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Nutrition and DietsChapter 11

Health Science 2

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What is Nutrition?

• Most people know there is a fundamental relationship between food and good health

• Many do not know what nutrients are needed

• Many are not able to choose proper foods for optimum health

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In short

• Nutrition: all body processes relating to food

• Nutritional status: state or condition of one’s nutrition

• Nutrition plays a large role in the physical, mental, emotional, and psychological processes of our bodies

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Effects of Good Nutrition

• Healthy appearance

• Good attitude

• Proper sleep and bowel habits

• High energy level

• Enthusiasm and freedom from anxiety

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Nutritional Effects on Genetics

• Research has determined that nutrition can affect a person’s gene expression in relation to many different diseases.

-e.g. obesity, heart disease and cancer.

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Nutrition and Psychology

• Behavior affects what we eat

• But what we eat may also affect our behavior!

• E.g. Influence of supplementary vitamins, minerals and essential fatty acids on the antisocial behaviour of young adult prisoners. Gesch et al in the British Journal of Psychiatry (July 2002)

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Nutrition and Epidemiology

• This is the study of how often diseases occur in different populations and why.

• Much of our evidence relating diet and disease comes from large epidemiological studies of different populations.

• e.g. Studies of Ancel Keys in the 1950s that led to the link between saturated fat and coronary heart disease.

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Cross Cultural Epidemiological Studies of Coronary Artery Disease

• Ancel Keys - studies starting in the 1950s highlighted the differences in the prevalence of CAD across the globe. CAD was unusual in Japan, Crete and Corfu while it was very common in Finland, the USA and the Netherlands.

• He demonstrated a link between blood cholesterol levels and CAD and dietary saturated fat.

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Chronic Diseases

• According to the World Health Organization (WHO), “the growing epidemic of chronic diseases affecting both developed and developing countries is linked to diet and lifestyle changes.”

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Chronic Diseases that are Related to Nutrition

• Obesity• Diabetes• Cardiovascular

Diseases• Cancer• Osteoporosis and

Bone Fracture• Dental Disease

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Nutrition and Obesity

The main determinant of the obesity epidemic is:The imbalance between low energy expenditure due to physical inactivity and high dietary calories.

Action: Increase physical activity and reduce intake of high fat foods and sugary drinks.

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Nutrition and Diabetes

• Escalating rates of type 2 diabetes due to:Obesity and physical inactivity

• Diabetes leads to increased risk of heart disease, kidney disease, stroke and infections

• Action: Maintenance of healthy body weight along with exercise.

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Nutrition and Cardiovascular Disease

• Major killers worldwide. Due to a great extent to: Poor nutrition and

physical inactivity• Leads to:

atherosclerosis• Action: Reduce the

intake of saturated fats, take enough fruits and vegetables, and less salt. Increase physical activity.

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Nutrition and Cancer

• Tobacco is the number one cause of cancer.

• But dietary factors contribute significantly to certain types of cancer

• Maintenance of a healthy weight will reduce the risk for cancers of the esophagus, colorectum, breast, endometrium, and kidney.

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Nutrition and Cancer

• Limiting alcohol intake will reduce risk frok cancers of the mouth, throat, esophagus, liver and breast.

• Adequate intakes of fruit and vegetables will further reduce risk for oral cavity, esophagus, stomach and colorectal cancer

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Nutrition and Osteoporosis

• Adequate intakes of calcium (500 mg or more) and Vitamin D intakes helps reduce the risk as does exposure to sunlight and physical activity.

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Dental Disease

• Cavities are prevented by:

Limiting the frequency and amount of consumption of sugars and by appropriate exposure to fluoride.

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Essential Nutrients

• Chemical elements are found in food

• Used by the body to perform many different body functions

• Nutrients are divided into six groups

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Essential Nutrients

• Carbohydrates

• Lipids (fats and oils)

• Proteins

• Vitamins

• Minerals

• Water

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Essential Nutrients: Carbohydrates

Carbohydrates:• major source of readily available energy• Commonly called starches or sugars• Cheaper source of energy because they are found mainly

in plants• Made of carbohydrates, hydrogen and water• Main sources of carbohydrates are breads, cereals,

noodles, pasta, crackers, potatoes, peas, beans, fruits, sugar, and syrup

• Cellulose is the fibrous, indigestible form of plant carbohydrate. It provides bulk in the digestive tract, causing regular bowel movements.

