Scientists Find Customised DNA Based Diet will Give You The Best Body .August 3, 2016
Gene in Focus: ADRB2August 6, 2016
Continuing our focus on specific genes, this week we place FTO under the microscope. This gene plays a role in determining how well we deal with fats, especially saturated fats, but it is also implicated in obesity risk – as such, FTO is called the fat mass and obesity-associated gene.
We don’t necessarily know why this gene is linked to obesity and weight gain, especially with diets high in fat, although recent research appears to suggest that it could be due to differences in levels of certain hormones, particularly ghrelin, which stimulate appetite. The research on FTO, though, does show that the gene has an effect on how well we tolerate fat in our diet, especially saturated fat. Two studies conducted by a research group headed by Emily Sonestedt illustrate this really nicely. The first, from 2009 looked at the effects of the FTO gene in 4839 men and women born in Malmo, Sweden, between 1923 and 1950. The researchers asked the subjects questions about their dietary intake and leisure time physical activity, and the subjects were weighed and had their height measured – from this their Body Mass Index (BMI) was calculated. What the researchers found was interesting; the FTO gene appeared to interact with the macronutrients found in the diet to have an effect on BMI. Those people with the AA genotype of FTO were over twice as likely to be obese on a high fat diet compared to the TT genotypes. On a low fat diet, this risk had reduced to almost the same as the TT genotypes.
The FTO gene is involved in overweight and obesity, about 42% Caucasians, 5% Africans and 21% Asians carry risk variants for overeating. For those people, calorie restriction through portion control and smart food choice are the best strategies to lose weight.
The second study from this research group was published in 2011, and again found that fat intake interacted with FTO genotype to have an impact on body fat percentage.
The trends showed, quite nicely, that those with the TT genotype don’t see an increase in body fat with a concurrent increase in fat intake; whilst those with the AA genotype do. In the highest quintile of fat intake, those with the AA genotype had a body fat almost one percentage point higher than those with the TT genotype. Similar results were found by another research group, headed by Corella, in 2011, but this time looking especially at saturated fat.
So what does this all mean? Essentially, those with the A allele of FTO should consume less saturated fat compared to those with the TT genotype, because they are more at risk of fat gain when intakes of saturated fat are higher. The good news is that exercise and healthy eating also help to almost completely mitigate any risks associated with FTO genotype – hopefully motivating people to exercise and follow a healthful diet more regularly. The effects of FTO genotype are summarised in the below table:
||Associated with a significantly increased sensitivity to fats, especially saturated fats. Should aim to limit consumption of saturated fats somewhat. Exercise has a very strong effect at mitigating the risk associated with this gene.
||This genotype is associated with an increased sensitivity to fats, although not to the same extent as AA genotypes.
||Associated with the standard sensitivity to saturated fats, and as such should consume saturated fats in line with current guidelines.