Adult Nutrition Chapter 12

Physiological Changes During Adulthood

• Young women are fully developed by 19 years of age
• Young men may continue to gain height, weight, muscle mass, and body hair through age 21
• Physiological functions begin to deteriorate after 30 years of age
• The rate of physiological changes is individual, based on lifestyle choices, environmental factors, and genetics

Senescence and Aging

• Senescence is the inevitable decline in organ function and physiological function that occurs over time in the absence of injury, illness, or poor lifestyle choices
• Also termed "normal aging"
• Healthy lifestyle practices, including diet, can minimize, prevent, and/or reverse many age-related changes

Body Composition Changes

• During the third decade of life, there is a decline in lean body mass (LBM) and bone mass, and an increase in adipose tissue
• These changes can be noticeable, especially with weight gain and loss of muscle mass and strength
• Endocrine changes occur in conjunction with body composition changes

Endocrine Changes

• There is a general decline in endocrine function with age, involving responsiveness of tissues to particular hormones and reduced hormone secretion from endocrine glands
• In women, a decline in estrogen levels leads to menopause, which increases the risk of cardiovascular disease and loss of lean body mass
• In men, a decline in testosterone levels leads to andropause, which increases fat mass, loss of bone and muscle mass, insulin resistance, and the risk of cardiovascular disease
• Growth hormone (GH) secretion and concentrations fall with age, leading to a reduction in protein synthesis, decrease in muscle and bone mass, and decline in immune function

Lean Body Mass (LBM) Changes

• Sarcopenia is the age-related decline in lean body mass, which is different from cachexia
• Sarcopenia is a metabolic consequence of aging, occurring in three stages: presarcopenia, sarcopenia, and severe sarcopenia
• Sarcopenia begins in the third decade of life and is influenced by physical inactivity and dietary deficiency
• Protein synthesis decreases with aging, with little change in protein degradation
• Muscle turnover and repair likely decrease with age

Bone Health Changes

• Bone mass loss begins around age 34 years due to decreases in estrogen in men and women and decreases in testosterone in men
• About 20-40% of bone mass is influenced by lifestyle factors, mainly diet and exercise
• Micronutrients important to bone health include calcium, phosphorus, fluoride, magnesium, sodium, and vitamin D

Metabolic Changes

• There is a reduction in basal metabolic rate (BMR) with age, likely due to multiple factors
• Additional research is needed to examine how BMR changes with age

Importance of Nutrition and Physical Activity

• It is important to stay healthy into adulthood
• Key factors that help maintain health and prevent disease include eating a healthy diet, maintaining a healthy weight, and consuming adequate nutrients
• Overweight and obesity are major concerns, stemming from a lack of energy balance and sedentary lifestyle

Fad Diets and Orthorexia

• Fad diets promise quick results for little effort but can be harmful to health and set people up for disappointment

• Orthorexia is an unhealthy obsession with eating healthy, which can lead to restrictive eating patterns and disordered eating behaviors### Nutritional Recommendations and Requirements

• No established AI or RDA for total fat consumption, but AMDR recommends 20-35% of total energy intake from fat.

Substituting Fats

• Substituting polyunsaturated fats for saturated fats or carbohydrates reduces risk.

Alcohol Consumption

• Does not meet the technical definition of a nutrient
• Dangers of overconsumption are dramatic and can lead to:
  • Addiction
  • GI system damage
  • Impacts nutrition
  • Increases cancer risk

Micronutrients of Concern

• Vitamins and minerals required in small amounts for normal development, disease prevention, and overall well-being
• Deficiencies affect over 2 billion people globally
• Underconsumed micronutrients include:
  • Potassium, choline, magnesium, calcium, and vitamins A, D, E, and C
  • Iron in adult women aged 19-50 years
• Results from low intake of vegetables, fruits, whole grains, and dairy
• Nutrients of public health concern:
  • Calcium, potassium, and vitamin D
  • Iron for women of childbearing age or who are pregnant

