NUTRITION IN MEDICINE

DR. SHRADDHA THOURANI

Nutrients are the substances that are not synthesized by the human body and are therefore to be supplied by the diet. Macronutrients and micronutrients Illness and injury alter the nutritional

requirements Increase need with growth, pregnancy,

lactation, exercise. Nutrient required for good health are Energy providing foods – carbohydrates,

fats and proteins Vitamins Minerals Water

Human requirements for organic nutrients include 9 essential amino acids, several fatty acids, glucose, 4 fat-soluble vitamins, 10 water-soluble vitamins, dietary fiber, and choline.

Several inorganic substances, including 4 minerals, 7 trace minerals, 3 electrolytes, and the ultra trace elements, must also be supplied by diet

ENERGY

LAW OF THERMODYNAMICS Energy intake= energy expenditure Average energy intake in males is

2600kcal/d and 1900kcal/d in females BMR is the obligatory energy reqd to

maintain the metabolic functions in tissues Extra metabolic energy is consumed during

growth, pregnancy, lactation and when febrile

Metabolic energy is also reqd for thermal regulation

Energy intake is determined by the ‘macronutrient’ content of food.

Energy provided by each is: Carbohydrates – 16kJ/g Fat 37kJ/g Proteins 17kJ/gTotal energy requirement can be

estimated by BMIEnergy given per kg of body weight is

inversely related to BMI

DAILY ADULT ENERGY REQ

FEMALES MALES

AT REST 1600 kcal 2000 kcal

LIGHT WORK 2000 kcal 2700 kcal

HEAVY WORK 2250 kcal 3500 kcal

ENERGY YIELDING NUTRIENTS

CARBOHYDRATES, FATS AND PROTEINS Carbohydrates (starches and sugar) supply the

major part of energy 45-55% of total calories. Sugars – fruits, milk and vegetables. Total

recommended intake of sugars is between 0 -15% of total energy intake

Starches – cereals, root vegetables and legumes. They are the nutrients which provide the largest proportion of calories reqd.

Dietary fibers – non-starch polysaccharides Glycemic index

FATS Because of the high calorie value

provide more energy and exessive consumption may be the insidious cause of obesity

Fats can be classified as saturated, and unsaturated (monounsaturated and polyunsaturated)

PUFA – Linoleic acid and alpha linoleic aid are “essential” fatty acids

Fish oils are rich in PUFA –prevent coronary heart disease

Trans fatty acids (TFA) and saturated fats should be limited to <10%

PROTEINS

Proteins form the structural component of the body cells.

Proteins are made up of 20 different amino acids out of which 9 are essential amino acids that cannot be synthesized within the body and has to be obtained from dietary sources

Nutritive value or biological value Proteins of animal origin like eggs , milk and

meat have higher biological value than proteins of vegetable origin

Recommended proteins is 10% of total calories or about 65g per day for an average adult

CLINICALLY IMP VITAMINS

Fat soluble – vitamin A,D,E,K Water soluble vitamins – B1,B2,B3,B6 Folate – B12 Biotin Ascorbic acid

MINERALS Calcium, phosphorus , magnesium, iron,

zinc, iodine , selenium, copper , fluoride, potassium and sodium

FACTORS ALTERING NUTRIENT NEEDSPHYSIOLOGICAL FACTORS

Age gender Growth Pregnancy & lactation Increased physical activity DIETARY COMPOSITIONAffects the biologic availability of nutrients.ex.Fe & Ca , Fe + vit C

ROUTE OF ADMINISTRATION Oral- CHO, fats, amino acids, Na, K, Cl

have good intestinal absorption Parenteral- mineralsDISEASE

specific dietery deficiency diseasesmegaloblastic anemia- vit B12 & FARickets- vit Dscurvy- vit CBer-Beri/pellegra

NUTRITIONAL STATUS ASSESSMENT

ASSESSMENT OF NUTRITIONAL DEFICIENCIES

(I) NUTRITIONAL HISTORY Poor intake (anorexia, food avoidance, NPO

status) Nutrient losses – malabsorbtion ,abscesses,

wounds Hypermetabolic states- fever,sepsis,trauma,

burns Steroids, antimetabolites(methotrexate),

immunosuppressants, anticancer drugs Advanced age, poverty, isolation Increased requirements of nutrients

(II) PHYSICAL FINDINGS HAIR AND NAILS

Coiled, sparse, easily pluckable hair Depigmentation of hair Transverse ridging of nails

SKIN Crackling, dry, hyperkeratotic skin Scaling Poor wound healing with ulcers

ORAL Angular stomatitis, cheilosis Dry crackling lips Glossitis Bleeding gums

BONES AND JOINTS Beading of ribs, epiphyseal swelling, bowlegs

NEUROLOGIC Drowsiness, lethargy, disorientation Dementia, headache Peripheral neuropathy

OTHERS Edema Hepatomegaly Heart failure

(III) ANTHROPOMETRY

Anthropometric measurements provide information on the body muscle mass and fat reserves.

Weight and height to know the BMI Triceps skinfold (TSF) Mid arm muscle circumference (MAMC)

BMI – BODY MASS INDEX= WEIGHT(kg)HEIGHT(m)2

Classification of weight status

BMI CLASS

< 18.5 UNDERWEIGHT

18.5-24.9 HEALTHY

25-29.9 OVERWEIGHT

>30 OBESE

(IV) Laboratory tests

Serum albumin or total proteins(3.5-5.5g/dl)

Serum iron binding capacity(240-450µg/dl)

Serum B12 levels(279-996pg/ml) Prothrombin time(21-15.5 sec) Serum Creatinine (0.6-1.6mg/dl) BUN (8-23mg/dl)

SUMMARY

NUTRITIONAL ASSESSMENT Proper and complete history Physical signs Anthropometry Laboratory investigations

PEM IN ADULTS

Protein–energy malnutrition occurs as a result of a relative or absolute deficiency of energy and protein.

