Your requirements for nutrients and energy are complex and vary over your life span. We all require the same basic nutrients, but your amount needed varies based on your age, gender, body size, genetic traits, growth, illness, lifestyle, medications and conditions such as pregnancy and lactation. Essential nutrients, those your body cannot manufacture or produce in sufficient amounts, need to come from your diet. They include carbohydrates, certain amino acids, linoleic acid and alpha-linolenic acid, vitamins, minerals and water. Other substances in plants, such as phytochemicals, also play important roles in health.
Reproduction
Pregnancy involves an intense period of growth and development. Key nutrients important during pregnancy include folate, vitamin A, vitamin D, calcium, iron, zinc, iodine and antioxidants. Variations in fetal growth generally relate to energy, nutrient and oxygen availability. Energy and nutrient availability can alter the expression of fetal genes, according to Judith Brown, PhD, MPH, RD, in "Nutrition Through the Life Cycle."
Growth and Development
Human milk provides the optimal food for infants. The USDA ChooseMyPlate for preschoolers provides an interactive method to create a USDA MyPyramid food plan for children of age 2 to 5 years and for older children. Meal plans for children aged 2 to 8 years are based on an average height and weight for their age and gender. Recommendations for the intake of iron, fiber, fat and calcium are particularly important during periods of rapid growth. Bone mineralization requires protein, vitamin D, calcium, phosphorus and magnesium. Calcium intake in childhood affects the peak bone mass that can be achieved to protect against osteoporosis later in life. Encourage school-age and adolescent children to eat a balanced diet, including a variety of foods, and increase physical activity.
Adult
Nutrition and dietary habits during adulthood can affect your risk of chronic diseases. Nutritional focus at this stage changes from growth and development to maintenance and physiological health. Nutrients of concern for adults include protein, vitamin D, vitamin B12, calcium, iron and omega-3 fatty acids.
Aging
Older adults experience decreased absorption of vitamin D and vitamin B12 and increased storage of vitamin A and iron. Older adults need more nutrient-dense foods because they consume less but have greater nutritional needs. Older adults generally do not consume enough vitamin E, folic acid, calcium and magnesium.
Dietary Reference Intakes
The Dietary Reference Intakes (DRI) provide quantitative estimates of nutrient intakes applicable to planning and assessing diets for healthy people. They are stated in terms of recommended dietary allowance (RDA), estimated average requirement (EAR), tolerable upper intake level (UL) and adequate intake (AI). These recommendations define the recommended level, average requirement and maximum safe level, based on scientific evidence and estimated requirement when sufficient scientific evidence is not yet available. An online interactive tool to calculate daily nutrient recommendations based on the DRI is available from the Food and Nutrition Information Center of the United States Department of Agriculture (USDA).
References
- "Nutrition Through the Life Cycle, Third Edition"; Judith E. Brown, PhD, MPH, RD; 2008
- Choose MyPlate.gov: Preschoolers; May 27, 2011
- ChooseMyPlate.gov: Daily Food Plan; June 4, 2011
- "Nutrition Across the Life Span"; Mary Kay Mitchell, PhD, RD; 2003
- USDA Food & Nutrition Information Center: Interactive DRI for Healthcare Professionals
- "Understanding Nutrition, Ninth Edition"; Eleanor Whitney, Ph.D. and Sharon Rolfes, M.S., R.D.; 2002
