Nutrition & Energy Balance Notes

Nutrition & Energy Balance Dr Louise Dunford PPD Theme Lead [email protected] Thank you to Dr Nick Hopcroft for some of the content in this presentati...

Nutrition & Energy Balance Dr Louise Dunford PPD Theme Lead [email protected] Thank you to Dr Nick Hopcroft for some of the content in this presentation. All images are copyright free unless otherwise indicated.  Introduction Talking about nutrition, diet and weight management can be a very sensitive issue for some people. As a doctor you will need to handle any such discussions with patients in a compassionate and caring manner. Further information about body mass index and how to categorise overweight and obese is within the online workbook rather than this session, so you can do that at your own pace In this lecture we will be focusing mainly on the biological basis of nutrition  Learning Outcomes 1. List the macronutrients and explain their function in health 2. Identify common micronutrients and explain their function in health 3. Calculate energy content from basic nutritional information 4. Describe healthy eating in terms of the major food groups and their contribution to intake of key dietary components  Nutritio n Nutrition is the intake of food, considered in relation to the body’s dietary needs Good nutrition – an adequate, well-balanced diet – combined with regular physical activity is a cornerstone of good health Malnutrition is when a person's diet does not provide enough nutrients or the right balance of nutrients for good health Can be too much, as well as too little!  Essential nutrients Carbohydrat Protein Fats e Water Vitamins Minerals  Essential nutrients Carbohydrat Protein Fats e MACRONUTRIENTS (needed in large quantities) Water Vitamins Minerals MICRONUTRIENTS (needed in small quantities)  Macronutrient s Macronutrient Energy content % energy intake Carbohydrates 4 kcal/g 50-75% Lipids (fats) 9 kcal/g 15-30% Proteins 4 kcal/g 10-20% Alcohol: 7 kcal/g The energy content above is a chemical value, rather than the net energy gained biologically – energy is used during digestion and absorption of ingested nutrients The thermic effect of food is the energy used obtaining energy from  Macronutrient s Macronutrient Main roles Carbohydrates Energy source, control of glucose and insulin metabolism, cholesterol and triglyceride metabolism Lipids (fats) Storing energy, regulation and cell signalling, insulating and protecting, aiding digestion Proteins Growth & maintenance of cells and tissues, gene expression, hormones, antibodies, digestion, muscle contraction and movement  Definition of a vitamin “Any of a group of organic compounds which are essential for normal growth and nutrition and are required in small quantities in the diet because they cannot be synthesised by the body.” Small quantities = mg or µg per day Deprivation leads to development of a clinical deficiency disease and abnormal metabolic signs AND Restoration leads to a cure or prevents that disease, and normalises metabolism  Classificati on Water soluble Fat soluble Vitamin Chemical name Vitamin name Chemical name(s) name A Beta-carotene, retinols, B1 Thiamin retinals B2 Riboflavin D Cholecalciferol, ergocalciferol B3 Niacin E Tocopherols, B5 Pantothenic acid tocotrienols B6 Pyridoxine K Phylloquinone, B7 Biotin menadiones, menaquinones B9 Folate B12 Cobalamin C Ascorbic acid  Daily Recommended Intakes Can vary for different age groups and male/female Some variation between countries – use UK recommendations Small quantities – mg or µg per day Recommendations for the general https://assets.publishing.servic population e.gov.uk/government/uploads/s ystem/uploads/attachment_dat a/file/618167/government_diet Ideally through dietary sources, but ary_recommendations.pdf certain groups of people may need  Vitamins Vitamin Source Function A Fish oil, green veg Eyesight, growth, immunity B1 (thiamine), B2 Peas, grain, dairy, meat, Carbohydrate, fatty acid and (riboflavin), B5, B6, fish, liver, egg, green veg protein metabolism, nucleic acid B7 (biotin), B9 synthesis (folate), B12 C Peppers, spinach, citrus Collagen synthesis, cartilage fruits and bones D Sunlight, eggs, butter Calcium and phosphate metabolism E Vegetable oil Antioxidant K Vegetables, fruit Clotting Medical Sciences, Naish & Syndercombe Court – Chapter 16, Vitamins https://www.clinicalkey.com/student/content/book/3-s2.0-B978070207337300 016X#hl0002581  Vitamin B9: Folate Folic acid is the manufactured form; converts into folate Transfer of one-carbon fragments in many biosynthetic and catabolic reactions Metabolically closely related to B12 Essential to make DNA and RNA Particularly important at times of increased cell division, e.g. pregnancy & developing foetus  Folate & Pregnancy Normal recommended daily intake is 200 µg/day in men and women aged 19 – 64 400 µg/day is recommended for women prior to pregnancy and for the first 12 weeks Why? To reduce the risk of neural tube defects, e.g. spina bifida Many countries have mandatory fortification of flour with folic acid; in  Vitamin C Deficiency = scurvy Humans are one of a few animals who can’t synthesis vitamin C, due to a lack of a working L-gulonolactone oxidase (GULO) enzyme, so must be provided in the diet Risk factors – alcoholism, serious mental illness, kidney dialysis Used to be common in sailors on long sea voyages (due to lack of access to fresh fruit and veg). Rare in UK now, but not unknown and seems to be increasing. 