Cravings for fatty foods linked to genes
"Fat is universally palatable to humans. Yet we have demonstrated for the first time that people who have particular forms of the CD36 gene tend to like higher fat foods more and may be at greater risk for obesity compared to those who do not have this form of the gene."
"In animals, CD36 is a necessary gene for the ability to both detect and develop preferences for fat. Our study is one of the first to show this relationship in humans," said Prof Kathleen Keller, who led the team. For their research, the researchers from Penn State, Columbia University, Cornell University and Rutgers University examined 317 African-American males and females as individuals in this ethnic group are highly vulnerable to obesity.
The team gave the participants Italian salad dressings prepared with varying amounts of canola oil, which is rich in long-chain fatty acids. The subjects were then asked to rate their perceptions of the dressings` oiliness, fat content etc on a scale with "extremely low" and "extremely high".
The team also gave participants questionnaires aimed at understanding their food preferences. Participants rated how much they liked each food on a scale anchored with "dislike extremely" and "like extremely".
Foods included on the questionnaire were associated with poor dietary intake and health outcomes, such as sour cream, mayonnaise, bacon, fried chicken, hot dogs, French fries, cheese, chips, cake, cookies and doughnuts.
The researchers collected saliva samples from the participants to determine which forms of CD36 they had. From the saliva samples, they extracted DNA fragments and examined differences in the CD36 gene contained within the fragments.
They found that participants who had the "AA" form of the gene rated the salad dressings as creamier than individuals who had other forms of the gene.
"It is possible that the CD36 gene is associated with fat intake and therefore obesity through a mechanism of oral fat perception and preference," Prof Keller said in a release by the university.