Lipids are esters and their derivatives produced by the interaction of fatty acids and alcohols.Lipids are a kind of organic macromolecular substances in the body. They cover a wide range. Their chemical structures are very different, and their physiological functions are different. Their common physical property is that they are insoluble in water but soluble in organic solvents such as ether, chloroform, benzene, etc. They can aggregate in water to form internal hydrophobic aggregates.But strictly speaking, lipids are not macromolecular substances, their relative molecular weight is not as large as sugar, protein and nucleic acid, and they are not polymers.[4]
Common procedures for extraction, separation and identification of cell lipids[3]
There are two main directions for understanding lipids: 1. Lipids in food: medical science, nutrition, sports and health are more concerned, mainly considering the relationship between diet and human/animal diseases;2. Lipids in human body/animals and plants: Physiology and pathology focus on the role of lipids in their physiological/pathological state.
Lipids are oils, fatslipid The general name of.The fat in food is mainly oil and fatnormal atmospheric temperatureThe liquid is called oil, while the solid at room temperature is called fat
Lipids are one of the important nutrients needed by the human bodycarbohydrateThey are the three major nutrients of productivity and play an important role in supplying energy to the human body.So are lipidsHuman cellsThe composition of tissue, such as cell membrane and nerve myelin sheath, must be involved with lipids.
lipidThe class I substance referred to is more thanFatWider.andestersFrom the chemical point of view, the material world, many of which are chemical raw materials.Some esters are components of fats.
As mentioned above,lipidIt consists of fatty acids (mostly long-chain monocarboxylic acids with more than 4 carbon) and alcohols (including glycerol alcohols, nitramine alcohols, higher monohydric alcohols and sterols)estersAnd its derivatives.includeSimple lipids、Complex Ester andDerived lipid。
FatIt refers to triglyceride in human or animal body, which is composed of one molecule of glycerol and three molecules of fatty acid.
estersIt refers to a kind of acid (carboxylic acid or inorganic oxygen containing acid) generated by reaction with alcoholOrganic compound。Low molecular weight esters are colorless and volatile aromatic liquids, such as:ethyl acetateCH3COOC2H5、Phenyl acetateCH3COOC6H5、Methyl benzoate C6H5COOCH3, etc;Higher saturated fatty acidsMonoesters are usually colorless and odorless solids,Higher fatty acidsAndHigher fatty alcoholThe ester formed is a waxy solid.So,estersAndlipidIt cannot be substituted.[1]
classification
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1. Grease
FattriglycerideOr calledFatty acylglycerol(triacylglycerol) is a general term for oil and fat.Generallynormal atmospheric temperatureThe lower liquid fat is called oil, while the lower solid fat is called fat.
Fat is formed by dehydration and synthesis of glycerol and fatty acids.Fatty acidcarboxyl- OH in glycerol and - H in glycerol hydroxyl combine to lose a molecule of water, so glycerol and fatty acid formEster bondAnd became fat molecules.
Three acyl groups in fat (inorganic or organic oxyacid removalhydroxylThe remaining atomic groups) are generally different and come from C16, C18 or other fatty acids.yesdouble bondOf fatty acids is called NoSaturated fatty acidIt is called saturated fatty acid if there is no double bond
Fat cartoon
There are few unsaturated fatty acids in animal fat and more in vegetable oil.dietToo much saturated fat will causeatherosclerosisBecause both fat and cholesterol will deposit on the inner wall of the blood vessel and form plaque, which will hinder blood flow and produceCardiovascular disease。Because of this, there is sediment on the blood vessel wall, and the blood vessel narrows, making obese patients prone to hypertension and other diseases.
The oil is widely distributed. There is a certain amount of oil in the seeds of various plants, tissues and organs of animals, especially in the seeds of oil crops and under the skin of animalsadipose tissue, rich in oil.Fat in human body accounts for 10%~20% of body weight.There are many kinds of fatty acids in human bodytriglycerideThere may be differentPermutation and combinationMode.Therefore, triglycerides exist in many forms.
Energy storage and energy supply are the most important physiological functions of fat.When 1g fat is completely oxidized in the body, 38kJ (9.3kcal) energy can be released, which is more than 1gGlycogenOr the energy released by protein is more than twice.Adipose tissue is the tissue used to store fat in the body. When the body needs energy, fatHistiocyteThe fat stored in can be mobilized and broken down to meet the needs of the body.In addition, fat in higher animals and human body can also reduce body heat loss and maintainBody temperature constancyTo reduce friction between internal organs and buffer external pressure.[1]
2. Lipids
Lipids includephospholipid(phospholipids)，Glycolipids(glycolipid) andCholesterol and its esters(cholesterol and cholesterol ester).