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Essential Nutrients: Lipids (Fats)

Lipids (Fats):• Three of the most common lipids found in both food and the human

body are triglycerides (fatty acids), phospholipids, and sterols (cholesterol)

• Lipids are the most concentrated form of energy but are more expensive than carbohydrates

• Also function to maintain body temperature by providing insulation, cushion organs and bones, and aid in the absorption of fat-soluble vitamins

• Main sources include butter, oils, cream, meats, cheese, dairy products, and egg yolk

• Saturated fats are solid at room temperature• Unsaturated fats are soft or oily at room temperature

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Essential Nutrients: Cholesterol

Cholesterol• A lipid (sterol) found in body cells and in animal products• Used in the production of steroid hormones, Vitamin D, and bile

acids. It is also a component of the cell membrane• Common sources are: egg yolk, fatty meats, shellfish, butter,

creams, cheeses, whole milk.• Cholesterol is also manufactured by the liver

Lipoproteins – cholesterol is transported in the bloodstream by two carrier molecules called lipoproteins:

• HDL – high density lipoprotein that transports cholesterol back into the liver and prevents it from accumulating in the arterial walls

• LDL – low density lipoprotein transports cholesterol to arterial walls where it causes plaque build-up, leading to atherosclerosis

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Essential Nutrients: Proteins

Proteins• Basic components of all body cells. Essential for building and

repairing tissue, regulating body functions, and providing energy• Made up of “22 building blocks”, called amino acids. Nine of these

amino acids are essential to life• Complete proteins – contain the nine amino acids that are

essential to life

-found in meats, fish, milk, cheese, and eggs• Incomplete proteins – contain any of the remaining thirteen

non-essential amino acids

-found in cereals, soybeans, peas, corn, and nuts

How does this affect vegetarians (especially vegans)?

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Essential Nutrients: Vitamins

Vitamins• Organic (living) compounds that are essential to life• Involved in metabolism, tissue building and repair, regulation of

body processes, digestion, and blood formation and clotting• Vitamins are classified as water soluble or fat soluble• Water soluble vitamins – dissolve in water and are not stored in

the body.

-Includes B-Vitamins, Vitamin C, and Folic Acid• Fat soluble vitamins – dissolve in fat (not in water) and are stored

in the body.

-Includes Vitamins A, D, E, and K

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Essential Nutrients: Minerals

Minerals• Inorganic (nonliving) elements found in all body tissues• Functions include:

-regulate body fluids (Sodium, Potassium)

-contribute to growth (Calcium, Phosphorus, Magnesium, Zinc)

-helps build tissues (Magnesium, Sulfur, Iron)

-formation of RBC’s (Iron, Copper)

-maintains heart rhythm (Calcium, Potassium)

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Essential Nutrients: Water

Water• Found in all body tissues• Essential for the digestion

(breakdown) of food• Makes up most of the

blood plasma, and cytoplasm of cells

• Helps the body tissues to absorb nutrients

• Moves waste materials through the body

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Utilization of Nutrients

• Digestion – the process by which the body breaks down food into smaller parts, changes the food chemically, and moves the food through the digestive system.

– Mechanical Digestion – food is broken down by the teeth and moved through the digestive tract by a rhythmic, wave-like motion of the muscles, called peristalsis.

– Chemical Digestion – food is broken down by digestive enzymes secreted by the mouth, stomach, small intestines, and pancreas.

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Utilization of Nutrients

Absorption• The process by which blood or lymph picks up the digested

nutrients. The nutrients are then carried by the circulatory system to every cell in the body

• Most absorption of nutrients occurs in the small intestine

Metabolism• The process in which nutrients are used by the cells• Nutrients are combined with oxygen and energy and heat

are released• Basal Metabolic Rate (BMR) – the rate at which the body uses

energy just for maintaining its own tissue, without doing any voluntary work.

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Maintenance of Good Nutrition

• Good nutrition is the best way of achieving and maintaining good health

• The US Department of Agriculture Developed a food guide called “My Pyramid” (See Figure 11-3 in text – page 303)

• If food is not appealing, people will not eat it even if it is healthy; consider variety, taste, color, aroma, texture, and general likes and dislikes

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Guidelines for Good Eating Habits

• Make smart choices from every food group (See Table 11-4 in text – p. 304)

• Find a balance between food and all physical activity – 30-60 minutes of physical activity per day

• Limit fats, saturated fat, and cholesterol. Eat lean meats and low fat dairy

• Choose nutritionally rich foods – high in nutrition but low in calories

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Guidelines for Good Eating Habits

• Don’t sugarcoat it – use sugar in moderation

• Reduce salt intake – flavor foods with herbs and spices

• Check food labels and calculate the calories per serving and the amount of fat

• Remember that alcohol can be harmful to your health

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Weight Management

• Weight in relation to height for– Males – for the first 60 inches of height, an

individual should weigh 106 lbs. For each inch over 60 inches, 6 lbs. should be added.

