Saturday, June 28, 2014

Nutritional Science Overview

Nutritional science is the study of the effects of food components and its molecules on the metabolism, health, performance and disease resistance of humans and animals. Nutritional science studies how the body breaks food down (catabolism) and repairs and creates cells and tissue (anabolism) -- catabolism and anabolism = metabolism.

Nutritional science interprets the interaction of nutrients and other substances in food (e.g. macronutrients, minerals, phytonutrients, anthocyanins, tannins, etc.) in relation to maintenance, growth, reproduction, health and disease of an organism. It includes food intake, absorption, assimilation, biosynthesis, catabolism and excretion.

Nutritional science focuses on how diseases, conditions and problems can be prevented or lessened with a healthy diet. In addition, nutritional science involves identifying how certain diseases, conditions or problems may be caused by dietary factors, such as poor diet (malnutrition), food allergies, metabolic diseases, etc.

And, as molecular biology, biochemistry and cell biology advance, nutritional science has become more focused on the steps of biochemical and biological sequences through which substances inside us and other living organisms are transformed from one form to another via metabolism and metabolic pathways.

The diet of an organism is what it eats, which is largely determined by the availability, processing and palatability of foods. A healthy diet includes preparation of food, meal planning and storage methods that preserve nutrients from oxidation, heat or leaching, and that reduce risk of food-born illnesses.

A poor diet may have an injurious impact on health, causing deficiency diseases such as scurvy; health-threatening conditions like celiac disease, obesity and metabolic syndrome; and such common chronic systemic diseases as cardiovascular disease, diabetes, and osteoporosis.

Similarly, a good diet may have a positive impact on health, causing an improvement in one's health and improving one's ability to live a life of wellness.

Note: Nutritional science also incorporates the elements of social science to explore the connection between diets, food choices, habits, lifestyle, finances and health.

Macronutrients and Micronutrients
The human body requires six major types of nutrients -- 4 macronutrients and 2 micronutrients -- where a nutrient is a source of nourishment, a specific molecule or component within a food.

Macronutrients are nutrients we need in relatively large quantities. Micronutrients are nutrients we need in relatively small quantities.

Macronutrients
There are four (4) key macronutrients:
-- Carbohydrates
-- Proteins
-- Fat
-- Water

The building blocks of carbohydrates are saccharides such as glucose. The building blocks of proteins are amino acids such as lysine. And, the building blocks of fats are fatty acids such as linoleic acid.

Carbohydrates
Carbohydrates are the most abundant biological molecules, and are an important nutritional component of many foods.

Carbohydrates consist of glucose molecules of carbon, hydrogen and oxygen atoms. Carbohydrates include monosaccharides (glucose, fructose, galactose), disaccharides, oligosaccharides, and polysaccharides (starch).

Carbohydrates are classified according to size. The smallest carbohydrates are called monosaccharides ( mono means "one"; saccharide means "sugar"). The largest carbohydrates are called polysaccharides ( poly, means "many").

As the name implies, monosaccharides are single sugar molecules. The most common monosaccharides, such as fructose and glucose, have six carbon atoms, but monosaccharides can have as few as three or as many as seven.

Monosaccharides with five or more carbons usually have a ring-shaped structure when they are in a solution.

Oligosaccharides ( oligo means "few") are more complex carbohydrates composed of chains of two or a few (up to about twenty) simple sugars joined with a type of covalent bond called a glycosidic bond.

Polysaccharides ( poly, means "many") are important energy-storage and structural molecules. They are formed of long chains of sugars, most commonly glucose.

Carbohydrates serve many purposes, from producing energy to structure to chemical communication.

Carbohydrates are at the center of cellular metabolic pathways. The most fundamental process, glycolysis , uses glucose to produce energy for cellular needs.

There are 4 major dietary types of carbohydrates:
-- Sugar
-- Starch
-- Non-starch
-- Fiber

There are 4 major carbohydrate chemical groups:
-- Monosaccharides
-- Disaccharides
-- Oligosaccharides
-- Polysaccharides

Key food sources for carbohydrates include: vegetables, fruits, whole grains, cereals, breads, baked goods, starches, pastries, sweets, soft drinks, juices, and foods made with flour and sugar.

Proteins
Proteins are chains of amino acids that fold into a three-dimensional shape. Proteins consist of molecules that contain nitrogen, carbon, hydrogen and oxygen. Simple proteins, called monomers, are used to create complicated proteins, called polymers, which build and repair tissue.

