Leason 5 Digestion and Helath Flashcards
(26 cards)
Definition of Digestion
Digestion is the process of breaking down food by mechanical and chemical action in the digestive tract into substances that can be used by the body.
3 Vital/Primary Functions of the Digestive System
- Digestion: the breakdown of food we eat:
-mechanical digestion (chewing(masseter and temporalis,teeth), peristalsis-movement from proximal to distal tube in the right direction-squeeze and push forward)
-chemical digestion (saliva, gastric juices, pancreatic juice, bile and enterocyte enzymes) - Absorption:-only can take place if we have good digestion:
-primary in the small intestine
-absorption into the blood (venous system) and lymph (lipids and fat soluble vitamins A,E,D,K) - Excretion:
-waste materials (including toxins acted on by the liver) are excreted via the intestines as faeces. Elimination also occurs via the urine, skin(sweat) and lungs.
Digestive System consists of
30ft tube from mouth to anus, supported by accessory organs. It ultimately functions to nourish the tissues of the body-supporting cellular processes.
Digestive tract:
Mouth, pharynx, oesophagus, stomach, small(duodenum,jejunum and ileum) and large intestine(cecum with appendix, colon, rectum, anal canal).
Accessory Organs:
Salivary glands, pancreas, liver(hepatic first pass and bile production), gall bladder and biliary tract.
Oral Cavity
Chewing breaks down food into smaller chunks and triggers salivary glands to release saliva containing the enzyme SALIVARY AMYLASE, which breaks down starches.
Chewing adequately up to about 20 times per bite. The more you chew, the more amylase is released and more CHs can be broken down and made available to the body.
-Avoid drinking with meals as it dilutes saliva and gastric juices. Less concentrated digestive juices result in fewer nutrients being made available to the body. Drink as much liquid as you need at least half an hour before food and half an hour to an hour after food.
Salivary Amylase
-Salivary amylase starts breaking down long CH chains (polysaccharides), found in starchy foods, into smaller sugar chains. They are fully digested in the small intestine. If you leave starch in your mouth long enough, you taste sweetness. Saliva provides medium for food to be tasted. Dry mouth conditions affect how people taste food (not much tasting hence not enjoying food).
-The optimal pH for salivary amylase to function is 6.8 (almost neutral).
-Amylase is denatured by stomach acid and becomes inactive once the bolus arrives in the stomach.
-CHs not adequately digested in the mouth might remain unutilised by the body as the small intestine (SI) can only absorb single sugars.
Saliva also contains antibodies IgA in particular and they decline with stress. Therefore the oral cavity and the whole digestive system could be compromised and overcome by opportunistic bacteria as defence is compromised.
We don’t break down cellulose-it will bypass all enzymes and hunger into the LI where it’s digested by microflora.
Saliva pH
The optimal saliva pH can be challenged by more acidic environment in the mouth.
-excess acidity in the body tissues will be excreted by saliva, lowering its pH. This impaired functionality of salivary amylase, and therefore impacts digestion of CH in the oral cavity reducing their utilisation in the body.
-the pH in the mouth can be lowered by factors such as refined sugars, meat and dairy, as well as processed foods, chewing gum, cigarettes, coffee and alcohol, chronic stress and being sedentary. Exposure to heavy metals from sources from sources such as dental amalgams lowers the pH of mouth, too. Aluminium (foil, antiperspirants). Heavy metals also damage proteins and cells in the body. We’d use natural chelators to excrete them such as algae, spirulina and chlorella and corriander as well as making sure elimination is optimal.
Stomach
The bolus enters the stomach through the lower oesophageal sphincter. Sphincter prevents acid reflux into the oesophagus.
-food stretches the stomach, which results in the release of the hormone GASTRIN (from g-cells) and the stimulation of ENTERIC NERVES in the stomach wall.
-both stimulate the PERISTALSIS of the stomach leading to the release and formation of gastric juice containing HCl (from parietal cells also produce inteinsic factor) cellsand DIGESTIVE ENZYMES (lipase and pepsinogen) (produced by chief cells).
-the stomach churns the bolus, mixing it with the gastric juice to break down food.
Stomach is a churning organ (3 layers of smooth muscle). It’s layered with a protective mucus (⬇️by stress, NSAIDS
Stomach: Enzymes
Two enzymes released from stomach wall:
1. Pepsinogen- an inactive enzyme which becomes activated when exposed to HCl. It converts to the active form PEPSIN which break down proteins into smaller protein chains.
2. GASTRIC LIPASE- breaks down lipids.
-The stomach absorbs some water, alcohol, iodine and fluoride. These substances enter the venous circulation and are escorted directly to the liver by the ‘portal vein’ to be processed.
Stomach Acid
Hydrochloric acid has a pH of 2-3.