-a 74 inch man should weigh _____ lbs– Females - for the first 60 inches of height, an

individual should weigh 100 lbs. For each inch over 60 inches, 5 lbs. should be added.

-a 68 inch woman should weigh _____ lbs

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Weight Management

• Weight in relation to height for– Large-boned individuals – increase the

weight by 10% for large-boned males or females

– Small-boned individuals - decrease the weight by 10% for small-boned males or females

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Weight Management

• Body mass index (BMI) – is a calculation that measures weight in relation to height and correlates this with body fat.

-determined by dividing a person’s weight in kilograms by height in meters squared

-Ideal range – 18.5-24.9 -A BMI of less than 18.5 indicates the individual is

underweight - A BMI of more than 25 indicates the individual is

overweight

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BMI

Chart

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Measuring Food Energy

• Food varies in the amount of energy they contain. The amount of heat produced during metabolism is the way the energy content of food is measured.

• The heat is measured by a unit called kilocalorie (kcal), or just calorie

• Carbohydrates – provide 4 calories per gram• Proteins – provide 4 calories per gram• Fats – provide 9 calories per gram• Vitamins, minerals, and water do not provide any

calories

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Weight Management

• 1 pound of body fat equals 3,500 calories.• A general guideline to maintain weight is that a person

needs to consume 15 calories per pound per day. -How many calories does a 120 lb person need to

take in per day to maintain this weight? 15 X 120 = 1,800 calories a day -If a person decreased her caloric intake by 500

calories a day, how much weight would she lose in a week?

500 X 7 = 3,500 calories = 1 pound

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Therapeutic Diets

• Modification of normal diet used to improve specific health condition

• Normally prescribed by physician and planned by dietitian

• May change nutrients, caloric content, and/or texture

• May seem strange and even unpleasant to patient

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Regular or Standard Diet

• Balanced diet

• Usually used for ambulatory patients

• May have slight calorie reduction

• Decreased or omitted: rich desserts, cream sauces, salad dressings, and fried foods

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Liquid Diets

• Clear and full liquids to be used only for short periods of time

• Liquid foods at body temperature• Clear: carbohydrates and water -apple juice, fat-free broth, plain gelatin, ginger ale, tea• Full: clear liquids plus other liquids -strained soups and cereals, fruit juices, yogurt, ice cream, pudding• Uses such as the following: surgery, digestive problems,

to replace lost fluids, and in preparation for X-rays of the digestive tract

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Soft Diet

• Similar to a regular diet, but foods require little chewing and are easy to digest

• Avoid meat, shellfish, coarse cereals, spicy foods, rich desserts, fried foods, raw vegetables, fruits, and nuts

• Uses: after surgery, patients with infections, digestive disorders, and chewing problems

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Diabetic Diet

• Used for patients with diabetes mellitus who often take insulin

• Exchange lists are used to choose foods on exchange lists

• Avoid sugar-heavy foods such as candy, soft drinks, desserts, cookies, syrups, honey, and jellies

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Calorie-Controlled Diets

• Low-calorie — used for patients who are overweight; avoid or limit high-calorie foods

• High-calorie — used for patients who are underweight, have anorexia nervosa, hyperthyroidism, or cancer. Avoid high-bulk foods such as green salads, watermelon, and fibrous fruits

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Low-Cholesterol Diet

• Restricts foods containing cholesterol

• Used for patients with atherosclerosis and heart disease

• Limit foods high in saturated fats, such as beef, liver, pork, egg yolk, cream cheese, shellfish, and whole milk

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Sodium-Restricted Diets

• Otherwise known as low-sodium or low-salt diets

• Used for cardiovascular diseases, kidney disease, and fluid retention

• Avoid or limit addition of salt; avoid salt-rich foods such as smoked meats, some fish, pickles, olives, sauerkraut

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Protein Diets

• Protein-rich foods such as meats, fish, milk, cheese, and eggs

• High-protein for children and adolescents for additional growth, pregnant or lactating women, surgery, burns, fevers, infections

• Low-protein for certain kidney or renal diseases and allergic conditions

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Bland Diet

• Easily digested foods that do not irritate the digestive tract

• Used for patients with ulcers, colitis, and other digestive diseases