1、 Overview
（1） Lipid classification and definition of hyperlipidemia
1 lipids and lipoproteins in plasma
Lipids in plasma: triglyceride, phospholipid, cholesterol ester, cholesterol and free fatty acid; lipoproteins in plasma
Protein electrophoresis method: it can be divided into α - lipoproteins, pre - β - lipoproteins, β - lipoproteins and Mi particles;
Density centrifugation: it can be divided into chylomicrons (CM), very low density lipoprotein (VLDL), low density lipoprotein (LDL) and high density lipoprotein (HDL).
2 hyperlipidemia and hyperlipoproteinemia
The upper limit of blood lipid above normal is called hyperlipidemia. Almost all lipids in plasma are transported by protein binding.
Lipoproteins are regarded as the basic units of lipid transport in the blood.
Hyperlipidemia or hyperlipoproteinemia can reflect the disorder of lipid metabolism.
WHO suggested that hyperlipoproteinemia should be divided into six types. The incidence rate of type 2 and IV is high in all types of hyperlipoproteinemia in China.
（2） The harm of hyperlipidemia
1. The harm of hyperlipidemia to people
Hyperlipidemia is one of the important risk factors of atherosclerosis.
Epidemiological investigation has shown that the continuous rise of plasma low density lipoprotein (LDL), very low density lipoprotein (VLDL) level and the decrease of high density lipoprotein (HDL) level are positively correlated with the incidence rate of atherosclerosis.
The results showed that there was no atherosclerotic disease in the population with total cholesterol less than 3.90mmol/l.
A study of more than 8000 white men by the pool project research group showed that the risk of coronary heart disease (CHD) in white men with serum cholesterol > 6.96mmol/l was twice as high as that in white men with serum cholesterol ≤ 5.67mmol/l. Framingham's study showed that the risk of coronary heart disease in patients with serum total cholesterol ≥ 8.06mmol/l was several times higher than that in patients with serum total cholesterol < 4.9mmol/l
The effect of hyperlipidemia on the body
Long term hyperlipidemia (high cholesterol, high triglyceride, high-density lipoprotein cholesterol, etc.) is the basis of atherosclerosis. Excessive lipid deposits in the blood vessel wall and the thrombus formed therefrom, leading to the stenosis and occlusion of the blood vessel. The thrombus on the surface of the thrombus can also fall off and block the distal artery. The thrombus is called cardiogenic cerebral embolism, which originates from the heart. Therefore, hyperlipidemia is the main cause of ischemic stroke. On the other hand, hyperlipidemia can also aggravate hypertension. On the basis of hypertension arteriosclerosis, the blood vessel wall becomes thin and easy to rupture. Therefore, hyperlipidemia is also a risk factor of hemorrhagic stroke. Atherosclerosis (as) is an inflammatory, multi-stage degenerative complex disease, resulting in the thickening and hardening of the damaged arterial wall, loss of elasticity, and narrowing of the lumen. Because of the yellow appearance of the lipid plaque gathered in the intima of the artery, it is called atherosclerosis.
（3） Factors causing hyperlipidemia
1 fatty acids
Fatty acids are divided into four categories: saturated fatty acids, monounsaturated fatty acids (mainly oleic acid, 18:1n-9), polyunsaturated fatty acids (mainly linolenic acid, 18:2n-6) and trans fatty acids (mainly 18:1 trans).
Although linolenic acid is the most abundant polyunsaturated fatty acid in the diet, a small number of polyunsaturated fatty acids in the diet are α - linolenic acid (ALA; 18:3 n-3), long-chain fatty acid (EPA; 20:5 n-3) and docosahexaenoic acid (DHA; 22:6 n-3) from fish oil. The effects of ALA and linolenic acid on plasma lipoproteins were similar. However, fish oil has the effect of reducing triglyceridemia, and there is no effect on LDL and HDL levels in subjects with normal blood lipids. For hyperlipidemia subjects, fish oil can reduce triglyceride content, but increase LDL-C and HDL-C concentration.
The structure of dietary triglycerides can also affect serum lipid levels.
2 fat substitutes
When the subjects took a diet containing non absorbable fat substitutes, the absorption of cholesterol was reduced, so these compounds would reduce the concentration of LDL-C in serum. HDL-C concentration also decreased when fat intake was reduced due to the presence of these fat substitutes.
