People with certain medical conditions, such as celiac disease, cancer, Crohn's disease, alcoholism, hypothyroidism, and anorexia, are more likely to develop nutrient deficiencies, including B vitamins. Our review of nine vitamins showed that older people, vegans, alcohol-dependent people, and patients with malabsorption are at greater risk of inadequate intake or absorption of several vitamins. Excessive doses of vitamin A during early pregnancy and fat-soluble vitamins taken at any time can cause adverse outcomes. Inadequate folate levels are associated with neural tube defects and some types of cancer.
Folate and vitamins B6 and B12 are required for homocysteine metabolism and are associated with the risk of coronary heart disease. Vitamin E and lycopene may reduce the risk of prostate cancer. Vitamin D is associated with a lower incidence of fractures when taken with calcium. Most individuals don't need to take vitamin supplements and can get all the vitamins and minerals they need if they eat a healthy, balanced diet.
However, at certain stages in life, women have greater nutritional needs and may need to take supplements to meet their requirements. Athletes who restrict energy intake or have strict weight-loss practices may be deficient in iron and calcium and may need supplements of these nutrients. People who cover their skin for cultural or religious reasons can easily have a vitamin D deficiency and need to take a supplement. This is especially important during pregnancy and breastfeeding, but also throughout life.
Vitamin D is essential for bone strength and muscle health. A deficiency is a major risk factor for osteoporosis. Associations between diet and disease in observational studies may be due to specific carotenoids, other vitamins or compounds found in fruits and vegetables, or to the replacement of meat and fat in the diet. Beta-carotene has received the most attention from carotenoids because of its provitamin A activity and its prevalence in many foods.
In the kidney, it is converted into two metabolites, the most active being 1,25-dihydroxyvitamin D3. If you feel exhausted, it's more likely due to stress, depression, lack of sleep, or other factors than a vitamin deficiency. In this section, only vitamins that are thought to be related to chronic diseases are discussed. Alcoholism is probably the number one cause of most cases of multivitamin deficiency in the United States. Food is a complex source of vitamins, minerals and phytochemicals (plant chemicals), which work together.
Variations in dietary vitamin K intake may cause difficulties with the dosage of warfarin; anticoagulated patients should receive clear dietary instructions. Enzymes in the small intestine break down beta-carotene (and certain closely related carotenoids) to produce vitamin A. Interest in carotenoids, specifically beta-carotene, initially arose because of their antioxidant effects, but retinol and provitamin A carotenoids may also reduce the risk of cancer through other mechanisms, such as the induction of cellular differentiation. Antipsychotic medications work by altering brain chemistry to help reduce psychotic symptoms, such as hallucinations, delusions, and thought disorders.
However, despite the higher levels of calcium in the blood, the bones in the treated group do not contain more calcium than the bones of people with osteoporosis who do not receive the vitamin. This could be because the vitamins and minerals in foods are also influenced by other components of the food, not just the “active ingredient”. Elderly patients are particularly vulnerable to vitamin B12 and D deficiencies; people who are dependent on alcohol are at risk of folate, B6, B12 and thiamine deficiencies; hospitalized patients are at risk of deficiencies in folate and other water-soluble vitamins; female athletes may be deficient in iron and calcium; people who cover their skin for cultural or religious reasons can easily have a vitamin D deficiency; pregnant women need extra nutrients; breastfeeding women need extra nutrients; athletes who restrict energy intake or have strict weight-reduction practices may be deficient in iron and calcium; antipsychotic medications can cause deficiencies; alcoholics are at risk for multiple deficiencies; food is a complex source of vitamins; variations in dietary vitamin K intake can affect warfarin dosage; enzymes break down beta-carotene into vitamin A; carotenoids can reduce cancer risk through cellular differentiation; vitamin A is essential for vision (especially night vision), immune response growth/repair.
