Digestive Enzymes

Fat Digestion

How fat is absorbed

Mouth

Fat needs to be suspended in water in an “emulsion” that starts with chewing.

Stomach

Fats mix with lingual (yes -from the tongue!) + gastric LIPASE.

The Duodenum Small Intestine

BILE and pancreatic LIPASE are added.

The pH has to be alkaline - 6.5 - to successfully mix with bile salts released by the gallbladder.

• Taking an acid supplement like Betaine HCl? It may be inactivating your ability to digest fat— oh and driving intestinal methane overgrowth!

The Jejunum Small Intestine

Then the digested fat particles are absorbed in the 2nd portion of the small intestine, the jejunum.

Bile salts are recycled in the ileum.

Enzymes +factors involved

Lipase, bile

Betaine HCl is commonly added to acidify the stomach but consider natural ACV (apple cider vinegar) first.

What are the main drivers of fat malabsorption?

EPI

exocrine pancreatic insufficiency: defective production of pancreatic lipase, colipase, and/or bicarbonate:- you need these to digest! Check your stool elastase.

SIBO

Bile salts, which are normally needed to digest fats, are broken down by the excess bacteria in the small intestine instead, rendering bile acids ineffective for fat absorption and therefore diarrhea and low vitamin ADEK.

Liver/gallbladder

Problems like cholestasis

Decreased gut surface area

With reduced exposure to digestive enzymatic activity- this includes Crohns, Celiac disease and Small bowel resection.

Lymphatic system disorders

Intestinal lymphangiectasia - impaired lymphatic flow impacting fat processing and Whipple disease - a systemic disease caused by Tropheryma whipplei.

What are the signs + symptoms of fat malabsorption?

Fatty stools

(steatorrhea) that are greasy and particularly smelly, may be light-colored and float.

Low fat-soluble vitamins

(A, D, E and K)

Bile acid malabsorption

fat malabsorption can be from a lack of bile from diseases of the gallbladder, bile ducts or liver OR leftover bile acids in the intestine and passing these on to your colon (bile acid malabsorption) that triggers water secretion and diarrhea

Protein Digestion

How protein is absorbed

Stomach

Protein digestion + absorption begins in the STOMACH with proenzymes (ex. PROTEASES like pepsinogen --> active PEPSIN) that become activated at low ACIDIC pH levels and become amino acids. (If stomach acid low in setting of Rxs this could be an issue!)

Small Intestine

the amino acids stimulate the release of CCK, and CCK stimulates the release of pancreatic enzymes (more PROTEASES - trypsin, chymotrypsin, elastase, and carboxypeptidases A and B). After various levels of protein digestion by pancreatic enzymes, the amino acids, dipeptides, and tripeptides are ready for absorption via gut brush border sodium-dependent amino acid co-transporters.

Enzymes + factors involved

Proteases

such as pepsin, most supplements have their own mix and two famous natural ones are:

Bromelain

is a mixture of enzymes found in pineapples (Ananas comosus) that digest protein

Papain

is a proteolytic enzyme from the latex of tropical papaya (Carica papaya L.), a cysteine protease

What are the main drivers of protein malabsorption?

• Impaired pancreatic bicarbonate and protease secretion and/or activity:
  • Chronic pancreatitis
  • Cystic fibrosis
• Lost absorptive gut surface area:
  • Inflammatory bowel disease (IBD)
  • Intestinal lymphangiectasia and other problems with lymphatic flow
  • Bowel surgery
• Pathology of the stomach or proximal small intestine (e.g., vitamin B12 deficiency)

What are the signs + symptoms of protein malabsorption?

• Milk protein intolerances and gluten intolerance
• Blood tests: low protein and albumin, which may present as low muscle mass, swelling

Carbohydrates Digestion

How carbs are absorbed

• Complex carbs (disaccharides) are digested into monosaccharides for absorption. This begins with salivary and pancreatic AMYLASE. In your small intestine Brush border enzymes, then hydrolyze that carbohydrate mixture into monosaccharides which are then absorbed.
• Any remaining carbs that are not absorbed (including non-absorbable cellulose) get fermented in the colon and degraded by your microbiome bacteria. This bacterial fermentation process creates fatty acids that are absorbed by your colon's epithelial cell lining and used for energy.

Enzymes +factors involved

• amylase, brush border enzymes (lactase, sucrase, maltase, palatinase) and there are MANY commercial enzymes, usually from fungus

Beta-glucanase

β-Glucanase enzyme causes the hydrolyzation of β-glucans which are the sugars present in microorganism cell walls for plants like barley and oats

Cellulase

break down insoluble cellulose (fiber!) to soluble sugars, often used on fruits to make fruit juice

Glucoamylase

breaks the α-glucose polymer into glucose to produce dextrose or d-glucose

Glucose

isomerase- breaks down D-glucose and D-xylose to D-fructose and D-xylulose

Hemicellulases

a group of enzymes involved in the breakdown of carbs like galactans (high fodmap!)

Invertase

break down sucrose to glucose and fructose

Inulinase

breaks down 2,1-β-d-fructosidic linkages in inulin

Pectinase

Pectinases are a group of enzymes that catalyzes the degradation of pectin (apples!)

Phytase

Phytases are phosphatases that can break down phytate and release phosphate in wheat, barley, rice, rape seed, soybean, corn, and rye

Xylanase

break down the plant cell component xylan

Also

• Alpha (α)-Galactosidase is an enzyme that binds specifically galacto-oligosaccharides (GOS) in plants and break them down to simple easy-to-digest galactose, fructose, and glucose molecules
• Fodzyme with fructan hydrolase (binds specifically to fructans and break them down to simple easy-to-digest fructose and glucose molecules), alpha-galactosidase ("beano") , lactase ("lactaid")
• Lactaid with lactase

What are the main drivers of carb malabsorption?

• Exocrine pancreatic insufficiency (EPI) with pancreatic amylase deficiency
• Low disaccharidase enzyme activity like lactase, CSID
• Celiac disease
• Tropical sprue
• Autoimmune enteropathy
• Intestinal lymphangiectasia and abnormal gut lymphatic drainage
• Inflammatory bowel disease (IBD) like Crohn's disease
• Systemic sclerosis
• Small bowel resection, blind loops, fistulas
• Ingestion of unabsorbable carbs: Sorbitol, cellulose

What are the signs + symptoms of carb malabsorption?

• What happens if you can't absorb carbs and they are excessively fermented by your colon? Acidic stool, gas, bloating, diarrhea.

Dont forget the MOST important digestive stimulation- your vagus nerve-- your parasympathetic "REST AND DIGEST" system that you should engage before you eat by taking some deep breaths, putting down your phone and work email and enjoying your feelings of hunger and nourishment either alone or with happy company!