He says genetic evidence implicates iron when it comes to Alzhemier's because all the most important genetic factors in the disease are involved in iron binding and transport, and all those genes are regulated by iron.

He adds that high iron levels in the brain cause the depositing of bits of protein that try to transport iron out of brain cells when the iron level is too high. And the depositing of the protein is what furthers the progress of Alzheimer's.

Further, he says that Alzheimer's and cancer have become the most-feared diagnosis in the United States. And doctors may not even tell the patient or the family about the diagnosis because it is incurable.

"You can slow the onset, you can delay the onset, you can even prevent the onset, and you can slow progression with the mindspan diet," he says.

For years, Estep and his team have examined diets in areas where people enjoy the longest lifespans and mindspans around the world－Japan and the Mediterranean－to discover their secrets and give dietary suggestions in the book.

For example, the book suggests that people should consume less red meat, sugar and food enriched with iron, and it adds that people can drink tea, coffee or red wine to lessen the intake of iron.

In the second half of the book, Estep offers cuisines from areas where people tend to live longer.

As for his own diet, Estep says he does not follow a strict pattern. He typically eats a lot of Chinese and Mediterranean food.

Chinese food has the nutrient composition of Japanese food, but the flavor is better, he says.