Could an Apple or an Orange a Day Keep Allergies and Asthma Away?

When the British National Health Service looked for a way to reduce the incidence of allergies and asthma in Scotland, they found a surprising remedy: apples.

Just one apple a week significantly reduced the frequency of both allergies and asthma. A similar benefit was found from eating oranges. In a later study of London school children aged 5 to 10, drinking apple juice at least once a day wasn't found to prevent every single asthma attack, but it was found to reduce wheezing. And a Dutch study found that women who eat apples during pregnancy bear children at lower risk for allergies, asthma, and eczema.

The British experience and subsequent laboratory studies in Japan suggest that the reason an apple a day (or even an apple a week) may keep atopic conditions is check is due to the fruit's content of quercetin.

This antioxidant flavonoid compound blocks the action of an enzyme called hyalouronidase. Hyalouronidase is responsible for swelling in the nasal passages.

Hyalouronidase also breaks open tiny packets inside mast cells filled with histamine, the agent of allergic irritation. Getting quercetin in the diet blocks the action of the enzyme and keeps the irritant from being released.

Eating foods with this useful plant chemical is associated not only with lower risk of skin and lung reactions, but also with lower risk of lung cancer.

Not everyone everywhere, of course, has access to an apple a day. You can also benefit from:

• Grapefruit,


• Onions,


• Red wine,


• Black tea, and to a lesser extent


• Beans and


• Green leafy vegetables

There are, however, certain foods that can wipe out the protective effects of quercetin (and your allergy medications, too). These are foods that contain the amino acid histidine, which the human body can convert to histamine (the irritant chemical anti-histamines are designed to fight). The list includes:

• Soy protein isolates,


• Dried tofu,


• Bacon,


• Game meats (especially whale and seal, but also venison, boar, and antelope), and


• Powdered eggs, although

Almost any kind of fish or meat is high in histidine.

Some foods, like fresh tuna, develop especially high levels of irritant chemcials from the breakdown of histidine if they are not stored under adequate refrigeration. If your tuna steak tastes peppery even before it's been seasoned, it will cause especially intense inflammation (scombroid poisoning) and aggravate any other allergies you may have.

So an apple a day may keep the allergies away, and blinky tuna will make them worse. Try eating apples, oranges, grapefruit, onions, or leafy vegetables and drinking tea every day and see if your allergies don't get better.