① Phospholipids are lipids containing phosphoric acid, including glycerolGlycerophospholipid(phosphoglycerides) andSphingosineConstitutiveSphingomyelin(sphingomyelin)。In animal brains and eggs, soybean seeds contain more phospholipids.
② Glycolipids are lipids containing sugar groups.
③ And cholesterol andSteroids(steroid）Such substances mainly include cholesterolCholic acid, sex hormone and vitamin D, etc.These substances play an important role in regulating the normal metabolism and reproduction of organisms.
In addition, cholesterol is also fatty acid salts andVitamin D3as well asSteroid hormoneSynthetic raw materials such as, for regulating the absorption of lipid substances in the body, especiallyFat soluble vitamin(A，D. E, K) absorption and calciumPhosphorus metabolismAll play an important role.These three classes of lipids are important components of biological membranes, forming a hydrophobic "barrier" to separate the water-soluble components of cells and divide cells intoOrganelle/Nuclear equivalentCompartmentTo ensure that multiple metabolic activities are carried out simultaneously in the cell without interfering with each other, and maintain the normal structure and function of the cell.
Wax:Higher fatty acidsWith higher monohydric alcohol, it is generally the surface covering of young plants, leaves, and animals, and also the main component of beeswax.
Glyceride: high fatty acids and glycerol, the most lipids.
twoCompound greaseDefinition: pure fat plus phosphoric acidGroupDerivatives produced.
Phospholipids: glycerol phospholipids (lecithinCephalin）Sphingomyelin (rich in nerve cells).
threePrecursors and derivatives of lipids
Terpenoids(sound ti e) andSteroids(sound z i) and its derivatives: no fatty acids, allisopreneDerivatives of.
Derived lipid:hydrolysisProducts include fatty acids and their derivatives, glycerin, sphingosine, etc.
fourConjugated fatDefinition: Complex formed by lipid and other biological molecules.Such as glycolipids, lipoproteins, etc.
Glycolipids: Compounds in which sugars and lipids are linked by glycosidic bonds（covalent bond）, such asCholera toxin。
Lipoprotein: Non covalent combination of lipids and proteins in the liver, such as several lipoproteins in the blood,VLDL, LDL, HDL and VHDL are the transportation modes of lipids.
Chemical structure
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generalization
Lipid molecular formula
Lipids, also known as lipids, is the general name of fats and lipids, which are insoluble in water but soluble in fat solvents（alcohol, etherchloroform, benzene) and other non-polar organic solvents.And can be used by the bodyOrganic compound。Lipids include a wide range ofclassification method There are also many kinds.Generally, it is divided into simple lipidsCompound lipid, derived lipid, nosaponificationLipids.
Lipids include a variety of molecules, which are mainly composed of carbon and hydrogen with non-polar covalent bonds.Because these molecules are right and wrongPolarityIt is not compatible with water, so it is hydrophobic.Strictly speaking, lipids are not macromolecules because theirrelative molecular massIt is not as big as sugar, protein and nucleic acid, and they are not polymers.[1]
Simple lipid
Simple lipids are fatty acids and variousalcoholsThe simple lipids formed from esters include acylglycerol esters and waxes.
（1） Acylglyceride
Acyl glycerides, also known as fats, take glycerol as the main chainFatty acid ester。For example, the chemical structure of triacylglycerol ester is that three hydroxyl groups in glycerol molecule are esterified by fatty acid, so it is calledtriglyceride(triglyceride) orNeutral fat。Glycerol molecule has no asymmetrycarbon atom。But its three hydroxyl groups can be esterified by different fatty acids, so the middle carbon atom of glycerol molecule isAsymmetric atomTherefore, there are two different configurations (L-configuration and D-configuration).All natural triglycerides are L-shaped.Acyl glycerides are divided intoMonoglyceride、Diacylglycerol, triglyceride, alkyl ether (or αβ alkenyl ether) acylglycerol ester.[1]
（2） Wax
Waxes are water insoluble solidsHigher fatty acidsAnd long-chain monohydroxy fatty alcohol, or higher fatty acidsterol The ester formed.Common waxSterolWax, etc.
