Human Nutrition the Fundamentals.

Nutrition is the study of how food, drinks, and their components interact with the human body. Nutrients are substances that perform essential functions in the body. These nutrients can be categorized into two main groups based on the quantity required by the body.

Micronutrients: Essential in Small Amounts

Micronutrients are vital nutrients needed in limited quantities. Despite being required in smaller amounts, they are just as crucial for overall health. This group includes vitamins and minerals.

Macronutrients: Energy-Boosting Essentials

Macronutrients are nutrients required in larger quantities to sustain bodily functions. This category comprises carbohydrates, proteins, lipids, and water – all essential for energy production and overall well-being.

Carbohydrates: The Body's Primary Fuel Source

Carbohydrates, meaning "hydrated carbon," comprise carbon, hydrogen, and oxygen. They're digested, converted to glucose, and serve as the body's main energy source. There are three types:

• Simple Carbohydrates (Monosaccharides): Glucose, fructose, and galactose

• Double Carbohydrates (Disaccharides): Lactose, sucrose

• Complex Carbohydrates (Polysaccharides): Cellulose, starch

Functions and Importance

Glucose is essential for every cell, particularly the brain and central nervous system. Excess glucose is stored as glycogen or converted to fat.

Deficiency and Consequences

Carbohydrate deficiencies are rare, but starvation can lead to severe consequences. Restricting carbohydrates can lead to weight loss, but it's not sustainable and can impair brain function.

Food Sources

Common carbohydrate sources include:

• Cereal grains (wheat, rice, corn, oats)

• Pasta, rice dishes

• Vegetables (especially root vegetables like potatoes)

• Fruits (Bananas, Mangoes, Apples etc )

Excess Intake and Health Risks

• Consuming excessive carbohydrates can lead to:

• Increased body fat and obesity

• Dental caries

• Excessive sugar intake from sources like soft drinks can provide empty calories with no nutritional value.

Proteins: The Building Blocks of Life

Proteins are essential for growth, repair, and maintenance of body tissues. They're composed of amino acids, linked like beads in a necklace, and contain carbon, hydrogen, oxygen, and nitrogen.

Functions in the Body

• Growth and repair of tissues

• Structure of soft and hard tissues (skin, muscles, bones, teeth)

• Fluid, electrolyte, and acid-base balance regulation

• Energy provision

Importance and Deficiency

Severe protein deficiencies are rare in developed countries, but can occur in cases of child abuse, anorexia nervosa, or starvation. Inadequate protein intake can slow growth rates, particularly in children.

Food Sources

Animal protein (contains all essential amino acids)

Plant-based protein sources (nuts, beans, milk, egg whites, meat)

Excess Intake

Consuming excessive protein can lead to:

• Deamination, producing ammonia and urea

• Excess nitrogen excretion through urine

• Conversion of excess carbon to energy or stored as fat

Lipids: Essential Fats for the Body

Lipids, or fats, are crucial nutrients that perform various functions in the body. They are insoluble in water and come in different types, including triglycerides, which are composed of glycerol and fatty acids.

Types of Lipids

Good Fats:

Monounsaturated and polyunsaturated fats, found in vegetable oils, fish oils, and nuts, which help lower blood cholesterol and combat negative outcomes.

Bad Fats:

Saturated fats, trans fats, and cholesterol, found in animal fats, fried foods, and processed snacks, which increase the risk of heart disease and obesity.

Functions in the Body

• Energy storage and supply

• Protection against temperature extremes and shock

• Assistance in carbohydrate and protein utilization

• Essential fatty acid provision for fat-soluble vitamin absorption and transport

Deficiency and Food Sources

Deficiency is rare, but may occur in cases of starvation ( hunger) or extreme dieting.

Main food sources include oils, butter, egg yolks, non-trimmed meat, fried foods, and fish oils.

Water: The Essential Nutrient

Water is crucial for human survival, making up approximately two-thirds of our body weight. We can survive weeks without food, but only days without water.

Water's importance lies in its numerous functions:

• Muscle movement and flexibility

• Eye function and blinking

• Oxygen and nutrient transport to cells

• Joint cushioning and protection

• Energy conversion from food

• Waste removal

Water Composition and Intake

Water is composed of hydrogen and oxygen (H2O) and is the only macronutrient that doesn't provide energy. The average adult:

• Contains approximately 76 pints of water

• Drinks around 70 ounces of water daily

• Gets an additional 30 ounces from food

• Needs about 1 quart of water per 1,000 calories used

A typical adult male requiring 2,500 calories daily needs around 2.5 quarts of water, with some of this coming from food, which is approximately two-thirds water.

Vitamins: Essential Nutrients

Vitamins are crucial compounds obtained from food, necessary for normal bodily functions. They're named alphabetically (A, C, D, E, K, and B vitamins). Here's a brief overview

• Vitamin A: Vision, immune function

• Vitamin C: Collagen production, skin health

• Vitamin D: Bone health, calcium absorption

• Vitamin E: Antioxidant, cell protection

• Vitamin K: Blood clotting, wound healing

• Vitamin B: Energy production, nerve function (B1-B12)

Remember, vitamins are essential but don't provide energy, strength, or cure diseases.

Minerals: Essential for the Body

Minerals are vital chemicals obtained from the earth, necessary for proper bodily functions. Unlike vitamins, minerals retain their chemical identity and are divided into two types:

Major Minerals (Higher Amounts)

1. Calcium: Bone health, muscle function

2. Sodium: Fluid balance, nerve function

3. Phosphorus: Bone health, energy production

4. Chloride: Fluid balance, digestion

5. Potassium: Heart function, muscle contractions

6. Magnesium: Muscle function, nerve function

7. Sulfur: Connective tissue health, detoxification

Trace Minerals (Smaller Amounts)

1. Iron: Red blood cell production, oxygen transport

2. Manganese: Bone health, wound healing

3. Zinc: Immune function, protein synthesis

4. Chromium: Blood sugar regulation

5. Copper: Connective tissue health, immune function

6. Molybdenum: Enzyme function, metabolism

7. Iodine: Thyroid function, growth development

8. Fluorine: Tooth health, bone health

9. Selenium: Antioxidant, immune function

Food Energy: Fueling the Body

Your body needs energy from food to function, grow, and move. The three energy-providing nutrients are:

- Carbohydrates: 55% of daily energy

- Protein: 15% of daily energy

- Lipids/Fats: 30% or less of daily energy

Water, vitamins, and minerals are essential but do not provide energy. A balanced diet with a variety of foods is recommended to meet your energy needs.