-Zn, Vit B6 are required to produce HCl. (And some B1).
ZINC SOURCES: nuts, seeds(esp. pumpkin seeds), eggs, oysters, fish and meat.
VITAMIN B6 SOURCES: whole grains, sunflower seeds, legumes, walnuts, green vegetables, carrots, potatoes, avocado, fish.
-Stomach acid performs following actions:
-breaking down proteins (pepsin) and fats (lipase)
-triggers pancreatic juice and bile release into the duodenum (via CCK) when acidic chyme enters the small intestine.
-eliminates micro-organisms such as bacteria, viruses and fungi, protecting against infection.
CCK=chilecystokinin-hormone released from the duodenum wall.
CCK
Cholecystokinin. CCK
Release from the duodenum in response to acidic chyme and chyme rich in protein and fats.
CCK is the primary signal that tells the gall bladder and pancreas to secrete bile and pancreatic juices to help with chemical digestion.
Acidic chyme is one of the main driver for releasing CCK.
Low Stomach Acid
Causes:
-chronic stress (excess sympathetic activity)
-low vit B6 and Zn (B1)
-autoimmune gastritis
-medications (PPI)
-chronic Helicobacter pylori infection (a bacterium associated with gastritis, peptic ulcer and gastric cancer)
-ageing (production gradually decline over 50).
Stomach acid test:
First thing in the am mix 1/2 tsp of bicarbonate of soda in a glass of water and swallow. Should belch within 2-3 minutes (sufficient HCl). If none, stomach acid is considered low.
Low Stomach Acid leads to…
And Symptoms
Low HCl leads to poor protein digestion, resulting in protein putrefaction in the SI.
-protein putrefaction creates compounds called ‘POLYAMINES’ which are implicated in colorectal cancer.
-undigested food allows bacteria to proliferate in the SI (where they would not normally reside in large numbers)-SIBO small intestinal bacterial overgrowth
-reduced gastric activity results in less intrinsic factor (a glycoprotein secreted in the stomach) compromising B12 ABSORPTION. Leading to deficiencies in Ca, Mg, Fe, Zn, Na as well.
-could lead to dysbiosis
-could lead to candida
-imbalance of gut bacteria
-could lead on to symptoms of heartburn and reflux (purification making gas pushing into the stomach and causing symptoms)
-H, pylori (diagnosed by C13 or C14 breath test-create ammonia or a stool test-pick up antigens for H.pylori )
Low stomach acid can present as:
-bloating, belching and flatulence within 1-2 hours after meals
-abdominal pain and ‘fullness’ after eating, with foul-smelling stools.
-nails may be depleted-thin and brittle due to low minerals due to low HCl
-people supplement and get nauseous when swallow a supplement
-foul smelling stools and possibly floating in the toilet
Low acid means bile and pancreatic enzymes are not well utilised - the message is not getting through.
How to ⬆️ Stomach Acid
-Apple cider vinegar with the mother in a little water before meals
-bitter herbs and foods stimulate stomach acid release. They should be taken 15-20 mins before meals. These include gentian (extremely bitter, found in Swedish bitters), barberry bark, andrographis, dandelion and goldenseal. Also include bitter foods such as rocket, chicory, artichoke and watercress.
-Zinc and B6 rich foods.
-avoid overeating and ensure meals are relaxed (eat mindfully). Avoid processed foods.
-eat a diet rich in fruit and vegetables
-eat fermented vegetables such as sauerkraut
-Himalayan and sea salt provide a chloride for HCl.
Cholecystokinin (CCK)
As chyme is drip-fed through the pyloric sphincter into the duodenum, CCK is released.
-CCK: A hormone released from the duodenal wall triggering the release of pancreatic juice and bile.
CCK also induces a sense of satiety.
-presence of acidic chyme in the duodenum is a key factor in CCK release, meaning that the low stomach acid can really impair the digestion.
-chyme has a pH of about 2. It is usually acted upon quickly by bicarbonate, which is secreted by the pancreas and liver. This neutralises chyme and creates a pH of about 6.5 in the duodenum.
Small Intestine SI
The SI is a 6.5m long structure that acts as a key site for digestion and absorption.
-90% of nutrient absorption takes place in the SI
.The SI has three regions:
1. Duodenum- 30cm. Most digestion occurs here, aided by the influx if pancreatic juices and bile.
2. Jejunum (2.5m)- most ABSORPTION occurs here, ie. sugars, AAs, fatty acids, vitamins (coeliac disease area-hence would every disturb absorption)
3.Ileum (3.5m)- vitamin B12 is absorbed-right at the end (Chrons disease area)
Small Intestine Absorption/surface area
To aid absorption the SI create a vast surface area.
