A study from the Jaffe Food Allergy Institute at New York's Sinai hospital found that from 1997 to 2008, peanut allergies have tripled from 1-in-250 children to 1-in-70. Other common food allergies are milk, eggs, wheat, soy, fish and other nuts but peanut allergies have become almost an epidemic. One of the theories as to why this has occurred is the "cleanliness theory" which suggests that children's immune systems are not being strengthened by exposure to germs. According to Dr. Scott Sicherer, the institutes director, "If you can increase the threshold let's say from 1/100th of a peanut to two peanuts, that's an amazing safety." The National Institutes of Health stated that exposure to peanut-containing foods could begin as early as 4-6 months could help prevent peanut allergies from developing.