The Digestive System The Brain
The digestive system’s activity starts in the brain even before we have a bite to eat.
The Hypothalamus is a centre in the brain which maintains and regulates metabolism, body temperature, thirst, appetite, sex drive and blood pressure.
Proper assimilation of food starts in the mouth :
“Drink your food and eat your drink”
Chewing and Swallowing first stop. The saliva consists of water and contains two major enzymes; alpha amylase and lyszym.
The amylase performs an initial breakdown of polysaccharides
The lysozyme breaks down the coating of certain germs which end up in the mouth thus eliminating them. Hence, the saliva prevents accumulation of germs
- Chew at least 20-30 times.
- Remember, the stomach has no teeth.
- Take care of your teeth for a proper break down of the food
- Eat slowly and intentionally.
- Avoid talking with your mouth full.
The different parts of the digestive tract are separated by sphincters, which are tubular muscles, such as the esophagus sphincter which separates between the esophagus and the stomach, or the one between the stomach and the duodenum.
Processing of food
The mechanical action.
- Peristaltic action –contraction of muscles along the digestive tract.
- Pendulum-like motion-assists in digesting food in the small intestines by moving it forward and backward.
- The sphincters contract and relax as needed, and regulate passage of food between the different parts of the digestive system.
An autonomic involuntary nervous system regulates the digestive muscles.
The chemical process
Breaking down of the food to its chemical components through
-electrolytes(such as sodium and potassium bicarbonate, bile and HCL)
-Controlled by the autonomic nervous system and by digestive hormones
The stomach has five main functions;
- Absorption of fluids
- Storage of food
- Mechanical breakdown of food and its preparation for further breaking down in the intestines
- Defense line against pathogens and toxins
- Initial chemical breakdown
· A secretion of the HCL changes ph to 1or2
· Pepsin denatures proteins into amino acids
· Intrinsic factor helps uptake of vit B12 critical for RBC production
Important facts about the stomach
- When the stomach is empty: its volume is 50cc, after a rich meal 1500cc
- Transition time of food in the stomach is between 2-6 hours.
- Main functions of the stomach; assembling mixing and breaking down of the food
- Fat rich food delays digestion
- The type of food and its quantity affect digestion time.
- Digestive enzymes: pepsin-breaks down proteins, lipase-breaks down fats.
- HCL =ph2, necessary for proper functioning of digestive enzymes.
- HCL fights against pathogens
- Their length is 9m, and their diameter is 3.5cm. Main function ; breaking down the food and absorbing food
- Digestion of carbohydrates begins in the saliva and then in the duodenum
- During 24 hours, the intestines receive 7 liters of fluids, most of them secreted by the digestive system, 2 liters from food
- The small intestine completes the process of food breakdown which starts in the mouth and in the stomach, aided by pancreatic enzymes, intestinal cells and bile.
- A final breakdown of the proteins, carbohydrates and fats is in the small intestines
- Its length is 1.5 m. It’s main function is elimination of food.
- No enzymatic action takes place in the colon.
- 90% of the water coming from the small intestines get absorbed in the colon
- The colon has a population of good and bad bacteria (flora).
- In a healthy colon there is harmony between the good and bad bacteria, a sick colon is a health hazard
- K and B vitamins, which are secreted by bacteria, get absorbed in the colon
Liver, Gall Bladder and Pancreas
Liver Main Functions
- Responsible for synthesizing glucose, vitamins and minerals
- Detoxes toxins
- Transforms glycogen, fat and proteins into glucose and vice versa
- Stores A,D,E,K,B12 vitamins
- The liver produces bile which is needed for emulsifying fats.
How to enhance liver function
- Low fat diet
- Avoid alcohol
- Eliminate negative emotions such as hate, envy and jealousy
Internal and external excreting gland
- Hydroxyl Ions are released via the pancreatic duct to raise the pH from 1-2 to 7.6-7.8
- Digestive enzymes are made and released into the duodenum
- Insulin is released to help deliver glucose into the cells and reduce blood sugar.
How to enhance Pancreatic Function
- Limit consumption of simple carbs, i.e. white sugar, white flower, white rice
- Consume more enzyme rich foods such as raw fruits, vegetables, seeds, and sprouts.
- Select foods with a low glycemic index
- Use digestive fibers(25-30 gr daily)
Each gr of carbohydrates gives us 4 calories. Carbs turn into glucose(sugar) which is a source of energy to the body (for brain function, for nervous system, muscles, heart, liver)
- Found in vegetables, whole grains, legumes, seeds and nuts.
