In the absence of Glucose, for example, during periods of fasting or carbohydrate restrictions, the liver will break down fatty acids to form Ketone bodies, which are then used as an alternative form of energy in the heart and muscle. As they are able, like Glucose, to cross the blood-brain barrier they can be utilised by the brain.
In normal conditions the body will produce Ketone Bodies, however their concentration is kept low and any excess excreted by the urine.
Excess reliance upon the use of Ketone Bodies will produce a state of Ketosis. That is when the amount used by the body is less that that produced by the liver. These Ketones are toxic and create a more acidic level of blood PH. The body will expel what it does not require through the urine and the respiratory system. The breath will take on fruity smell due to the acetone produced.
The use of Ketones can also signify the body's inability to use Glucose effectively, as in Type I Diabetes. In this condition there will be a build up of not just Ketone Bodies but also Glucose in the Blood. The blood will become more acidic and the excess glucose excreted within the urine. This condition is know as Ketoacidosis. The Kidneys will become overwhelmed and the excess glucose will cause the removal of water and electrolytes from the blood which will then be excreted, leading to excess urination, resulting in dehydration. The body will attempt to compensate for this by increasing thirst. Typical symptoms of Ketoacidosis would include; excessive thirst, frequent urination, nausea and vomiting, abdominal pain, weakness or fatigue, short rapid breathing, fruity-scented breath, and confusion. Ketoacidosis is a medical emergency and needs to be treated.
In normal conditions excess glucose is stored in the form of Glycogen in the liver and muscles (however the store of glycogen in the muscle, and its release as glucose is only for its own needs. While glycogen stored in the liver is used more systemically).
Carbohydrates also play an important regulatory role within the body. This is particularly the case within the digestive system, where they have a beneficial effect on intestinal flora. They act as a prebiotic, providing the microflora with energy. Microflora in return provide many benefits towards health. Helping to break down toxins, synthesise some vitamins, and supporting the immune system.
The fibre contained within plants aids in regulating the absorption of nutrients, facilitates the elimination of waste, and increases the satiety value of a meal.
Combined with proteins they form glycoproteins and with fats glycolipids. Glycoproteins have numerous functions, including; structural in the form of collagen, lubricant as in synovial fluid, and protective as in mucin. They are also found in transport molecules such as Transferrin, which carries iron, and the Thyroxine-binding globulin which carries the thyroid hormone in the blood. Some hormones are also glycoproteins; Follicle-stimulating hormone (FSH), Luteinising hormone (LH), Thyroid-stimulating hormone (TSH) and the human chorionic gonadotropin (hCG). Immunoglobulins are also glycoproteins and play an important role within the immune system.
Glycolipids help maintain the stability of the cell membrane, and also facilitate cellular recognition, play a role in the body's immune response, the regulation of cell growth, and its Apoptosis (cell death).
Carbohydrates are broken down, initially by salivary Amylase and then by Pancreatic Amylase into Glucose and Fructose and assimilated Into the bloodstream. The presence of Glucose in the bloodstream causes the release of Insulin which enables the glucose to enter cells and used as a source of energy. Fructose does not cause the same rise in Insulin levels and usually passes to the liver where it is then converted into Glucose before being used. The liver can use Fructose without requiring Insulin. Excess Glucose in the blood is removed and stored as Glycogen and then stored within the Liver and Muscle, and converted back into Glucose when levels in the blood drop.
Glycemic Index and Load
The Glycemic Index measures how quickly glucose is absorbed after a person eats. That is, how high the blood glucose rises and then how quickly it returns to normal. The Glycemic Index is a method of classifying foods according to the body’s response to glucose levels in the blood. The higher the glucose response the higher the GI. 100 is the highest value, therefore High would be a response of 70 and above, intermediate between 56 to 69 and low, below 55. Sucrose has a lower GI than Glucose, which is one reason why fruit, despite being sweet, has a low to moderate GI. Fats slow down carbohydrate digestion thereby lowering GI.
