Vitamin deficiencies and their effects
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Vitamin A Deficiency: Effects on Vision, Immunity, and Child Survival
Vitamin A deficiency is a major global health problem, especially in children from developing countries. It is the leading cause of preventable blindness in young children and is associated with increased risk of death from severe infections such as diarrhea, measles, and respiratory diseases. Even mild vitamin A deficiency can contribute to higher fatality rates among children. The deficiency impairs vision (causing xerophthalmia and blindness), weakens immune function, increases susceptibility to infections, and can lead to anemia and poor growth. Breastfeeding has a protective effect against clinical vitamin A deficiency in young children. The deficiency is most common in children aged 2-4 years and in populations with poor nutrition and frequent infections West1998Wiseman2017.
Vitamin D Deficiency: Bone Health, Chronic Diseases, and Physical Performance
Vitamin D deficiency is widespread globally, affecting over a billion people. It is caused mainly by insufficient sun exposure and inadequate dietary intake. In children, vitamin D deficiency leads to rickets, while in adults it causes osteopenia, osteoporosis, and increased risk of fractures. The deficiency is also linked to a higher risk of chronic illnesses such as cardiovascular disease, type 2 diabetes, autoimmune disorders, certain cancers, and infectious diseases. In older adults, vitamin D deficiency contributes to muscle weakness, falls, and frailty. Among athletes and physically active individuals, low vitamin D levels can impair bone and muscle health, reduce physical fitness, and negatively affect sports performance. Supplementation and food fortification are recommended, especially for at-risk groups such as children, pregnant women, the elderly, and people with limited sun exposure Holick2017Holick2008Lips2019+2 MORE.
B Vitamin Deficiencies: Neurological and Metabolic Effects
Deficiencies in B vitamins (such as B1, B2, B6, B9, and B12) are common, especially in the elderly, people with alcoholism, those with certain medical conditions, and vegetarians/vegans. B vitamin deficiencies can cause a range of neurological problems, including developmental delays in children, ataxia, abnormal eye movements, and cognitive impairment. In adults, chronic B vitamin deficiency is linked to neurodegenerative diseases like Alzheimer's and Parkinson's. Severe vitamin B12 deficiency can lead to anemia, impaired lipid metabolism, increased body fat, adverse pregnancy outcomes, and developmental problems in offspring. Early diagnosis and supplementation are crucial to prevent irreversible complications Sechi2016Gana2021Dupuy2024+1 MORE.
Vitamin C Deficiency: Muscle Weakness and Gait Disturbances
Vitamin C deficiency, though less common in high-income countries, can still occur, particularly in older adults and those with poor diets. It can cause muscle weakness, gait disturbances, and, if untreated, may lead to more severe complications. Vitamin C also works synergistically with vitamin E as an antioxidant, playing a role in preventing frailty and supporting healthy aging Gana2021Dupuy2024.
Vitamin Deficiencies and Aging: Frailty, Sarcopenia, and Disability
In older adults, deficiencies in vitamins D, C, and B (B6, B9, B12) are linked to frailty, sarcopenia (loss of muscle mass), and increased risk of disability. Poor nutritional status is a major cause of morbidity and mortality in the elderly. Early diagnosis and targeted nutritional interventions can help reduce the risk of frailty and improve quality of life in aging populations .
Conclusion
Vitamin deficiencies have wide-ranging effects on health, from impaired vision and immune function to bone disease, neurological disorders, and increased risk of chronic illnesses. Children, the elderly, pregnant women, and people with limited access to nutritious foods are especially vulnerable. Early detection, dietary improvements, supplementation, and food fortification are key strategies to prevent and manage vitamin deficiencies and their serious health consequences West1998Holick2017Holick2008+7 MORE.
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Most relevant research papers on this topic
Vitamin D deficiency: a worldwide problem with health consequences.
Vitamin D deficiency is a global issue, leading to rickets, osteopenia, osteoporosis, and fractures, and increasing the risk of common cancers, autoimmune diseases, hypertension, and infectious diseases.
Analysis of the Impact of Selected Vitamins Deficiencies on the Risk of Disability in Older People
Vitamin D, C, and B deficiencies in older adults can lead to frailty and sarcopenia, highlighting the need for early diagnosis and management of nutritional deficiencies.
Vitamin deficiencies in children: Lessons from clinical and neuroimaging findings.
Acquired vitamin deficiencies in children may present reversible clinical symptoms mimicking inherited metabolic disorders, and should be treated without waiting for definitive biochemical confirmation.
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