Allergy and Asthma: Key Nutrients

Managing a food allergy is tricky business. When a diagnosis is new, the allergy is severe or multiple allergies exist, avoiding food triggers can be so much the focal point of one's diet that nutritional balance becomes the secondary consideration. Still, nutrient needs are no less for people with allergies and asthma. In fact, some nutrient needs may actually increase.

Several vitamins and minerals have been found to help the immune system work the way it should. Nutrients involved in immune system regulation are essential fatty acids, copper, iron, selenium, zinc, vitamin A (or beta carotene), vitamin E, vitamin C and several B vitamins including B6, folic acid and pantothenic acid. Obtaining these key nutrients in adequate amounts from your diet or, if necessary, supplements can help your immune system work most effectively for you.

Anytime a whole group of foods or combination of many foods must be excluded from the diet, a supplement providing 100% of the recommended daily values for both vitamins and minerals is encouraged. Significant broad dietary restrictions will make it very difficult to obtain an adequate amount of several nutrients. This is true for anyone following the Elimination Diet or a diet that prohibits many common foods or ingredients. In other cases, one specific nutrient may be at risk. This will be true when the excluded food group is a major source of a key nutrient. Milk Free diets, for example, are at high risk for calcium inadequacy. Here, calcium supplementation is recommended.

A real concern with supplements, however, is the binder or filler used in the preparation. It is important to screen all vitamin-mineral supplements for their complete list of ingredients, not just nutrients. For example, wheat fillers, 'natural' flavors or unspecified stabilizers may be used. When in doubt about ingredients, call the manufacturer listed on the label directly. A pharmacist or dietitian specializing in food allergies can also help you select appropriate products.

Omega-3 fatty acids are important to buffer the reactivity of our immune system, but most people do not get enough of this essential fatty acid. Because of its anti-inflammatory properties, some research suggests a higher intake of omega-3 fatty acids may help improve asthma symptoms in some individuals.

The current evidence for omega-3 fat suggest that a minimum of 0.2 and 0.4 grams be consumed on a daily average. Some experts recommend a higher intake, 2.0 to 4.0 grams per day, for an optimal balance of essential fatty acids.

Fish is an excellent source of omega-3 fats, for those who are not allergic. Fatty fish like tuna, mackerel, and salmon are the rich sources. Plant sources of this fatty acid include flaxseed (crushed or oil), canola oil and soybean oil. Where possible, a combination of both fish and plant food sources of omega-3 fats is best. As far as omega-3 fatty acid supplementation goes, a little goes a long way. Too much omega-3 fat can upset the immune system in the opposite direction, suppressing the body's ability to heal wounds or fight infection.

Antioxidants are the body's defense against free radicals, the unstable oxygen molecules that damage healthy cells. Free radicals are found naturally in the environment, and the body produces others during normal metabolism. Many factors increase the body's production of free radicals, including ultraviolet radiation (sun exposure), cigarette smoke and physical trauma. Overactive inflammatory cells also increase free radical production. Over time, free radical damage to cells can lower the body's normal defenses and increase susceptibility to disease.

Antioxidants neutralize free radicals. In doing so, they protecting healthy cells from the toxic effects of unstable oxygen. Nutrients that have antioxidant properties include vitamin C, vitamin E, selenium and carotenoids. The best was to maximize your intake of antioxidants is to get them from foods. If, however, food allergies make dietary adequacy difficult, these nutrients can be obtained from supplements. A daily multivitamin-mineral that provides 100 percent of the RDA for vitamin C, E, selenium and beta-carotene is a safe bet for those who don't or can't always get adequate food sources of antioxidants. Discuss your specific needs or recommendations with your physician. Smaller doses for children are generally recommended.

Vitamin C:

Vitamin C is present in the airway surface liquid of the lung where it can protect against oxidation. Studies have shown protective effects of vitamin C, the most powerful water soluble antioxidant, especially in exercise induced asthma. A diet that is rich in fruits and vegetables usually provides ample amounts of this vitamin.

