**1. Types of Nutrients and Essentiality:**
– Nutrients are substances essential for survival, growth, and reproduction in organisms.
– Essential nutrients for animals include energy sources, amino acids, fatty acids, vitamins, and minerals.
– Plants require minerals, carbon dioxide, and oxygen for survival.
– Nutrients can be organic (carbon-containing) or inorganic.
– Essential nutrients are vital for normal physiological functions and must be obtained from the diet.
– Apart from water, essential nutrients include amino acids, fatty acids, vitamins, and minerals.
– Nine amino acids, two fatty acids, thirteen vitamins, fifteen minerals, and choline are considered essential for humans.
– Conditionally essential nutrients are required in specific developmental or pathological states.
– Amino acids and fatty acids are crucial components of essential nutrients.
**2. Macronutrients and Micronutrients:**
– Macronutrients are consumed in large quantities and provide energy for the body.
– Carbohydrates, proteins, fats, water, and ions like calcium and sodium are classified as macronutrients.
– Proteins are made up of amino acids linked by peptide bonds.
– Fats consist of glycerin and fatty acids and are essential for cell maintenance.
– Micronutrients are essential for metabolic and physiological functions.
– Dietary minerals like copper and iron are required in small amounts.
– Vitamins are organic compounds needed in microgram or milligram quantities.
– Diseases can develop if certain vitamins are absent from the diet.
– Micronutrients are crucial for overall health and well-being.
**3. Nutrient Sources and Regulation:**
– Nutrients can be obtained from a variety of sources, including plants, animals, and supplements.
– Edible plants contain phytochemicals like polyphenols with potential health benefits.
– Dietary minerals are derived from plants or animal sources.
– Vitamins can be obtained from a balanced diet or supplements.
– Adequate nutrient intake is crucial to prevent deficiency states.
– Excessive intake of certain nutrients can have harmful effects on health.
– Consumer advisories like the United States Dietary Reference Intake provide guidelines for nutrient consumption.
– Regulations in many countries require food labels to display nutrient information.
– Understanding nutrient requirements and following dietary guidelines is essential for overall well-being.
**4. Essential Nutrients and Conditionally Essential Nutrients:**
– Only two essential fatty acids for humans are alpha-linolenic acid and linoleic acid.
– Humans require thirteen essential vitamins in their diet, including vitamins A, C, D, E, K, and various B vitamins.
– Essential minerals for humans include potassium, calcium, iron, zinc, and selenium.
– Choline is an essential nutrient for humans.
– Inositol, taurine, arginine, glutamine, and nucleotides are classified as conditionally essential.
– These nutrients are crucial in neonatal diet and metabolism.
– Conditions like premature birth and limited nutrient intake may lead to insufficient quantities of these nutrients.
**5. Non-Essential Nutrients and Deficiencies/Toxicity:**
– Dietary fiber impacts health but is not absorbed in the digestive tract.
– Nutrient deficiencies can result from inadequate intake or utilization issues.
– Nutrient toxicity occurs with excessive consumption.
– Recommended dietary intake levels vary among countries and organizations.
– Government guidelines differ on amounts needed to avoid deficiency or toxicity risks.
– Nutrient categories include EAR, RDA, AI, and PRI.
A nutrient is a substance used by an organism to survive, grow, and reproduce. The requirement for dietary nutrient intake applies to animals, plants, fungi, and protists. Nutrients can be incorporated into cells for metabolic purposes or excreted by cells to create non-cellular structures, such as hair, scales, feathers, or exoskeletons. Some nutrients can be metabolically converted to smaller molecules in the process of releasing energy, such as for carbohydrates, lipids, proteins, and fermentation products (ethanol or vinegar), leading to end-products of water and carbon dioxide. All organisms require water. Essential nutrients for animals are the energy sources, some of the amino acids that are combined to create proteins, a subset of fatty acids, vitamins and certain minerals. Plants require more diverse minerals absorbed through roots, plus carbon dioxide and oxygen absorbed through leaves. Fungi live on dead or living organic matter and meet nutrient needs from their host.
Different types of organisms have different essential nutrients. Ascorbic acid (vitamin C) is essential to humans and some animal species, but most other animals and many plants are able to synthesize it. Nutrients may be organic or inorganic: organic compounds include most compounds containing carbon, while all other chemicals are inorganic. Inorganic nutrients include nutrients such as iron, selenium, and zinc, while organic nutrients include, protein, fats, sugars, and vitamins.
A classification used primarily to describe nutrient needs of animals divides nutrients into macronutrients and micronutrients. Consumed in relatively large amounts (grams or ounces), macronutrients (carbohydrates, fats, proteins, water) are primarily used to generate energy or to incorporate into tissues for growth and repair. Micronutrients are needed in smaller amounts (milligrams or micrograms); they have subtle biochemical and physiological roles in cellular processes, like vascular functions or nerve conduction. Inadequate amounts of essential nutrients, or diseases that interfere with absorption, result in a deficiency state that compromises growth, survival and reproduction. Consumer advisories for dietary nutrient intakes, such as the United States Dietary Reference Intake, are based on the amount required to prevent deficiency, and provide macronutrient and micronutrient guides for both lower and upper limits of intake. In many countries, regulations require that food product labels display information about the amount of any macronutrients and micronutrients present in the food in significant quantities. Nutrients in larger quantities than the body needs may have harmful effects. Edible plants also contain thousands of compounds generally called phytochemicals which have unknown effects on disease or health, including a diverse class with non-nutrient status called polyphenols, which remain poorly understood as of 2017.