True wax is a kind of long chain monohydric alcoholFatty acid ester。
Solid ester wax is an ester formed by sterols and fatty acids, such asvitamin AEster, vitamin D ester, etc.[1]
Compound lipid
Lipid molecular formula
Complx lipids are fatty acid esters containing other chemical groups, mainly containing phospholipids andGlycolipidsTwo complex lipids.
（1） Phospholipid
Phospholipid is an important component of biomembrane, which is characterized by the mixture containing fatty acid and phosphoric acid after hydrolysis.According to the main chain structure of phospholipidsGlycerol phosphateReverse and sphingomyelin.
Know the center of glycerol molecule from its molecular structureatomIt is asymmetric.Therefore, there are different solid configurations.All the naturally occurring glycerophosphate esters have the same main chemical configuration.According to chemical convention.These molecules can be expressed by two-dimensional projection.D - and LGlyceraldehydeThe configuration ofX-ray crystallographyThe result is certain.Right rotation is D configuration, and left rotation is L configuration.The stereochemical configuration and nomenclature of glyceryl phosphate were thus determined.
2. Sphingomyelin: Sphingomyelin contains sphingosine orDihydrosphingosinePhospholipids, whose molecules do not contain glycerol, are a molecule of fatty acidamideBond and sphingosineaminoto be connected.Sphingosine or dihydrosphingosine is an amino group with long chain of aliphatic groupDiols。Hydrophobic long chainAliphatic alkylTail and two hydroxyl groups and one amino groupPolar head。
Sphingomyelin contains phosphoric acid, and its terminal hydroxyl substituent group isCholine phosphateAcid ethanolamine.The sphingomyelin with the largest content in human body isSphingomyelin, bySphingosine, fatty acid and choline phosphate.Phosphoester of nerve sheath is an important phosphate to form biological membrane.It often coexists with lecithin on the outside of cell membrane.[1]
（2） Glycolipids
Glycolipids are a kind of lipid compounds with different chemical structures of complex lipids containing carbohydrate residues, and new members of glycolipids are constantly found.Glycolipids are also divided into two categories: glycosyl acylglycerol and sugarSphingolipids。Glycosphingolipids can be divided into neutral and acid glycosphingolipids.
Lipid metabolism
1. Glycosylacylglycerins. Glycosylacylglycerins are similar to phospholipids in structure. The main chain is glycerol, which contains fatty acids, but does not contain phosphorus, choline and other compounds.Glycosic residues are linked to 1,2-DiacylglycerolC-3 ofGlycosyl glycerideMolecules.KnownGlycolipidsIt can be composed of various sugarsPolar head。There are not only diacyl oil esters, but also 1-acyl congeners.
The sugars in natural glycolipid molecules mainly include glucose and galactose, and most of the fatty acids areUnsaturated fatty acid。Named according to the International Committee on Biochemical Names: Single HalfLactose groupDiacylglycerolAnd digalactosyl diacylglycerol are 1,2-diacyl-3-O - β - D-galactopyranosyl glycerol and 1,2-diacyl-3-O - (α - D-galactopyranosyl (1 → 6) - O - β - D-galactopyranosyl) glycerol.
In addition, there are trigalactosyl diacylglycerol, 6-O-acyl monocalactosyl diacylglycerol, etc.
2. Glycosphingolipids has been listed as sphingolipids and sphingomyelin, so it is also calledGlycosphingolipid。sugarSphingolipidsThe molecular parent structure isceramide。Fatty acids linked in long chainsSphingosineThe ceramide saccharides formed on the C-2 amino group are hydrophilic glycosphingolipidsPolar head。Sugar containing one or more neutral sugar residues as polar headSphingolipidsIt is called neutral glycosphingolipids orGlycosylCeramide, whose polar head is charged, is the simplestCerebrosideIt links a sugar group (glucose orGalactose）。
The important glycosphingolipids are cerebrosides andGanglioside。Brain glycosides are the most abundant in brain, followed by lung and kidney, liver, spleen and serum.The cerebroside in the brain is mainly galactoside, and its fatty acid is mainly twenty-four carbon fatty acid;The blood is mainly composed of glucose, cerebroside, gangliosidesialic acidAcid glycosphingolipids.Sialic acid is also calledN-acetylneuraminic acidIt interacts withGlycolipidsto be connected.Gangliosides are composed of galactose (Gal)N-acetylgalactose (GalNAc), glucose (Glc)N-aliphatic nitramine (Cer), sialic acid (NeuAc).Gangliosides are widely distributed on the outer surface of cell membranes in various tissues of the body, with brain tissue being the most abundant.[1]
Derived lipid
1. Fatty acids and their derivativesprostaglandinEtc.
2. Long chain fatty alcohol, such asCetyl alcoholEtc.
Unsaponifiable lipid
Unsaponifiable lipid is a kind of lipid without fatty acid.There are mainly terpenoids and steroids.
