UNIT 2: NUTRIENT BIOCHEMISTRY

Expanded Learning Outcomes and Study Resources

By the end of this unit, students should be able to:

1. Identify macronutrients and micronutrients and explain their biochemical roles.

2. Explain how nutrients are digested, absorbed, transported, stored, and metabolized.

3. Describe how the body regulates nutrient levels.

4. Recognize the effects of nutrient deficiency and nutrient toxicity.

5. Apply knowledge of nutrient biochemistry to health, disease, nutrition, and naturopathic practice.

6. Explain the relationship between nutrition, energy production, growth, repair, and body regulation.

7. Interpret simple food labels and identify important nutrients in common foods.

8. Develop basic nutrition-support plans using locally available foods.

9. Explain why a balanced diet is generally safer than excessive reliance on supplements.

10. Recognize situations where professional nutrition or medical advice is required.

1. Understanding Nutrients

Nutrients are substances found in food that the body needs to function properly.

They help the body to:

• Produce energy.

• Build and repair tissues.

• Support growth and development.

• Maintain healthy bones and muscles.

• Support the immune system.

• Regulate body temperature.

• Produce hormones and enzymes.

• Maintain healthy blood.

• Protect cells from damage.

Nutrients are divided into two main groups:

1.1 Macronutrients

Macronutrients are nutrients required in relatively large amounts.

The three main macronutrients are:

• Carbohydrates

• Proteins

• Fats

Water is also required in large amounts and is essential for life.

Carbohydrates

Carbohydrates are an important source of energy.

Examples include:

• Rice

• Maize

• Yam

• Cassava

• Plantain

• Bread

• Potatoes

• Fruits

The body breaks many carbohydrates down into glucose. Glucose can be used by cells to produce energy.

Proteins

Proteins are needed for:

• Growth.

• Muscle development.

• Tissue repair.

• Enzyme production.

• Hormone production.

• Immune function.

Examples include:

• Beans

• Fish

• Eggs

• Meat

• Milk

• Groundnuts

• Soybeans

• Lentils

Proteins are made up of smaller units called amino acids.

Fats

Fats are needed for:

• Energy storage.

• Cell membrane formation.

• Hormone production.

• Absorption of vitamins A, D, E, and K.

• Insulation and protection of organs.

Examples include:

• Avocado

• Groundnuts

• Vegetable oils

• Seeds

• Fatty fish

• Coconut

• Shea butter

Fats should not be completely avoided because the body needs certain fats for normal functioning.

2. Micronutrients

Micronutrients are needed in smaller amounts but are still essential for health.

They include:

• Vitamins

• Minerals

Micronutrients do not usually provide energy directly. Instead, they help the body use macronutrients and regulate important processes.

2.1 Vitamins

Vitamins are organic substances required for normal body functions.

They are divided into two groups.

Fat-Soluble Vitamins

These include:

• Vitamin A

• Vitamin D

• Vitamin E

• Vitamin K

They can be stored in body fat and the liver.

Because they can accumulate, excessive supplementation may cause toxicity.

Water-Soluble Vitamins

These include:

• Vitamin B-complex

• Vitamin C

Most water-soluble vitamins are not stored in large amounts. They generally need to be consumed regularly.

Vitamin B12 is an important exception because the body can store it for a considerable period.

2.2 Minerals

Minerals are inorganic elements needed for body functions.

Examples include:

• Calcium

• Iron

• Magnesium

• Potassium

• Zinc

• Iodine

• Sodium

• Phosphorus

Minerals support:

• Bone formation.

• Blood production.

• Nerve function.

• Muscle contraction.

• Fluid balance.

• Immune function.

• Thyroid activity.

3. Biochemical Roles of Nutrients

Biochemistry is the study of the chemical processes that occur in living organisms.

Nutrients participate in many biochemical processes.

3.1 Nutrients as Sources of Energy

Carbohydrates, fats, and proteins can provide energy.

