Bile acid is the main component in bile, it is the final product of metabolization of cholesterol via liver tissue, when bowel liver circulation is destroyed, bile acid cannot be reused. Carry on principal component analysis (PCA) to bile acid we can discover a series of physiology action of bile acid, serum bile acid is measured can reflect the anabolism of liver cell, absorb and excrete a condition, the generation of bile acid and metabolization and liver concern are very close, liver cell produces pathological change, serum total bile acid can follow change.

The main reason for introducing principal component analysis in the Bile Acids analysis is that each principal component can reflect most of the information of the original variables and the contained information is not repeated. In this method, multiple variables are introduced and complex factors are reduced to several principal components to simplify the problem. At the same time, more scientific and effective data information can be obtained. In the study of the practical problems of bile acids, we must consider many influencing factors in order to comprehensively and systematically analyze bile acids. The factors involved are generally called indicators, which are also called variables in multivariate statistical analysis. Because each variable reflects some information of the studied problem to some extent, and there is a certain correlation between the indicators, the information reflected by the obtained statistical data overlaps to some extent.

The analysis of bile acids is essential. Human endogenous bile acids are dominated by hydrophobic bile acids. When the excretion of bile acids occurs, hydrophobic bile acids are highly compatible with lipids, dissolve and destroy the cell membrane and mitochondrial membrane structure, cause cell apoptosis or death, and aggravate liver damage. Hydrophilic bile acid can promote the metabolism of endogenous bile acid, improve the content of bile acid and phospholipid in bile, change the composition of bile salt, reduce the toxicity of hydrophobic bile acid, and play a role in protecting liver cell membrane and promoting gallbladder.

Short chain fatty acid known as volatile fatty acid, according to the amount of carbon atoms of carbon chain, the carbon atom number is 1-6 of organic fatty acids for short chain fatty acids, short chain fatty acids, including formic acid, acetic acid, propionic acid, isobutyric acid, butyric acid, isovaleric acid, valeric acid, etc., after a short chain fatty acids analysis can be found that this kind of fatty acid absorbed by the intestine quickly after, is to store the energy and reduce the osmotic pressure, and short chain fatty acids to maintain the normal function of the large intestine and colon epithelial cells morphology and function plays an important role. Short-chain fatty acids also promote the absorption of sodium, and butyric acid is more effective in this regard than acetic acid and propionic acid, and butyric acid can increase the production of lactobacillus and reduce the number of e. coli.

Univariate analysis of short-chain fatty acids shows that short-chain fatty acids play an important role in electrolyte balance, blood glucose balance and balance of the digestive system. They are also the main energy supply substance for cells in the intestine and an important factor in inhibiting pathogenic microorganisms in the intestine. Clinical studies have shown that short chain fatty acids can strong to maintain intestinal morphology and function, and has a certain therapeutic effect, by measuring the biological level of short chain fatty acids in the matrix can be overall diagnosis of the change of the anaerobic bacteria in the body, also can reflect the activity of bacteria at the same time, the study of nutrition, microbes and environment has important significance.

In addition to univariate analysis and principal component analysis, there are also physical analysis methods and correlation analysis that can be used for short-chain fatty acids. Correlation analysis requires that a large amount of corresponding data between variables should be collected for unfamiliar phenomena, and preliminary judgment should be made by drawing correlation diagrams. From the direction of the relationship between variables, variables sometimes have the same direction change with the increase with the decrease, is a positive correlation; Sometimes there is a negative correlation between the variables in the opposite direction. From the expression of the correlation between variables, there are linear relations and curve relations, and from the number of variables involved in the correlation, there are unitary correlation or simple correlation and multivariate correlation or complex correlation.