Nutrition is a science that examines the relationship between diet and health. Nutrition includes the foods that provide energy and health, including proteins, carbohydrates, fats, vitamins, minerals and water. A nutritional deficiency is a state where an individual's intake of nutrients is insufficient for the body's normal functioning. The body's needs for nutrition change as it grows. So, for example, babies have different nutritional needs than a pregnant woman or an elderly person.
The body needs a regular intake of many nutrients such as protein, fat, carbohydrates, vitamins, and minerals for the health of bones, nerves, organs, and other body functions. Proteins help build body tissue (such as muscle and organs), carbohydrates provide energy, and fats are a component of all cell membranes and are an important source of stored energy in the body.
Vitamins are important for the cellular functions of the body. They are chemical substances that help the body use energy, build proteins, make cells, and repair injuries. Vitamins are divided into two general categories: fat soluble and water soluble. The fat soluble vitamins are A, D, and E. Vitamin A is necessary for eyes, bones, and skin. Vitamin D is necessary to make bones and teeth, and it allows the body to use calcium from the diet. Vitamin E is important for the immune system and for the cardiovascular system.
The water soluble vitamins are vitamin C and the B vitamins. Vitamin C is important for fighting infection and for using the stored energy in the body. Vitamin C is generally found in citrus fruits and other vegetables like tomatoes and peppers. The B vitamins are important for building blood cells, nerve cells, and are vital for many of the body's chemical reactions. These are found in many meats and vegetables.
Minerals, such as calcium, iron, zinc, and magnesium, are also essential for health.
Deficiencies, excesses, and imbalances in the diet can produce negative impacts on health, which may lead to diseases such as cardiovascular disease, birth defects, diabetes, scurvy, obesity, seizures, or osteoporosis.
Many common diseases and their symptoms can often be prevented or alleviated with better nutrition; nutritional deficiencies are very common worldwide.
Achlorhydria, appetite stimulant, B12 absorption, beriberi, biotin deficiency, cachexia, copper deficiency, familial hypophosphatemia, folate deficiency, hypercalciuria, hypocalcemia, hypophosphatemia, iodine deficiency, iron absorption enhancement, iron deficiency, Korsakoff's psychosis, Kwashiorkor, malnutrition, marasmus, nutritional deficiencies, nutritional support (TPN), pantothenic acid deficiency, pellagra, pyridoxine deficiency, riboflavin deficiency, rickets, scurvy, thiamin deficiency, total parenteral nutrition, TPN, vitamin A, vitamin B12, vitamin C, vitamin D, vitamin E, vitamin K, Wernicke-Korsakoff syndrome, Wernicke's encephalopathy.
selected nutritional deficiency symptoms and complications
Note: See the Integrative Therapies section for a more detailed explanation of each nutrient and its function in the body.
Biotin: Symptoms of biotin deficiency include dermatitis, eye inflammation, hair loss, loss of muscle control, insomnia, and muscle weakness.
Symptoms of calcium deficiency include brittle nails, cramps, delusions, depression, insomnia, irritability, osteoporosis, palpitations, periodontal disease, rickets, and tooth decay.
Symptoms of copper deficiency include anemia, arterial damage, depression, diarrhea, fatigue, fragile bones, hair loss, hyperthyroidism, and weakness.
Essential fatty acids: Symptoms of essential fatty acid deficiency include diarrhea, dry skin and hair, hair loss, immune impairment, infertility, poor wound healing, premenstrual syndrome, acne, eczema, gall stones, and liver degeneration.
Folic acid: Symptoms of folic acid deficiency include anemia, apathy, diarrhea, fatigue, headaches, insomnia, loss of appetite, neural tube defects in fetus, paranoia, shortness of breath, and weakness.
Iodine: Symptoms of iodine deficiency include cretinism, fatigue, hypothyroidism, and weight gain.
Iron: Symptoms of iron deficiency include anemia, brittle nails, confusion, constipation, depression, dizziness, fatigue, headaches, inflamed tongue, and mouth lesions.
Symptoms of niacin deficiency include bad breath, canker sores, confusion, depression, dermatitis, diarrhea, emotional instability, fatigue, irritability, loss of appetite, memory impairment, muscle weakness, nausea, skin eruptions, and inflammation.
Pantothenic acid: Symptoms of pantothenic acid (vitamin B5) deficiency include abdominal pains, burning feet, depression, eczema, fatigue, hair loss, immune impairment, insomnia, irritability, low blood pressure, muscle spasms, nausea, and poor coordination.
Pyridoxine (vitamin B6): Symptoms of pyridoxine (vitamin B6) deficiency include acne, anemia, arthritis, eye inflammation, depression, dizziness, facial oiliness, fatigue, impaired wound healing, irritability, loss of appetite, loss of hair, mouth lesions, and nausea.
Riboflavin: Symptoms of riboflavin (vitamin B2) deficiency include blurred vision, cataracts, depression, dermatitis, dizziness, hair loss, inflamed eyes, mouth lesions, nervousness, neurological symptoms (numbness, loss of sensation, "electric shock" sensations), seizures, sensitivity to light, sleepiness, and weakness.
Thiamin: Symptoms of thiamin (vitamin B1) deficiency include confusion, constipation, digestive problems, irritability, loss of appetite, memory loss, nervousness, numbness of hands and feet, pain sensitivity, poor coordination, and weakness.
Vitamin A: Symptoms of vitamin A deficiency include acne, dry hair, fatigue, growth impairment, insomnia, hyperkeratosis (thickening and roughness of skin), immune impairment, night blindness, and weight loss.
Vitamin B12: Symptoms of vitamin B12 deficiency include anemia, constipation, depression, dizziness, fatigue, intestinal disturbances, headaches, irritability, loss of vibration sensation, low stomach acid, mental disturbances, moodiness, mouth lesions, numbness, and spinal cord degeneration.
Vitamin C: Symptoms of vitamin C deficiency include bleeding gums, depression, easy bruising, impaired wound healing, irritability, joint pains, loose teeth, malaise, and tiredness.
Vitamin D: Symptoms of vitamin D deficiency include burning sensations in the mouth, diarrhea, insomnia, blurred vision, nervousness, osteomalacia, osteoporosis, rickets, and scalp sweating.
Vitamin E: Symptoms of vitamin E deficiency include neurological problems (such as gait disturbances and poor reflexes) and shortened red blood cell life.
Vitamin K: Symptoms of vitamin K deficiency include heavy menstrual bleeding, gastrointestinal bleeding, hematuria (blood in the urine), nosebleeds, bleeding gums, and easy bruising.