The body converts nutrients into usable energy through chemical reactions.

A major energy-carrying molecule is called ATP, which means adenosine triphosphate.

ATP supplies energy for activities such as:

• Muscle contraction.

• Nerve transmission.

• Movement.

• Active transport across cell membranes.

• Building new molecules.

• Tissue repair.

Practical Example

When a person walks, muscle cells require ATP to contract.

The body produces ATP using nutrients obtained from food.

3.2 Nutrients as Building Materials

Some nutrients provide materials for constructing and repairing the body.

Examples include:

• Amino acids from proteins help repair muscles.

• Calcium and phosphorus support bones and teeth.

• Fatty acids help form cell membranes.

• Iron is needed to produce hemoglobin.

• Zinc supports growth and wound healing.

Practical Example

A person recovering from an injury may require adequate protein, vitamins, minerals, and energy to support tissue repair.

3.3 Nutrients as Regulators

Some nutrients help control body processes.

Examples include:

• Iodine supports thyroid hormone production.

• Calcium helps regulate muscle contraction and nerve activity.

• Vitamin K supports normal blood clotting.

• Magnesium participates in many enzyme reactions.

• B vitamins help enzymes release energy from food.

4. Digestion, Absorption, and Metabolism

Students should understand that eating food is only the beginning of nutrition.

The body must process nutrients before cells can use them.

The main stages are:

1. Digestion

2. Absorption

3. Transport

4. Storage

5. Metabolism

6. Elimination

4.1 Digestion

Digestion is the process of breaking food into smaller substances that the body can absorb.

Examples:

• Carbohydrates are broken down into simple sugars.

• Proteins are broken down into amino acids.

• Fats are broken down into fatty acids and other smaller substances.

Practical Example

When a person eats beans, the digestive system breaks down the proteins and carbohydrates so that the body can use them.

4.2 Absorption

Absorption is the movement of digested nutrients from the digestive tract into the blood or lymph.

Most nutrient absorption occurs in the small intestine.

Practical Example

After eating an orange, vitamin C and other nutrients are absorbed through the digestive system and transported to body tissues.

4.3 Transport

After absorption, nutrients are transported to different parts of the body.

The blood carries many nutrients to:

• Muscles.

• The brain.

• The liver.

• The kidneys.

• Bones.

• Other tissues.

Some fats are transported through the lymphatic system before entering the bloodstream.

4.4 Storage

The body stores some nutrients for later use.

Examples include:

• Glycogen stored in the liver and muscles.

• Fat stored in adipose tissue.

• Iron stored in certain body proteins.

• Vitamin A stored in the liver.

• Vitamin B12 stored in the liver.

Practical Example

If a person eats more carbohydrate than the body immediately needs, some of it can be stored as glycogen.

4.5 Metabolism

Metabolism refers to all the chemical reactions that occur in the body.

It includes two major processes.

Catabolism

Catabolism is the breakdown of substances to release energy or produce smaller molecules.

Example:

• Breaking down glucose to produce ATP.

Anabolism

Anabolism is the building of larger molecules from smaller ones.

Examples include:

• Building muscle proteins from amino acids.

• Building glycogen from glucose.

• Producing new cell components.

Easy Way to Remember

Catabolism = breaking down

Anabolism = building up

5. Regulation of Nutrients

The body attempts to keep internal conditions stable. This is called homeostasis.

Nutrient regulation involves hormones, organs, enzymes, and feedback systems.

5.1 Blood Glucose Regulation

Glucose is an important source of energy.

Two important hormones are:

• Insulin

• Glucagon

Insulin

Insulin helps lower blood glucose by helping cells take up glucose and by encouraging storage of glucose.

Glucagon

Glucagon helps raise blood glucose when it becomes too low by encouraging the release of stored glucose.

Practical Example

After eating a meal containing rice or yam, blood glucose may rise. The body responds by releasing insulin.

