Understanding Energy Balance

Energy Balance

• Energy balance means the total energy expended equals the total energy taken in
• Positive energy balance ( E. Input > E. Output) results to overfeeding
• Negative energy balance (E. Input < E. Output) leads to lower energy expenditure
• Energy intake refers to the energy from food sources
• Energy storage represents energy from food stored for fuel
• Chemical Energy (GE) is the energy released from food
• Metabolized Energy refers to the actual energy used by the body
• Methods to measure metabolizable energy include duplicate portions of diet, feces, and urine

Energy Balance Values

• Gross Energy of Food is represented as (a) kJ/day
• Digestible Energy is calculated as (a-b) (kJ/day)
• Digestibility Coefficient is calculated as (100(a-b)/a) (%)
• Metabolizable Energy is represented as (a-b-c) (kJ/day)
• 4.184 kJ equals 1 kcal

Energy Values

• Carbohydrate's energy value is 4 kcal/g or 17 kJ/g
• Protein's energy value is 4 kcal/g or 17 kJ/g
• Fat's energy value is 9 kcal/g or 37 kJ/g
• Alcohol's energy value is 7 kcal/g or 29 kJ/g

Measurements of Energy Expenditure

• Direct Calorimetry measures heat loss to calculate energy expenditure
• Heat loss occurs through radiation, conduction, and evaporation
• Examples of direct calorimetry include whole body chambers or bodysuits
• Indirect Calorimetry calculates heat production from oxygen consumption and carbon dioxide production
• Methods of indirect calorimetry include whole body chambers, ventilated hoods and douglas bag

Other methods for energy expenditure

• Additional methods for measuring energy expenditure are doubly labelled water method, labelled bicarbonate method, heart rate method, movement sensors, and time-and-motion studies

Components of Energy Expenditure

• Basal metabolic rate (BMR) is the energy needed for basic life processes
• These life processes include breathing, circulation, tissue repair/renewal, and ionic pumping
• The human body uses 70% of its energy for BMR
• Affecting factors of BMR include body size/composition, lean tissue amount, physiological condition, stimulants, and clinical conditions
• Diet-induced Thermogenesis (DIT), also known as the thermic effect of food, is the energy needed to absorb, digest, transport, interconvert, and store a meal
• DIT accounts for <10% of total energy intake
• DIT for carbohydrate and protein is higher than fat reflecting greater energy needs for their processing

Physical Activities

• Physical Activity represents energy expenditure from both conscious and non-conscious movements
• Factors influencing the amount of activity includes how much the person has done
• Adequate energy intake is essential for growth during fetal, neonatal, and adolescent stages
• Fast tissue deposition occurs during illness, malnutrition, or starvation recovery
• During pregnancy, an extra 10% energy required, increasing to 25% during lactation

Effects of Fatty Acids on Health

• Adults need fats for 15% of total energy intake, while women at reproductive age need 20%
• Essential Fatty Acids (EFA) is needed at 2% as Omega-6 and 0.5% as Omega 3
• To lower saturated fat intake, consume less than 10% of energy, while limiting trans fatty acids to 1%

Fatty Acids Notes

• EFA deficiency is rare, but happens in people with fat malabsorption
• This can cause high thirst, impaired liver function, dry skin
• Increased fat intake can cause cardiovascular diseases, obesity, and growth development issues
• Reducing saturated fats with polyunsaturated may decrease coronary heart disease risk

Lipid Sources Notes

• Unsaturated fatty acids are healthier than saturated fats as they are easier to break down
• Phospholipids are abundant in animal and vegetable foods
• Lecithin is the most abundant phospholipid and acts as an emulsifier
• Sterols from animals are called cholesterols while plants sterols are phytosterols, and act as Vitamin D precursors
• Trans fatty acids have a tough structure to breakdown, which increases total and LDL cholesterol while decreasing HDL, raising chronic heart disease risks

