加拿大华人论坛 加拿大生活信息A Weak or Strong Immune System
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[FONT="arial,]A Weak or Strong Immune System[/FONT] (What can weaken your immune system) Our genes play a part in determining how strong or weak our immune system is. Under the right or wrong set of circumstances, we can and will get sick. We compound our vulnerabilities by not taking care of our defense system. So, what can weaken our immune system? The following may weaken our immune system, our health and ultimately our lives. You can increase your odds by taking the proper precautions. Micronutrient Starvation: The main cause of poor immune function is due to micronutrient starvation. This is a silent foe as its harmful effects may not be felt or seen till years later. Micronutrients are vitamins, minerals and phytochemicals. Although many micronutrients don’t have an RDA, they are essential for optimal health. You can be well fed and even overweight and yet still be malnourished. Micronutrient starvation is not the same as having a severe vitamin deficiency disease, such as scurvy, a deficiency of vitamin C or beri-beri, a deficiency in thiamin, a B vitamin. It will not kill us right away but over time it will have a devastating impact on health. Our immune system consumes vitamins and minerals greedily as every few days our body replaces about 25% of all our immune cells RDA mentioned in any supplement is the bare minimum to avoid deficiency disease. You require more than the RDA for a healthy body. Numerous studies have documented that our defense system don’t function properly when blood levels of key vitamins, mineral, and phytochemicals drop below optimal level. top Toxic Overload : Excessive exposure to toxic substances can have a harmful effect on immune function. Our environment contains numerous toxins. Insecticides in food and water, cleaning fluids used at home and at work, chemicals commonly used on the job and prescription drugs can be dangerous substances. Smoking and alcohol not excluded. Even our bodies produce toxic substances as part of normal metabolism. The organ that does the work of detoxification is our liver. The liver produces large amounts of the antioxidant glutathione, an essential part of the detoxification process. When glutathione encounter toxic compounds, it attaches to them and triggers a chemical reaction that flushes the toxins through the kidneys. However take note that when we are in toxic overload, our livers cannot keep up the workload. Because our liver cannot cope, this may cause inflammation that can destroy healthy tissues. Toxins can directly weaken immune cells. Studies have shown that NK cells activity is reduced, making us vulnerable to a host of infections and cancer. In high enough doses, toxins can poison bone marrow, the heart of the immune system. We cannot eliminate all toxins from our lives. But we can minimize it by reducing exposure to potentially harmful chemicals at home or in the workplace. top Excessive Stress : Experiencing stress for an extended period of time, put your immune system at risk. Scientific evidence has shown that chronic stress causes a measurable decline in the immune system’s ability to fight disease. Normal stressors like traffic jams, demanding work situations, family squabbles are usually temporary. Others can be more long lasting such as divorce and death in the family. What happens when we encounter a stressful situation? Our brains signal our adrenal glands to start releasing stress hormones. This causes our blood pressure to rise, hearts to pump faster, pupils dilate and we are ready for action. And within a short time our bodies return to normal. However under constant stress, it can have a harmful effect on the immune system. Our T cells do not work efficiently. People who are depressed have depressed NK cell activity. Any type of stress, physical or emotional increases stress hormones which can dampen immune response. top The Aging of the immune system : Like everything else in your body, your immune system ages as you age. Although no one knows precisely why it does, it has been linked to decline in key hormones, such as DHEA, and general wear and tear. As we age, our immune cells begin to lose some of their vigor, resulting in diminished protection. They do not respond as quickly or effectively against potential enemies anymore. Poor diet and lifestyle as seen in most elderly folks, accelerates the decline in immune function. The good news is no matter how old you are, you can rejuvenate your immune system by taking the right supplements and maintaining a healthy lifestyle. top The young immune system : Newborns have an immature immune system during the first few months of life, leaving them vulnerable to sicknesses. When the baby falls ill, some doctors are too hasty to prescribe antibiotics, to prevent the problem from becoming serious. While well intentioned, this may not always be the wisest thing to do. During this period, the immune system is learning some important lessons like recognizing self and non self, building antibodies, and bombarding a baby with