Hypertension is the highest incidence of cardiovascular disease in the world, is the main clinical manifestation of systolic blood pressure ≥ 140 mmHg and diastolic blood pressure ≥ 90 mmHg elevation, with or without cardiovascular risk factors, is the result of long-term interaction between genetic factors and external environment, it is generally believed that genetic factors account for about 40%, environmental factors account for about 60%, and in the environmental factors are mainly The main environmental factors are related to nutrition and diet.
I. Risk factors of hypertension
1.Salt intake
Salt intake is significantly associated with hypertension and is seen in children and adolescents, and even high salt intake within 5 weeks after birth is positively associated with hypertension in adolescence. Blood pressure response to salt is influenced by certain components of the diet, such as low potassium or low calcium diets can increase blood pressure response to high salt, and conversely, high potassium and high calcium diets can prevent or reduce the high salt-induced hypertensive response.
2.Overweight and obesity
A large number of studies have confirmed that obesity or overweight is an important risk factor for the development of hypertension, and is also an independent risk factor for coronary heart disease and stroke. The prevalence of hypertension in obese children is 2 to 3 times that of normal weight children. Weight loss has become an important measure to reduce blood pressure, weight loss 9.2kg can cause systolic blood pressure reduced by 6.3mmHg, diastolic blood pressure reduced by 3.1mmHg. obesity lead to hypertension mechanism may be attributed to obesity caused by high blood lipids, increased adipose tissue leading to increased cardiac output, increased sympathetic nerve activity and insulin resistance.
3.Potassium
Dietary potassium has the effect of reducing blood pressure, high sodium caused by hypertension patients supplemented with dietary potassium, blood pressure lowering effect is more obvious. This may be related to the role of potassium to promote urinary sodium excretion, inhibit the release of renin, diastolic blood vessels, reduce the production of thromboxane.
4.Calcium
Insufficient dietary calcium intake can raise blood pressure, while increasing calcium can cause blood pressure to decrease. It is generally believed that dietary calcium intake <600mg per day may lead to increased blood pressure, and calcium promotes sodium excretion from the urine may be one of the mechanisms to lower blood pressure.
5.Lipids
Increase the intake of unsaturated fatty acids and reduce the intake of saturated fatty acids are conducive to lower blood pressure, clinical research found that the daily intake of fish oil (rich in polyunsaturated fatty acids) 4.8g can reduce blood pressure about 3.0 ~ 1.5 mmHg. The mechanism of its hypotensive effect may be related to changing the metabolism of prostaglandins, changing the function of vascular endothelial cells and inhibit the proliferation of vascular smooth muscle cells.
6, alcohol and tobacco
Most studies have found a “J”-type relationship between alcohol consumption and blood pressure, with small amounts of alcohol (1 to 2 times/day, converted by pure alcohol, not >14g per drink) having lower blood pressure than absolute abstainers, but those who drank ≥3 times a day had significantly higher blood pressure. This phenomenon suggests that a small amount of alcohol has a diastolic effect, while a large amount of alcohol has a vasoconstrictive effect.
The effects of alcohol on blood pressure are divided into acute and chronic effects. The acute effect refers to the effect a few hours after drinking, and it is generally believed that the blood vessels are dilated, blood flow is accelerated, and the spirit is relaxed, which can temporarily cause a decrease in blood pressure, but the heart rate is accelerated and the heart beat volume is increased, which has certain damage to the heart. The chronic effect that several days later can cause a rise in blood pressure, and the more alcohol consumed, the higher the blood pressure. Wine can cause hypertension and aggravate hypertension, damage the heart and cerebrovascular. Nicotine in cigarettes can cause vasoconstriction, causing a mild increase in blood pressure and a rapid heartbeat. Smoking can increase adrenal secretion and promote the development of hardening of the arteries.
Second, the nutritional prevention of hypertension
1, weight control, avoid obesity
Maintaining standard weight is an important task for patients with hypertension. Limiting caloric intake is the main dietary measure to control body weight, especially the caloric energy provided by saturated fatty acids should be reduced. The intake of fat in hypertensive patients should be limited to less than 25% of the total caloric energy. Try to use soybean oil, rapeseed oil, sesame oil, corn oil, sunflower oil, etc.
Measures to reduce weight, while including increased physical activity. The way of movement daily walking about 3km, time > 30 minutes; or choose a regular exercise program suitable for individuals, such as cycling, aerobics, taijiquan, etc.. 5 times a week, the heart rate per minute after exercise is about “170 minus age” is more appropriate, such as 60-year-old people, the heart rate after exercise to 110 times / min, so grasp the right amount of exercise, can achieve safety and maintain the purpose of aerobic metabolism.