Between meals, glucagon helps maintain blood glucose.

5.2 Calcium Regulation

Calcium is important for:

• Bones and teeth.

• Muscle contraction.

• Nerve transmission.

• Blood clotting.

Calcium levels are regulated by hormones such as:

• Parathyroid hormone.

• Vitamin D-related processes.

• Calcitonin.

Practical Example

If blood calcium becomes too low, the body can adjust calcium absorption, storage, and release to help restore balance.

5.3 Iron Regulation

Iron is needed to produce hemoglobin, which carries oxygen in the blood.

Iron balance is influenced by:

• Dietary intake.

• Absorption in the intestine.

• Storage.

• Blood loss.

• Body requirements.

Practical Example

A person who loses blood regularly may require more attention to iron intake and may need professional assessment for anemia.

6. Nutrient Deficiency

Nutrient deficiency occurs when the body does not receive or absorb enough of a required nutrient.

Deficiency may result from:

• Poor diet.

• Limited food variety.

• Malabsorption.

• Chronic illness.

• Increased body requirements.

• Excessive nutrient loss.

• Certain medications.

• Food insecurity.

Examples of Deficiency

Iron Deficiency

Possible effects include:

• Fatigue.

• Pale skin.

• Weakness.

• Shortness of breath.

• Reduced concentration.

Vitamin A Deficiency

Possible effects include:

• Poor night vision.

• Dry eyes.

• Increased risk of infection.

Vitamin C Deficiency

Possible effects include:

• Bleeding gums.

• Poor wound healing.

• Fatigue.

• Scurvy in severe cases.

Vitamin D Deficiency

Possible effects include:

• Weak bones.

• Rickets in children.

• Osteomalacia in adults.

Iodine Deficiency

Possible effects include:

• Goiter.

• Reduced thyroid function.

• Problems with growth and development.

Practical Activity

Students should identify a nutrient deficiency and prepare a short presentation explaining:

1. The nutrient involved.

2. Its normal function.

3. Possible causes of deficiency.

4. Signs and symptoms.

5. Food sources.

6. When professional assessment is needed.

7. Nutrient Toxicity

Nutrient toxicity occurs when excessive amounts of a nutrient cause harm.

Toxicity may result from:

• Excessive supplementation.

• Incorrect dosage.

• Accidental ingestion.

• Certain medical conditions.

• Reduced ability to eliminate nutrients.

• Interactions with medicines.

Examples of Toxicity

Vitamin A Toxicity

Excessive vitamin A may cause:

• Headaches.

• Nausea.

• Liver damage.

• Harm to a developing fetus during pregnancy.

Vitamin D Toxicity

Excessive vitamin D may increase blood calcium levels and contribute to:

• Nausea.

• Kidney stones.

• Kidney problems.

• Abnormal heart rhythms in serious cases.

Iron Toxicity

Excess iron may cause:

• Nausea.

• Constipation.

• Organ damage.

• Serious poisoning in some situations.

Practical Example

A person may believe that taking several vitamin supplements is always beneficial. However, combining products may lead to excessive intake of certain nutrients.

8. Applying Nutrient Biochemistry to Health and Disease

Knowledge of nutrient biochemistry helps students understand how nutrition relates to health conditions.

8.1 Anemia

Anemia may occur when the body does not have enough healthy red blood cells or hemoglobin.

Nutrients involved may include:

• Iron.

• Folate.

• Vitamin B12.

Possible symptoms include:

• Tiredness.

• Weakness.

• Dizziness.

• Pale skin.

• Shortness of breath.

A person with suspected anemia should receive appropriate assessment rather than relying only on herbal or dietary treatment.

8.2 Diabetes

Diabetes involves problems with blood glucose regulation.

Nutritional considerations may include:

• Carbohydrate quality.

• Portion sizes.

• Dietary fibre.

• Physical activity.

• Weight management.

• Medication adherence.

