nutrition in adolescences, adulthood and the elderly

growth in adolescents

• total amount of nutrient needed during adolescence surpasses needs at any other time of life

• the needs for many nutrients increase due to rapid growth

• iron particularly important for hemoglobin production in expanding blood volume and perfusion of tissues for all and female requirements increase due to the onset of menstruation

• increased need for calcium and zinc as well for bone and muscle growth, respectively

• both males and females grow rapidly but males develop greater lean body mass

• it is physiologically normal that females develop more adipose mass and less lean body mass

link of childhood obesity and puberty

• adipose tissue is an endocrine tissue and secretes hormone, it also expresses aromatase which is an enzyme involved in the production of estrogen

• leptin, an adipokine, can stimulate the expression of the protein kisspeptin, which stimulates the release of GnRH, contributing to the increased production of estrogen

• hence females who have higher adipose tissue or BMI tend to have early onset of puberty than those who do not 

common deficiency in adolescents

common deficiencies in boys

• 9 to 18 years: vitamin A, calcium

• 14 to 18 years: magnesium (40%)

common deficiencies in girls

• 9 to 18: vitamin A, phosphorus, calcium

• 9 to 13: zinc (15%)

• 14 to 18: B6, folate, B12, iron (~12%), zinc (20%), magnesium (65%)

vegan diet concerns for adolescents

• vegetarianism or veganism may be adopted in teen years

• health teaching is important to prevent nutrient deficiencies, esp. for teens following different dietary plan than their family members; supplement include

  • optimal non-meat protein sources

  • possible requirement for iron and zinc supplementation

  • avoiding deficiencies in vitamin B12, calcium and vitamin D in vegans

bone health in adolescence

• milk consumption decreases

• calorie-free soft drinks often chosen

• especially concern for females that calcium intake in inadequate, especially when we never have that much in the first place

window of opportunity for calcium intake in adolescent girls

• calcium supplementation of postmenarcheal girls with low calcium intakes enhances bone mineral acquisition, especially in girls > 2years past the onset of menarche

• must be within the 2 years after first menstruation, after this window any further calcium supplement are less effective

importance of window of opportunity in adolescent girls

since we are more susceptible for osteoporosis, getting a head start within the two year window can have long term benefits

main dietary concerns for adolescents

• eating disorders may be diagnosed during this time

• adolescent pregnancy impacts nutritional needs, nutrients are required for growth of the fetus and teen

• smoking is a risk factor for chronic diseases later in life, it increases the need for nutrients such as vitamin C due to added oxidative stress from tobacco use

• alcohol consumption alters the absorption and metabolism of nutrients; it also replaces calories from nutritious foods. adolescence often engage in binge drinking

• cannabis use in adolescence, research ongoing, but exposure is linked to changes in brain structure

changes during aging

• as organisms become older, the number of cells they contain decreases, and the function of the remaining cells decline

• as tissues and organs lose cells, the ability of the organisms to maintain homeostasis decreases

• people are living longer, though not everyone has enjoyed the same increases in life expectancy

what impacts the rate of aging

• life expectancy is determined by a combination of genetics, lifestyle and environmental factors

• exposure to damage as well as the ability to repair and replace damaged cells influence aging (more damage fastens aging whereas better repair slows down aging)

the only method to extend longevity and studies

• calorie restriction studies in animals proven this fact

• another study is the Indigenous Okinawans of Japan has one of the longest life expectancies in the world

  • lower incidence and mortality of chronic diseases including CV and cancer

  • nutrient dense, traditional diet including many leafy and root vegetables, soy, little meat, sweet potato instead of rice

  • potentially related to long term calorie restriction as adults only eat ~80% if typical Japanese adult

  • hard to determined due to multifactorial factors such as higher activity, genetics and even incorrect ages in studies

the CALERIE study

• the comprehensive assessment of long term effects of reducing intake of energy

• assessed young and middle aged (21-50), healthy non obese (BMI 22-27.9) men and women

• participants randomly assigned to a 25% calorie restriction diet or an ad libitum controlled diet

• 2 years of moderate calorie restriction significantly reduced multiple cardiometabolic risk factors in young, non obese adults

• essentially evidence suggest the ability to increase life span by 1-5 years with an improvement in health span and quality of life. calorie restriction moderates intrinsic processes of aging through cellular and metabolic adaptation and reducing risk for the development of many cardiometabolic diseases.