（1） Terpenoids
Terpenoids are also called isopentene lipids.Isopentene has two double bondsPentacarbon compound, also called "2-methyl-1.3-butadiene"StructuralFor:
CH2=CCH3CH=CH2
lipid
AlkeneTerpenoidMany isoprene unitscondensationBody.TwoisopreneThe unit is connected from head to tailMonoterpene；Terpene compounds containing 4, 6 and 8 isoprene units are calledDiterpene, triterpenoids orTetraterpene。The isoprene units are arranged in a regular way by connecting the head and tail;On the contrary, tail tail is connected by irregular arrangement.Two one semimonoterpenes are formed by tail tail arrangement and connectionTriterpene, such as squalene;Two diterpenoid tails are linked to tetraterpenes, such as β - carotene.SomeTerpenoidCompounds areCyclic compoundSome follow the rule of connecting head and tail, and some do not follow the rule of connecting head and tail.In addition, although some compounds are closely related to terpenoids, their structural formulas are not even multiples of five carbon units;For example, camphene is a monoterpene with bicyclic structure, while sandalene with similar structure lacks a carbon atom.Isopentene lipids include a variety of substances with different structures. It is difficult to give systematic names to these substances with complex structures existing in nature.The name that is customarily used now mostly comes from the raw material source of the compound, which is even more disorderly.
The common points of natural isopentene polymers and other polymers are: ① They are composed of repeating units with common structure (isopenteneskeletonEquivalent to sugar, amino acid or nucleotide unit); ②The structure of this unit may vary in detail (e.gIsoprenoidAnd arranged in order; ③The chain length varies greatly, from two units to monoterpene, to hundreds of times more units to rubber.The differences are: ① the repeating units are connected together by C-C key; ②Relatively speaking, they are non-polar and belong to lipids.Once the isopentene lipid is polymerized, it can no longer be cracked back to the monomer form.[1]
（2） Steroid
Steroid is a derivative of cyclopentadienyl phenanthrene.The number and position of double bonds in natural steroid molecules, the type, number and position of substituent groups, the configuration between substituent groups and ring nuclei, and the configuration between rings are different.Its chemical structure is composed of three hexacarbonsCyclohexane（A、B. C) and a five carbon ring (D).Each carbon atom in the steroid molecule is numbered sequentially, and no matter whether there is a carbon atom at any position, the number of the carbon atom is retained in the steroid parent skeleton structure.Hexacarbon ring AB. C is in the "chair" conformation (ring has structure), which is also the most stable conformation.The only exception isestrogenThe A-ring in the molecule is aromatic ring with planar conformation.The junction between A ring and B ring of steroids may be cis configuration or trans configuration;The junction between C ring and D ring is generally trans configuration, but cardiac glycosides andToxinIs an exception.[1]
function
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Energy storage
Is the best way to store energy, such as animals and oil seedstriglyceride。It can be concluded by comparing the following data:
Comparison of two energy substances in the body (sugars, lipids)
Energy supply per unit weight: sugar 4.1 kcal/g, fat 9.3 kcal/g.
Storage volume: 1 glycogen or starch: 2 water, fat is pure and much smaller.
Use order: sugar is consumed first, then lipid.Therefore, many weight loss/weight loss principles, Pigu, etc. are derived from this.
Animal adipose tissue has protective functions such as heat preservation and mechanical pressure prevention, while plant wax can prevent water evaporation.
Electrical insulation: sheath cells of nerve cells, prepuce of wires, nerve short circuit.
Thermal insulation: keep warm in winter, penguins, polar bears, etc.
