When you begin to explore the wide variety of foods that people consume all around the globe, you’re likely to be surprised at the number of foods that don’t cause allergic reactions in most people. Only a handful of edibles are predominantly responsible for causing the most problems. In fact, I can count the number of common suspects on my fingers and still have one finger left.

In the United States, the following foods cause the most problems:

• Cow’s milk
• Hen’s eggs
• Peanuts
• Soy beans
• Wheat
• Tree nuts
• Fish
• Shellfish
• Sesame seed, sunflower seed, and other seeds

Because allergies are caused by a genetic disposition combined with exposure, common allergic foods vary by geographical location and culture. Populations that consume more fish, for example, have a higher incidence of fish allergies.

Cow’s Milk Allergy

Milk is often touted as “the perfect food.” One distraught lactose-intolerant patient amended that claim by stating, “Milk is the perfect food . . . for cows.” Around the world, cow’s milk is the most common cause of food allergy, especially in children, because they drink the most milk at an age when allergies are most likely to develop.

The amount of milk protein that triggers a reaction and the severity of the reaction vary tremendously from one person to another. An extremely sensitive person can have a severe reaction to a small amount of milk protein hiding in a candy bar, while another person who’s allergic to milk may be able to drink a half glass of milk and have little or no reaction to it.

If you have milk allergy, consult your allergist to determine just how sensitive you are.

• Milk allergy is an allergic reaction to one or more of the major milk proteins, the most important of which are casein, whey, and lactoglobulin. When you’re allergic to milk, your doctor is likely to recommend that you avoid all forms of milk protein.

• Lactose intolerance has nothing to do with milk proteins, but with the sugar in milk. People who are lactose intolerant don’t have the enzyme required to break down the sugar in milk.

Avoiding all forms of milk sounds bad enough. No milk? No cheese? No butter? No ice cream?! But the reality is even worse. Milk is an ingredient in a multitude of foods, from baby foods to breads to baked goods and milk chocolate, as well as all kinds of processed foods, so avoiding milk typically involves scratching about half of the most common foods off your grocery list.

The good news is that the food industry offers plenty of milk, cheese, butter, ice cream, and yogurt substitutes. Children often outgrow a milk allergy later in childhood. Later, I'll explain the likelihood of growing out of various food allergies and show you how to safely introduce foods later in life with your doctor’s supervision.

Eggs Allergy

Eggs are a great source of protein for some and an equally great source of distress for people who are allergic to them. As with milk, several egg proteins can cause allergic reactions, the most common of which is called ovalbumin. Although you can’t miss the eggs in your grocery store’s dairy section, you really have to look hard to spot them out in the real world.

Here are some tips to guide you in finding hidden eggs and avoiding them:

• Read labels carefully, because eggs hide in many food products.

• Most egg substitutes contain eggs or egg proteins, but later, I'll name one egg substitute that’s completely safe.

• While the egg white is much more allergenic than egg yolk, most people with egg allergy need to avoid all forms of egg. Why? Two reasons. First, because the egg yolk contains allergenic proteins. Second, because no one can separate an egg any better than you can — all egg yolks also contain egg white allergens.

• Some vaccines, especially the common flu shot, contain egg protein.

Peanuts Allergy

Peanut allergy ranks about third on most top-food-allergy lists, but this ranking is misleading. Peanut allergy occurs in less than 1 percent of young children, but then becomes more common than milk and egg allergy as people outgrow those allergies. (You’re less likely to outgrow peanut allergy than you are to outgrow milk or egg allergy.)

The medical community doesn’t have the statistics to know for sure, but more Americans may be allergic to peanut than to any other food. Peanut allergy also earns a top spot on the common-food-allergy charts, due to the potential severity of its reactions.

While milk and egg allergies can and do cause very serious reactions in some people, most people with peanut allergy are at risk of severe reactions. Peanuts commonly cause reactions with very small exposures, so even a contaminated product, such as a sugar cookie that shared a spatula with a peanut cookie, is capable of causing a severe reaction.

Researches have thoroughly characterized the specific peanut proteins that commonly cause allergic reactions, and have observed unique aspects to the way these proteins are constructed that make them such potent allergens. In next articles I'll tell you how to find out more about what makes peanut proteins so sinisterly special and gather tips on how to survive and thrive with a peanut allergy.

Soy Allergy

Soy, short for soybean, is a member of the legume family, and as such, it’s in the same family as the peanut. Of course, the peanut is the black sheep of the legume family due to its notoriety for causing the most severe allergic reactions, but soy has its own nefarious reputation because soy is everywhere.