Proteins are probably the most important class of material in the body. Proteins are not just building blocks for muscles, connective tissues, skin, and other structures.

Proteins are also needed to make enzymes. Enzymes are complex proteins that control and carry out nearly all chemical processes and reactions within the body. The body produces thousands of different enzymes.

Thus, the entire structure and function of the body is governed by the types and amounts of proteins the body synthesizes. Protein synthesis is controlled by genes, which are contained on DNA molecules called chromosomes.

Proteins (including their lipoprotein and glycoprotein forms) constitute 10 percent of the weight of the blood plasma of living organisms, carrying various nutrients throughout the body and acting as signals to coordinate bodily functions between the different organs.

The amino acids of a protein are connected to each other by peptide bonds. Each amino acid has several common features: an amino and a carboxyl chemical group both bonded to the alpha carbon (Cα) and an R group that defines a particular amino acid.

Types of Dietary Proteins
From a nutritional perspective, the key types of proteins are: plant, animal and dairy.

Proteins are made up of building blocks called amino acids. There are 20 different amino acids that join together to make all types of protein. 

The (9) essential amino acids are: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.

The (11) non-essential amino acids are arginine, cysteine, glycine, glutamine, proline and tyrosine; alanine, aspartic acid, asparagine, glutamic acid and serine.

A complete protein source is one that provides all of the essential amino acids. Animal-based foods such as meat, poultry, fish, milk, eggs, and cheese are considered complete protein sources.

An incomplete protein source is one that is low in one or more of the essential amino acids.

Complementary proteins are two or more incomplete protein sources that together provide adequate amounts of all the essential amino acids.

Key food sources for proteins include: vegetables; eggs; nuts and seeds; legumes (dry beans and peas); soy (tofu, tempeh, miso); blue-green algae (spirulina); dairy (milk, cheese); animal meats, poultry, fish; and, whole grains.

Types of Functional Proteins
From a cell biological perspective, the key types of proteins include: hormonal, enzymatic, structural, storage, transport, receptor, and contractile.

These proteins support the function, growth and maintenance of all our cells and body tissues.

Structural: Also known as fibrous proteins, these are the largest class of proteins that include collagen, keratin and elastin. These protein types serve as essential components to your body's construction. Keratin and collagen are the most common structural proteins.  Collagen forms the connective framework of your tendons, bones, muscles, cartilage and skin. Keratin is the main structural component in your skin, nails, hair and teeth.

Hormonal: Hormonal proteins act as chemical messengers secreted by the cells of the endocrine glands. Usually transported through the blood, hormones act as chemical messengers that transmit signals from one cell to another. Each hormone affects certain cells in your body, known as target cells.

Enzymatic: Enzymes serve as biological catalysts needed for chemical reactions, including liver functions, stomach digestion, blood clotting and converting glycogen to glucose.

An example is digestive enzymes that break down complex food molecules into simpler forms that your body can easily absorb. Amylolytic digestive enzymes reduce carbohydrates and starches to glucose and proteolytic enzymes reduce proteins to amino acids.

Defensive: Antibodies, or immunoglobulins, are a core part of your immune system, that protects your body from pathogens and other foreign substances, keeping diseases at bay. Antibodies are formed in the white blood cells and attack bacteria, viruses and other harmful microorganisms, rendering them inactive.

Storage: Storage proteins house critical elements that your cells need. Hemoglobin is a vital protein that stores oxygen in your red blood cells. This critical protein is transported to all of your cells and tissues as your blood circulates. Ferritin is a storage protein that houses the crucial element iron, which is required for the formation of hemoglobin, the main structural component of red blood cells.

Transport: Transport proteins carry vital materials to the cells. Hemoglobin, for example, carries oxygen to body tissues from the lungs. Serum albumin carries fats in your bloodstream, while myoglobin absorbs oxygen from hemoglobin and then releases it to the muscles. Calbindin is another transport protein that facilitates the absorption of calcium from the intestinal walls.

Receptor: Located on the outer part of the cells, receptor proteins control the substances that enter and leave the cells, including water and nutrients. Some receptors activate enzymes, while others stimulate endocrine glands to secrete epinephrine and insulin to regulate blood sugar levels.

Contractile: Also known as motor proteins, contractile proteins regulate the strength and speed of heart and muscle contractions. These proteins are actin and myosin. Contractile proteins can cause heart complications if they produce severe contractions.