Involved in signal recognition and immunity (glycolipids).
biosynthesis
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fatty acid
Lipolysis
Fatty acidbiosynthesisBiosynthesis of fatty acids Synthesis of higher fatty acids based on acetyl CoAcoenzymeA carboxylase combines with CO2 while ATP decomposes to produceMalonic acidMonoacyl CoA, the first step of this phase is speed control step, which is promoted by citric acid.malonyl coa With acetyl CoAFatty acid synthaseSynthesis of C16 catalyzed byPalmitic acid(or C18stearic acid）, but this is included inAcyl carrier proteinDecarboxylationC2 unit condensation and repeated complex process including NADPH reduction process.As CoA derivatives, the fatty acids produced inmitochondrionMedium and acetyl CoA, inmicrosomeMiddle andMalonic acidMonoacyl CoA condensation, adding two carbons each time, continuously extendingCarbon chain。andMonounsaturated fatty acid, which is produced by the aerobic unsaturation of saturated acyl CoA (or ACP) (microsomes, microorganisms, etc. There must be O2 and NADH), or by β - hydroxyacyl ACP in the process of fatty acid biosynthesisDehydration reaction(and carbon bond extension).PolyUnsaturated fatty acidIt may not be produced in higher animals, but can be formed from the extension of the carbon chain of unsaturated acid ingested.In addition, cyclopropane fatty acid consists ofS-adenosylmethionineC1, which is produced by binding to the double bond of unsaturated acid.Fatty acids, as CoA derivatives, are used to synthesize varioussubstrate。[1]
Other lipids
Phospholipid production
Phosphatidic acidIt is the simplest phospholipid and the precursor of other glycerol phospholipids.Phospholipid acid reacts with CTP to produce CDP-Diacylglycerol, respectively with inositolserine、Glycerol phosphateReact to generate corresponding phospholipids.Phosphatidylic acid is hydrolyzed to diacylglycerol, and then mixed withCDP CholineOr CDP ethanolamine reaction, respectivelyPhosphatidylcholineandPhosphatidylethanolamine。[1]
Digestion and absorption
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Normal people generally digest fats from food every day, includingTriglycerideAccounting for more than 90%. In addition, there are a small amount of phospholipids, cholesterol and its esters, and somefree fatty acids(free fatty acids)。Lipids in food cannot be digested in the mouth and stomach of adults. This is because there is no enzyme in the mouth to digest lipids. Although there is a small amount of lipase in the stomach, this enzyme is only active at neutral pH value, so this enzyme is almost inactive in normal gastric juice (but in infancy, the gastric acid concentration is low, the pH value in the stomach is close to neutral, and fat, especially milk fat, can be partially digested).Digestion and absorption of lipids are mainly carried out in the small intestine. First, in the upper part of the small intestine, food lipids are made by bile salts in bile through peristalsis of the small intestineemulsificationTo disperse insoluble lipids into small oil in watercolloidParticles, improving the solubility increases the contact area between enzymes and lipids, which is conducive to the digestion and absorption of lipids.At the formed water oil interfacePancreatic juiceEnzymes contained in, which start to digest the lipids in food, including pancreatic lipase, coenzyme,Cholesterol esterPancreatic cholesteril ester hydrolase or cholesteril esterphospholipaseA2(phospholipase A2)。
After emulsification, the fat in food is catalyzed and hydrolyzed by pancreatic lipasetriglycerideFatty acids at positions 1 and 3 of, generating 2-MonoglycerideAnd fatty acids.This reaction needs the assistance of coenzyme, and the lipase is adsorbed on the water interface, which is conducive to the function of pancreatic lipase.Phospholipids in food arePhospholipase A2Catalysis, hydrolysis at position 2 to generate lysophospholipids and fatty acids,pancreasIt secretes phospholipase A2, which is inactiveZymogenFormed byTrypsinHydrolysis releases a 6-peptide and then becomes an active phospholipase A to catalyze the above reaction.Cholesterol esters in food are hydrolyzed by cholesterol esterase to generate cholesterol and fatty acids.Lipids in food are digested by the above enzymes in pancreatic juice to produce monoglyceride, fatty acid, cholesterol, lysophospholipids, etc. The polarity of these products is significantly enhanced, and they are emulsified with bile to form mixed micelles.This micro mass is small in size (20 nm in diameter), with strong polarity, and can be absorbed by intestinal mucosal cells.
