Food Science: Nutrition and Digestion

Fundamentals of Science - Level 6 Certificate in Food Science and Technology

• Session focuses on nutrition

Learning Objectives

• Able to describe the digestion process of food
• Understanding of the roles of macro and micronutrients
• Understanding of the classification and function of vitamins

Nutrition

• Digestion starts in the mouth by chewing and swallowing
• Mechanical forces in the stomach further digestion of food.
• Enzymes in the stomach start breaking down proteins, fats, and carbohydrates
• Hydrochloric acid released from stomach cells activates the enzymes
• The small intestine has a large surface area due to villi
• Villi are the site of absorption for nutrients, water, and drugs
• Nutrients absorbed in the small intestine go to the liver for processing
• In the large intestine water is absorbed resulting in solid stool being expelled
• Commensal bacteria in the large intestine produce Vitamin K through symbiosis

Food Digestion

• Complex carbohydrates (starch) are broken down into smaller sugars by amylase in saliva.
• Amylase deactivates in the stomach due to stomach acid
• More amylase is released by the pancreas in the small intestine to help turn carbohydrates into glucose which goes into the blood stream
• Proteins are broken down into smaller chains of amino acids by stomach acid and pepsin
• Trypsin and chymotrypsin released by the pancreas in the small intestine, help break down chains of amino acids into individual amino acids.
• These amino acids go into your blood stream and help to build and to repair tissues.
• Fats mainly digested in the small intestine
• Bile, which is produced by the liver, helps with emulsification
• Lipase from the pancreas breaks down fats into glycerol and fatty acids
• The fats are absorbed through the intestine, and moved into the blood or lymphatic system for future use.

Introduction to Nutrients

• Two types of nutrients exist
• Macronutrients are required in large quantities and examples include protein, fats and carbohydrates
• Micronutrients are only needed in small quantities such as vitamins and minerals
• Foods contain a mix of some or all of the nutrient types
• Some nutrients like fat-soluble vitamins can be stored
• Others need to be constantly replenished as the body requires.
• Poor health occurs when there is not enough nutrients, or too much

Macronutrients

• Proteins, fats, and carbohydrates provide structural material and energy
• Energy measured in joules or calories
• Carbohydrates and proteins provide approximately 17 kJ (4 kcal) of energy per gram
• Fats give 37 kJ (9 kcal) per gram
• Proteins, fats, and carbohydrates absorbed through the GIT
• Vitamins, minerals, fibre, and water do not provide energy

Macronutrients Review

• Proteins composed of carbon, hydrogen, oxygen and nitrogen atoms
• Carbohydrates range from simple monosaccharides (e.g. glucose, fructose, galactose) to complex polysaccharides (starch, cellulose)
• Fats are variety of fatty acids bound to a glycerol backbone

Water

• Water is excreted via urine, faeces, sweat and vapor (breath)
• It's very important to replace lost fluids via rehydration
• For good health it is recommended to drink 6-8 glasses of water a day
• Monitoring water consumption through food and beverages is difficult Approximately 80% of water intake comes from the beverages while 20% is from food

Micronutrients - Minerals

• Dietary minerals are inorganic elements excluding carbon, hydrogen, oxygen and nitrogen.
• Minerals are required for all living organisms
• Necessary for building bones and teeth
• They control body fluids inside and outside cells.
• Minerals help turning the food you eat into energy
• Minerals can come food sources or dietary supplements
• They can occur naturally or as complex compounds

Macrominerals

• This class of minerals is usually called "bulk minerals"
• Calcium is a common electrolyte
• Calcium is needed for the muscle and digestive system, bone strength
• Calcium is used to neutralize acidity, may help clear toxins, and involved in cell signaling for nerve and cells
• Chloride is very common
• Magensium required for processing energy as ATP and related reactions and for Synthesis of bone
• Phospherous (P) is required for bone synthesis for energy processing

