and RNA Synthesis

Folate is indispensable for building DNA, the body's genetic blueprint. This makes it vital for the development of the fetus, infants, and children.

3. Red Blood Cell Formation

Folate is necessary to produce healthy red blood cells, which carry oxygen throughout the body.

4. Protein Metabolism

It works closely with Vitamin B12 to regulate the breakdown and use of proteins, playing a key role in converting the amino acid homocysteine into methionine. High homocysteine levels are linked to cardiovascular disease risk.

5. Brain and Nervous System Development

Adequate folate intake is vital for brain growth and function, supporting the central nervous system and affecting mood and cognitive function in children.

The daily recommended dose of biotin for kids is between 110-160 µg per day.

Deficiency

Folate deficiency can occur due to poor diet, malabsorption issues (like Celiac disease), or certain medications.Because Folate is essential for cell division, a deficiency primarily impacts rapidly dividing cells (blood cells, cells lining the gut). A lack of Folate leads to megaloblastic anemia, diarrhea, loss of appetite, poor growth and developmental delays.

Overdose

A Tolerable Upper Intake Level UL has been established at 300- 600 ug per day for Folic Acid (the synthetic form) from fortified foods and supplements. There is no UL set for Folate that occurs naturally in food, as there is no evidence of adverse effects from consuming natural food sources.

The concern with excessive Folic Acid intake is that it can mask a Vitamin B12 deficiency. High-dose Folic Acid may correct the anemia caused by a B12 deficiency.

calcium-L-methylfolate
pteroylmonoglutamic acid

Panda, P. K., Sharawat, I. K., Saha, S., Gupta, D., Palayullakandi, A., & Meena, K. (2024). Efficacy of oral folinic acid supplementation in children with autism spectrum disorder: A randomized double-blind, placebo-controlled trial. European Journal of Pediatrics, 183(11), 4827–4835.

Zhang, S., Yang, M., Hao, X., Zhang, F., Zhou, J., Tao, F., & Huang, K. (2023). Peri-conceptional folic acid supplementation and children's physical development: A birth cohort study. Nutrients, 15(6), 1423.

Williams, B. A., McCartney, H., Singer, J., Devlin, A. M., Vercauteren, S., Amid, A., Wu, J. K., & Karakochuk, C. D. (2025). Folic acid supplementation in children with sickle cell disease: A randomized double-blind noninferiority cross-over trial. American Journal of Clinical Nutrition, 121(4), 910–920.

Vitamin K1

Vitamin K1, chemically known as phylloquinone (or phytomenadione/phytonadione), is the natural plant form of Vitamin K. It is a fat-soluble vitamin essential for the human body.

K1 is the predominant form of Vitamin K in the human diet, making up approximately 75%-90% of the total intake. However, its bioavailability is low. In addition, vitamin K1 is extremely sensitive to daylight and fluorescent light.

The primary source of vitamin K1 are green leafy vegetables including kale, spinach, chard, parsley, broccoli, and brussels sprouts.

Vitamin K1’s primary role is as a cofactor necessary for the activation of proteins.

1. Blood coagulation

Vitamin K is traditionally associated with its role in the blood coagulation cascade. It is required for the posttranslational modification of seven proteins involved in this cascade.

2. Tissue calcification

Vitamin K1 participates in the calcification of connective tissue, physiologically necessary in bones.

As a consequence of both functions is directly related to cardiovascular health.

Daily intake recommendations vary by age. In children the recommended dose varies from 20 to 30 µg/day.

Deficiency

Deficiency is rare in healthy children and adults, as it is widely available in food. Newborns and kids suffering intestinal disease are more common to have Vitamin K1 deficiency due to absorption problems.The primary symptom is uncontrolled bleeding (hemorrhage) due to impaired blood clotting

Toxicity

For Vitamin K1 derived from food or supplements, there is no established Tolerable Upper Intake Level. This means that, based on current evidence, high intakes of K1 are not known to cause adverse health effects.

phylloquinone (phytomenadione)
menaquinone

Tsugawa, N., & Shiraki, M. (2020). Vitamin K nutrition and bone health. Nutrients, 12(7), 1909.

Booth, L. S.(2012). Vitamin K: food composition and dietary intakes. Food & nutrition research, 56(1), 5505.

Mladěnka, P., Macáková, K., Kujovská Krčmová, L., Javorská, L., Mrštná, K., Carazo, A., Protti, M., Remião, F., Nováková, L., & OEMONOM researchers and collaborators. (2022). Vitamin K—Sources, physiological role, kinetics, deficiency, detection, therapeutic use, and toxicity. Nutrition Reviews, 80(4), 677–698.

Vitamin E

Vitamin E is a lipid-soluble vitamin and a widely popular dietary supplement for overall health. It is one of the major components of the cell's antioxidant defense system and is exclusively obtained from the diet.

Vitamin E is a general term that encompasses eight different fat-soluble compounds of plant origin. These compounds are divided into two groups, each with four variations:

Tocopherols
Tocotrienols

The primary and most active form of Vitamin E in the human body is α-tocopherol.