3 soybean protein preparation
Anderson et al. (1995) published a comprehensive analysis of the effect of soy protein on human serum lipid concentration. It is estimated that the daily intake of 47g soybean protein will reduce the serum total cholesterol concentration by 0.60mmol/l, mainly due to the decrease of LDL-C by 0.56mmol/l. The serum total cholesterol level of subjects whose total cholesterol concentration was lower than 6.5mmol/l decreased about 4% (0.2mmol / L), while that of subjects whose cholesterol level was higher than 8.7mmol/l decreased about 20% (1.85mmol / L). Triglyceride level decreased by 0.15 mmol / L, while HDL-C level did not change significantly. There was no difference in the effect of separating soybean protein and tissue soybean protein. It remains to be determined whether this effect of soy protein may be caused by soy protein itself or by phytoestrogens.
4 monosaccharide and disaccharide
Black and saris (1995) study concluded that in most studies conducted by subjects with normal blood lipid, hypertriglyceridemia or diabetes mellitus, the effect of monosaccharide and disaccharide on the distribution of serum lipoproteins was similar to that of starch when taking Western diet.
5 inhibitory starch
Inhibitory starch cannot be degraded (at least not completely) in the small intestine, but it is metabolized by some bacteria in the large intestine. Although studies have shown that metabolites can promote cholesterol metabolism, raw starch and aged starch do not seem to have a beneficial effect on the distribution of serum lipoproteins.
6 cellulose
Based on the comprehensive analysis of ten experiments, ripsin et al. (1992) concluded that the total cholesterol concentration in serum can be reduced by 0.15mmol/l by taking about 3G soluble cellulose from oat products every day. This effect was positively correlated with the initial serum cholesterol concentration. It is reported that other water-soluble cellulose can also reduce the total cholesterol concentration, mainly by reducing LDL-C. Insoluble cellulose had little effect on serum total cholesterol.
（4） Principles of nutrition control
1. Control the total energy intake and maintain the ideal weight
2 limit fat and cholesterol intake
3. Increase the intake of plant protein and eat less sweets
Ensure adequate dietary fiber intake.
Supply sufficient vitamins and minerals
6 eat more protective food properly
Phytochemicals can promote cardiovascular health and encourage people to eat more plant-based foods rich in phytochemicals, such as onions, mushrooms, etc.
2. Substances with the function of assisting in lowering blood lipid
（1） Wheat germ oil
1 main components
Basic composition: palmitic acid 11% - 19%, stearic acid 1% - 6%, oleic acid 8% - 30%, linoleic acid 44% - 65%, linolenic acid 4% - 10%, natural vitamin E 2500mg / kg, phospholipid 0.8% - 2.0%.
2. Physiological function
It is rich in natural VE, including α -, β -, γ -, δ - tocopherol and α -, β -, γ -, δ - tocotrienol, all of which belong to D configuration. Natural VE is superior to synthetic VE in both physiological activity and safety (only DL - α - tocopherol is synthesized), and the ve effect of 7Mg wheat germ oil is equivalent to synthetic ve 200mg. Therefore, the price of natural VE in the United States, Japan and other countries is about 30% - 40% higher than that of the finished product, and synthetic VE is mainly used for animal feed.
Its main functions are to reduce cholesterol, regulate blood lipid and prevent cardiovascular and cerebrovascular diseases. It is responsible for the supply and transportation of oxygen in the body, preventing the oxidation of unsaturated fatty acids in the body, controlling the production of harmful lipid peroxide, and helping the blood circulation and the movement of various organs. In addition, it has anti-aging, fitness, beauty, prevention and treatment of infertility and prevention of peptic ulcer, constipation and other functions.
（2） Rice bran oil
1 main components
Fatty acid composition: 14:0, 0.6%; 16:0, 21.5%; 18:0, 2.9%; 18:1, 38.4%; 18:2, 34.4%; 18:3, 2.2%. In addition, it contains phospholipid, glycolipid, phytosterol, oryzanol and natural vitamin E (91-100mg / 100g).
2. Physiological function
It is rich in unsaturated fatty acids, natural vitamin E and oryzanol, and has corresponding physiological functions; it can reduce serum cholesterol, prevent arteriosclerosis, and prevent coronary heart disease. One week later, the serum cholesterol decreased by 18%, which was the highest among all the oils. The mixture of 70% rice bran oil and 30% safflower oil decreased by 26%.
