Nutrition - §130.245. Lifetime Nutrition and Wellness

Role of Nutrients in the Body

(1) The student understands the role of nutrients in the body. The student is expected to:

(A) classify nutrients, their functions, and food sources and compare the nutritive value of various foods;
(B)assess the effects of nutritional intake on health, appearance, effective job performance, and personal life;
(C)analyze and apply various dietary guidelines throughout the life cycle, including pregnancy, infancy, childhood, and late adulthood; and
(D)compare personal food intake to recommended dietary guidelines.

Classify Nutrients, Their Functions, and Food Sources and Compare the Nutritive Value of Various Foods

Groups of NutrientsNutrients are the chemical substances in the foods we eat. Our bodies use these nutrients for energy and to support growth, maintenance, and repair of tissues. Essential nutrients are those which our bodies need and must be provided through the foods we eat. There are six major groups of nutrients: carbohydrates, fats and oils, proteins, vitamins, minerals, and water.

Macronutrients provide energy so they are needed in greater amounts. The macronutrients are carbohydrates (CHO), proteins (PRO), and lipids (fats).

Sources of carbohydrates include breads, cereal grains, pasta, rice, fruit, vegetables, milk, and sugar.

Proteins from animal sources (meat, poultry, milk, fish) are considered to be of high biological value because they contain all of the essential amino acids. Proteins from plant sources (wheat, corn, rice, and beans) are considered to be of low biological value because an individual plant source does not contain all of the essential amino acids. Therefore, combinations of plant sources must be used to provide these nutrients.

Some sources of lipids or fats are meat, poultry, fish, milk and milk products, nuts and seeds, oils, butter, margarine, salad dressing, and candy.

Micronutrients are needed in smaller amounts. This group includes vitamins and minerals. Vitamins and minerals are needed to process (metabolize) the carbohydrates, proteins, and lipids to obtain energy from them. Have you ever heard anyone say, "These new vitamins give me so much energy?" They don't really, but if that person were deficient in something, he or she probably couldn't metabolize as well the macronutrients that do provide energy. OR it was a placebo effect (they just think they feel better).

Vitamins are divided into water-soluble and fat-soluble groups. Fat-soluble vitamins can be stored in the body and water-soluble cannot. Therefore, fat-soluble vitamins may be toxic if large doses are taken for a period of time. Vitamins are an essential nutrient because they build and maintain healthy bones and muscle tissue. They also support our immune system, maintain the health of our blood, and ensure healthy vision. Vitamins are micro-nutrients, meaning they are needed in small amounts to sustain our normal health and body functions. Some examples of common vitamins are Vitamin C and K, and the many B Vitamins.

Overview of Vitamins

Minerals are divided into major or trace minerals, depending on the amount needed by the body. A trace mineral is only needed in "trace" amounts. Minerals assist in the regulation of many body functions, some of which involve regulating fluids and producing energy and health of our bones and blood. This nutrient also helps rid our body of harmful byproducts of metabolism. Some examples of well-known minerals are calcium, potassium, sodium and iron.

Overview of Minerals

Water is the sixth nutrient/ group. It is vital for survival because it supports all body functions. Water is essential in regulating body temperature. It is also necessary to regulate nerve impulses and muscle contractions, as well as for nutrient transport, and excretion of wastes. Drinking eight to ten glasses of water will ensure that all the above body functions are carried out properly.

Note: Alcohol provides 7 kcal /g. It is not considered a nutrient because it provides ONLY energy. Large doses can be harmful.

Source: HMS 138 - Diet and Fitness

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Assess the Effects of Nutritional Intake on Health, Appearance, Effective Job Performance, and Personal Lifes

Nutrition is just one of several factors contributing to wellness. Wellness is an active process in our daily lives. It encompasses physical, emotional, and spiritual factors.

Intense schedules, long commutes, indulgent business entertainment, skipped breakfasts, nutritionally impoverished canteens and vending machines, all make it increasingly difficult for employees to find the time to prepare, cook and eat a balanced healthy diet. This translates to a larger problem for organizations: increased absenteeism, reduced employee performance and morale, and customer satisfaction.