Vitamin E is commonly found in plant sources as leafy vegetables, whole grains, nuts, seeds, vegetable oils (olive oil) and avocados.

Vitamin E's critical roles are primarily driven by its antioxidant activity

1. Antioxidant Defense:

As a well-known antioxidant, α-tocopherol protects cells from oxidative stress and damage caused by free radicals.

2. Cellular Integrity and Immunity

It is essential for maintaining cellular integrity and supporting immune function.

3. Blood Health

Vitamin E may prevent platelet hyperaggregation, which is linked to atherosclerosis. It does this by helping to reduce the production of prostaglandins like thromboxane, which cause platelets to clump.

4. Regulation

α-tocopherolsare also involved in other processes such as cell signaling and gene expression.

In children the recommended daily dose is 9 mg/day.

Deficiency

Symptomatic deficiency is rare but can occur. It can result from an acquired or inherited condition that impairs its absorption. The classic clinical sign of a deficiency is neurological dysfunction and vision alterations.

Overdose

Vitamin E has a relatively low level of toxicity, but high doses of supplements pose potential risks.

Toxicity can manifest as interference with other fat-soluble vitamins, specifically Vitamin K's action, which can lead to severe bleeding issues. Also, high dose Vitamin E can act as a pro-oxidant under certain conditions, particularly when the body does not sufficiently recycle it using other antioxidants like Vitamin C.

D-alpha-tocopherol
DL-alpha-tocopherol
D-alpha-tocopheryl acetate
DL-alpha-tocopheryl acetate
D-alpha-tocopheryl acid succinate
mixed tocopherols
tocotrienol tocopherol

Xiong, Z., Liu, L., Jian, Z., Ma, Y., Li, H., Jin, X., Liao, B., & Wang, K. (2023). Vitamin E and multiple health outcomes: An umbrella review of meta-analyses. Nutrients, 15(15), 3301.

Shahidi, F., Pinaffi-Langley, A. C. C., Fuentes, J., Speisky, H., & de Camargo, A. C. (2021). Vitamin E as an essential micronutrient for human health: Common, novel, and unexplored dietary sources. Free Radical Biology and Medicine, 176, 312–321.

Kaye, A. D., Thomassen, A. S., Mashaw, S. A., MacDonald, E. M., Waguespack, A., Hickey, L., & Hickey, L. C. (2025). Vitamin E (α-tocopherol): Emerging clinical role and adverse risks of supplementation in adults. Cureus, 17(2), e78679.

Biotin

Biotin, also known as Vitamin B7, is a water soluble B-vitamin.

Biotin, also known as Vitamin B7 (or sometimes Vitamin H), is a water-soluble B-vitamin that is essential for human health and serves as a powerful micronutrient supporting numerous fundamental metabolic processes. Since the body cannot synthesize it on its own, it must be obtained through the diet.

Biotin is found in a wide variety of foods, though generally at low concentrations.

Biotin is readily available in both animal and plant-based sources. Key foods include:

Animal Sources: Liver, egg yolk, and milk.

Plant Sources: Whole-grain cereals, soy, nuts, avocados and seeds.

One of its most crucial functions is its role as a coenzyme for carboxylase enzymes. These enzymes are critical "switch-points" in metabolism, essential for three major pathways:

1. Gluconeogenesis and fatty acid synthesis

It helps convert non-carbohydrate sources (like amino acids) into glucose, which is the primary fuel for the body and brain. Biotin also contributes to the creation of fats your body needs.

2. Amino acids catabolism

Biotin assists in the breakdown of branched-chain amino acids, the base of protein building blocks

3. Support hair, skin and nails

Biotin supports the structure of keratin, a fundamental protein that makes up your hair, skin, and nail tissues.

4. Nervous system

It is needed for the proper functioning of the central and peripheral nervous system. High-dose biotin is being studied for its potential to help with some progressive neurological diseases.

The daily recommended dose of biotin for kids is 25 µg per day.

Biotin deficiency is rare in healthy individuals consuming a mixed diet. However, it can occur in individuals receiving long-term parenteral nutrition without supplementation, in those with the genetic disorder biotinidase deficiency, or due to prolonged consumption of raw egg whites (which contain avidin, a protein that binds biotin). The common symptoms of biotin deficiency are hair loss, conjunctivitis and dermatitis.

A tolerable upper intake level has not been established for Biotin due to a lack of evidence of adverse health effects from high doses in humans. Biotin is generally considered safe, even at high amounts.

D-biotin

Stokke Solvik, B., & Strand, T. A. (2024). Biotin: A scoping review for Nordic Nutrition Recommendations 2023. Food & Nutrition Research, 68.

Mock, D. M. (2017). Biotin: From nutrition to therapeutics. Journal of Nutrition, 147(8), 1487–1492.

Sakurai-Yageta, M., & Suzuki, Y. (2024). Molecular mechanisms of biotin in modulating inflammatory diseases. Nutrients, 16(15), 2444.