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As part of a new series on Know Your Gene, we are going to look at a specific gene in detail, see what the science says about it, and how it can affect you with regards to fitness and diet.
The first gene to be put under the microscope in our series is ACE, or the angiotensin-converting enzyme gene. ACE is a special gene because it appears in three different sections of the DNAFit reports – power/endurance profile, carbohydrate sensitivity, and salt sensitivity. This gene is reported to slightly differently to most other genes too, in as much as you can have the Insertion (or I) allele, or the deletion (D) allele. The main function of angiotensin-converting enzyme is to convert angiotensin-I to angiotensin-II. Those with the DD genotype tend to have more of the ACE enzyme, and so generally are more effective at converting angiotensin-I to angiotensin-II.
Power & Endurance Response
ACE was the first gene to be linked to human performance. In a 1998 paper, researchers got military recruits to do bicep curls with a 15kg barbell, both before and after basic military training. What they found was that after training, those with the I allele (II or ID genotypes) saw improvements in how long they could carry out these bicep curls for, whilst those with the DD genotype did not. This enabled the researchers to predict that the I allele was associated with greater improvements to endurance training, and the D allele associated with greater improvements from higher intensity training. Research has also shown that those with the II genotype tend to have more slow twitch muscle fibres, and those with the DD genotype tend to have a greater number of fast twitch muscle fibres (you can read more on slow and fast twitch muscle fibres here).
ACE has also been found to affect sensitivity to carbohydrates. Individuals with the DD genotype are more likely to suffer from lower insulin sensitivity, which in turn can increase the risk of developing type II diabetes. In a study from 2009 in Czech adults, when daily carbohydrate intake was high, those with the DD genotype were much more likely to be obese compared to the II genotype. This suggests that those with the DD genotype tolerate carbohydrate less well compared to those with the II genotype, and so as a result should consume fewer refined carbohydrates, and also aim for a lower total glycaemic load per day.
ACE also plays a role in blood pressure control, and so has been implicated in the development if salt sensitive hypertension, or high blood pressure with high salt intake. In a group of studies, it was repeatedly shown that those with the II genotype of ACE were more sensitive to salt with regards to hypertension – that is if II genotypes consumed high amounts of salt, they were more likely to suffer from hypertension. This effect was much lower in DD genotypes.
Using your ACE genotype to make better decisions
So what does all this mean to you? Well, knowing your ACE genotype can empower you to make better decisions regarding your training and also your diet. If you have the II genotypes, you are more likely to respond favourably to endurance-based training, be able to consume more carbohydrates, and you should also consume less salt on a daily basis. If you have the DD genotype, you are more likely to have a favourable response to power training, not have an increased risk of developing salt sensitive hypertension, and also limit carbohydrates more than II genotypes. ID genotypes would sit somewhere in between the two.