The minimum Recommended Dietary Allowance (RDA) is 60 mg. However, recent research showed that 500 mg of vitamin C taken regularly could reduce the number and severity of acute asthma attacks. Caution against excessive supplementation is urged, especially in children. High does of vitamin C can cause diarrhea, stomach irritation and increase one's risk of kidney stone formation.

Vitamin E:

This vitamin is the most potent fat soluble antioxidant. Vitamin E deficiencies are rare since it is widely distributed in foods and readily stored by the body. The best sources of vitamin E are polyunsaturated oils such as soybean oil, safflower oil and corn oil. Other good sources are fortified cereals, grains and wheat germ.

The Recommended Dietary Allowance for Vitamin E is 15 IU for adult males and 12 IU for adult females. Higher doses are sometimes recommended for prevention of chronic diseases such as heart disease and cancer. Doses of 100 IU to 400 IU are generally felt to be safe and effective. Persons taking anticoagulant medications should check first with their doctor, as vitamin E has blood-thinning properties.

Carotenoids: Carotenoids are a huge group of substances that are responsible for the bright orange, yellow and green colors in many fruits and vegetables. Though they are not vitamins, some carotenoids are readily converted to Vitamin A, and many act as powerful antioxidants. Choosing the bright colored fruits and vegetables are your best bet for getting good sources of carotenoids.

Selenium:

This is a mineral that is essential in the enzyme activities of antioxidants. It is widely available in meat, fish, poultry, grains and nuts. Selenium seems to work in conjunction with Vitamin E as an antioxidant.

Low levels of selenium have been linked to worsening of inflammation in persons with asthma. The RDA for adult males is 70ugs and for adult females is 55ugs. Use caution as toxicity can occur at doses of 100ug.

Water is often an overlooked nutrient, but staying well-hydrated is very important for lung health. This is a special concern for adults or children who exercise, participate in sports, or enjoy active outdoor play or recreations. Even mild dehydration can increase the risk of an asthma attack, as airways are more prone to dryness and irritation.

Daily water losses must be replaced. Everyone should drink a minimum of 6-8 cups of water, or other rehydrating fluids. Those who exercise, especially in dry climates, need to drink more. A good rule of thumb is to sip 3-4 ounces of cool water about every 15 to 20 minutes while exercising. Limit alcohol and caffeinated beverages (tea, coffee, cola-type soft drinks) since these act as diuretics and increase the body's water losses through urine.

Older adults are more susceptible to infection and disease when their diets are deficient in vitamin B6. It has been suggested that people with asthma cannot utilize vitamin B6 normally and may require more of this nutrient to maintain normal body functions. Some people who have increased their dietary vitamin B6 report a reduction in the severity and frequency of wheezing and asthma attacks. However, the theories about the benefits of vitamin B6 supplementation for asthma control have not been scientifically proven.

This nutrient is present in a wide variety of foods, both plant and animal origin. The addition of a general multivitamin-mineral supplement suggested above will typically add another 100% of the daily intake recommendation. Beyond this, additional B6 supplementation should be discussed with your physician for individual guidance.

Magnesium is a mineral with an active role in lung function. This nutrient appears to block chemicals that inflame the lungs and thus provide protection against airway constriction. Too little magnesium may increase lung susceptibility and asthma symptoms.

Major dietary sources of magnesium include milk, meats, nuts, wheat germ and legumes. People with food allergies to one or more of these foods will need to supplement. Again, a general multivitamin-mineral supplement will typically add 100% of the daily intake recommended for magnesium. Beyond this, additional supplementation should be discussed with your physician for individual guidance.

Zinc is another mineral with an important role in immune function. It is also critical nutrient for child development and growth. Zinc balance will be more difficult to maintain when the diet is restricted of the key foods containing it or if chronic diarrhea is a problem.

The best dietary sources of zinc include shellfish, meats, eggs and liver. Wheat germ and legumes are also good sources. Again, a general multivitamin-mineral supplement will typically add 100% of the daily intake recommended for zinc. Beyond this, additional supplementation should be discussed with your physician for individual guidance.