Digstion And Health Flashcards
(49 cards)
3 primary functions of digestive system
- Digestion
Mechanical and chemical - Absorption
Primarily small intestine
Into blood and lymph - Excretion
Waste materials
30 foot tube
Digestive tract:
Mouth, pharynx, oesophagus, stomach, small and large intestines
Accessory organs
Salivary gland, pancreas, liver, gall bladder, biliary tract
Oral cavity
Linked to lifespan
Chewing breaks down food and triggers amylase to be released from salivary glands to break down starches
Breaks down long carb chains (polysaccharides) found in starchy foods
Optimal pH is 6.8
Carbs not adequately digested in the mouth can remain initialised by the body as the small intestine can only absorb simple sugars
Saliva pH
Excess acidity in the body tissues will be excreted via saliva, lowering pH.
Impairs functionality of salivary amylase
Can be lowered by refined sugars, meat and dairy, processed foods, chewing gum, chronic stress, coffee
Stomach
Boils enters stomach through lower oesophageal sphincter (prevents acid reflux)
Food stretches stomach:
1. Releases hormone gastrin and Stimulation of enteric nerves in stomach wall
3. Stimulates peristalsis, leading to formation of gastric juice containing HCI and digestive enzymes (lipase and pepsinogen)
4. Stomach churns boils
Stomach absorbs:
Water, alcohol, iodine, fluoride
Enters venous circulation and escorted directly to liver by portal vein to be processed
Enzymes released by stomach wall
Pepsinogen and gastric lipase
Pepsinogen:
Inactive enzyme which comes active when exposed to HCI
Concerts to active pepsin to break down proteins into smaller protein chains
Gastric lipase: breaks down lipase
Stomach acid
Zinc and B6 required to produce HCI
PH 2-3
Functions:
Breaking down protein and lipids
Triggers pancreatic juice and bile release into duodenum where acidic chyme enters small intestine
Eliminates micro organisms such as bacteria, virus, fungi - protecting against infection
Low stomach acid can be caused by
Chronic stress
Low B6 and zinc
AI gastritis
Medications (eg proton pump)
Chronic h.pylori
Ageing
Helping low stomach acid
Fermented foods, butter foods, ACV with mother, protein
Zinc and B6 foods
Himalayan sea salt
Low HCI leads to poor digestion, resulting in protein putrificafion in the small intestine
Creates compounds called polyamines which are implicated in colorectal cancer
Undigested food allows bacteria to proliferate small intestine (SIBO)
Results in low intrinsic factor (glycoprotein secreted in stomach) compromising B12 absorption
Presents as bloating, belching and flatulence after eating with foul smelling stools
Intrinsic factor
glycoprotein secreted in stomach
CCK: cholecystokinin
As chyme drip fed from the pyloric sphincter into the duodenum, CCK is released
Hormone released from duodenum wall, triggering release of pancreatic juices and bile
Also induces sense of satiety
Affected by low stomach acid, as the presence of acidic chyme in duodenum is key factor in CCK secretion
Chyme has pH of 2. Usually acted upon quickly by bicarbonate, secreted by pancreas and liver. Neutralised to about pH 6.5
Small intestine
6.5m long structure, key site for digestion and absorption.