Wellness Diagram

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Analyze and Apply Various Dietary Guidelines Throughout the Life Cycle, Including Pregnancy, Infancy, Childhood, and Late Adulthood

Pregnancy

Macronutrient Requirements - The first thing that comes to mind for many people when the topic of pregnancy comes up is “eating for two”. While a woman is eating for two, the increase in energy need is not what most people think. For one thing the smooth muscles of the digestive tract relax so digestion slows down and more calories and nutrients can be absorbed than normal. Foods which are nutrient dense should be the focus during pregnancy because the need for protein and other specific nutrients does increase. For example, an extra 25 g of protein per day is required for the developing fetus. Most Americans already get that much extra, but it can be provided in 3 ½ ounces of meat or 3 servings of dairy each day. A low carbohydrate diet is not recommended because the developing fetus needs an adequate supply of glucose as it is the primary metabolic fuel. Choosing whole grains and fruits and vegetables will also ensure an adequate fiber intake. Because the smooth muscles are relaxed, constipation is common. An adequate fluid and fiber intake can alleviate this problem. Refined carbohydrates are fine occasionally, but too much may cause an increase in blood sugar. The need for fat does not increase during pregnancy but the type of fat consumed is important. Limiting trans fats is recommended for everyone pregnant or not. Monounsaturated fats (MUFA) and polyunsaturated fats (PUFA) are the best choices. DHA (docohexaenoic acid) is an omega-3PUFA that is essential for development of the eyes, nervous system and the rapidly growing brain. DHA is also essential during breastfeeding for this reason. Best sources include oily fish such as salmon, mackerel, sardines, and anchovies. Women can safely consume up to 12 oz. of most types of cooked fish each week. More than this might lead to excess mercury consumption which could have a negative effect on the developing fetal nervous system. Fish with the highest mercury content should be avoided. These include swordfish, shark, tile fish, and king mackerel. Fish oil supplements may be used in place of fish. For more information on the mercury content of fish visit www.cfsan.fda.gov/pregnancy.html

Micronutrient Requirements - There are 4 vitamins and 3 minerals needed in greater amounts during pregnancy. The following table provides a summary of the changes in recommendations for these micronutrients during pregnancy.

Nutrient Requirement Changes During Pregnancy

Folate is especially critical in the first four weeks after conception. It is necessary for cell division, and both maternal and fetal cells are rapidly multiplying. Inadequate folate can cause neural tube defects including spina bifida and anencephaly (lack of brain tissue). While there may be some predisposition toward neural tube defects, it is estimated that the incidence could be reduced by 70% if mothers had an adequate intake. Any women who could possibly become pregnant should consume an extra 400 µg of folic acid per day from fortified foods or supplements. During pregnancy this need increases to 600 µg per day.

Vitamin B12 is important during pregnancy to regenerate the active form of folate, therefore, macrocytic anemia can also result from inadequate intake of vitamin B12. The need for vitamin B12 increases only slightly compared to some other nutrients because it is one nutrient that is absorbed much more efficiently during pregnancy. It is easily obtained from animal foods. Women on a vegan diet should choose fortified foods or take supplements containing vitamin B12.

Vitamin C helps form collagen, a part of connective tissue in skin, blood vessels, and tendons, as well as the organic matrix of bones. Vitamin C deficiency can increase the risk of premature birth, preeclampsia, and premature rupture of the membranes. Pregnant women who smoke need additional vitamin C.

Vitamin A is necessary for growth. Vitamin A deficiency during pregnancy can lead to intrauterine growth retardation, low birth weight, and preterm delivery. Adequate vitamin A can be obtained from a balanced diet. Supplementation in excess can lead to teratogenic effects such as craniofacial malformations, heart defects, and abnormalities of the CNS.

Vitamin D is needed at the same level in pregnancy as it is prior to pregnancy to aid in calcium absorption. Vitamin D supplements are used in pregnancy by women who do not drink milk or have limited sun exposure. Prenatal vitamins have enough vitamin D to meet the needs of pregnancy. More than that amount can be toxic and cause developmental disability in the newborn.

