Prefer tea over coffee? It could be your genes, study finds

(CNN)Whether you're inclined to choose coffee or green tea for your morning boost could be determined by your genes, a recent study found.

To examine genetic associations with food preferences, researchers from the Riken Center for Integrative Medical Sciences (IMS) and Osaka University in Japan studied the genetic data and food preferences of more than 160,000 people in Japan.
The research, published in the journal Nature Human Behavior, found genetic links for 13 dietary habits including consumption of alcohol, other beverages and foods, and also complex human diseases such as cancer and diabetes.
    "We know that what we eat defines what we are, but we found that what we are also defines what we eat," said Yukinori Okada, Senior Visiting Scientist at Riken IMS and professor at Osaka University, in a press release.

    The relationship between our genes and our favorite foods

    Genome studies are typically conducted to associate specific genetic variations with particular diseases, according to the National Human Genome Research Institute, part of the US National Institutes of Health.
    This involves grouping thousands of people together depending on whether they have a disease and looking at DNA markers called single nucleotide polymorphisms, or SNPs, which can be used to predict the presence of that disease. If researchers find a SNP that is repeatedly associated with the disease group, they can assume that people with that genetic variation might be at risk for the disease.
    Rather than looking at diseases, the Riken team examined dietary habits to find out if there were any markers that made people "at risk" for typically eating certain foods.
    The researchers used data of more than 160,000 Japanese people from the BioBank Japan Project, launched in 2003 with a goal to provide evidence for the implementation of personalized medicine. The project collects DNA and clinical information, including items related to participants' lifestyles such as dietary habits, which were recorded through interviews and questionnaires.
    They found nine genetic locations that were associated with consuming coffee, tea, alcohol, yogurt, cheese, natto (fermented soy beans), tofu, fish, vegetables and meat.
    Variants responsible for the ability to taste bitter flavors were also observed. This association was found among people who liked to eat tofu; while those without the variant consumed less alcohol or none at all.
    Those who ate more fish, natto, tofu and vegetables had a genetic variant that made them more sensitive to umami tastes, best described as savory or "meaty" flavors.
    The main ingredients of the foods mattered, too -- for example, there were positive genetic correlations between eating yogurt and eating cheese, both