90% of nutrient absorption here
3 regions
1. Duodenum: most digestion occurs here, some vits and minerals absorbed
2. Jejunum: most absorption: eg sugars, fatty acids, aa, vitamins
3. Ileum: B12 absorbed
To aid absorption, huge surface area is created
Folding of small intestine, forming finger like projections known as villi, contains blood and lymph capillaries
Further increased by cell membranes of intestinal cells folding to create microscopic projections microvilli
Nutrients into blood; fatty acids to lymph
Brush border enzymes BBE
Attached to small intestinal lining and imperative for absorption
BBE break double chained carbs and proteins allowing to be absorbed
Maltase, sucrase and lactase: breaks down sugar into glucose, fructose, galactose, etc
Dipeptidase: proteins into aa
Intestinal absorption
Carbs, protein and fats are only absorbed once they have been digested into their simplest forms
Emphasise importance of optimal function in areas as the mouth, stomach, pancreas, gall bladder
Proteins chemically digested into aa
Carbs and aa enter the blood capillaries in small intestine and go into liver
Fatty acids including fat soluble Vits are into lymph capillaries
Pancreas
Both endocrine and exocrine function
Exocrine: produces enzymes to digest carbs, proteins and fats. Excreted to small intestine
Pancreatic enzymes are imperative for digestion and are part of pancreatic juice (1.2/1.5L) per day
Pancreatic enzymes:
Pancreatic amylase
Pancreatic lipase
Proteases
6 inches long and sits posterior abdomen l, behind stomach
Connected to duodenum by pancreatic duct
If pancreatic enzyme production is poor, foods ferment in intestines, resulting in symptoms such as bloating, flactulence and abdominal pain about 1 hour after eating
Over eating
Digestive enzymes used up
Not all good can be digested
Junk food leads to cravings of nutrients
Organs such as pancreas and stomach are placed under stress
Energy directed away from healing / repair
10% of energy goes to digestion in well balanced individuals, can go up to 50% for those eating junk and dense protein
Bernard Jensen
Found undigested materials are stored in mucous secreting lining of intestines, imparting absorption and delivery of nutrients
Thicker, worse absorption
Creates optimal environment for parasites and Candida
Support detoxification: intermittent fasting, dietary changes
Gallbladder
Pear shaped sac under liver
Stored and released bile produced by liver
Bile contains mostly water, bile salts, cholesterol and bilirubin
Bile ducts collect bile products by hepatocytes, before pooling in the gallbladder
Bile enters small intestine via common bile duct
Poor bile flow affects fat digestion and body’s ability to eliminate toxins via the bowel
Functions:
1. Fat emulsification
2: carries detoxified products from the liver
3. Stimulated peristalsis
4. Excretes excess cholesterol
Biliary tree
Bile carried from hepatic ducts into gallbladder via cystic duct
Upon stimulation (ie by CCK), gallbladder contrasts and ejects bile
Pancreatic duct meets the common bile duct and carries both bile and pancreatic juice through the sphincter of oddi into the duodenum
Adequate production and release of bile and pancreatic juice is depend on upon sufficient water consumption
Bitters also stimulate release of pancreatic juice and bile
Liver
Portal vein transports all nutrients and toxins from the GIT to the liver
Filters 1.4L/ every minute
Stores carbs, fats, minerals, vitamins (not water soluble vits, except B12)
Performs detoxification and denatures hormones
Liver detoxification
Hepatocytes concerts toxins into non toxic metabolised which can then be excreted from the body via the kidneys, bowels, skin or lungs
Healthy liver deals with thousands of toxins a day
If lacks essential nutrients, or exposed to lots of trans fats, heavy metals, alcohol, caffeine and pesticides, liver detox becomes impaired
Then only partially broken down toxins and dead cells and other waste being recirculated
Phase 1 liver detox
Toxins arrive inside hepatocytes - most undergo phase 1
Concerts volatile toxins into smaller substances that are also water soluble
CYP450 enzymes create an active binding site on the toxin or hormone so it can be conjugated
Phase 1 is complete when toxin is oxidised.
Free radicals are being formed and must be neutralised by anti oxidants such as VIT A, C & E
To support, digestion to be optimised to ensure co factors and antioxidants are liberated from food.
Phase 2 liver detox
Involves conjugation
Chemical reactions which modify reactive toxins to make them safe and excreted by binding a chemical group to them.
Blind toxins are then pumped into the blood or bile for excretion, mostly via the kidneys or bowels
Nutrients include sulphur, magnesium, B vits are required
Herbs such as dandelion, milk thistle (for hepatocytes health) and liquorice root support liver detox
Key antioxidant for neutralising free radicals in liver is glutathione which is a Tripeptide formed of cysteine l, glycine and glutamine
Eliminates waste
Large intestine
Any remaining materials enter the large intestines (pH 5-7) though the ileocaecal valve, permits 1 way flow
Most nutrients should have been absorbed
Large intestine is site for final stage of digestion and absorption
Digestion assisted by MICROFLORA
Water and some vits and minerals are absorbed
Mucus is produced by goblet cells in large intestine and lubricates the lining but no digestive enzymes are released here
Regions of large intestine
- Caecum: appendix is attached
- Colon: ascending, traverse and descending regions
- Rectum: pushes stool into anal canal
- Anal canal: contains involuntary and voluntary external anal sphincter
No enzymes are here so microbiome isn’t eaten
Gut associated lymphoid tissue (GALT)
70% immune system based in GIT as GALT
Found in GIT walls (beneath epithelium) and glide leukocytes - macrophages and lymphocytes (in close proximity to trillions of microbes)
Leukocytes learn to identify microbes through close interactions with bacterial surface antigens located in cell membranes
GALT clusters in tonsils, walls of oesophagus, stomach and intestine
Secretory IgA is secreted into GIT mucosa providing immune defence.
IgA production is reduced during periods of stress