Nutritional Requirements Marie Černá

A nutritionally adequate diet satisfies three needs: chemical energy for all cellular work of the body, the generation of ATP by cellular respiration, from the oxidation of organic molecules (carbohydrates, proteins and fats) the organic raw materials are used in biosynthesis (carbon skeletons to make many of own molecules) essential nutrients, substances cannot be made from any raw material, but must be obtained in food in prefabricated form

Nutritional terms over nourishment - obesity (caloric excess) - storing the excess calories in the form of glycogen (liver and muscles) and fat (adipose tissue) undernourishment (caloric deficiency) - breaking down its own proteins (muscles and brain) malnourishment (mineral or protein deficiencies) - missing one or more essential nutrients

Homeostatic mechanism in nutritional requirements: The human body tends to hoard fat, to immediately store any excess fat molecules obtained from food instead of using them for fuel or biosynthesis. By contrast, when we eat an excess of carbohydrates, the body tends to increase the rate of carbohydrate consumption. Thus, the amount of fat in the diet can have a more direct effect on weight gain than carbohydrates.

Paleolithic hunters Fat hoarding can be a liability today, but it may have provided a degree of fitness for our hunting/gathering ancestors. Individuals with genes promoting the storage of high-energy molecules during feasts may have been those that survived famines.

Complex feedback mechanisms regulate fat storage Leptin – a hormone produced by adipose cells ↑ of body fat (in adipose tissue) increases leptin levels in the blood → signaling the brain to depress appetite and increase energy-consuming muscular activity and body heat production ↓ of body fat (in adipose tissue) decreases leptin levels in the blood → signaling the brain to increase appetite and weight gain

There are four classes of essential nutrients: essential amino acids (9 of 20 required amino acids) sources: animal products: meat, eggs, cheese essential fatty acids (unsaturated fatty acids) for phospholipids in membranes vitamins (0.01 – 100 mg per day) - water-soluble (B + C) - their excesses are excreted in urine, moderate overdoses are harmless - fat-soluble (A, D, E, K) - their excesses are not excreted but are deposited in body fat, overdoses result in their accumulation to toxic levels minerals (1 – 2500 mg per day)

Vitamins Water-soluble Vitamin B 1 (thiamine) Vitamin B 2 (riboflavin) Vitamin B 6 (pyridoxine) Vitamin B 12 Folic acid (folacin) Pantothenic acid Niacin Biotin Vitamin C (ascorbic acid) Fat-soluble Vitamin A (retinol) Provitamin A (beta-carotene) Vitamin D Vitamin E (tocopherol) Vitamin K (phylloquinone)

Minerals higher quantity Calcium (Ca) Phosphorus (P) Sulfur (S) Potassium (K) Sodium (Na) Chlorine (Cl) Iron (Fe) Iodine (I) Fluorine (F) lower quantity Magnesium (Mg) Zinc (Zn) Cooper (Cu) Manganese (Mn) Cobalt (Co) Selenium (Se) Chromium (Cr) Molybdenum (Mo)

Literature Biology, eighth edition, Campbell, Reece Unit seven: Animal Form and Function Chapter 41: Animal Nutrition Concept 41.1: An animal’s diet must supply chemical energy, organic molecules, and essential nutrients Concept 41.5: Homeostatic mechanisms contribute to an animal’s energy balance Pages 875 – 880, 893 – 896