What you need to know about allergies and asthma

Although both allergies and asthma are characterized by an immune response, allergies usually result in watery and itchy eyes, runny nose, sneezing, congestion and sometimes hives. Asthma is a chronic inflammatory respiratory disorder that affects almost 2.5 million Canadians.

1. Allergies are a reaction to substances that are triggers only in certain people.
2. An asthma "attack" takes place when the bronchial tubes that conduct air to the lungs become constricted, causing difficulty in breathing, shortness of breath, wheezing and coughing.
3. Inflammation is present in the lungs (bronchial tubes) of people with asthma, even those with mild cases, and this plays a key role in all forms of the disease. Inflammation is also present in some people who suffer from allergies.
4. Allergies or asthma may be linked to a genetically inherited tendency.
5. Preliminary research also suggests that asthma may be caused by allergies. It is important to note, however, that while many asthma sufferers also have allergies, not all people with allergies have asthma.
6.  The release of a chemical called histamine can cause many of the physical manifestations of both allergies and asthma. Histamine has been linked to inflammation, congestion and excessive mucus secretion and muscle contraction in the airways, as well as itching accompanied by hives.
7. Numerous irritants — such as dust and dust mites, mold, cockroaches, pollen and pet dander — can set off both allergies and asthma.
8. Other asthma triggers include tobacco smoke, cold air, humidity, exercise, food or drug allergies, as well as respiratory infections such as colds, flu and bronchitis.

Some foods can help those living with asthma or allergies. It is suggested that people with allergies or asthma eat a low-fat diet rich in fruits and vegetables, which are linked to respiratory health.
A recent study showed that eating at least five apples a week may strengthen your lungs. The study discovered that men who ate nearly an apple a day had slightly stronger lung function than those who excluded apples from their diets.  Apples are loaded with healthy compounds, including antioxidants and flavonoids, which are thought to fight disease by protecting the body from free-radical damage. Other foods to eat include amaranth, avocados, quinoa, sunflower seeds, apples, berries, cherries, red onions, Brazil nuts, fish, oysters, sunflower seeds, broccoli, citrus fruit, peppers, strawberries.
Fruits and vegetables contain vitamin and minerals important to lung health and the immune system:

• Magnesium. It is believed that magnesium may help the lungs to relax and may also reduce inflammation. There is also some research that indicates magnesium may help to usher you into a calm sleep, which is important, since insomnia (usually caused by coughing) tends to occur frequently in people with allergies and asthma.
• Quercetin: Believed to be a potent lung protector, the flavonoid quercetin is thought to also have the capacity to reduce the release of histamine. It also appears to have anti-inflammatory properties.
• Lutelin. Another flavonoid, luteolin, may also have the capacity to reduce the release of histamine.
• Selenium. The antioxidant mineral selenium teams up with vitamin E to protect cells against free-radical damage, and this protective effect is thought to benefit membranes in airways. Selenium may ensure adequate levels of glutathione peroxidase, which is believed to be a potent free-radical-fighting enzyme.
• A diet rich in omega-3 fatty acids may help to reduce inflammation, and immune-boosting foods rich in zinc may help maintain a strong immune system.
• Vitamin C functions as an antioxidant and helps to shield the lungs from environmental pollutants, which can often worsen asthma.