Fats and Lipids
Lipids are a group of naturally occurring molecules that include fats, waxes, sterols, monoglycerides, diglycerides, triglycerides, phospholipids, and others.

Lipids contain molecules that consist of carbon, hydrogen, and oxygen atoms. Fats are triglycerides - three molecules of fatty acid combined with a molecule of the alcohol glycerol. Fatty acids are simple compounds (monomers) while triglycerides are complex molecules (polymers).

The main biological functions of lipids include storing energy, signaling, and acting as structural components of cell membranes.

Lipids play vital roles in many cellular processes including energy storage, vitamin storage, structural cell membrane support, protection, communications, the functioning of nerve cells and acting as raw materials that can be converted to other substances that perform special duties in the body such as hormones.

There are four biologically important lipids:
-- Fats (or dietary fats)
-- Phospholipids (for cell membranes)
-- Steroids (such as cholesterol)
-- Waxes (for protection)

Fats are large molecules composed of three fatty acid molecules bonded to a glycerol molecule (and configured as triglycerides) 

There are 4 major types of fats: saturated, monounsaturated, polyunsaturated and trans fat.

Note: Although the term lipid is sometimes used as a synonym for fats, as you can see, fats are a subgroup of lipids.

Phospholipids are similar to fats except they have two fatty acid chains bonded to a glycerol molecule and phosphoric acid, with the fatty acid component being saturated or unsaturated.

Phospholipids are unique because they have a hydrophobic (water-insoluble) and a hydrophilic (water-soluble) end.

Phospholipids are biologically important because they are the main structural components of cell membranes. But, the cell membrane incorporates other lipids, such as cholesterol, that contribute to its structural integrity; and, glycolipids, which help with cellular communications.

As a result, there are three common types of membrane lipids: phospholipids, glycolipids, and cholesterol [Structural Biochemistry].

Steroids are structurally different from the other lipids. The carbon skeleton of steroids is bent to form four fused rings that do not contain fatty acids. The most common steroid, cholesterol, is an important component of cell membranes that helps to provide cell structure and integrity.

Cholesterol is important for nerve cells. The molecule binds to the myelin sheath which provides an outer coating that protects the nerve cell. Also, cholesterol is needed to make both the male (testosterone) and female (estrogen) sex hormones. So, you see, cholesterol is not as bad as you thought. :-)

Another popular steroid group is the anabolic steroids that are man-made and mimic the effect of the male hormone, testosterone. Athletes have recently been using these steroids to increase muscle mass, stamina, and strength. Certain beneficial fat-soluble hormones, such as cortisol, are also familiar steroids.

Waxes are similar to fats except that waxes are composed of only one long-chain fatty acid bonded to a long-chain alcohol group attached. Both plants and animals use the waterproofing characteristic of waxes. For example, plants most noticeably use waxes for a thin protective covering of stems and leaves to prevent water loss.

Types of Dietary Fats
There are four major types of fats or fatty acids, based on how many of their carbon bonds are paired with hydrogen:
-- Saturated
-- Monounsaturated
-- Polyunsaturated
-- Trans-unsaturated

Saturated fats are fully loaded with hydrogen atoms forming straight chains. More specifically, saturated fats have single bonds between all the carbon atoms, and therefore all the carbons are bonded to the maximum number of hydrogen atoms.

These chains are fairly straight and can pack closely together, making these fats solid at room temperature.

Examples of saturated fats: butter, coconut oil.

Unsaturated fats have some double bonds between some of the carbons in the tail, causing the molecule to bend. As carbon atoms with double bonds are not bonded to as many hydrogens as possible, they are called unsaturated fats. The kinks in the tails mean that unsaturated fats can't pack as closely together, making them liquid at room temperature.

Monounsaturated fatty acids (MUFAs) are unsaturated fatty acids that are missing one pair of hydrogens -- they have one double bond in the fatty acid chain with all of the remainder carbon atoms being single-bonded.

Examples of monounsaturated fats: olive oil, avocado.

Polyunsaturated fatty acids (PUFAs) are unsaturated fatty acids that are missing more than one pair of hydrogens -- they have more than one double bond.

Examples of polyunsaturated fats: vegetable oil (corn oil), Omega-3 (fish), Omega-6 (evening primrose oil).