Vitamins and Minerals

• Vitamin A:
  • Essential for immune function, vision, reproduction, cell differentiation, and cellular communication
  • RDA measured in micrograms of retinol activity equivalents (RAE)
  • Found in dairy products, liver, fish, and fortified cereals
• Vitamin C (ascorbic acid):
  • Water-soluble
  • Essential cofactor in enzymatic reactions
  • Potent antioxidant
  • RDAs based on physiological and antioxidant functions in white blood cells
  • Severe deficiency results in scurvy
  • Found in fruits and vegetables
• Vitamin D:
  • Fat-soluble vitamin
  • Found in limited number of foods
  • Obtained via diet, sun, and supplements
  • Promotes bone health and regulates calcium and phosphorus levels
  • Deficiency common in lactose intolerance, milk allergy, ovo-vegetarians, and vegans
  • Best dietary sources: fatty fish, fish liver oils, and fortified dairy products
• Vitamin E:
  • Fat-soluble antioxidant
  • Exists in eight distinct chemical forms
  • Alpha-tocopherol only form known to meet human requirements
  • RDA established at 15 mg/day for individuals aged 14 years and older
  • Deficiency very rare
  • Found in nuts, seeds, and vegetable oils
• Calcium:
  • Vital for vascular contraction, muscle function, nerve transmission, and hormonal secretion
  • Serum calcium tightly controlled and doesn't respond quickly to changes in dietary intake
  • 99% stored in bones and teeth
  • RDA based on amount needed to promote bone health and calcium retention
  • Found in milk, yogurt, and cheese
• Iron:
  • Essential component of hemoglobin and myoglobin
  • Necessary for physical growth, neurological development, and synthesis of some hormones
  • Adults most likely to have inadequate iron intake: frequent blood donors, people with certain GI disorders, and women of reproductive age
  • Risk of iron intoxication due to hemochromatosis, a hereditary disorder
  • RDAs for vegetarians 1.8 times greater than for individuals who consume meat products
• Potassium:
  • Essential major mineral and electrolyte
  • Normal body function depends on tight regulation
  • Positively charged intracellular ion (cation)
  • Creates membrane potential with sodium across cell membranes
  • Important for nerve impulse transmission, muscle contraction, and heart function
  • Deficiency typically related to losses
  • Found in leafy greens, bananas, grapes, blackberries, root vegetables, and citrus fruits
• Magnesium:
  • Cofactor for hundreds of enzymes
  • Involved in many physiologic pathways
  • Deficiency rare, but increased risk with gastrointestinal disorders, renal disorders, and chronic alcoholism
  • Found in green leafy vegetables, whole grains, nuts, meats, and milk

Sodium

• Essential mineral consumed in excess
• Essential for supporting blood pressure and fluid in the body
• Also needed for nerve transmission
• Typically found in most foods as salt
• Healthy sodium consumption:
  • Required in small amounts
  • Limit to less than 2,300 mg/day
  • Excessive intake a key modifiable risk factor for hypertension and cardiovascular disease
  • Effects of restriction more evident at higher starting blood pressure levels
  • Genetic basis to whether a person is salt-sensitive
  • DASH dietary pattern can help reduce blood pressure

Dietary Supplement Use

• Come in various forms
• Use continues to rise in the United States
• Scientific evidence supports health benefits for some supplements, but not for many others
• Two categories of use:
  • Moderate doses in range of Daily Values (DVs)
  • Megadoses typically multiples of DVs
• Often taken for health, but without a healthcare provider's recommendation
• Groups that may be vulnerable to nutrient inadequacies:
  • Food-insecure individuals
  • People dependent on alcohol or drugs
  • Those with altered nutritional needs
• Look for brands that contain no more than 100% of the Daily Value unless otherwise instructed by a doctor

Promoting a Healthy Lifestyle

• Healthy eating patterns:
  • Outline that allows individuals to consume foods that meet their personal, cultural, and traditional predilections and fit within their budget
  • Consist of the sum of all foods and beverages consumed
  • Can include all forms of foods
• Should strive to meet nutritional needs using nutrient-dense foods
• May need to consume fortified foods and supplements
• Symbols increasingly used on food packaging
• IOM supports standardized front-of-packaging system
• Current research supports DASH diet, Mediterranean diet, and vegetarian diets to positively influence risk for developing heart disease, cancer, and diabetes

Physical Activity Recommendations

• Physical activity guidelines for adults:
  • Aerobic activities (endurance activities)
  • Involves moving large muscles in a rhythmic manner for a continuous period
  • Moderate-intensity for 150 minutes per week decreases risk of premature death, coronary heart disease, stroke, and hypertension
  • Decreased risk for colon cancer, breast cancer, and weight gain observed at 300 minutes per week
  • Should occur at least three times per week
  • Moderate- and vigorous-intensity aerobic exercise in episodes of at least 10 minutes
• Muscle-strengthening activities:
  • Improve bone strength and muscle fitness
  • Help maintain muscle mass through weight loss
  • Force muscles to complete activities not normally performed
  • Increasing amount of weight used or days a week activity is performed yields stronger muscles
  • At least 2 days per week for all major muscle groups

Nutrition Interventions for Risk Management

• Prevention opportunities:
  • Health promotion
  • Primary prevention
  • Secondary prevention
• Strategies to promote healthy lifestyle:
  • Promote increased physical activity
  • Increase fruit and vegetable intake
  • Decrease screen time
• Promoting healthy habits:
  • Utilize community engagement programs
  • Develop strategies that involve individuals and social, organizational, and public policy entities
• Health promotion:
  • Federal assistance programs can help encourage healthier eating
  • SNAP and other programs
  • Health awareness programs help promote a healthy lifestyle