Nutrition is critical for health and well-being and is important at every stage of life. Foods provide energy, nutrients and other substances needed for health. Optimal nutritional status helps ensure a healthy pregnancy and a robust newborn. Poor nutrition can result from either inadequate or excessive levels of nutrient intake and influences the development of chronic disease. Healthful nutrition reduces stress, enhances immunity, affects longevity and improves outlook and the quality of life.
Body Function
Specific nutrients are needed to yield energy, regulate blood pressure and glucose, improve eyesight in dim light, stop bleeding and the myriad other tasks the body performs. Food choices made every day influence the body's health and ability to function for better or worse. Individual choices may have only a small effect on health, but repeated over years and decades, the accumulated consequences for good or ill are major.
Healthy Weight
Maintaining a healthy weight reduces the risk of diabetes, heart disease and other chronic diseases. For maintaining weight in a healthy range, the Dietary Guidelines for Americans 2005 published jointly by the Department of Health and Human Services and the U.S. Department of Agriculture recommends balancing calories from foods and beverages with calories expended. And to prevent small weight gains over time, make small decreases in food and beverage intake and increases in physical activity.
Prevent Disease
The three leading causes of death in adults in the United States are heart disease, cancer and stroke. Diabetes is in the top ten. The risk for each of these diseases that can result in reduced quality of life, reduced mobility, blindness, amputation, osteoporosis or loss of independence can be reduced or nearly eliminated by diet modification. Both prevention and treatment are in part diet related.
Healthy Babies
Even before conception and pregnancy, nutrition plays an important part in reproduction because it affects the fertility of both the mother and the father. The best predictors of a healthy baby at birth are the weight and nutritional status of the mother at conception and dietary intake during pregnancy. Vitamin, mineral and other nutrient deficiencies during pregnancy can result in low birth weight babies and some birth defects. Without folate, for instance, the neural tube fails to develop completely in the first month of pregnancy. Nutrition in the womb can affect the child's health outcomes throughout life.
Stress Response
Brain chemicals and adrenal hormones are released in response to stressful situations to enable the body to avoid danger. Neurotransmitters such as serotonin, dopamine and norepinephrine produce feelings of calmness and happiness. Deficiencies can lead to depression, irritability and anxiety. These neurotransmitters are produced in part from foods so the body's moods and response to stress can be modified by diet. In stressful times, choose a balanced diet of nutrient-rich foods.
Vitamin C also plays a role in stress relief. During stress from infections, burns, high or low temperatures, toxic heavy metals or chronic use of certain medications and cigarette smoking, the adrenal glands release vitamin C along with stress hormones. Vitamin C acts as an antioxidant in conjunction with the stress response.
Immunity
Nutrition is critical to immune response. Protein-energy malnutrition compromises the immune system. Deficiency of single nutrients such as zinc; selenium; copper; iron; vitamins A, C, E and B6 as well as folic acid alters immune response. Obesity also impairs immunity. Low birth weight impairs immunity in infants and is treated with dietary zinc. In elderly people, impaired immunity is treated with a combination of vitamins and minerals.
Quality of Life
Nutrition is important not only to longevity, the years of life, but also to the life in those years. Aging adults want to stay healthy, and good nutrition can improve the quality of life. Eating patterns contribute to the progression of chronic diseases such as hypertension, heart disease and cancer, and this affects functional ability and the activities of daily living. Nutritional status is a major factor throughout life in disease prevention, treatment and recovery of health.
References
- Dietary Guidelines for Americans 2005
- Krause's Food, Nutrition, & Diet Therapy, 10th Edition; L. Kathleen Mahan and Sylvia Escott-Stump; 2000
- Meals Matter: Nutrition and Stress
- Center for Science in the Public Interest: Why good nutrition is important