-Created mostly by the finger-like projections, foldings:VILLI. they contain blood and lymphatic capillaries.
-The cell membranes of of small intestinal cells fold to create microscopic projections-MICROVILLI. Also known as BRUSH BORDER.
-Nutrients contact the microvilli and are absorbed into blood capillaries with fatty acids entering the lymph.
Brush Border Enzymes
Attached to the SI lining.
-break down disaccharides (starch, glycogen broken down by amylase into disaccharides) and dipeptides, allowing them to be absorbed.
-1. DIPEPTASE- break down proteins into AAs
-2. MALTASE, SUCRASE and LACTASE - break down
Maltose-glucose x 2
Sucrose-glucose and fructose
Lactose-glucose and galactose
Intestinal Absorption
-Only simplest forms get absorbed:monosaccharides , AAs and fatty acids.
-CHs (simple sugars) and AAs enter blood capillaries in the SI to be sent to the liver.
-Fatty acids including fat-soluble vitamins (A,D,E,K) are digested in the SI and enter lymphatic capillaries-lacteals.
Pancreas
An accessory organ that has endocrine and exocrine functions.
-EXOCRINE-produce enzymes that digest CHs, proteins and fats, secreted into the SI.
-pancreatic enzymes are part of ‘pancreatic juice’ (1.2-1.5L/day).
-They are:
-PANCREATIC AMYLASE
-PANCREATIC LIPASE
-PROTEASES (trypsin and chymotripsin)
Pancreas. Anatomy
About 6inches long. Sits in the upper posterior abdomen, behind the stomach.
-Connected to duodenum via pancreatic duct.
-If pancreatic enzymes production is poor, foods ferment in the intestines causing symptoms such as bloating, flatulence and abdominal pain about 1hr after eating. Similar to symptoms of candida overgrowth.
Might have stool floating/if fats not digested properly(problems flushing stools).
The lack of digestion can lead to weight loss.
Over-eating
Eating often and too much- digestive enzymes are used up. Not all food can then be digested resulting in malnutrition and bodily distinctions.
-eating junk-body is starving for nutrients feeling hungry
-places pancreas and stomach under stress, potentially depleting their capacity for digestive juice’s production.
-E directed away from healing, repair, ⬆️ the risk of disease.
-keep eating window small
-what is driving craving and how to balance it out
-soups, smoothies and juices are very easy to digest with lot of enzymes from fruits and vegetables facilitating digestion ie Gerson therapy
-Individuals eating a well-balanced and nutritious diet use about 10% of their daily E expenditure digesting and absorbing food. This can increase to 50% in those who eat dense forms of protein (meat, soya) and junk food.
-therefore over-eating and excessive ingestion of animal proteins compromises other bodily functions leading to fatigue, reduced immunity and so on.
-to support digestive system health:
-do not eat more than 3 meals a day
-avoid overeating and snacking between meals
-don’t drink with meals.
Overeating Bernard Jensen
-Bernard Jensen found that undigested materials are stored in the mucus-secreting lining of the intestines, impairing the absorption and delivery of nutrients to body tissues. The thicker the lining of digested materials the lower the absorption of nutrients.
-this would create an optimal environment for the parasites and candida to flourish, as well as under-nourishing body tissues and organs.
-supporting detoxification is key to aid the body’s elimination of these wastes. By supporting liver and the bowel emptying.
Intermittent fasting and dietary changes to minimise the the digestive system load are also important.
Jensen also recommended vegetable broths. (Celery onions potatoes carrots broths), apple cider vinegar, juice fasting and rest, supplemented chlorophyll, dry brushing to support detoxification.
Gallbladder
A pear shaped sac, 7-10cm in length, sits under the liver.
-contracts in response to CCK hormone. (Need good levels of HCl and presence of fats in chyme). Gallbladder contracts predominantly after ingesting fat and ejects bile down the common bile duct into SI.
-stores and releases bile produced by the hepatocytes in the liver.
-Bile consists mostly of water, and bile salts (conjugated with the AAs glycine and taurine in liver), cholesterol and bilirubin(waste product from haem-determines brown colour of stool)
Bile Functions
-FAT EMULSIFICATION-bile breaks lipids into small molecules. This ⬆️ surface area for pancreatic lipase.
-CARRIES DETOXIFIED PRODUCTS FROM THE LIVER- after the liver has detoxified harmful materials, it excretes them into bile, which provides a medium for excreting these substances.
-STIMULATES PERISTALSIS-bile stimulates intestinal peristalsis (and hence the removal of wastes via the bowels)
-EXCRETES EXTRA CHOLESTEROL-bile contains excess cholesterol that the body wants to excrete.
Therefore poor bile flow affects fat digestion and the body’s ability to eliminate toxins via the bowel.