Trans-unsaturated fatty acids (trans fats, for short) are a man-made unsaturated fat that is more linear and rigid, where hydrogen atoms are added via a process called hydrogenation causing double bonds to become single ones.

Partial hydrogenation results in the addition of hydrogen atoms at some of the empty positions, with a corresponding reduction in the number of double bonds.

Examples of trans fats: margarine, fried food, French fries, packaged foods.

Micronutrients
There are two (2) key micronutrients:
-- Vitamins
-- Minerals

Vitamins are organic molecules in our food that are essential nutrients for good health.

Minerals are inorganic chemical elements required by living organisms, other than the four elements carbon, hydrogen, nitrogen, and oxygen that are present in nearly all organic molecules.

Vitamins
Vitamins are organic compounds in food that are required for normal cell function, growth, and development.

There are probably hundreds of these organic compounds in the food, but, as of today, we have discovered 13 essential vitamins.

These vitamins fall into 2 categories: fat-soluble and water-soluble.

Fat-Soluble Vitamins: Fat-soluble vitamins are those that bind to fat in the stomach and are then stored in the body for later use. We are less likely to become deficient in these vitamins (A, D, E, and K), but more likely to build up to toxic levels, usually due to extreme over-consumption or overzealous supplement use.

Water-Soluble Vitamins: The rest of the vitamins are water-soluble, meaning they can be absorbed directly by cells. The water-soluble vitamins (Vitamin B-Complex, Vitamin C), niacin, folic acid, pantothenic acid, and the four B complex vitamins — need to be restored more frequently, but the body can tolerate higher doses. When taken in excess, these vitamins are flushed out of our system with each bathroom break.

Minerals
Dietary minerals are the other chemical elements our bodies need, apart from carbon, hydrogen, oxygen and nitrogen.

Six minerals are required by people in gram amounts: sodium (Na), potassium (K), calcium (Ca), magnesium (Mg), phosphorus (P), and chlorine (Cl). Daily requirements range from 0.3 to 2.0 grams per day.

Nine trace minerals (microminerals) are required by people in minute amounts: chromium (Cr), copper (Cu), iodine (I), iron (Fe), fluorine (F), manganese (Mn), molybdenum (Mo), selenium (Se), and zinc (Zn).

Note: The term "minerals" is misleading, and would be more relevant if called "ions" or "dietary ions".

Author's Sidebar:
Have you noticed that there’s an abundance of nutrition experts with dietary systems and approaches that are vastly different –  and yet they lack scientific substance and validation? And, more importantly, these systems don't appear to work in the long run when fighting a disease like Type 2 diabetes.
 
So ,now that we understand the key components of nutrition, we need to better understand the following:
-- Which are the best carbohydrates, proteins and fats for us to eat?
-- How do these macronutrients help us to prevent and fight disease?
-- How do we design and plan our meals on a daily basis?

These questions are answered in other blog posts; and, in the Death to Diabetes book, DTD science ebook and DTD training program.

Metabolism of Carbs, Proteins and Fats
The body must be able to metabolize or break down the macronutrients in order to eventually produce energy for your body.

When you eat food, the body digests and breaks down the carbohydrates into glucose, the proteins into amino acids, and the fats into fatty acids.

The glucose causes your blood sugar level to rise, triggering the release of insulin. This enables your cells to absorb the glucose; and, along with oxygen, your cells produce chemical energy, called adenosine triphosphate (ATP). 

ATP is then made available to other parts of the cell so that the cell can do its job and perform all of its functions.

Proteins and Fats can be broken down and used as energy sources, but, it takes more work.

How Cells Obtain Energy from Food
Cells require a constant supply of energy to generate and maintain the biological order that keeps them alive. This energy is derived from the chemical bond energy in food molecules, which thereby serve as fuel for cells.
Sugars are particularly important fuel molecules, and they are oxidized in small steps to produce energy (ATP), carbon dioxide (CO2), water and heat.

The 3 major stages that transform food into energy are three main sets of reactions that act in :
1. Glycolysis (which occurs in the cytosol)
2. Krebs cycle (in the mitochondrial matrix)
3. Electron Transport Chain (on the inner mitochondrial membrane)

Reference: DTD Training Program PowerPoint Slides
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Nutritional Science Concerns
Let’s take a big picture look at the field of nutritional science:

It’s the wild wild west – everyone’s an expert! There’s a new diet every week!

It’s still a young science – meaning nutrition is still developing, and we still don’t truly understand the depth of this science.