Calcium needs do not change during pregnancy because absorption of calcium is greatly enhanced in pregnancy as long as there is adequate vitamin D intake. Adequate calcium for those who are lactose intolerant can be provided by calcium-fortified foods and beverages and lower-lactose dairy products.

Iron needs in pregnancy increase as much as folate. Both are important in the formation of red blood cells. Maternal blood volume increases greatly which “dilutes” the amount of iron in the mother’s blood. Heme iron sources such as lean meats provide the best sources of iron. Non-heme iron sources combined with vitamin C- rich foods provide additional iron. Iron stores of the mother may be robbed to provide for the needs of the developing fetus. Inadequate iron intake can lead to preterm birth, low birth weight, still birth and high infant mortality. Iron needs increase from 18 mg /day  to 27 mg /day during pregnancy.
 
Zinc is necessary for DNA synthesis, RNA synthesis, and protein synthesis and facilitates proper growth and development of the fetus. Inadequate zinc intake is associated with malformations in the fetus, decreased birth size, and prolonged labor. Iron supplements can interfere with zinc absorption, but heme iron does not block zinc uptake and red meats are an excellent source of both zinc and iron.

Sodium needs are the same during pregnancy. Excess sodium can lead to fluid retention and high blood pressure, but sodium is not restricted to be sure an adequate intake of iodine from iodized salt is obtained. The recommendation of 1500 mg of sodium /day is generally exceeded several times due to consumption of fast foods and other processed foods.

Supplements of prenatal vitamins are not necessary for anyone consuming a balanced diet. However, vegans, adolescents, and anyone whose diet is not varied enough to provide a balance of all nutrients would benefit from prenatal vitamins. Other supplements during pregnancy may be harmful. Note: Supplements do not take the place of a healthful diet. They should be used as a “supplement” to an otherwise balanced diet.

Fluid needs increase because the blood volume increases during pregnancy. The amniotic sac also contains fluid and needs to be refiltered daily. Adequate fluid is also needed to prevent fluid retention by flushing sodium from the kidneys, and to prevent constipation, and minimize the risk of bladder infections. At least 12 cups of fluid per day, including about 10 cups from beverages is recommended.

Infancy

Breast milk, or an approved infant formula, provide the main source of nutrition for the whole first year of life. A small amount of solid food is introduced in the second six months to help the infant acquire new tastes and to get a little more iron. There are several ways to assess normal growth and development, including growth charts, measuring head circumference, and “well baby” visits by a healthcare provider. Babies only need one to two thin teaspoons of cereal twice a day to start with. It should be thinned with breastmilk or formula. Rice cereal is usually the first choice because it is the least allergenic, although I had a mom in class whose baby was actually allergic to rice cereal. After about a week a second cereal can be introduced and so on with vegetables at seven months, meats at eight months and fruits at nine months as the ideal pattern. Fruits are saved until last, because they have the least nutritional value and are the most allergenic. Also, at nine months a baby can takes sips from a cup. Juice should never be put in a bottle because it can cause tooth decay. Fruit is also the best tasting. Since breastmilk is very high in lactose or milk sugar, babies love anything sweet and may prefer fruits over other foods if introduced too early. A minimum of 3-5 days between each new food will help determine if the baby is allergic to any foods. Foods should also be pure and not mixed as well. By nine months a total of 3 - 4 tablespoons (max 1/2 jar) of each type of food is enough. At about 10 months when all foods are tested, mashed table foods are good and will save lots of money over buying baby foods. Never add salt or sugar to an infant’s foods.