- A healthy ratio in the diet should be: 65% carbs, 20% proteins,15% fat.
- Consuming complex carbohydrates results in a prolonged digestive process in which sugar level in the blood remains steady. This stability contributes to a feeling of fullness
- Too many carbohydrates turn into fat.
- Sugar, honey, jam, chocolate and fruits get absorbed fast
- Sugar is present not only in carbonated drinks or cakes, but in many food items
- Even foods which don’t have a sweet taste contain sugar, such as raw apples, milk and dairy products as well as orange and grapefruit juice.
- The average person consumes 60kg sugar per year
Dangers from Sugar
- Sugar depletes the body from minerals
- Sugar causes a rise in adrenalin level
Diseases from sugar
High Cholesterol and triglycerides, diabetes, tooth decay, cardio vascular disease, emotional imbalance, hypertension and especially craving for more food (due to overactive insulin)
We obtain protein from two sources: from plants and from animals
Protein’s main function
- Building and reconstructing of tissues
- Building immune cells which fight infections
- Transporting of food and oxygen in the blood to and from the cells
- Regulating the water, acidity/alkalinity levels
- Regulating metabolism and turning food into energy
Proteins are built from amino acids, which carry nitrogen (vital for life)
There are 22 amino acids 13 are non essential and 9 are essential.(which means, we have to take them in from food)
Examples of complete protein (meat, chicken, fish, legumes+ whole grains, soy, pumpkin seeds)
We need to consume a variety of foods during the day.
- Each gram of fat gives 9 calories
- 15% of total calories per day should come from fat.
- Fats are essential for proper functioning of body systems
- Fats are essential for absorption of fat soluble vitamins E,D,A,K
- Fat support different organs, serves as insulator from heat and cold.
- Saturated fats are harmful
- The food industry uses S.F in many products to prolong shelf life.
Mono and Poly-unsaturated fats
Polyunsaturated fats can be found in seeds, many legumes, sunflower, nuts, almonds, sesame, soy, corn, etc
These fats are preferable to the saturated fats.
Fats like olive oil, avocado oil and Canola oil
- N.F are found in plant food
- Refined foods and juices have no fiber
- Consuming fiber gives a feeling of fullness for a longer time, reduces cholesterol levels, as well as blood sugar and triglycerides
- There are two kinds of fiber. Soluble and insoluble
- Fiber aids in cases like constipation, high cholesterol, diabetes, etc.
- There has been a link between a low consumption of fiber and colon cancer, prostate cancer, and breast cancer etc.
- In cases of colon blockage, diverticulitis or stomach ulcer, fiber can irritate and even damage these organs.
- Vitamins are nutritional components which are vital to the body.
- Each vitamin has its function.
- Deficiency in one vitamin may lead to health hazard
- Over consumption of vitamins may lead to health hazards
- Our body cannot synthesize vitamins on its own (except for vitamin D) and is therefore dependent on the various kinds of food we consume.
- Vitamins can be divided into two groups
- Fat soluble(A,E,D,K) and water soluble (B vitamins and C)
- Most of the vitamins are heat and acid sensitive
- Fruit juice oxidizes within minutes
- Fruit skin preserves the fruit from oxidizing
- Eat the foods in the natural form as much as possible.
- Foods which require cooking should be cooked briefly, in a small amount of water, or steamed and be eaten immediately or kept refrigerated until meal time
- Usually the vegetable stock is rich in vitamins from the food and it is therefore a good idea to use it and not to throw it away.
Minerals are natural components that are found in the crust of the earth.
The human body contains similar minerals to those found in the earth.
Tips for Health
In order to support the digestive process, we need to remember the following
- Eat calmly
- Chew every byte 36 times
- Do not drink while you eat. in order not to dilute the enzymes.
- Our body is not a garbage can
- Do not talk while eating
The Glycemic Index of Foods
The glycemic index of foods is a ranking of foods based on their immediate effect on blood glucose (blood sugar) levels.
Generally a low glycemic food (lower than 55) is recommended for stabilizing blood sugar levels. The next group includes foods that have a glycemic index between 56 and 69 (medium). Foods with a high glycemic index (70 and up) should be limited.
Fresh vegetables, legumes and fruits are mostly with a low GI, thanks to their nutritional fiber. Root Vegetables (especially when cooked or baked) become high on the GI. For instance a potato cooked in its skin (70) and a baked potato (85).