Most of us take breathing for granted. But if you suffer from asthma, the simple act of inhaling and exhaling can be a painful, even life-threatening struggle. Asthma causes dramatic tightening of the bronchial tubes, making breathing difficult or even impossible. It can be triggered by a number of factors, ranging from airborne allergens to exercise and stress or certain foods.

Processed foods and some vitamins and medications may contain food coloring and additives that can worsen asthma; yellow dye #5 (tartrazine), for example, is well known for provoking attacks. Asthma attacks may also be triggered by a high-salt diet, and some studies have shown that reducing salt intake can enhance pulmonary function. Some people are sensitive to foods that trigger mucous production in the body, especially dairy and wheat. Additionally, excess dietary tryptophan can aggravate respiratory conditions. Foods high in tryptophan include turkey, chicken, dairy products, soy and seafood.

Avoiding foods that may lead to an inflammatory condition in the body can also be helpful. These foods include fried and processed foods, which are high in pro-inflammatory omega-6 fatty acids and trans fats; sugar and refined carbohydrates, which can cause the body to increase production of inflammatory compounds and red meat which contains pro-inflammatory arachidonic acid.

Certain foods can help lessen the symptoms of asthma by reducing inflammation, relaxing spasms and acting as natural antihistamines.

1. Salmon. This oil-rich fish is loaded with omega-3 fatty acids that are well known for their ability to reduce the body's production of inflammatory compounds. Studies have shown that fish oil can improve pulmonary function in people with asthma and can protect against exercise-induced bronchoconstriction. Fish oil can also reduce airway narrowing and inflammation. Other good sources of omega-3 fatty acids include tona, mackerel, and other cold-water fish. Flax seeds, hemp seeds, walnuts and canola oil are high in alpha-linolenic acid (ALA) which the body converts to eicosapentaenoic acid (EPA), the form found in fish.

2. Spinach. Spinach is a great source of magnesium, which may improve symptoms of asthma. Studies have found that people with asthma tend to have lower blood and tissue levels of magnesium, and increasing magnesium intake over the long run can reduce the incidence of asthma attacks. In one study, 400mg of magnesium per day significantly decreased asthma symptoms. Researches think that magnesium works by calming asthma's characteristic spasms in the smooth muscles of the upper respiratory tract and it also appears to have a mild antihistamines effect. A diet high in salt can deplete magnesium, as can calcium supplements, soft drinks, refined carbohydrates, and stress, so you may not be getting enough. Also, spinach is high in B vitamins and may help reduce stress-related asthma attacks. Other good sources of magnesium include almonds, cashews, sunflower seeds, pumpkin seeds, tofu and beans.

3. Red peppers. Red peppers are rich in vitamin C, which is especially helpful in treating asthma brought on by exercise. In other studies, a diet high in vitamin C appears to reduce inflammation. Ascorbic acid may also lessen asthma symptoms by acting as an antihistamine. And it appears to inhibit production of an enzyme called phosphodiesterase, which is how common asthma drugs work. Red peppers are also rich in vitamin A, and new research shows a correlation between vitamin A deficiency and asthma attacks. Other great sources of vitamin C include peaches, papayas, strawberries, broccoli, Brussels sprouts, organs and grapefruit.

4. Onions. A number of older studies have found that onions have an anti-inflammatory and anti-asthmatic effect, inhibit the release of histamines, and reduce bronchial obstruction. Onions contain prostaglandins that relax the bronchial passageways. Onions are also high in quercetin, a type of flavonoid that has anti-inflammatory and anti-allergic properties and in vitamin C. And onions contain L-cysteine, an amino acid that factors into the production of glutathione, a naturally occurring antioxidant in the body that is necessary for maintaining immunity. Glutathione production is often compromised in asthmatics. (Note: raw and picked onions may provoke asthma attacks in a small number of sensitive people.)

5. Chickpeas. Chickpeas are rich in vitamin B6, which may help decrease wheezing and asthma symptoms, especially in children. Getting additional B6 becomes especially important if you use the asthma drug theophylline, which seems to depress the liver's metabolism of B6 and can deplete the body's stores of this crucial nutrient. Vitamin B6 also appears to correct abnormalities in tryptophan metabolism, which are common in asthmatics. And since many cases of asthma are stress related, it makes sense to eat adequate amounts of this stress-relieving nutrient. Other good sources of vitamin B6 include fish, chicken, turkey, barley, brown rice, sweet potatoes, sunflower seeds and peas.