Childhood

Toddlers - Toddlers are using lots of energy to explore their world and develop new skills. With this increase in activity comes an increase in total energy needs. The Estimated Energy Requirements (EER) is the total amount of energy needed per day for any age group. The EER varies according to age, body weight, and activity level. The formula for toddlers is:

Kcal/day = (89 x weight [kg] – 100) + 20

Fat is necessary to provide adequate energy, especially for those who have smaller appetites. Fat is especially important to the developing nervous system. There is no DRI set for toddlers with regard to fat intake, but about 1/3 of their total kcal is about average. The RDA for protein is usually easy to get at 1.1 g/kg body weight. This amounts to about 13 g of protein /day. Three 4 oz servings of milk will provide 12 g. Milk is an excellent source of calcium as well. It is important not to let a child fill up on milk and miss out on meats which are an important source of iron.

Depending on activity levels, carbohydrate should be about 45% to 65% of total energy intake. At least half of all grain servings should be from whole grains, and the rest of the “carbs” should be from fruits and vegetables. Fruit in the form of juice should be limited to about 4-6 oz per day between the ages of 1 to 6. Juice does not provide fiber and has become a source of excess calories in children. While too much fiber can interfere with absorption of some nutrients as in a vegan diet, most children do not get enough fiber. The AI for fiber is 14g/ 1000 kcal for all age groups. The AI for the average toddler is about 19 g.

A greater variety of vegetables would provide vitamin A, C, and E as well as the minerals calcium, iron, and zinc. Fruits and vegetables contain up to 90% water. This age group is not as aware of thirst and yet their activity level causes them to lose significant amounts of fluid through sweat. In addition to the 4-6 oz of juice, another 3 cups of fluids including water is recommended.

Snacks are an important part of any toddler’s meal plan. Serving small portions and allowing a child to ask for seconds when hungry is also helpful. Looking at adult-sized portions is too overwhelming. The rule of thumb is one tablespoon of each food for each year of age. That’s only a few bites to an adult. Allowing enough time to eat and not rushing is also important.

Preschoolers - The preschooler's growth rate is slower than during the infant and toddler years, but they are more skillful in their activities and more fluent in language. They have all their baby teeth so they can chew, but foods that are choking hazards are still a concern. Snacking to obtain adequate calories is still important at this age. Hopefully, they have had enough exposure to a variety of foods in their toddler years to be able to enjoy a variety of nutritious foods to meet their nutritional needs at this age. Even though they are normally very active, it is important to reduce the amount of saturated fat in their diet by introducing skim and low fat dairy products. The RDA for protein is .95 g/kg body weight for a total of 19 g protein/day. Protein from non-meat sources such as peanut butter or beans in addition to meat and milk is acceptable. Meats should be tender and easy to chew. As with toddlers, the carbohydrate intake should be about the same, including the need for fiber from whole grains, fruits, and vegetables. Sweets should be considered foods for occasional use – not every day foods or rewards. A minimum of 5 servings of fruits and vegetables a day is a must. Serving fruits and vegetables at snack time in addition to meals is a great habit to learn and provides more vitamins and minerals, and have a higher water content. An additional 5 cups of beverages including water is recommended. Preschoolers do not always realize when they are thirsty and can become dehydrated. Keeping a special cup or sports bottle of water in the fridge can help keep track of fluid intake. Adequate fluid intake in addition to fiber will help prevent constipation.

School-aged Children - School-aged children's physical growth is slow and steady with an average increase in height of 2 to 3 inches per year. Activity levels are more varied among those in this age group. Some enjoy lots of physical activity while others prefer to quietly read or draw. The theme of MyPyramid for Kids is “Eat Right. Exercise. Have Fun.” School-aged children are more independent and make more of their own food choices. Recommendations for fat and carbohydrate remain the same as in the preschool years, but due to differences in maturation, the DRI values for micronutrients are different for children 4 to 8 years and 9 to 13 years. The AI for calcium increases to 1,300 mg/day at age 9 because this age begins the period of increased bone density that lasts into early adulthood. Fluid needs increase to about 7 – 9 cups/day and water should be the beverage of choice. Sports drinks, fruit drinks and soda can contribute to inappropriate weight gain and may "displace" milk which is necessary for proper bone mineral formation.

