Vitamin deficiency is the condition of a long-term lack of a vitamin. When caused by not enough vitamin intake it is classified as a primary deficiency, whereas when due to an underlying disorder such as malabsorption it is called a secondary deficiency. An underlying disorder can have 2 main causes: Metabolic causes: Genetic defects in enzymes (e.g. kynureninase) involved in the kynurenine pathway of synthesis of niacin from tryptophan can lead to pellagra (niacin deficiency). Lifestyle choices: Lifestyle choices and habits that increase vitamin needs, such as smoking or drinking alcohol. Government guidelines on vitamin deficiencies advise certain intakes for healthy people, with specific values for women, men, babies, children, the elderly, and during pregnancy or breastfeeding. Many countries have mandated vitamin food fortification programs to prevent commonly occurring vitamin deficiencies.
Conversely, hypervitaminosis refers to symptoms caused by vitamin intakes in excess of needs, especially for fat-soluble vitamins that can accumulate in body tissues.
The history of the discovery of vitamin deficiencies progressed over centuries from observations that certain conditions – for example, scurvy – could be prevented or treated with certain foods having high content of a necessary vitamin, to the identification and description of specific molecules essential for life and health. During the 20th century, several scientists were awarded the Nobel Prize in Physiology or Medicine or the Nobel Prize in Chemistry for their roles in the discovery of vitamins.
Defining deficiency A number of regions have published guidelines defining vitamin deficiencies and advising specific intakes for healthy people, with different recommendations for women, men, infants, the elderly, and during pregnancy and breast feeding including Japan, the European Union, the United States, and Canada. These documents have been updated as research is published. In the US, Recommended Dietary Allowances (RDAs) were first set in 1941 by the Food and Nutrition Board of the National Academy of Sciences. There were periodic updates, culminating in the Dietary Reference Intakes. Updated in 2016, the US Food and Drug Administration published a set of tables that define Estimated Average Requirements (EARs) and (RDAs). RDAs are higher to cover people with higher than average needs. Together, these are part of Dietary Reference Intakes. For a few vitamins, there is not sufficient information to set EARs and RDAs. For these, an Adequate Intake is shown, based on an assumption that what healthy people consume is sufficient. Countries do not always agree on the amounts of vitamins needed to safeguard against deficiency. For example, for vitamin C, the RDAs for women for Japan, the European Union (called Population Reference Intakes) and the US are 100, 95 and 75 mg/day, respectively. India sets its recommendation at 40 mg/day.
Individual vitamin deficiencies
Water-soluble vitamins
Vitamin Symptoms & Diagnosis InformationThiamine (Vitamin B1) deficiency Weight loss, emotional disturbances, impaired sensory perception, weakness and pain in the limbs, and periods of irregular heart beat. Deficiency is assessed by red blood cell status and urinary output. Especially common in countries that do not require fortification of wheat and maize flour and rice to replace the naturally occurring thiamine content lost to milling, bleaching and other processing. Severe deficiency causes beriberi, which became prevalent in Asia as more people adopted a diet primarily of white rice. Wernicke encephalopathy and Korsakoff syndrome are forms of beriberi. Alcoholism can also cause vitamin deficiencies. Long-term deficiencies can be life-threatening.Riboflavin (Vitamin B2) deficiency Deficiency causes painful red tongue with sore throat, chapped and cracked lips, and inflammation at the corners of the mouth (angular cheilitis). Eyes can be itchy, watery, bloodshot and sensitive to light. Riboflavin deficiency also causes anemia with red blood cells that are normal in size and hemoglobin content, but reduced in number. This is distinct from anemia caused by deficiency of folic acid or vitamin B12. Especially common in countries that do not require fortification of wheat and maize flour and rice to replace the naturally occurring riboflavin lost during processing.Niacin (Vitamin B3) deficiency Deficiency causes pellagra, a reversible nutritional wasting disease characterized by four classic symptoms often referred to as the four Ds: diarrhea, dermatitis, dementia, and death. The dermatitis occurs on areas of skin exposed to sunlight, such as backs of hands and neck. Niacin deficiency is a consequence of a diet low in both niacin and the amino acid tryptophan, a precursor for the vitamin. Low plasma tryptophan is a non-specific indicator, meaning it can have other causes. The signs and symptoms of niacin deficiency start to revert within days of oral supplementation with large amounts of the vitamin. Chronic alcoholism is a contributing risk factor.Pantothenic acid (Vitamin B5) deficiency Irritability, fatigue, and apathy.Extremely rare.Vitamin B6 deficiency Microcytic anemia, electroencephalographic abnormalities, dermatitis, seborrhoeic dermatitis-like eruption, atrophic glossitis with ulceration, angular cheilitis, conjunctivitis, and intertrigo. Neurologic symptoms of depression, somnolence, confusion, and neuropathy (due to impaired sphingosine synthesis) and microcytic anemia Uncommon, although it may be observed in certain conditions, such as end-stage kidney diseases or malabsorption syndromes, such as celiac disease, Crohn's disease or ulcerative colitis.Biotin (Vitamin B7) deficiency Rashes including red, patchy ones near the mouth and fine, brittle hair. Hallucinations, Lethargy, Mild depression, which