Experts disagree – and it’s okay as long as you understand the science behind the differences.

There's too much selling on the Internet. A lot of times, it’s “marketing” trying to sell something instead of helping people with their health issues.

No field in Science operates with universal agreement – that’s just the way it is. You need to build up your tolerance for disagreement and understand it.

Scientists can be very passionate, very religious, and very dogmatic. Scientists are just like you and me – they’re human beings. So, don’t strictly rely on them – educate yourself by reading multiple authors and science studies.

Nutrition is not respected by most medical doctors; and, that has become a major problem because people are noticing that taking drugs for most health problems isn’t working.

As a result, more and more people are looking at Alternative Medicine, especially those aspects of Alternative Medicine that are focused on nutrition.

Nutrition is not infallible – a lot of mistakes have been made over the years. Today’s nutrition facts are often tomorrow’s fallacies.

For example, we used to think margarine was good for us. We thought butter was bad. We thought all saturated fat was bad. We thought that low fat diets were good for us. We thought that it was okay to put artificial colors in food. We thought that all protein was the same, and all fat was the same. We thought grain was good for everyone.

So, what do you do? How do you prevent yourself from becoming a victim of another mistake? The best thing to do is to educate yourself at the lowest level possible; and, read/learn from multiple sources.

Humans are still growing and evolving – and so is our nutrition. So it makes perfect sense that we continue to educate ourselves about nutrition and disease.

It’s quite useful to note that innovation in the field of nutrition often comes from the outside. Most of what you eat and the foods you purchase didn’t originate in some high-end scientific laboratory or in the hallowed halls of an Ivy League school.

Nutrition and dietary innovation is largely a grassroots affair. Here are examples: macrobiotics, the Atkins diet, the Mediterranean diet,  the Pritikin diet,  the Zone diet, the Paleo diet, The Death to Diabetes diet, veganism, raw foods, cleansing programs, orthomolecular nutrition, the use of supplements and herbs.

All of these ideas were brought to you by outsiders, some through ancient wisdom, some from people who have no formal university and scientific education, some from doctors who were considered to be on the fringe of quackery, and some from people who were desperate because they were dying from a chronic disease.

Key Learning Elements of Nutritional Science
If you plan to acquire a degree in nutritional science or teach yourself about nutritional science, there are several key components of nutritional science that you need to learn.

The first part of nutritional science is understanding the basic nutrients that are found in the foods we eat on a day to day basis.

The next part of nutritional science is learning how food influences our health: weight gain, disease, allergies, etc. Understanding which foods are good for your health and those which are bad is key to being able to help clients.

Another key component of nutritional science is understanding how food relates to exercise performance. Whenever exercise is undertaken, the body’s energy demands will go up considerably and different foods will impact exercise performance in different ways.

Nutritional science is also going to address how food will correlate to your own disease risk. With heart disease and diabetes on the rise in today’s world – two diseases that can be prevented largely through diet, more people are seeking help to prevent them.

When you study nutritional science, you’ll learn what factors most contribute to these diseases and how food can help to reverse the risk an individual sustains. Many people do not realize just how much power they have when it comes to reducing their chances of heart disease or diabetes, so the nutritional consultants role is to help raise awareness and then empower individuals to do something about it.

Truly understanding the science goes beyond “just the science”. You need to understand your client’s incentives, motivations, lifestyles, spirituality and other social influences to fully understand nutritional science systemically.

With more information coming out regularly on what nutrients and what foods best help beat some of the most prevalent diseases today, this is an ongoing area of nutrition science. Learning will never stop, so you can really grow into this field if you wish.

Finally, as you study nutritional science you’ll also learn how to interact with clients so that you can help them learn how to manage their lifestyle better with superior nutrition choices.

Many clients struggle to eat healthy for a number of reasons, so nutritional science will look at why this is and what can be done to overcome some of the problems that are in place.

Since eating is not just the simple act of fueling the body, but rather, people eat for a wide number of reasons (happiness, fear, sadness, in social environments, etc.), it’s important to understand how these correlate to food choices, health, and body weight, and then make recommendations for ways to best manage eating in these situations to prevent negative impacts on the body.

Nutritional science encompasses many different areas and will provide the learner with ongoing challenges to expand their knowledge and then put it into practice with the clients they work with. 

The bottom line: Acquire knowledge from multiple sources about nutritional science in order to acquire the power to help yourself and others.