Practical Example

Students can compare two meals and discuss which contains more fibre and which may cause a faster rise in blood glucose.

8.3 Osteoporosis

Osteoporosis involves weakened bones.

Nutrients relevant to bone health include:

• Calcium.

• Vitamin D.

• Magnesium.

• Protein.

• Phosphorus.

Nutrition is important, but osteoporosis may require medical evaluation and treatment.

8.4 Poor Wound Healing

Poor wound healing may be associated with:

• Inadequate protein.

• Vitamin C deficiency.

• Zinc deficiency.

• Poor blood circulation.

• Diabetes.

• Infection.

Practical Example

Students can develop a food plan containing protein-rich foods, fruits, vegetables, and adequate fluids to support general nutritional needs during recovery.

8.5 Poor Immune Function

The immune system requires adequate nutrients.

Nutrients involved include:

• Protein.

• Vitamin A.

• Vitamin C.

• Vitamin D.

• Zinc.

• Iron.

• Selenium.

A balanced diet supports normal immune function, although no single food or supplement can guarantee protection from infection.

9. Local Food Examples

Students should learn to identify nutrients in commonly available foods.

Examples include:

Kontomire

May provide:

• Vitamin A-related compounds.

• Vitamin C.

• Folate.

• Iron.

• Calcium.

• Magnesium.

Mango

May provide:

• Vitamin A-related compounds.

• Vitamin C.

• Potassium.

Beans

May provide:

• Protein.

• Folate.

• Iron.

• Magnesium.

• Potassium.

• Fibre.

Tilapia

May provide:

• Protein.

• Vitamin B12.

• Selenium.

• Other minerals.

Groundnuts

May provide:

• Protein.

• Healthy fats.

• Vitamin E.

• Magnesium.

• Zinc.

Small Fish Eaten with Bones

May provide:

• Calcium.

• Protein.

• Other minerals.

Practical Activity

Students should select five local foods and identify:

• Macronutrients present.

• Micronutrients present.

• Possible health benefits.

• A simple meal in which each food can be used.

10. Practical Classroom Activities

Activity 1: Nutrient Identification

Students examine food packages or pictures of foods.

They identify:

• Carbohydrates.

• Proteins.

• Fats.

• Vitamins.

• Minerals.

• Fibre.

• Water.

Activity 2: Meal Analysis

Students record one day's meals and identify:

• Sources of carbohydrates.

• Sources of protein.

• Sources of healthy fats.

• Fruits and vegetables.

• Possible missing nutrients.

• Possible improvements.

The activity should focus on learning rather than judging a person's eating habits.

Activity 3: Food Label Reading

Students examine a food label and identify:

• Serving size.

• Energy.

• Protein.

• Fat.

• Carbohydrates.

• Sugar.

• Sodium.

• Vitamins and minerals.

They then discuss how serving size affects interpretation.

Activity 4: Deficiency Case Study

Scenario

A student feels tired, has poor concentration, and often skips meals.

Students discuss:

1. Which nutrients might be lacking?

2. What other causes should be considered?

3. Which foods may help improve dietary quality?

4. Why might professional assessment be necessary?

Activity 5: Toxicity Case Study

Scenario

A person takes several supplements containing vitamin A, vitamin D, and iron without professional advice.

Students discuss:

• Why excessive intake may be dangerous.

• Why product labels should be checked.

• Why supplements should not be combined carelessly.

• Why professional advice may be needed.

Activity 6: Nutrient Metabolism Demonstration

Students use a simple flow diagram to show:

Food → Digestion → Absorption → Blood/Lymph → Cells → Energy, Growth, Repair, and Regulation

They explain each stage in their own words.

11. Suggested Learning Resources

Students should use reliable educational resources to deepen their understanding.

11.1 World Health Organization

The World Health Organization provides information on:

• Healthy diets.

• Micronutrient deficiencies.

• Vitamin and mineral requirements.

• Malnutrition.

• Public health nutrition.