• may have unique considerations for the elderly and other populations 

compression of morbidity

• refers to the delaying of onset of the symptoms of disease so that they take up less of later life

• increase the health of the aging population and spare the healthcare system 

nutrient requirements in older adults

• higher vitamin B6 dietary intakes are needed to maintain the same functional levels in the body

• increased vitamin D and calcium as low intakes of these contributes to osteoporosis

• iron needs in females is decreased due to menopause

• RDA for vit B12 is not increased but fortified foods recommended in >50 years of age due to reduced absorption and low dietary intakes

• folate can be a concern due to anemia (low B12 also contributing factor) which is common in older adults

• concern with zinc due to a combination of lower energy intake, damage and medication which can impact taste acuity and contribute to low food intake

• vitamin C and E are often reduced in intake in the elderly due to decreased fruit and vegetables intake

physiological effects of aging

• sensory decline: macular degeneration and cataracts

• periodontal disease

• atrophic gastritis

• decline in size and functioning of liver and kidneys

• Alzheimer’s disease and dementia

• reduced hormone levels

• decrease in mobility

• increase in body fat, decrease in lean body tissue

• immune function and underlying illness

sensory decline in older populations

• >60 years, there is sensory decline leading to impaired taste and smell

• a decrease in the amount of saliva also contributes to decreased senses

• thirst sense is decrease, increasing risk for dehydration

• decreased in visual acuity makes shopping and food preparation difficult

GI changes in older populations

• periodontal disease may impact chewing and swallowing

• stomachs empty slower, allowing older adults to feel full longer and decreasing food intake

• 10-30% of adults >50 have atrophic gastritis; incidence can be as high as 40% in adults >80

• decreased motility and elasticity of the large intestine, along with low fibre and liquid intake can result in constipation

• pharmaceuticals can decrease nutrient absorption and food can enhance or inhibit the absorption and metabolism of medications

shift in body composition in the older population

• body composition shifts to a greater percentage of fat (sarcopenia)

• decreased strength and endurance affect mobility and balance, which increases the risk of fractures and falls

• also impacts cardiac muscles and muscles associated with breathing

• emerging research highlight the role of exercise in delaying these effects

immune function in the older population

• there is decline due to aging and/or associated with nutritional deficiencies

• sickness limits nutrient intake and absorption, this in turn affects the body’s ability to mount an immune response=increased risk for disease, including cancer

• immune surveillance and destruction of cancerous cells may be impacted

intervention to reduce risk of infection and illness in the older population

• supplementation

• proper nutrition including omega-3 fatty acids and

• exercise

risk for malnutrition in the older population

• the prevalence of malnutrition increases with age

• decreased basal metabolic rate means that fewer calories are needed, but the same or increased amount of nutrients are still needed for bodily functions, hence if they eat according to their basal metabolic rate they wont get enough nutrients to support bodily functions which could essentially lead to malnutrition

• less enjoyment of food and eating

  • > 60, sensory decline leading to impaired taste and smell

  • less saliva

• thirst sense is decreased

health-promoting factors in older adults

• never smoked daily or quit for 15 years or more

• not obese

• sleeps well

• good oral health

• eat 5 or more servings of fruits and vegetables per day

• frequent walker

• frequent social participation

• low daily stress 

how can healthy aging reduce cognitive impairment

• physical activity can delay the onset of Alzheimer’s and dementia

• multidomain approach that includes diet, exercise, cognitive training and vascular risk monitoring demonstrated improvement or maintenance of cognitive function

economic, social and psychological play in healthy aging

seniors are often on a fixed or low income, however rising costs, including those related to healthcare can push individuals into poverty, impacting their quality of life

• healthy nutritious food is often expensive

• risk of malnutrition may also be due to mobility issues, making it more difficult to get and prepare food

• depression is also a factor, social isolation or loss of a loved one can have an effect on the desire to eat

• health teaching is important so pts make good choices for their health

significance of exercise

• important for prevention of illness and maintenance of independence

• regular exercise can help reduce the incidence of chronic disease and maintain mobility, bone and muscle mass, importantly independence

significance of social connections

• social interactions is important for mental health and can provide motivation to eat or to get out of house and do something

• increased social participation demonstrates physical, psychological, social and self related wellness