The rate of glucose absorption is particularly important for people with diabetes, who benefit from limiting foods that produce too great a rise, or too sudden fall in blood glucose. Studies have shown that a high GI diet in combination with a low fibre intake increases the risk of Type II diabetes more than twofold. Increasing acidity in the meal can lower its GI due to the acid in food slowing down stomach emptying, thereby slowing the rate in which carbohydrates are digested. High GI foods increase circulating insulin levels, raises levels of insulin-like growth factors, which are potent cancer growth stimulators.
Low GI foods may help with weight management. Fibre slows down digestion and prolongs the presence of food in the digestive tract, leading to greater insulin sensitivity and diminishing the insulin released. Rapid absorption of glucose from a high glycemic diet is followed by a similar fall of blood sugar levels which stimulates overeating.
A number of factors influence the GI of the food.
- The physical structure of the carbohydrate.
- The presence of other nutrients in the foods, for example, fat and fibre.
- Food preparation methods, for example; macaroni has a GI of 47 spaghetti 38.
- The GI of a food can also vary within the same person at different times in the day. The GI effect being greater after breakfast than after lunch. It can also vary between individuals.
GI alone may be misleading as it may not include the other healthy benefits contained within the food, for example; antioxidants, vitamins, minerals and fibre.
Another method of looking at the glycemic effect of for is to look at Glycemic Load. This is a ranking system for carbohydrate content and food portions based on the glycemic index and portion size. Some foods with a high GI would normally be eaten in smaller portions thus lowering their GL. However high GI/GL foods are associated with insulin resistance, lower concentrations of HDL cholesterol, high levels of triglycerides in the blood, and inflammation. All of which are risk factors for heart disease.
In the diet Proteins are initially broken down in the stomach. The enzyme pepsin breaks down the protein into smaller polypeptides and amino acids, this process is continued within the small intestine, where the pancreatic enzymes trypsin, chymotrypsin and elastase continue the process. These are then assimilated by the body. The amino acids are then transported throughout the body for protein synthesis. Amino acids in excess of needs are unable to be stores, so any excess is converted to glucose or Ketones, or are broken down and the excess ammonia created is excreted by the body in the form of urea.
Each food will have a different combination of amino acids. Some foods are considered complete proteins in that they contain all the essential amino acids required. Many amino acids are considered non-essential because the body is able to synthesise them as quickly as they are utilised. Foods that are considered complete proteins are generally found in animal sources. Soybeans and Quinoa are also good sources of foods that contain all the essential amino acids. The body does not require that all the essential Amino acids come from the one source as long as the diet contains them within the variety of foods eaten.
Essential Amino Acids; Non-Essential Amino Acids
Phenylalanine Alanine Glycine. Selenocysteine
Isoleucine Arginine Ornithine. Tryptophan
Leucine Aspartic acid Proline. Creatine (energy storage)
Valine Cysteine Serene.
Threonine Citrulline Tyrosine,
Methionine Glutamic acid Asparagine
Lysine Glutamine. Taurine
Histidine (Required in childhood and growth periods. As demand exceeds production during these times.)
For more information go to AminoAcidsGuide.com.
Protein is involved in a number of regulatory functions, such as: Growth, hormones, enzymes, cytokines, transcription factors and also neurotransmitters. Protein is required for the immune system, and can act as transport carriers in the blood. Protein is also involved in fluid balance, PH levels, detoxification and energy. Some protein enzymes, such as kinases and phosphatases act in a regulatory manner, controlling the action of other enzymes. There is no specific storage of protein in the body but the breakdown of muscle will serve as a fuel reserve in times of energy needs. During protein metabolism the amino acids which make up the protein are broken down and the nitrogen content, which is toxic to the body is eliminated through the urine.
The amount of daily protein required is usually calculated as 0.8 - 1.0 g per Kg of body weight.
An important distinction needs to be made between two aspects of protein, that is, protein quantity and protein quality. Protein is broken down through digestion into its constituent amino acids and then absorbed. The amino acids have been traditionally divided into essential and nonessential. However many of these nonessential amino acids can be further differentiated as conditionally essential. In that it is possible to be deficient if the body is unable to synthesise them. This may be due to the body's needs being greater than its ability to synthesise the relevant amino acid. For example cystine plays an important anti-inflammatory and antioxidant role. Increased exposure to toxins may increase the body's need to utilise more cystine than it is able to produce.
