Clinical Biochemistry: Nutrition

Flashcards based on key concepts from the Clinical Biochemistry of Nutrition lecture notes.

Nutrient

A substance in food the body uses to promote normal growth, maintenance, and repair.

Macronutrients

Nutrients required in larger amounts, including carbohydrates, lipids, and proteins.

Micronutrients

Nutrients needed in small amounts, including vitamins and minerals.

Balanced Diet

A diet that guarantees adequate amounts of all necessary nutrients and energy.

Energy (kcal)

A measure of the energy value of food, where 1 kilocalorie is the amount of energy needed to raise the temperature of 1 kg of water by 1°C.

Carbohydrates

Nutrients that provide energy, mostly sourced from sugars and starch.

Protein

Nutrient that plays a key structural and functional role in the body, providing amino acids.

Vitamins

Organic compounds essential for normal growth and nutrition, usually required in small quantities.

Fiber

Dietary components that are not hydrolyzed by digestive enzymes and promote digestive health.

Assessment of Nutritional Status

Evaluating whether individual patients' nutritional needs are being met, to identify risks and monitor progress.

Anthropometry

The science of measuring the human body to assess nutritional status.

Biochemical tests

Laboratory assessments used to evaluate nutritional status, including measurements of blood protein, glucose, and lipids.

What are the three categories of nutirent

macronutrients, micronutrients, and water.

What is an essential nutrient

cannot be made by the body and must, therefore, be consumed from food has a particular function in the human body (e.g. vitamins and some proteins).

What is the purpose of energy in the body

Body uses energy in the maintenance of metabolic processes, physical activity and growth.

Resting individual → energy-requiring processes include active pumping of ions across cell membranes, thermoregulation, cell division and basal function.

Thus energy requirement of individual varies with body size and composition, sex, age, nutritional status and climate.

What is the importance of essential fatty acids

important components of phospholipids; help to maintain cellular function and subcellular membranes

→ Regulation of cholesterol

→ Synthesis of prostaglandins, thromboxanes and leukotrienes

→ Deficiency in diet → dermatitis, alopecia and fatty liver

What can a deficiency of micronutrients lead to

Vitamins and certain trace elements are essential components of the diet required in very small amounts

➢ Deficiency of individual micronutrients classically results in typical symptoms and signs according to the vitamin or trace element involved

such as scurvy from vitamin C deficiency

and rickets due to vitamin D deficiency.

Chronic deficiencies can lead to more severe health issues, impairing overall health and bodily functions.

What is the importance of fibre and what can deficiency lead to

Fibre is crucial for digestive health, helping to regulate bowel movements and prevent constipation.

A low dietary fibre intake → constipation, diverticular disease, appendicitis, gallbladder disease and carcinoma of the large bowel

What are the 4 main apporaches to assessing nutrintanl status

• Anthropometry

• Biomarkers

• Clinical assessment

• Dietary assessment

Why is clinical assessment used for nutritional status

Evidence of nutritional disorders may become apparent during history taking and physical examination.

➢ Past medical history → changes patient’s usual weight, poor wound healing or increase susceptibility of infection.

➢ Any difficulties in chewing or swallowing, symptoms such as anorexia, nausea, vomiting or altered bowel habit.

➢ Chronic use of alcohol or drugs & socioeconomic factors.

➢ Physical examination → generalised nutritional depletion

(muscle wasting, oedema).

Why is dietary assessment used for nutritional status

Dietary assessment involves → intake of food and individual dietary components, and comparing the amount consumed with reference values → deficiency or excess.

➢ Methods of dietary assessment:

▪ record current intake → all food is weighed or measured prior to being eaten.

▪ dietary recall methods → 24 h or 7-day period → can reveal major areas of deficiency, or excess

Why is Anthropometric Measurements used for nutritional status

➢ Anthropometry → measurements of the human body

o Height and weight

o Body mass index (BMI; kg/m2) → used to grade the severity of obesity or of chronic energy deficiency

o Circumference measurements: waist:hip ratio, reflects the distribution of fat rather than the degree of obesity.

What are the lab assessments for nutrition

Biochemical tests used to complement history: none are completely satisfactory

✓ Protein → serum albumin, indicator of protein nutritional status, however related to many factors such as hepatic & renal diseases.

✓ Blood glucose → maintained even during prolonged starvation periods.

✓ Lipids → fasting plasma triglyceride levels provide some indication of fat metabolism; but affected by many metabolic processes.

✓ Faecal fat → assessment malabsorption.