A recent article in the Baltimore Sun by an author with a honeydew allergy made me think of some of the reader correspondence and forum threads about unusual food allergies.

Estimates are that about 90% of allergies are to the so-called "big eight" (dairy, wheat, peanuts, tree nuts, fish, shellfish, eggs, and soy), which means that at least 10% of people with allergies can't eat a food other than this group. The actual number of people with less common allergies is likely significantly higher, since many people are allergic to more than one food.

If you tell waitstaff at restaurants about your uncommon allergy, do you feel you get the same treatment and understanding that you'd expect for disclosing a severe nut allergy? Are you frustrated with poor disclosure on ingredient labels? Consider this an open thread on less common food allergies.

By now you've probably heard of a recent study in the journal Pediatrics that's been the subject of a great deal of buzz: about 70% of kids in the U.S. aren't getting enough Vitamin D. Vitamin D, which is produced naturally during sun exposure and can be found in some fish and in supplemented foods like milk and some breakfast cereals, is known to be crucial for building bones and protecting against diseases like type 2 diabetes.

This study has possible ramifications for food allergies -- a 2007 study in the Journal of Allergy and Clinical Immunology noted that EpiPen prescriptions and prescriptions for other allergy and asthma medications were highest among children in the New England states. The study posited that inadequate Vitamin D intake in areas with longer, colder winters might account for the difference.

The takeaway? Ten to fifteen minutes of sun exposure (sans sunscreen) per day is sufficient for your body to generate levels of Vitamin D that are currently considered adequate. It's a worthy goal and just may help in preventing the development of allergies.

• About.com Allergies: Vitamin D Deficiency Causes Allergies and Asthma
• CNN: Vitamin D Deficiency Common in U.S. Children

A new study in the Annals of Allergy, Asthma & Immunology examines allergy awareness among the general public and finds some encouraging signs -- plus some places where knowledge could be better.

The good: Despite the inevitable flame wars that break out on message boards, blogs, and newspaper sites whenever the thorny topic of nuts in school is on the agenda, programs and policies designed to protect allergic kids in school are mostly popular. Some 85% of adults support action plans in school aimed at protecting allergic children, although nut-free tables and classrooms are more contentious. Also good: the vast majority of subjects (95%) recognize that food allergies can be deadly.

The bad: Many people believe that food allergies can be treated medically, through daily medicine or through some type of cure, rather than by a strict allergen-free diet. So while most people recognize the importance of avoiding reactions, many may not be aware that you need to be careful about your diet all the time.

There's also still broad confusion about the difference between food allergies and food intolerances. If you have a severe food intolerance, you may find that people say you have an allergy if you try to explain your condition.

Do these findings reflect your experience? What's the one thing you'd want people who don't have allergies to know? Vote in the poll and share your own experiences in the comments.

• Newswise: Food Allergy Knowledge Found Lacking in General Public

A study in the July issue of BMJ reviews research on a gene controlling the protein filaggrin. Defects in this gene are strongly associated with eczema, an allergic skin condition. Researchers noted that defects in this gene are related to allergic rhinitis (hay fever) and in the development of asthma in those with atopic eczema.

What is less clear -- and what researchers noted as a subject for further study -- is whether this gene is related to food allergies. It is believed that there is a genetic component to food allergies, as having a close relative with food allergies or another atopic condition is a strong risk factor. It's also known that people with one allergic condition are predisposed to others later in life, a phenomenon known as the "atopic march." Still to be determined is whether, and how, genes interact with environmental factors to cause allergies.

_{Rosanne A H M van den Oord and Aziz Sheikh, "Filaggrin Gene Defects and Risk of Developing Allergic Sensitisation and Allergic Disorders: Systematic Review and Meta-analysis." BMJ. 2009;339:b2433.}

• Risk Factors for Food Allergies
• Eczema and Food Allergies
• What is the Hygiene Hypothesis?