Lipid metabolism
The absorption of lipids is mainly in the lower duodenum andcecum。Glycerin and short chain fatty acids (<=10C) can be directly absorbed into small intestinal mucosal cells without the assistance of mixed micelles, and then enter the blood through the portal vein.Long chain fatty acidsAnd other lipid digestion products were absorbed into small intestinal mucosal cells along with the microparticles.Long chain fatty acids in acyl CoAsynthetase(fattyacyl CoA synthetase), and this reaction consumes ATP.Fatty acyl CoA can be transferredacylUnder the action of acyltransferaseMonoglyceride, lysophospholipids and cholesterol are esterified to form corresponding triglycerides, phospholipids and cholesterol esters.There are a variety of acyltransferases in the body, which recognize different lengths of fatty acids to catalyze specific esterification reactions.These reactions can be seen as the process of lipid modification, which is generated in the small intestinal mucosal cellstriglyceride, phospholipids, cholesterol esters and a small amount of cholesterolApolipoprotein(apolipoprotein) compositionChyle microparticle(chromacrons), through lymph and finally into the blood, are used by other cells.It can be seen that the absorption of lipids in food is different from that of sugar. Most lipids enter the systemic circulation directly through lymph, but not through the liver.Therefore, the fat in food is mainly used by extrahepatic tissues, and the liver uses little exogenous fat.
Hydrolysates of lipids, such as fatty acids, monoglycerides and cholesterol, are insoluble in water.They are associated withBile saltformationWater solubilitytinyColloidal particlesAfter that, it can reach the microvilli through the hydrostatic layer on the surface of small intestinal mucosa.Here, fatty acidsMonoglycerideThey enter the intestine through the lipid membraneepithelial cellsThe bile salt returns to the intestinal cavity.IntraepithelialLong chain fatty acidsAnd monoglyceride, mostly re synthesizedtriglyceride, and with theLipoprotein synthesisChyle microparticleSeveral chyle particles are wrapped in a vesicle.When the vesicles migrate to the cell membrane side, they leave the epithelial cells by exocytosis and enter the lymphatic circulation.And then put it into blood.The fatty acids and monoglycerides produced by the hydrolysis of medium and short chain triglycerides are water-soluble and can enter the portal vein directly without entering the lymph.[1]
Enzymatic hydrolysis
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1. Lipase is widely found in animals, plants and microorganisms.In the human body, fat digestion is mainly in the small intestine, which is catalyzed by pancreatic lipase, bile salts andCoenzymeWith the help of, the fat is gradually hydrolyzed into fatty acids and glycerol.
2. There are many phospholipases, which act on ester bonds at different parts of phospholipid molecules.Phospholipases A1 and A2 act on ester bonds at position 1 and 2, respectively, to generate lysophospholipids andfree fatty acids。What acts on 3 bits is calledPhospholipase CThe enzyme that acts as the ester bond between phosphate substituents is called phospholipase D.The enzyme that acts on the ester bond of lysophospholipids at position 1 is called phospholipase B1.
3. Cholesterol esterase hydrolyzes cholesterol esters to generate cholesterol and fatty acids.
4. Hydrolysate of absorbable lipids in small intestine.Bile salts help emulsify and bindApolipoprotein（apoprotein，Apo) formationChyle microparticleIt is absorbed by intestinal mucosa cells and enters the blood circulation.So chylomicron,CM) is a lipoprotein that transports exogenous lipids (mainly TG).
Clinical significance: The rise of triglyceride is of great significance in the occurrence of coronary heart disease.Primary hyperlipidemia, obesityArteriosclerosisObstructive jaundice, diabetes, extreme anemiaNephrotic syndrome、pancreatitis、HypothyroidismIt can increase after long-term hunger and high-fat diet.After drinking alcohol, triglycerides can be instantly increased.Reduction seen inHyperthyroidism、adrenal cortexHypofunction, severe liver function damage, etc.
Note: serum shall be separated as soon as possible after sample collection to prevent triglyceride hydrolysis.
Precautions: Stabilize the weight 4 weeks before sampling, maintain the original eating habits and living habits, and empty 12-14 hours before blood collection.
summary
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Reasonable intake of fat food can ensure the normal operation of the stomach, and too much or too little intake is not conducive to the normal absorption and digestion of the stomach.If too much lipid is ingested, when it enters the duodenum, it will stimulate the production of gastrostatin, which will block the gastrointestinal peristalsis, and then affect the gastrointestinal function;Too little intake is not enough to maintain the metabolism of the body.Take more ofUnsaturated fatty acidOur food, such as sea fish, olive oil, bean products, is good for our health[2]。