67 cases in England in 2007/8 vs. 171 in 2021/22  Vitamin D A group of fat soluble compounds. Most important in humans are D3 (cholecalciferol) and D2 (ergocalciferol) Vitamin D is only found in a few foods Some foods are fortified with vitamin D; mandatory in some countries Main source is via sunlight (so not technically a vitamin!) Exposure to UVB radiation leads to a chemical  Vitamin D Deficiency Very high levels of deficiency worldwide In children, deficiency causes rickets, which leads to soft weak bones that deform and bend, “bow legs” In adults it leads to osteomalacia Rickets is most common in low and middle income countries, but does occur in the UK Around 400 – 500 cases of rickets in the UK per year since 2007/8  Vitamin D Deficiency Also found in higher income countries in certain risk groups: Older people (skin does not synthesise cholecalciferol as well) People who are not exposed to the sun People who are fully covered with clothing Breastfed infants People with fat malabsorption issues  Minerals Mineral Source Function Iron Red meat, fortified cereals, Component of haemoglobin for leafy green veg O2 transport Calcium Milk, tinned sardines with Bones and teeth, nerve and bones muscle function Zinc Meat, seafood, wholegrains Enzymes, immunity Magnesium Meat, dairy, green veg, nuts Metabolism, nerve and muscle function Potassium Fruit, vegetables Fluid balance, nerve and muscle function Medical Sciences, Naish & Syndercombe Court – Chapter 16, Minerals https://www.clinicalkey.com/student/content/book/3-s2.0-B978070207337300 016X#hl0002682  Iron Deficiency Common issue globally, including developed countries Leads to iron deficiency anaemia Common causes: Heavy menstrual bleeding Bleeding from the GI tract Inadequate diet Malabsorption issues  Hypocalcaemia Common issue globally, including developed countries Many causes, e.g. Hypoparathyroidism Vitamin D deficiency Chronic liver disease Chronic kidney disease Acute kidney injury And many more… Can be treated by addressing underlying issue (if possible), e.g. vitamin D supplementation, or giving Nutritional Information 1. If someone eats one pie, how much energy (kcal) is obtained from fat, assuming 9 kcal/g fat? 2. What percentage of the energy content of the pie comes from fat? 3. What percentage of their daily energy requirement (guideline daily amount) has come from fat in this pie? Nutritional Information 1. If someone eats one pie, how much energy (kcal) is obtained from fat, assuming 9 kcal/g fat? 9.4 g x 9.0 kcal/g = 84.6 kcal 2. What percentage of the energy content of the pie comes from fat? 84.6 ÷ 218 x 100 = 39% What percentage of their daily energy requirement (guideline daily amount) has come from fat in this pie? 84.6 ÷ 2000 x 100 = 4.23% (women) 84.6 ÷ 2500 x 100 = 3.38% (men)  Energy Balance Calories in > calories out = weight gain Calories in = calories out = stable weight Energy Expenditure Basal metabolism The energy required to keep your body functioning at rest – energy used for activities such as maintaining body temperature and supporting vital systems  Basal Metabolic Rate BMR formula There are 2 formulae used to calculate BMR, in [kcal / 24hrs] for men and women: BMR Men = 66.47 + (13.75 * weight [kg]) + (5.003 * height [cm]) − (6.755 * age [years]) BMR Women = 655.1 + (9.563 * weight [kg]) + (1.85 * height [cm]) − (4.676 Q: What* is age [years]) the BMR for a woman aged 50, who is 1.70 metres tall and weighs 60kg? BMR Calculator - Metabolism Calculator (Basal Metabolic Rate) (diabetes.co.uk)  Knowledge check Quiz to check knowledge at the end of the session Vevox – Dashboard  Learning Outcomes 1. List the macronutrients and explain their function in health 2. Identify common micronutrients and explain their function in health 3. Calculate energy content from basic nutritional information 4. Describe healthy eating in terms of the major food groups and their contribution to intake of key dietary components  Resources Eatwell guide Basal Metabolic Rate Calculator Medical Sciences, Naish & Syndercombe Court – Chapter 16, Vitamins https://www.clinicalkey.com/student/content/book/3-s2.0-B978070207337 300016X#hl0002581 Medical Sciences, Naish & Syndercombe Court – Chapter 16, Minerals https://www.clinicalkey.com/student/content/book/3-s2.0-B 978070207337300016X#hl0002682 UK Government daily dietary recommendations