Adolescents - Ages 14 – 18 years of age are referred to as the adolescent period. This period begins with puberty, the point in life when sexual development occurs as the body prepares for reproduction. Physical activity levels vary widely and excess weight may become a problem if adolescents are too sedentary. The breakdown of energy needs with regard to fat and carbohydrate remains the same as in childhood. The RDA for protein decreases slightly to 0.85 g /kg body weight. The AI for calcium is 1300 mg/day to allow bone mass to be built. The RDA for iron for boys is 11 mg/day and for girls is 15 mg/day. Vitamin A is critical for growth and the RDA is set at 900 µg for boys and 700µg for girls. This level is easy to achieve if 5-9 servings of fruits and vegetables are consumed. The higher physical activity levels of this age group increase fluid requirements to 14 cups/day for boys and 10 cups/day for girls. A good portion of this should include drinking water. Food choices of adolescents are often more strongly influenced by their friends than family at this stage. Skipping meals and eating non-nutritious foods is also common. For example, many girls in an attempt to “cut back” choose French fries and Cokes. A wiser choice would be to eat the hamburger which would help with iron intake. Many teens substitute sodas for milk which makes it extra difficult to get calcium at the most crucial time for building bone mass.

Late Adulthood

The following table summarizes the changes in nutrient recommendations for older adults. Energy needs decrease while the need for some nutrients increases. The rationale for these changes is also listed in the table.

Nutrient Recommendations for Older Adults

Calcium is not absorbed as easily in the gut and vitamin D is not produced as easily by the skin. Many elderly adults get little or no sun at all. Foods such as milk containing both calcium and vitamin D are best, but if the individual is lactose intolerant or has difficulty getting the right foods, calcium supplements with vitamin D are important to minimize the incidence of osteoporosis.

An adequate intake of B-complex vitamins, especially vitamins B6, B12, and folate is necessary to reduce the levels of homocysteine in the blood. Elevated homocysteine levels have been linked with increased risk for cardiovascular, cerebrovascular, and peripheral vascular disease. Some research indicates that elevated homocysteine levels may be a factor in dementia and Alzheimer’s disease.

One nutrient with increased absorption in the elderly is vitamin A and toxic levels can cause liver damage. Foods high in β-carotene do not contribute to toxic levels of vitamin A.

The recommendations for fluid remain the same throughout adulthood. The thirst mechanism of elderly adults is not as sensitive as it is during younger adult years. This can be dangerous, especially in hot weather. Some adults limit their fluid intake due to urinary incontinence. Medical treatment for incontinence can alleviate this fear and allow for a healthier level of fluid consumption.

Source: HMS 138 - Diet and Fitness

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Compare Personal Food Intake to Recommended Dietary Guidelines

Originally, the RDA’s (Recommended Dietary Allowances) were developed to make recommendations for each nutrient to prevent deficiency diseases. For example, During the Great Depression in the 1930’s when some of the vitamins were being discovered and people were not getting enough to eat because there were no jobs, this was an important focus. In recent years, we have social programs available to assist those in need and we have also shifted from not enough to too much for some. Our focus has shifted as well to wellness which is about chronic disease prevention – mostly related to over consumption.

We now use reference values known as Dietary Reference Intakes (DRIs) which are standards for healthy people. The DRIs for most nutrients consist of four values:

Estimated Average Requirement
Recommended Daily Allowances

Different standards are used for energy and the macronutrients. EER (Estimated Energy Requirement) is the average dietary intake predicted to maintain energy balance in an individual. It is based on age, gender, height, weight, and level of physical activity. AMDR (Acceptable Macronutrient Distribution Ranges) is expressed as a percentage of total energy (kcal). The range has an upper and lower limit and is associated with reduced risk of chronic disease while still providing an adequate intake of essential nutrients.

Acceptable Macronutrient Distribution Ranges for Healthful Diets

Using the DRIs together with MyPyramid or the Dietary Guidelines for Americans will help ensure an individual consumes a diet that is nutritionally adequate and healthful.

Source: HMS 138 - Diet and Fitness

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© Stephen F. Austin State University | School of Human Sciences | 2010