Human Nutrition » Vitamins and Minerals

What you'll learn this session

Study time: 30 minutes

The essential vitamins and minerals needed by the human body
The functions of key vitamins and their dietary sources
The importance of minerals in maintaining bodily functions
Deficiency diseases linked to vitamin and mineral shortages
How to maintain a balanced diet with adequate micronutrients

Introduction to Vitamins and Minerals

Vitamins and minerals are micronutrients - substances we need in tiny amounts but that play massive roles in keeping our bodies working properly. Unlike carbohydrates, proteins and fats, they don't provide energy directly, but they're essential for nearly all our body processes.

Key Definitions:

Vitamins: Organic compounds required in small amounts that the body cannot produce (or produces insufficiently) and must be obtained from food.
Minerals: Inorganic elements needed by the body for various functions, including building strong bones, transmitting nerve impulses and maintaining fluid balance.
Micronutrients: Nutrients needed in small amounts, including vitamins and minerals.

💧 Water-soluble Vitamins

These vitamins dissolve in water and aren't stored in the body for long periods. They include vitamin C and the B vitamins. Because they're not stored, you need a regular supply in your diet.

🧈 Fat-soluble Vitamins

These vitamins dissolve in fat and can be stored in the body's fatty tissues and liver. They include vitamins A, D, E and K. Because they're stored, you don't need them in your diet every day.

Essential Vitamins

Let's explore some of the most important vitamins, their functions and what happens if we don't get enough of them.

Vitamin A

Vitamin A is crucial for vision, immune function and cell growth. It helps maintain healthy skin and mucous membranes that defend against infections.

Sources: Liver, dairy products, fish, orange-coloured fruits and vegetables (carrots, sweet potatoes, mangoes)
Deficiency disease: Night blindness, increased susceptibility to infections

Vitamin C (Ascorbic Acid)

Vitamin C is essential for the growth and repair of tissues. It helps the body make collagen, an important protein used to make skin, cartilage, tendons and blood vessels.

Sources: Citrus fruits, strawberries, kiwi fruit, broccoli, peppers
Deficiency disease: Scurvy (bleeding gums, bruising, poor wound healing)

Vitamin D

Vitamin D helps the body absorb calcium, making it essential for bone health. It's unique because our skin can produce it when exposed to sunlight.

Sources: Sunlight exposure, oily fish, egg yolks, fortified foods
Deficiency disease: Rickets in children (soft, weak bones), osteomalacia in adults

🍞 Vitamin B1 (Thiamine)

Helps convert food into energy. Found in whole grains, meat and legumes. Deficiency causes beriberi (nerve damage, muscle weakness).

🥛 Vitamin B2 (Riboflavin)

Important for growth and red blood cell production. Found in milk, eggs and green vegetables. Deficiency causes sore throat and mouth ulcers.

🥩 Vitamin B12

Essential for nerve function and DNA production. Found in animal products. Deficiency causes pernicious anaemia and nerve damage.

Case Study Focus: Scurvy and Sailors

In the 18th century, scurvy killed more British sailors than enemy action! Scottish physician James Lind discovered that citrus fruits could prevent and cure scurvy. His findings led to British sailors being given lime juice on long voyages, earning them the nickname "limeys". This was one of the first examples of a controlled clinical trial and demonstrated the essential nature of what we now know as vitamin C.

Essential Minerals

Minerals are inorganic elements that come from the soil and water and are absorbed by plants or eaten by animals. Our bodies need various minerals to function properly.

Calcium

Calcium is the most abundant mineral in the body and is vital for building and maintaining strong bones and teeth. It also plays roles in muscle contraction, nerve signalling and blood clotting.

Sources: Dairy products, green leafy vegetables, fortified plant milks, small fish eaten with bones
Deficiency effects: Osteoporosis (brittle bones), muscle cramps, poor blood clotting

Iron

Iron is essential for making haemoglobin, the protein in red blood cells that carries oxygen around the body. It's also important for energy production and immune function.

Sources: Red meat, liver, beans, nuts, dried fruits, fortified cereals
Deficiency disease: Iron-deficiency anaemia (fatigue, weakness, pale skin)

🧂 Sodium

Sodium helps maintain fluid balance and is needed for nerve and muscle function. Found in table salt and processed foods. Too much can lead to high blood pressure, while too little can cause hyponatraemia (low blood sodium).

🍌 Potassium

Potassium is essential for heart function, muscle contractions and maintaining fluid balance. Found in bananas, potatoes and leafy greens. Deficiency can cause weakness, cramps and irregular heartbeat.

Iodine

Iodine is needed to make thyroid hormones, which control metabolism, growth and development.

Sources: Seafood, iodized salt, dairy products
Deficiency effects: Goitre (enlarged thyroid gland), impaired physical and mental development

Case Study Focus: Goitre in Inland Areas

Before iodized salt became common, people living in inland areas far from the sea often suffered from goitre - a swelling in the neck caused by an enlarged thyroid gland. This was because their diets lacked iodine, which is naturally abundant in seafood. In some mountainous regions like the Alps and Himalayas, goitre was so common it was considered normal! The introduction of iodized salt in the early 20th century dramatically reduced goitre rates worldwide, making it one of the most successful public health interventions in history.

Balancing Your Diet

Getting enough vitamins and minerals doesn't have to be complicated. Here are some simple tips:

Eat the rainbow: Different coloured fruits and vegetables contain different vitamins and minerals, so eating a variety ensures you get a good mix.
Include all food groups: A balanced diet should include fruits, vegetables, whole grains, proteins and dairy or alternatives.
Consider your needs: Some groups need more of certain nutrients - for example, teenagers need more calcium for growing bones and women of childbearing age need more iron.
Limit processing: Highly processed foods often have vitamins and minerals removed and may be high in salt, sugar and unhealthy fats.

Should I Take Supplements?

Most people can get all the vitamins and minerals they need from a balanced diet. However, some groups may benefit from supplements:

Pregnant women (folic acid and vitamin D)
Infants and young children (vitamin A, C, D)
People with darker skin or limited sun exposure (vitamin D)
Older adults (vitamin D and B12)
People with certain medical conditions or on restricted diets

Always talk to a healthcare professional before starting supplements, as some can be harmful in high doses, especially fat-soluble vitamins which can build up in the body.

Quick Reference: Signs of Deficiency

Watch out for these potential signs of vitamin and mineral deficiencies:

Fatigue and weakness: Could indicate iron, vitamin B12, or vitamin D deficiency
Brittle hair and nails: Might suggest biotin (B7) deficiency
Mouth ulcers or cracks: Could be B vitamin deficiencies
Poor night vision: Possible vitamin A deficiency
Bleeding gums: May indicate vitamin C deficiency
Bone pain: Could be vitamin D or calcium deficiency

Remember: These symptoms can have many causes, so always consult a doctor if you're concerned.

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