Chylomicron Transport

• Chylomicron transport starts when lipids combine from broken down re-synthesized lipids
• Lipids leaves mucosal cells via lymphatic vessels
• Chylomicrons transport fats into blood
• They pick up Apolipoproteins C and E from HDL once in the blood
• Apolipo C activates Lipoprotein Lipase (LL), breaking TGC into glycerol and 3 fatty acids
• Cholesterol, Cholesterol Esters, phospholipid and Apolipo C/E pinch off to form HDL when TGC breaks down
• Chylomicrons degrade TAG for 70-80%, resulting remnants bind with liver cell receptors
• Synthesized Lipids are packaged into VLDL and secreted into blood
• VLDL picks up apo C and E from HDL, LL enzymes break down this VLDL where FAs transferred to tissues creating an Intermediate-Density Lipoprotein
• IDL removals cause cholesterol-rich LDL
• Cholesterol delivers to the cells and receptors
• Excess cholesterol delivers to cells when high in LDL
• Cholesterol Ester transfers proteins, redistributes cholesterol esters from HDL to VLDL, IDL and LDL

Vitamin Functions

• Vitamin C (Ascorbic Acid) is an antioxidant that readily oxidizes
• Vitamin C regenerates Vitamin E by quenching its free radicals leading to oxidation
• Vitamin C acts as a cofactor for enzymes that converts lysine and proline to hydroxylated forms and cross-linking of collagen
• Vitamin C is needed for carnitine synthesis from lysine
• Vitamin C is required for synthesis of peptide hormones, hormone releasing factors and bile acid
• Vitamin C deficiency lead to scurvy, small skin hemorrhage, larger bruises, and internal hemorrhage
• Vitamin C toxicity results in urinary oxalate stones, and improves iron absorption, this poses a risk to people with iron overload
• Vitamin B1 (Thiamin) metabolizes carbohydrates as TPP

Vitamin B1 Notes

• Vitamin B1 (Thiamin) is responsible for glucose oxidation, an alternative pathway for glycolysis by transketolase reactions in pentose pathway
• Vitamin B1 (Thiamin) is involved in catabolism of Leu, Isl, and Val
• Vitamin B1 (Thiamin) deficiency causes beri-beri characterized by loss of sensation in feet/high output cardiac failure and wernicke-korsakoff syndrome

Vitamin B3 (Niacin)

• Vitamin B3 (Niacin) acts as coenzymes for NADH and NADP
• NAD is made from hydrogen receptor for electron chains during oxidative phosphorylation in mitochondria
• NADP is made from hydrogen donor in fatty acid synthesis
• Vitamin B3 (Niacin) deficiency results in pellagra (sour skin), this results in inflamed skin exposed to sunlight resembling sunburn
• Vitamin B3 (Niacin) daily requirement is related to energy expenditure, 70 g of protein requires 12mg however, the RDI is 14 mg for women and 16 mg for men

Vitamin B9 and B12

• Vitamin B9 (Folate) RDI is 400 mcg, but an increase to 600 and 500 mcg recommended for pregnant and lactating women
• Vitamin B9 (Folate) is needed for carbon transfers from Ser, Gly, His and Trp to purine and pyrimidine synthesis, also insertion of methyl group to make thymidylic acid, and cooperates with Vit B12 to form Methionine and THF
• Vitamin B9 (Folate) deficiency causes reduced ability of cells to double nuclear DNA, megaloblastic anemia, and an inability to form thymidylate for DNA synthesis
• Vitamin B12 (Cobalamin) functions as a coenzyme for methylcobalamin and deoxyadenosylcobalamin (for RBC production) and a dependant enzyme (methylmalonyl-CoA mutase and Methionine Synthase)
• Body can store Vitamin B12 (Cobalamin) around 3-5 mg for several days

Vitamin A and D

• Vitamin A (Retinol, Retinal, Retinoic Acid and Retinyl ester) helps vision, reproduction, cellular differentiation, embryogenesis, GAGs synthesis, immune and host defense, and growth
• Vitamin A (Retinol, Retinal, Retinoic Acid and Retinyl ester) RDI is 600-900 for adults, an increase to 700-800 and 850-1300 recommended for pregnant and lactating
• Vitamin D divided into 2 forms, D3 (Cholecalciferol) and D2 (Ergosterol) used as food additives
• Vitamin D functions decrease anxiety and depression. Vitamin D is necessary to prevent rickets and osteomalacia.

Vitamin E and K

• Vitamin E (Tocopherols and Tocotrienols) acts as antioxidants for cell components and components for plasma lipoproteins, LDL in particular
• Vitamin E (Tocopherols and Tocotrienols) deficiency is rare, an exception being infants born with poor placental transfer
• Vitamin K (Menadione, Phylloquinone and Menaquinones) increases blood viscosity and bacterial synthesis (with menaquinones) for treating scars/dark spots.