2.Improve dietary structure
① Limit dietary sodium: salt is the main source of sodium. WHO recommends that the upper limit of salt intake is 6 grams/day; if you have mild hypertension, it should be controlled at less than 5 grams/day; moderate hypertension should be less than 3 grams/day. Each gram of table salt can be converted into 5 ml of soy sauce.
Pickles, squash, salted meat and other excessively salty foods are best eaten sparingly or not at all. Milk, eggs, meat, fish and poultry are also high in sodium, while plant foods, such as vegetables, cereals and fruits contain lower sodium. Special attention should be paid to other sources of sodium besides table salt, including preserved foods as well as sodium salts contained in the food itself.
②Increase potassium intake: Patients with hypertension should consume foods with high potassium content, such as fresh green leafy vegetables, legumes and roots, bananas, apricots and plums. Potassium in food mainly comes from vegetables, fruits and legumes. Foods high in potassium and low in sodium include soybeans, adzuki beans, mung beans, fava beans, fava beans and peas, various fruits, potatoes (potatoes), winter squash, cabbage, Chinese cabbage and light-colored vegetables such as yams. Although dark vegetables are rich in potassium, but at the same time the sodium content is also high, such as celery, lettuce, rape, spinach, etc., leek is low potassium and high sodium, hypertensive patients should eat less.
③ increase the intake of calcium and magnesium: eat more calcium-rich foods, such as milk, beans, etc. The main source of magnesium is nut foods, such as pecans (thousand), pine nuts (raw), sticks (fried), etc. Although there is still controversy about the impact of dietary calcium on blood pressure, but most experts believe that low calcium is a risk factor for hypertension. Physiologically, magnesium reduces vascular tension and contractility, and lack of magnesium causes enhanced vascular contraction.
④Maintain a good fatty acid ratio: Fat intake in hypertensive patients should be controlled at 25% of total energy or less, and the energy provided by saturated fatty acids should be limited, with 1:1:1 for saturated, monounsaturated and polyunsaturated fatty acids.
⑤ Cholesterol and high quality protein: Due to the increase of cholesterol content in the blood, it contributes to the formation of atherosclerosis and is not conducive to lowering blood pressure. However, cholesterol is also necessary for the human body, so the total daily cholesterol intake should be controlled at less than 300 mg. Vegetables and fruits are rich in dietary fiber, and foods rich in iodine such as sea fish, sea shrimp, sea chestnut, kelp and nori can lower blood cholesterol. Eat less or no cholesterol-containing foods such as animal offal and egg yolk.
Fish is rich in methionine and taurine, and fish oil is also rich in unsaturated fatty acids, which can reduce the incidence of hypertension and stroke. Soy protein also has a role in preventing strokes, so patients with high blood pressure can eat more fish, soybeans and soy products to increase the intake of high-quality protein and unsaturated fatty acids.
3, with the role of blood pressure regulation of food
Diet and health are closely related, many foods in daily life have antihypertensive effect, reasonable diet, can effectively prevent hypertension.
3.1 Onion
Contains a mixture of cholesterol-lowering cyclic allicin and sulfur-containing compounds, as well as prostaglandins and components that activate the activity of hemolysis fibrin, which can reduce the resistance of peripheral blood vessels and coronary arteries and lower blood pressure.
3.2 Hawthorn
The flowers, leaves and fruits of hawthorn all contain antihypertensive ingredients, which can reduce the excitability of vasomotor center and lower blood pressure.
3.3 Apples
Apples contain a large amount of vitamin C and zinc, which can promote the excretion of sodium in the body and play a role in lowering blood pressure.
3.4 Garlic
Garlic has a variety of health functions and pharmacological effects, and in recent years, its antihypertensive effect has been discovered. At present, more studies believe that allicin is the main active ingredient of garlic to lower blood pressure. According to the relevant research, the effect of lowering blood pressure is more obvious in rats fed with garlic with higher allicin than those with lower allicin.
3.5 Celery
Celery contains mannitol and other substances, which can lower blood pressure and serum cholesterol levels, and has a protective effect on blood vessels.
3.6 Shiitake mushroom
Shiitake mushrooms contain an amino acid that has the effect of lowering blood lipids and cholesterol, accelerating blood circulation, and lowering blood pressure.
3.7 Carrot
Carrots contain quercetin and camptothecin, which can increase coronary blood flow and lower blood pressure and blood lipids.
4, limit smoking and alcohol
Alcohol is an independent risk factor for hypertension and stroke, it is recommended that patients with hypertension should not drink alcohol and should limit the amount of alcohol.