And since exposure is a key component to the acquisition of a food allergy, soy’s widespread use makes soy a very common problem food. In fact, one of the first major uses of soy was as a substitute for milk protein in infant formulas, where it was introduced largely because the medical community in the 1950s and ’60s thought it to be much less allergenic than milk.

Because of the widespread use of soy, avoiding soy is a monumental challenge. Food manufacturers commonly use soy flour in breads and other bakery items, and soy makes its way into a number of food substitutes, especially substitutes designed for those with peanut, milk, and egg allergies. Because soy is high in protein, it helps boost the protein content of many foodstuffs.

Wheat Allergy

Western diets are chock full of wheat. It’s the main ingredient in most breads, cereals, pastas, and almost all baked goods. It also finds its way into numerous crackers and a host of popular snacks and finger foods. When you realize just how ingrained wheat is in the Western diet, when you look out over the aisles at your local grocery store, you may begin to envision amber waves of grain.

As with the other entries on our list of common allergenic foods, wheat’s proteins instigate the trouble, and separating the protein from the grain is nearly impossible. If you have wheat allergy, read food labels carefully and remain aware of the foods that most commonly contain wheat.

Wheat commonly sneaks its way into soups and sauces as a thickening agent, so don’t let your guard down by thinking that you’re safe ordering the soup without the French bread. Find out what’s in the soup, too.

Nut Allergy

Most people don’t know or care where their nuts come from, but people who have tree nut allergies sure need to know. While peanuts, which aren’t really nuts, grow below the soil, almonds, Brazil nuts, cashews, hazelnuts, macadamias, pecans, pistachios, and walnuts hang out in trees.

Like peanuts, however, these tree nuts have a nasty habit of causing severe reactions through even the smallest exposure. Technically, tree nuts have no family ties with peanuts, but their allergens share structural characteristics, which may explain why they are so potent and why 30 to 40 percent of the people who have peanut allergy also have tree nut allergies.

If you’re allergic to one tree nut, chances are pretty good that you’re allergic to at least one or two other members of the tree nut family, so you’re best bet is to avoid the entire family. For a tree-nut allergen identification chart and instructions on how to pick the tree nuts out of a food label. Finding a suitable substitute for tree nuts can be quite a challenge. If you’re not allergic to seeds, sunflower seeds may be nutty enough to satisfy your cravings.

Fish Allergy

For those with a genetic predisposition to allergies, the more fish they eat, the more likely they are to develop a fish allergy. Consequently, if you troll the globe and compare the prevalence of fish allergies in various countries, you find that countries that consume a lot of fish have a higher incidence of fish allergies than countries that consume less fish.

Fish allergy is far more common, for example, in Japan and Scandinavian countries than it is in the United States. As with the tree nut family, when you’re allergic to one fish you’re usually allergic to others, and your doctor is likely to recommend that you shun every member of the fish family.

Shellfish Allergy

Although shellfish allergy ranks eighth on our list of common food allergies, it’s the number one most common food allergy in adults. Consider it a late bloomer, developing later in a person’s life, commonly in young adults. A recent study shows that more than 2 percent of adults have shellfish allergy.

When you’re dealing with a shellfish allergy, you may be tempted to lump all shellfish together, but they’re actually divided into two major groups:

• Crustacea, including shrimp, crab, and lobster
• Mollusks, including clams, scallops, oysters, and mussels

Complete shellfish avoidance is usually the rule once a shellfish allergy develops, although many people with a crustacea allergy may be able to tolerate mollusks, and vice versa. Discuss this with your allergist before indulging.

Sesame, Sunflower, and Other Seedy Culprits

Batting clean-up on the food allergy roster is sesame seed and other seed allergies, but in at least one country, Israel, sesame allergy is number one. If you hung with me through the previous sections, you can probably guess why that is — the Israeli diet includes a lot of sesame seeds and oil.

In the United States, the medical community has witnessed a surge in sesame allergy over the past 10 to 20 years, and some allergists estimate that sesame may well now be in the top five bracket. One reason for this dramatic increase may be due at least in part to the introduction of more sesame in our diets.

With restaurants offering sesame seed buns and bread sticks and the increased use of sesame oil in dressings and other food products, exposure is on the rise. Other seed allergies, such as allergies to sunflower seeds, poppy seeds, and pumpkin seeds, do occur but are much less common, and most people with one seed allergy do not need to avoid all seeds.