Why Some Like it Hot: Food, Genes, and Cultural Diversity.

Why Some Like it Hot: Food, Genes, and Cultural Diversity

Nabhan GP, Shearwater Books Island Press, Washington, 2004, 240 pages, $48.00, ISBN 1-55963-466-9

I must admit I just love to read books like this one and I know I'm not the only one. The links between food choices and human evolution fascinate many of us. Jared Diamond's books The Rise and Fall of the Third Chimpanzee and Guns, Germs and Steel continue on the non-fiction best-seller lists worldwide. Although both of Diamond's books address some of the links between food and evolution, there is still a lot unsaid. Gary Nabhan's book Some Like It Hot fills part of that need by taking us on a personal journey to look first hand at how one's genetic makeup affects food choices and patterns of illness today.

What is different about Nabhan's book is that he sees the subject of food and genes through a unique perspective--he is not just knowledgeable about evolution, but also ethnobotany and ethnic cuisines. He even has words for it, 'evolutionary gastronomy'. Gary is well recognised around the world as an ethnobiologist and his writing and other initiatives have earned him several awards. Long before anyone else, he saw the parallels between the evolution of Pima Indians of Arizona and Australian Aborigines, both of whom occupy desert niches and have a high incidence of type 2 diabetes today. In the late 1980s, he approached me to test the glycaemic index of Pima Indian foods and I still recall the unusual smell of baking mesquite seeds in our laboratory oven.

In his latest book, Gary takes us on a 'cook's tour' to various places, in which the genes vary along with the food choices/cuisines. We start in Arizona and Mexico close to Nabhan's home and where some of his native American friends find small amounts of alcohol hard to handle but really enjoy over-the-top hot chilli flavour, not just 'suffer' it. Nabhan postulates that this desire for chilli (hence the name of the book) is hard-wired, just like the taste for phenylthiocarbamide (PTC) and 6-n-propylthiouracil (PROP) (that only 'super-tasters' find excruciatingly bitter).

In the following chapters, we travel to Sardinia where favism is still evident today (glucose-6-phosphate dehydrogenase deficiency) and discover why the 'disease' became a buffer against malaria. Then onto Bali, Java and thence to Crete where we join conversations with the locals and the experts, all the while 'sampling' the local foods and cuisines.

When we finally arrive in Australia, it gets even more personal. I can't recall the specific conversation over dinner, but apparently it was me who suggested to him that desert foods bind water so tightly with high concentrations of mucilaginous fibre that it led to an adaptation to slowly released carbohydrates in the humans who ate them. It could be true but then I think everyone is adapted to eating low-glycaemic index foods. We return home via the final chapter devoted to Hawaii and its indigenous people's cuisine.

If genetics is not your thing, then you'll be grateful to Nabhan. He gets the technical bits over and done with in one of the early tables, where he lists the common gene adaptations that are linked to food choices and specific genes. Included are alcohol dehydrogenase, apolipoprotein A, coeliac disease, type 2 diabetes, insulin resistance, lactose intolerance, glucose-6-phosphate dehydrogenase and PTC and PROP.

Nabhan's writing is evocative, he calls it the coevolutionary dance between our genes and our foods, one that began long before the first farmers and herdsmen. We can almost taste the food, herbs and flavours he describes. He introduces us to many scientists and people in each chapter, those whose lives are affected everyday by the food choices of their ancestors. The larger issue of how the chemical arsenals in food plants have literally shaped us is one that we are only just beginning to understand.

His writing reminds us just how diverse human kind is in its genes, its tastes and its ethnic histories. No one diet will suit all, either culturally or genetically. His journey into our genetic and culinary history celebrates those differences and offers a word of warning about 'one diet for all' and quick genetic 'fixes'.

Jennie Brand-Miller

Human Nutrition Unit, University of Sydney