Mineral Classification

• Macrominerals include Sodium, Potassium, Chlorine, Calcium, Phosphorus, Magnesium and Sulphur
• Microminerals include Iron, Zinc, Selenium, Iodine, Copper, Fluorine, Chromium, Molybdenum, Cobalt, Manganese, Arsenic, Nickel and Vanadium

Co-ingestion

• Calcium absorption is increased with consumption of Vitamin D
• Bone disorders may occur in deficiency
• Vitamin C (ascorbic acid) promotes iron absorption and folate stability
• Cobalt is the main component of Cobalamin (Vit B12)

Mineral Absorption

• Magnesium is absorbed via simple diffusion in the small intestine
• Iron: goes through solubilization by gastric acid in the proximal duodenum for absorption
• Iron needs to be in the ferrous form (Fe2+) to pass/absorb through the membrane
• Iron is stored as ferritin, released to circulation by oxidation to ferric form (Fe3+)

Other Mineral Absorption

• Calcium is absorbed in the small intestine (duodenum and jejunum)
• Iodine is absorbed in the stomach and small intestine (duodenum)
• Iron is more absorbable in the body as, and needs to be, in its ferrous form, therefore it needs to be water soluble. If iron is its ferric form, it results in hydrophobicity causing toxicity and low absorption levels

Iron Depletion

• The stages of iron depletion shows:
• Normal levels which indicates iron store is adequate
• Mild deficiency where the mobilizable iron stores in the bone marrow are depleting, but iron-dependent proteins still provide iron
• Marginal iron deficient where the production of iron dependent proteins are compromised, but still normal haemoglobin production levels
• Iron deficiency anaemia (IDA): hemoglobin and erythrocytes production are compromised and misshapen

Mineral Functions

• Calcium is needed to offset obligatory losses in urine/feces, slows osteoporotic bone loss, and reduces risk of falling
• Magnesium acts as cofactor for enzyme, energy metabolism, DNA replication, RNA and Protein synthesis
• Iron is needed to act as a component in Hemoglobin and myoglobin to carry out oxygen
• Iron acts as a cofactor for enzymes (catalase, hydroxylase and flavin)
• Iodine is contained in the integral part of thyroid hormones, thyroid and brain with peripheral tissues

Food Dietary Guidelines

• Food based dietary guidelines are for promoting health and chronic disease prevention
• Nutrient Intake Recommendations (NIR) are to ensure minimum intake of essential nutrients
• Food Based Dietary Guidelines (FBDG) focuses on balanced macronutrients, while NIR focuses more on required nutrients
• Food Based Dietary Guidelines (FBDG) and Nutrient Intake Recommendations (NIR) include factors like as age, life stages, gender, lactation and pregnancy

Reference Values

• Estimated Average Requirement (EAR): average amount of nutrient needed by 50% of the population to be healthy
• Recommended Intake (RI): amount of intake for 98% population to stay healthy, guarantees healthy
• Upper Limit (UL): maximum limit that prevents disease from forming
• Adequate Intake (AI): minimum requirement, also has low probability of inadequacy

Indonesia Dietary

• Indonesia's food dietary FBDG now uses “isi piringku” system that emphasizes more variety
• This includes having have of the plate filled with fruits and vegetables, and specifically vitamin A C and E, iron, potassium, carotenoids and folate
• Including carbohydrates and proteins in other half (Makanan pokok; Lauk Pauk)

Nutrient Purposes

• EAR is meant to show intake is adequate by monitoring what is okay, population effects by intake amounts
• Population Recommendation (RDA, RDI, RNI) is to show that adequate amounts results in lower risk of not getting adequate amounts
• Adequate Intake (AI) is the same for individuals and groups: shows intake results in the average amount
• Upper Level (UL) measures if intake cause and pose any individual risk, as monitoring for effects on the population

Dietary Index

• Examples of diet's quality Indices and is divided into three parts
• Food and/or nutrient-based indices includes:
• Healthy Eating Index (HEI) assesses a person’s dietary intake based on 10 components This:
• Monitors dietary quality
• Evaluates interventions and research
• Can be calculated from multiple records
• Has parts divided into 2: 5 food groups and 5 nutrients
• Rates diets of high and low meeting standards, therefore scoring a diet's success
• Provides graphical representation to illustrate a radar graph and scoring system