How genetics is partly to blame for your cravings

While growing up, my sister liked to eat salt that gathers at the bottom of the pretzel bags. She always needs salty foods, just like her 3 year old son. On the other hand, I had a sweet tooth all my life, like our father.

The sweet and salty cravings of my family raise a curious question: could genetics play a role in our taste preferences? A growing body of research suggests a possible link.

Nanette Steinle, associate professor of medicine and endocrinology at the University of Maryland School of Medicine and head of the diabetes section at the Maryland Veterans Affairs Medical Center, has studied the relationship between genetics , taste preferences and food choices.

"There are specific receptors that regulate the taste of salt in relation to the taste of sugar," she said. "There are no large and robust studies on this issue, but for those that are available, we suspect there may be a genetic component for salt, bitter, sweet preferences."

Steinle co-author Genetics of eating behavior: established and emerging concepts, a 2011 study examining the role of genetics and the five taste profiles: sweet, bitter, salty, acid and umami. He identified some genes that may influence the preferences of sweet and umami and others that are related to bitter taste receptors. There are also proteins that regulate the absorption of salt and water in the body and are related to salt preferences, she said.

Many researchers believe that, in addition to taste receptors, there are many genetic factors, including body mass index, metabolism, brain reward center, and the hormones involved in the feeling of hunger and satiety. have an influence on cravings. Health and nutrition experts caution, however, that preferences influenced by genetic factors should not be seen as an excuse for poor eating habits.

Scientists at 23andMe, a direct-to-consumer genetic testing company, have identified 43 genetic markers for which individuals have variants that may indicate a preference for sweet or salty foods, said senior scientist Janie Shelton. the data collection unit of the company. 23andMe offers users to check how their genetics can be associated with preferences for sweet, salty and other foods.

"The genetic factors related to sugar preference versus salt preference were actually related to genes associated with metabolism and body mass index," Shelton said. The way people prefer certain foods and metabolize what they eat may be related to weight and the tendency to be obese.

By comparison, other dietary preferences, as for some ice cream flavors, are related to the genes of the olfactory pathway, or smell. Dietary behaviors and personality traits, such as a tendency to to feel hanged, are related to the genes associated with mental health issues and the characteristics of personality and well-being, she said.

"If you prefer sweets, you might tend to prefer high-calorie foods," said Shelton. "It's a feature of evolution that historically would have helped us survive. When it comes to salt, there is a whole other metabolic pathway that depends on how your kidneys process salt and the metabolism of different minerals in your body. But the trend from sweet to salty was significantly more related to the genes related to metabolism and body mass than to anything we saw related to salt and metabolism. "

Several genes are associated with the fact that someone prefers salt to sugar or vice versa, and have a connection with how people metabolize food and the tendency to be overweight. One of them is the "famous FTO gene", often called "obesity gene," Shelton said. Research by 23andMe has also found that people with certain genotypes are more likely to prefer salty or sweet foods.

People with a variant of the FGF21 gene, associated with food regulation, were 20% more likely than those with another variant to search for sugary substances, according to a separate study from the University of Copenhagen published in Cell Metabolism.

According to 23andMe's genetic data, 24% of women probably prefer sweet or salty foods, compared to 2.6% of men. Geography was another variable, with Oregon residents being more likely to eat sweets than the rest of the country, depending on their genes, and those in Maine and Hawaii more likely to consume salty foods.

Genetically, however, sweet and salty preferences are "not a black and white association," said Shelton.

"We say that people with these genetic variants might prefer salt," she said. "That does not mean they'll never eat a piece of cake, so it's more nuanced. The number of changes in the genome that would place you on one side or the other of the line is rather small. We divide people into categories based on these 43 different variants. So you can be in the center, 45% of people with your genetics prefer sweets and 55%, salty ones. If you landed at 10% against 90%, this could be much more strongly predicted by your genetics. "

How the body treats and reacts to sugar and salt can affect cravings, and James DiNicolantonio – a cardiovascular researcher at the Mid America Heart Institute in St. Luke's Kansas City, Missouri, and editor of the 39 Open Heart of the British Medical Journal – a probable link between the desires of salt and sugar.

Not eating enough salt can overactivate the brain's reward center, increasing salt and sugar cravings, and some people may be genetically predisposed to feeling a greater reward for sugar or salt, DiNicolantonio said. Author of The salt solution.

the the body needs saltbecause it is composed of the essential minerals that are sodium and chloride and that the body can not produce it, he said. But oneFor sugar, "our body can use fats and proteins to create glucose," so it's not necessary to get it directly from outside sources. Refined sugar can offer a stronger reward, and it can be more addictive, increasing cravings.

Healthy kidneys regulate the level of salt in the blood. Again, DiNicolantonio urged people to pay attention to their salt cravings, as this could signal a salt deficiency.

"For the majority of people, a craving for salt is very much like your thirst for water," he said. "The reason people are recommending a low-salt diet is that, in some people, it lowers blood pressure slightly, but not consuming enough water or dieting poor water can also lowering blood pressure Sometimes your thirst for water can cross or salt-deficient people, like athletes, abuse it, and some hydrate and develop low levels of sodium in the blood. "

The Centers for Disease Control and Prevention, however, predict that the majority of Americans "consume more sodium than they should – an average of more than 3400 mg per day". For most adults, the the recommended sodium intake is less than 2,300 mg per dayequivalent to about a teaspoon of salt, and less than 10% of a person's daily calories should come from added sugars, according to the dietary guidelines of the United States Government. the American Heart Association recommends a diet low in sodiumideally limited to less than 1500 mg per day.

With the urge to eat, it is difficult to distinguish the influences of genetics and the environment from the eating habits that people develop during their lifetime, said Sonya Angelone, spokesperson for the Academy of Nutrition and Nutrition. of dietetics based in the San Francisco Bay Area.

However, she agrees that there is a genetic cause to cravings. Just like Shelton from 23andMe, she said the FTO gene plays a key role because it affects hormone levels ghrelin, which makes you hungry, and leptin, which brings people together. Other important genes that influence the appetite can interfere with our satisfaction with food consumption and may cause cravings, "she said.

"There is a lot to do," Angelone said. "It's a bit more difficult to define what is really a compelling need versus a hunger versus a bad habit. This has to do with the reward center in your brain and what triggers when you eat. So it's quite complex.

Having cravings for sweet or salty tastes at times can be a habit, she said. "After dinner, I want something sweet or my cup of coffee. People then think that it is a psychological need, but it is not really the case. They have just prepared to desire dessert after dinner. "

Food behaviors are complex. In addition to genetics and the environment, lack of sleep, nutrient deficiency, poor diet, low blood sugar, dehydration and stress can also contribute to the feeling of hunger, Angelone said. Because there is rarely a factor that contributes to cravings, people must learn what causes them, how to manage them and adjust their environment. But it's okay to give in to sweet and salty cravings from time to time.

"This idea of ​​perfect eating, I do not even know what it is," she says. "Does that mean you can never have sugar or salty things? Sure you can. But what I say to people, is to use the word "manage". Manage your desires.

Genetics can predispose someone to crack sugar or salt, but lifestyle changes help manage cravings and do not reinforce unhealthy eating habits, Steinle said.

"You can blame your genes for loving it, but we have the ability to say," Is it healthy behavior? And change it, "she said. "We are smart, not just machines. If you like potato chips, you can change your eating behavior if you like. "