It may be primary, due to inadequate food intake,

or secondary, as a result of other illness. Protein–energy malnutrition has been described

as two distinct syndromes. Kwashiorkor, caused by a deficiency of protein

in the presence of adequate energy, is typically seen in weaning infants.(protien poor diet)

Marasmus, caused by combined protein and energy deficiency, is most commonly seen where adequate quantities of food are not available.(end result of long term dietery deficiancy)

Kwashiorkor like secondary protein–energy malnutrition occurs primarily in association with hypermetabolic acute illnesses such as trauma, burns, and sepsis.

Marasmus-like secondary protein–energy malnutrition typically results from chronic diseases such as chronic obstructive pulmonary disease (COPD), congestive heart failure, cancer, or AIDS.

Pathophysiology

Protein–energy malnutrition affects every organ system.

The most obvious results are loss of body weight, adipose stores, and skeletal muscle mass.

Weight losses of 5–10% are usually tolerated without loss of physiologic function; losses of 35–40% of body weight usually result in death.

Loss of protein from skeletal muscle and internal organs

Protein mass is lost from the liver, gastrointestinal tract, kidneys, and heart.

Hepatic synthesis of serum proteins decreases.

Cardiac output and contractility are decreased

Respiratory function is affected due to atrophy of the muscles of respiration.

The gastrointestinal tract is affected by mucosal atrophy and loss of villi of small intestine, resulting in malabsorption.

mild pancreatic insufficiency also occur. Changes in immunologic function are

seen.

CLINICAL FEATURES Loss of weight Loss of subcutaneous fat Muscle wasting Thirst, weakness, feeling cold Lax, pale, dry skin Hair thinning or hair loss Generalized oedema Distended abdomen Diminished tendon jerks Apathy, depression Increased susceptibility to infections

Progressive wasting that begins with weight loss and proceeds to more severe cachexia

body fat stores disappear and muscle mass decreases, most noticeably in the temporalis and interosseous muscles.

Laboratory studies may be unremarkable—serum albumin,

The serum protein level, however, typically declines and the serum albumin is often < 2.8 g/dL (< 28 g/L).

Dependent edema, ascites, or anasarca may develop.

Infections asso with PEM

Gastroenteritis Respiratory infections –

bronchopneumonia Tuberculosis Streptococcal and staphylococcal

skin infections Viral infections like herpes Helminthic infestations

Treatment

Initial efforts should be directed at correcting fluid and electrolyte abnormalities and infections.

The second phase of treatment is directed at repletion of protein, energy, and micronutrients.

Treatment is started with modest quantities of protein and calories calculated according to the patient’s actual body weight.

vitamins and minerals by enteral or parenteral route

Enteral refers to feeding via a tube placed into the gut to deliver liquid formulas containing all essential nutrients.

For short-term use, enteral tubes can be placed via the nose into the stomach, duodenum, or jejunum.

For long-term use, these sites can be accessed through the abdominal wall using endoscopic, radiologic, or surgical procedures

Parenteral refers to the infusion of complete nutrient solutions into the bloodstream via a peripheral vein or, more commonly, by central venous access to meet nutritional needs

Percutaneous placement of a central venous catheter into the subclavian or internal jugular vein with advancement into the superior vena cava can be accomplished at the bedside by trained personnel using sterile techniques

OBESITY

OBESITY

Obesity is one of the most common disorders in medical practice and among the most frustrating

Obesity is defined as an excess of adipose tissue.

Physical examination is usually sufficient to detect excess body fat.

More quantitative evaluation is performed by calculating BMI.

The BMI is calculated by dividing measured body weight in kilograms by the height in meters squared.

classification

The National Institutes of Health (NIH) define a normal BMI as 18.5–24.9.

Overweight is defined as BMI = 25–29.9.

Class I obesity is 30–34.9, class II obesity is 35–39.9, and class III (extreme) obesity is BMI

> 40.

Obesity is associated with significant increases in both morbidity and mortality

Obese patients have a greater risk of diabetes mellitus, stroke, coronary artery disease, and early death

The most important and common of these are hypertension, type 2 diabetes mellitus, hyperlipidemia, coronary artery disease, degenerative joint disease, and psychosocial disability.

Certain cancers (colon, ovary, and breast),

thromboembolic disorders, digestive tract diseases (gallbladder

disease, gastroesophageal reflux disease), and

skin disorders are also more prevalent in the obese

Obese patients also have a greater risk of pulmonary functional impairment including sleep apnea.

endocrine abnormalities, proteinuria, and increased hemoglobin concentration.

Patients with obesity have increased rates of major depression and binge eating disorder

TREATMENT

Dietery restrictions and modifications Exercise Medications – Orlistat which reduces

fat absorbtion. Bariatric surgery is an increasingly

prevalent treatment option for patients with severe obesity. Roux-en-Y gastric bypass (RYGB), done laparoscopically

Gastric banding (GB) surgeries

EATING DISORDERS

Anorexia Nervosa typically begins in the years between adolescence and young adulthood. Ninety percent of patients are females.

The diagnosis is based on weight loss leading to body weight 15% below expected.

fear of weight gain or of loss of control over food intake and, in females, the absence of at least three consecutive menstrual cycles.

Bulimia Nervosa is the episodic uncontrolled ingestion of large quantities of food followed by recurrent inappropriate compensatory behavior to prevent weight gain such as self-induced vomiting, diuretic or cathartic use, or strict dieting or vigorous exercise.

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