Trace Minerals

• Trace minerals are used as catalysts for enzymes
• Some trace mineral elements Recommended Daily Allowance is less than 200mg/day
• Chromium (Cr) is needed for sugar metabolism
• Iodine (I) needed for biosynthesis of hormone thyroxine
• Iron (Fe) required for enzymes and the synthesis of haemoglobin and other proteins
• Manganese (Mn) is needed for processing of oxygen

Vitamins

• There are 13 universally recognized vitamins
• Vitamins categorized according to biological, chemical activity rather than structure
• Two types of vitamins include:
• Fat-soluble
• Water-soluble

Fat Soluble Vitamins - (A, D, E and K)

• Found in vegetable oils, milk and dairy foods, eggs, liver, oily fish and butter
• The body stores them in, in the liver and fatty tissues, for future use
• The Vitamin stored can build up and be harmful, like liver damage

Water Soluble Vitamins- (B Group and C)

• These vitamins are not stored in the body and should be taken more frequently
• Any excess vitamins are removed by the body through urination
• Over consumption is not harmful, be mindful of consumption levels

Vitamins: Water Soluble

• Vitamin C supports the formation of blood vessels, cartilage, muscle and collagen and is important for healing
• For adults 40mg of Vitamin C a day is needed
• Can be sourced via brightly coloured fruit and vegetables like oranges, kiwis, peppers, broccoli
• Supports the absorption of iron
• If amounts are greater than 1,000mg per day of vitamin C can cause Reversible Stomach pain (diarrhoea, and flatulence).
• A list of Vitamin B's can be seen

Vitamins: Water Soluble (B Group)

• Types of B Vitamins include:: -Thiamine (B1) -Riboflavin (B2) -Niacin (B3) -Pantothenic acid -Vit. B6 -Biotin (B7) -Folic Acid -Vit. B12 These Vitamins have differing Roles, source and requirements

Vitamins: Thiamine

• Thiamine Helps to turn food into energy and keep the nervous system healthy
• Source: Nut, eggs, pork, sunflower seeds, fortified cereal, peas
• Daily requirement: 1mg a day (men) and 0.8mg a day (women)

Vitamin: Riboflavin

• Needed to metabolize carbohydrates, fats, and proteins into glucose for energy
• Helpful as Antioxidant for proper function of immune system
• Source: Mushrooms, almonds, beef, spinach, salmon and avocados.
• 1.3mg a day (men) and 1.1mg a day (women)

Vitamin: Folic Acid

• Works together with B12 to form healthy red blood cells Source: Broccoli, Brussel sprouts, leafy green veg, chickpeas and fortified cereals Adults need 0.2mg of folic acid a day 400 microg each day for supplementing during pregnancy Reduces the risk of central nervous system defects (spina bifida in unborn babies)

Vitamins: Fat Soluble - Vitamin E

• Supports the immune system
• Supports the production of red blood cells
• Helps reduce risk of blood clots
• 15 milligrams a day is needed and is commonly found in plant oils, nuts, and seed germ.
• It can help the body use Vitamin K

Vitamins: Fat Soluble - Vitamin K

• Supports blood clotting
• Needed for calcium circulation
• 1 microgram a day per kg weight is needed and is sourced via leafy green vegetables/ oils.

Vitamins: Fat Soluble - Vitamin A

• Supports normal vision, the immune system, and growth and development
• Obtained commonly via liver, fish, eggs and dairy
• 0.7mg a day (men) and 0.6mg a day (women) is needed

Vitamins: Fat Soluble - Vitamin D

• Is required to keep oily fish (salmon, sardines and mackerel), eggs, fortified fat spreads/ breakfast cereals/ powdered milks.
• Supplements over a long period can cause more calcium to be absorbed than excreted.
• Needed for bones and teeth

Healthy Diet

• The food pyramid is an important way to determine what is nutritious or not.
• This helps show how many of each food groups needs to be consumed

Healthy Diet Options

• Common diets include Vegan/ Vegetarian
• Other current popular diets are Ketogenic and Carnivore
• Gluten Free/ Lactose Free diets have become common place
• Diets which are high in protein are also popular

Summary

• A varied diet is required for all living creatures.
• Supplements rarely required.
• Inclusion of:
• water -fruit/veg