A number of nonessential amino acids are involved in detoxification. The branched chained amino acids: leucine, isoleucine and valine can be oxidised in the mitochondria to provide energy. Creatine and carnitine also play key roles within energy production. Creatine is stored in muscles as phosphocreatine and helps in the regeneration of ATP, (Adenosine Triphosphate) the energy currency of the body. Carnitine helps to transport fatty acids and pyruvate into the mitochondria to be used for energy production. Arginine generates Nitric Oxide and is involved in the Urea cycle which enables the body to dispose of excess nitrogen. Taurine and Glycine play an important role in detoxification. While Cysteine also plays an important role in converting Homocysteine into Methionine. High levels of Homocysteine are related to cardiovascular disease, while Methionine plays an important antioxidant role and is involved in detoxification. Glutamine combined with Alanine transports Nitrogen.
Glutathione; produced from Cysteine, Glycine and Glutamic acid is an antioxidant produced in cells and possess many benefits. It reduces oxidative stress, supports immune function, contributes to the making of DNA, supports enzyme function, regenerate vitamins C and E, and regulates prostaglandin synthesis as well as many other functions. While the body is able to synthesise Glutathione, levels can drop with age and poor diet.
The amino acid glutamate acts as an excretory neurotransmitter in the brain, and is involved in; memory, cognition, movement and sensation. Gamma-Aminobutyric Acid GABA acts as an inhibitory neurotransmitter. While Aspartate acts as an excretory neurotransmitter and Glycine inhibitory. Glutamate and GABA account for 90% of activity.
Sometimes a protein or a peptide can cause an allergic reaction invoking an immune response. A person may be intolerant to certain proteins due to not having the requisite enzyme to break it down. For example lactose found in milk and dairy products. Without the enzyme lactase, lactose is not broken down and ferments in the stomach causing bloating, flatulence, and diarrhoea.
An elimination diet can be beneficial in identifying the underlying cause and relieving the symptoms of foods that initiate an allergic response.
The two main types of fats are, Saturated, which is solid at room temperature, and Unsaturated, which is liquid. Unsaturated fats can be further divided into Monounsaturated and Polyunsaturated (PUFAs). Related to the number of hydrogen atoms they possess. Most vegetable oils are high in PUFAs.
Fats are obtained mainly from meat, dairy food, nuts and seeds, but most foods contain some fat. Saturated and unsaturated fats can be further sub-divided into, long, medium, and short chained fatty acids, which will have different properties, and differing functions within the body.
Generally the more saturated tend to have structural properties, while the unsaturated play more of an interactive role. Two polyunsaturated fatty acids, Linoleic (omega6) and Alpha - linolenic (omega3) cannot be synthesised in the body and need to be obtained through the diet.
Lipids are also involved in metabolic regulation, for example, steroid hormones. They are also required for the uptake of certain nutrients, for example the fat soluble vitamins; A, D, E and K.
Cholesterol is a steroid hormone that plays an important role in the; transmission of nerve impulses, formation of Vitamin D, the synthesis of testosterone and oestrogen and the formation of bile. It also helps provide stability to the phospholipid structure of the cell wall. Cholesterol is manufactured by the liver and also obtained through the diet. The liver produces cholesterol on demand. As the body's total cholesterol level increases its synthesis decreases. However this process may be compromised when cholesterol intake through the diet is very high. Also the body requires a good fibre diet to help get rid of any excess. Cholesterol synthesis also produces the regulatory hormones; cortisol, dehydroepiandrosterone DHEA, testosterone and oestrogen.
Lipids are susceptible to damage, Oxidative stress (Reactive Oxygen species ROS). An increase has been linked to a number of degenerative conditions within the body, such as, atherosclerosis. ROS is created as a result of a number of physiological processes, for example, during the production of ATP (the energy currency of the body). This occurs within the mitochondria of the cell. Reducing the potential free radical damage the body utilises antioxidants; Vitamin C, Vitamin E, Glutathione, Lipoic Acid, Cysteine, and Coenzyme Q10. Also the supporting enzymes, Superoxide Dismutase (SOD), Glutathione Peroxidase (GPO) and Catalase, which require the minerals, zinc, copper and manganese.