antibiotics may interfere with its development. This may result in the infant starting with a weak immune system. However in some cases, antibiotics may be absolutely necessary. Since infants are defenseless and vulnerable during this time, mothers can help them avoid getting sick by breast-feeding. A mother passes important immune factors onto her baby especially colostrums when she breast feeds her baby. Whatever the nursing mother eats can be passed through breast milk to infants and by keeping her own immune system healthy will give her child a good start in live and vice versa. top Overexposure to antibiotics : Overexposure to antibiotics can create antibiotic-resistant organisms. An antibiotic may kill most of the bacteria but a few tough bacteria, not being killed off, can go on to reproduce and transfer their resistance to others. Overuse of antibiotics can weaken immune function leaving you more vulnerable to illness. For example, long-term use of sulfa drugs (a type of antibiotic) causes a decline in white blood cell count, which weakens the immune system. Other studies have shown that antibiotics can reduce levels of cytokines the hormonal messengers in the immune system. It is especially important that children avoid antibiotics if possible. The child’s immune system must learn how to live in a world filled with threatening organisms and toxins. With each viral and bacterial infection, the immune system learns an important lesson on survival. By giving a child an antibiotic for every problem, we prevent the immune system from doing its job and learning these important lessons. top Sleep Deprivation : Lack of sleep can have a powerfully detrimental effect on your immune system. Have you noticed that when you don’t get enough sleep and feel run-down you are more prone to fall sick? What can cause sleep deprivation? Anxiety, depression, side effects from medication, and hormonal changes due to aging can all contribute to sleep problems. However in many cases people are simply so busy that they don’t set aside enough time to sleep. When we are sleeping, our bodies perform two essential tasks. Our bodies get a chance to rest and refuel. Our heart rate and blood pressure drop, and our metabolism slows down, our cells can concentrate on repairing and creating new cells in every system of the body including the immune system. What happens to the immune system when we are deprived of sleep? According to tests conducted by a psychiatrist at San Diego Veterans Affairs Medical Centre, lack of sleep showed a notably decline in natural killer cell activity, ie they are more vulnerable to infection. However when they are allowed to sleep, their immune system returned to normal. Clearly adequate sleep is important for a strong immune system. top Strenuous Physical Exercise : Moderate exercise is good and can enhance immune health. However too much exercise can overtax your immune system. When you are engaged in intense physical activity, eg intense training for competition, body building or fitness, you burn more oxygen, which in turn produces more free radicals, through lipid peroxidation. Excessive amount of free radicals deplete antioxidants and dampen immune response. Although after a while the body repairs the lipid damaged, not 100% is repaired. It’s the accumulation of the damaged lipids that will cause problems. If you do any form of vigorous exercise, be sure to replenish the lost antioxidants through food and supplements. top Too much exposure to sunWe know that some sunlight is good for us – source of vitamin D and too much can cause severe damage to the skin, premature aging and skin cancer. What is less known is that the intense exposure to the sun can weaken the immune system. How? First the ultraviolet (UV) radiation from the sun causes the formation of free radicals. Your body’s supply of antioxidants are depleted when destroying these free radicals. Secondly, UV radiation may also raise levels of stress hormones, which will also weaken the immune function. Just be careful about too much exposure to the sun. Abusing your body by smoking, drinking heavily, living under a great deal of stress, not exercising, or eating poorly leaves you with an immune system that acts like it is old, no matter what its age. top A high Cholesterol diet : Laboratory studies discovered that macrophages (cell in bloodstream that recognizes self and non-self cells) slowed down considerably in people with high cholesterol levels. This then allow the invaders ample time to multiply before the macrophages reached them. A high fat diet Diets high in saturated fat have been associated with colon, breast, ovary and prostate cancer, although other factors are also involved. This is because the saturated fat makes the T-cells not able to recognize self cells gone bad. Unprotected polyunsaturated fats can cause the thymus (T-cell factory) to shrink and slow down production. These unprotected saturated fats undergo lipid peroxidation which releases free radicals. This in turn reduces immune response and promote development of tumors.
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