Health Articles

The Basics of Human Nutrition

If we want to take our health into our own hands and live a long and healthy life, it is important to understand the basics of human nutrition.

We know what to feed most pets in order for them to be healthy or which fuel to put into our cars for optimal performance. But many people lack knowledge about the optimal diet for humans.




There are many different opinions on what constitutes a healthy diet so the subject can be very confusing. To understand better which diet is generally right for us humans I think it is important to better understand our biology: Every organism needs energy to carry out life processes. Most organisms, including us humans, get this energy from the foods that they eat.

Food also provides the building blocks that we need to make and repair body materials.

Chemically, food can be divided into groups of macro- and micronutrients.

Macronutrients include carbohydrates, protein and lipids (fat).

Micronutrients consist of vitamins and minerals.

Nutrients are metabolized (chemically broken down) and may be converted into other nutrients during the process.

Metabolism (all chemical reactions in the body) is assisted by enzymes (enzymes are biological catalysts and nearly all of them are proteins), some of which need certain co-enzymes (co-factors that assist them).

Vitamins

Many vitamins are known to act as coenzymes.

There are two groups of vitamins: water-soluble and fat-soluble vitamins:

  • Fat-soluble vitamins can accumulate in the body’s fat reserves while the water-soluble vitamins circulate in the body’s fluids.
  • The fat-soluble vitamins consist of the vitamins A, D, E and K.
  • All other vitamins are water-soluble.

We need all vitamins for our body to function properly but the amounts can vary individually.

Deficiencies may lead to an array of health problems.

Let’s look at the table for an overview of all the vitamins, their functions and signs of deficiencies:

Vitamin Overview| Real Food Real Health UK

Minerals

Minerals are inorganic ions and atoms that we need for many body functions.

There are seven macrominerals that we need in higher amounts.

They are: calcium, chloride, magnesium, phosphorus, potassium, sodium and sulphur.

There are also over thirty trace minerals that are essential to life but we only need them in minute amounts.

The following tables give an overview:

Macromineral Overview| Real Food Real Health UK

Trace-mineral Overview| Real Food Real Health UK

Chlorine, sodium and potassium are the principal electrolytes that are needed by the cells to maintain the right voltage across their membranes.

Proteins

Proteins are molecules that are essential for many biological processes in the body.

Structural proteins are the building blocks of our body whilst other proteins function as enzymes, hormones and antibodies.

Proteins consist of over twenty amino acids of which around half are essential (the body can’t manufacture them so they need to be ingested).

Most animal proteins have all essential amino acids whereas plant sources only contain some.

Protein is essential for all growth processes, hormones and blood clotting.

They also play a big role in maintaining the right acid-alkaline balance.

Enzymes are catalysts for most biochemical processes.

All enzymes are proteins though some have non-protein portions.

Over five thousand enzymes have been discovered so far.

  • The biggest group are the metabolic enzymes needed for all bodily processes, maintenance of the immune system and detoxification.
  • The next group are the digestive enzymes which are manufactured by the pancreas.
  • There are enzymes in foods which also play a big role in the digestive process and help lower the burden on the pancreas. These are destroyed by heat and therefore are found mainly in raw and fermented foods.

Carbohydrates

Carbohydrates are everything that is not protein or fat.

They consist of simple sugars (monosaccharides), double sugars (disaccharides) and multiple sugars (polysaccharides).

They’re the main source of energy for most organisms.

There are many types of sugars:

  • Fructose and glucose for example are monosaccharides.
  • Sucrose is a disaccharide.
  • Polysaccharides are starches.
  • Glucose is the sugar found in the blood and is used to produce energy in cells.

However, we do not need to ingest plain sugar or large amounts of carbohydrates in order to produce energy.

Fats (lipids)

Fats and oils are sources of stored energy made from fatty acids and glycerol. They’re chains of carbon atoms with hydrogen atoms filling the available bonds.

Most body- and dietary fat come in the form of triglycerides, meaning three fatty-acid chains are attached to a glycerol molecule.

Dietary fats slow down the release of nutrients so that we can feel satisfied for longer. They also provide the building blocks for hormones and cell membranes.

All lipids are a combination of monounsaturated- and saturated-fatty acids as well as polyunsaturated linoleic acid and linolenic acid.

All solid fats are higher in saturated fat while liquid oils are mainly polyunsaturated fatty acids.

Saturated fats are highly stable because all available bonds are saturated with hydrogen.

Monounsaturated fatty acids have a double bond of two carbon atoms and lack two hydrogen atoms. They’re slightly less stable.

Polyunsaturated fatty acids are divided into omega-3 and omega-6. They’re called essential fatty acids (EFAs) because our body can’t make them and therefore we must ingest them. They have 2+ bonds of double atoms and therefore lack 4+ hydrogen atoms. These oils go rancid very easily.

Lipids are also classified by their length into short-chain, medium-chain, long-chain and very-long-chain fatty acids. Animal-fats also contain cholesterol.

Cholesterol is a high-molecular-weight alcohol which is produced in the liver and cells. It is important for cell membrane integrity, hormone production including anti-stress and sex hormones, bile production, serotonin levels and the integrity of the intestinal wall. It also acts as a strong antioxidant.

The Bottom Line

So we can see that our bodies actually need ALL of these nutrients in order to carry out ALL of its functions. A lack of nutrients can lead to decrease in body functions which in turn may lead to disease.

Where do we get these all nutrients?

From whole foods that are as close to their natural state as possible. The more nutrient dense these foods are, the better.

Processed foods are denatured and lack most of these vital nutrients.

Nutrients are the fuel our bodies need to function – if we put the wrong fuel in a car the engine is going to break. The same can happen to our body…
Photo license: Frutas e Vegetais (license)

Sources

  • Paxton, Fay Foundations of Naturopathic Nutrition  (Crows Nest: Allen & Unwin, 2015)
  • Mindell, Earl New Vitamin Bible  (New York: Grand Central Life & Style, 2001)
  •  Minkoff, Eli C., Biology (New York: Barron’s Educational Series, Inc., 1991)
  • Roberts, Michael and Ingram, Neil, Biology (Cheltenham: Nelson Thornes Ltd., 2001)
  • Stone, Carol Leth, The Basics of Biology (Westport: Greenwood Publishing Group, 2004)
  • Minkoff, Eli C. and Baker, Pamela J., Biology Today: An Issues Approach (New York: Garland Science, 2001)
  • Fallon, Sally, Nourishing Traditions (Washington: NewTrends Publishing, Inc., 2001)

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