Essential Fatty Acids
Essential Fatty Acids are polyunsaturated Fatty Acids (PUFAs). They perform a number of important functions. There are several types of PUFAs, the main ones being Omega 3 (Alpha-Linolenic Acid W3) and Omega 6 (Linoleic Acid W6). They are important for the body's normal growth and development.
Omega 3 oils play a significant role in the brain, the cardiovascular system, immune function, physical performance, and bone health. They also play a role in the transfer of Oxygen from the air into the lungs, across the membranes of red blood cells to the haemoglobin and then from the red blood cells into cells and into the mitochondria, to be used for energy. Omega 6 oils play an important role in regulating genes and promoting immune health and blood clotting.
Omega 3 and 6 are part of the structural component of the cell's phospholipid wall. They interact with proteins in the cell wall to transfer electrons and energy, and are also involved in the production of Prostaglandins, Leukotrienes, Thromboxanes, and Lipoxins, which act locally and play a significant role in inflammation. All the cells, except erythrocytes, are involved in their production.
Prostaglandins play a role in the contraction and relaxation of blood vessels, and inflammation. They can be pro or anti-inflammatory dependent upon which Omega is being synthesised. Generally Omega 6 are Both anti and Pro-inflammatory while Omega 3 is anti-inflammatory.
Thromboxanes are involved in the constriction of blood vessels and blood clotting.
Leukotrienes cause a tightening of airway muscles and the production of excess mucus and fluid. They also synthesise Lipoxins which are anti-inflammatory and help resolve excess inflammation.
Omega 6 oils tend to be more abundant within a typical diet, and Arachidonic acid is easily obtained from meat sources, and when synthesised lead to pro-inflammatory conditions. It is believed that the average western diet has an imbalance between the Omega 6 and Omega 3 fatty acids. Historically the ratio of Omega 6 to Omega 3 was closer to 1:1. It is now closer to 25:1, shifting the body's response to a more inflammatory condition. The body uses the same enzymes to break down the Fatty Acids into the necessary Prostaglandins. Therefore the excess Omega 6 to Omega 3 within the diet will also promote a more inflammatory condition, through interfering with the conversion of Omega 3 fatty acids. Hemp oil tends to have the better ratio of Omega 6 to 3 between 2:1 to 3:1. It is important to stress however that pro-inflammatory prostaglandins play an essential role in the body's inflammatory response, and problems that arise are due to the imbalance in the ratio of Omega 6 to Omega 3.
Acting on the phospholipid cell membrane the enzyme Phospholipase A2 releases Arachidonic acid. This pathway can be inhibited by the actions of; Vitamin E, Quercetin, Turmeric and Liquorice, and further along the pathway by Ginger and Turmeric which inhibit the enzyme responsible for producing the Series 2 pro-inflammatory prostaglandins. Onion, Garlic, Turmeric, Quercetin and Vitamin E inhibits the production of inflammatory leukotrienes. Other inhibitors of pro-inflammatory prostaglandins are EPA and DHA produced by Omega 3 oils. If the ratio of Omega 6 to Omega 3 is too high this will inhibit the production of EPA and DHA.
The difficulty for most diets is obtaining enough EPA and DHA. The body does not convert Omega 3 (alpha-linolenic acid) as easily due to the issues stated above. Fatty oily fish tend to have plentiful amounts of both EPA and DHA. Vegans may consider supplementing their diet with a good source of both EPA and DHA. However if the ratio of Omega 6 to Omega 3 was more balanced this may not be such an issue.
Flax seeds are a good source of W3, but one needs to be grind the seeds so that the body can assimilate the Omega 3 content. They also contain; Lecithin, Carotene and Vitamin E, and mucilage which acts as a buffer for excess acid. Other properties of Flax seeds are that they prevents the reabsorption of cholesterol, produces a laxative effect, helps stabilise and modulate blood glucose level, and are a good source of minerals and some Vitamins; E, B1, B2, and C. They also contain Lignans, anti viral, and anti fungal and anti-bacterial and anti-cancer properties.
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