may progress to profound fatigue and, eventually, to somnolence, Generalized muscular pains (myalgia) and Paresthesias. Decreased urinary excretion of biotin and increased urinary excretion of 3-hydroxyisovaleric acid are better indicators of biotin deficiency than concentration in the blood. Rare, although biotin status can be compromised in alcoholics and during pregnancy and breastfeeding.Deficiency affects hair growth and skin health.Folate (Vitamin B9) deficiency Symptoms may include feeling tired, heart palpitations, shortness of breath, feeling faint, open sores on the tongue, loss of appetite, changes in the color of the skin or hair, irritability, and behavioral changes. In adults, anemia (macrocytic, megaloblastic anemia) can be a sign of advanced folate deficiency. Common, and associated with numerous health problems, but primarily with neural tube defects (NTDs) in infants when the mother's plasma concentrations were low during the first third of pregnancies. Government-mandated fortification of foods with folic acid has reduced the incidence of NTDs by 25% to 50% in more than 60 countries using such fortification. Deficiency can also result from rare genetic factors, such as mutations in the MTHFR gene that lead to compromised folate metabolism. Cerebral folate deficiency is a rare condition in which concentrations of folate are low in the brain despite being normal in the blood.Vitamin B12 deficiency Anemia, neurological and digestive disorders. This may result in feeling tired, shortness of breath, lightheadedness, headaches, mouth ulcers, pale skin, rapid heartbeat, loss of appetite, hair loss, low blood pressure, decreased ability to think, joint pain, numbness and tingling to the fingers and toes, and tinnitus. Damage to nerves may result in depression, confusion, memory loss, difficulty walking, sense loss, mania, and psychosis.Lead to megaloblastic anemia, subacute combined degeneration of spinal cord, and methylmalonic acidemia, among other conditions. Supplementation with folate can mask vitamin B12 deficiency. Consuming a vegan diet increases the risk, since Vitamin B12 is mostly found in food and drinks made from animal products, including eggs and dairy products.Vitamin C deficiency Deficiency leads to weakness, weight loss and general aches and pains. Longer-term depletion affects connective tissues, severe gum disease, and bleeding from the skin. Rare, consequently, no countries fortify foods as a means of preventing this deficiency. The historic importance of vitamin C deficiency relates to occurrence on long sea-going voyages, when the ship food supplies had no good source of the vitamin. Deficiency results in scurvy when plasma concentrations fall below 0.2 mg/dL, whereas the normal plasma concentration range is 0.4 to 1.5 mg/dL.
Fat-soluble vitamins Vitamin Symptoms & Diagnosis InformationVitamin A deficiency Can cause nyctalopia (night blindness) and keratomalacia, the latter leading to permanent blindness if not treated. The normal range is 30 to 65 μg/dL, but plasma concentrations within the range are not a good indicator of a pending deficiency because the normal range is sustained until liver storage is depleted. After that happens, plasma retinol concentration falls to lower than 20 μg/dL, signifying a state of vitamin A inadequacy.Vitamin A of Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc, Food and Nutrition Board of the Institute of Medicine, pages 82–161. 2001 It is the leading cause of preventable childhood blindness, afflicting 250,000 to 500,000 malnourished children in the developing world each year, about half of whom die within a year of becoming blind, as vitamin A deficiency also weakens the immune system.Vitamin D deficiency Usually asymptomatic, causes reduced bone density (osteomalacia), rickets, myopathy, and is associated with the development of schizophrenia. It is typically diagnosed by measuring the concentration of the 25-hydroxyvitamin D (25(OH)D) in plasma, which is the most accurate measure of stores of vitamin D in the body. Deficiency is defined as less than 10 ng/mL, and insufficiency in the range of 10–30 ng/mL. Common, most foods do not contain vitamin D, indicating that a deficiency will occur unless people get sunlight exposure or eat manufactured foods purposely fortified with vitamin D. Vitamin D deficiency is a known cause of rickets, and has been linked to numerous other health problems.Vitamin E deficiency Causes poor conduction of electrical impulses along nerves due to changes in nerve membrane structure and function. The US Institute of Medicine defines deficiency as a blood concentration of less than 12 μmol/L. Rare, occurring as a consequence of abnormalities in dietary fat absorption or metabolism, such as a defect in the alpha-tocopherol transport protein, rather than from a diet low in vitamin E.Vitamin K deficiency Signs and symptoms can include sensitivity to bruising, bleeding gums, nosebleeds, and heavy menstrual bleeding in women. Rare as consequence of low dietary intake. A deficient state can be a result of fat malabsorption diseases. Newborn infants are a special case. Plasma vitamin K is low at birth, even if the mother is supplemented during pregnancy, because the vitamin is not transported across the placenta. Vitamin K deficiency bleeding (VKDB) due to physiologically low vitamin K plasma concentrations is a serious risk for premature and term newborn and young infants. Untreated, consequences can cause brain damage or death. The prevalence of VKDB is reported at 0.25 to 1.7%, with higher risk in Asian populations. The recommended prevention treatment is an intramuscular injection of 1 mg of vitamin K at birth (called the Vitamin K shot.). There are protocols for oral administration, but intramuscular injection is preferred.
Prevention Food fortification