Your genes load the gun but your lifestyle pulls the trigger

Advances in easily accessible genetic testing could affect the way your clients train – and live their lives.

Genetics, epigenetics, nutrigenomics, copy numbers, single nucleotide polymorphisms or SNPs (pronounced ‘snips’)… are these the latest buzz words in the nutrition world? Or are we about to enter the start of what will become a truly individualised health service?

Hopefully it is the latter, as genetics currently lies safely in the hands of health professionals and is yet to be picked up by café owners. We always knew genetic testing was a possibility, but finally it has become less invasive for patients and cheap enough to be accessible by the masses. In addition to genetic testing being affordable, it has also accumulated the evidence to support nutrition and lifestyle interventions around specific genes.

This last point is a very important one, as there are literally thousands of genes that we can now test for. As a sports dietitian, however, I have aligned myself with a company that ethically has decided to do the following:

a) Only test genes that can be altered by diet and or lifestyle

b) Only test genes whose diet and lifestyle interventions are supported by evidence.

No information without action

The reason these points are so important is because I work mostly with athletes and active clients who, if presented with a picture representation of their genetic make up, will immediately ask ‘so what?’

Athletes hate doing tests that do not result in them being provided with an ‘action’ plan that can then help their performance. The same thinking applies to clients. If they are testing their genetic makeup it seems logical that it is to obtain some answers as to how they can make changes to help them achieve their personal goals. Or in the case of the gene I’m specifically discussing, to get results faster and figure out the type and timing of foods that are best for your body.

You’re with Amy. Lucky?

So let’s get technical. One of the simplest tests on the market currently is the genetic testing for Amy-1 CN, or the Amylase – 1 gene, copy number variation. This specific gene (Amy-1) can have many different copy numbers (CN), from one to 20 to be exact. A copy number variation is when the gene is literally multiplied, i.e. CN 2 means that the gene is multiplied twice. The number of copy numbers has been found to correlate with a person’s ability to produce Amylase in the whole body (mostly found in saliva but also found in a large number of organs throughout the body).

Put simply, we can test for a variation in a specific gene that is linearly correlated with the amount of Amylase the body produces.

So what does this mean in terms of physiology, activity and lifestyle?

We know that Amylase production is strongly correlated with our body’s ability to metabolise the starch component of carbohydrate foods. Therefore, the health benefits of knowing this gene variation begin to unfold. The statistics are pretty remarkable, with low copy numbers (i.e. low Amylase) associated with:

  • an 800 per cent increased risk of being overweight
  • significantly increased risk of type 2 diabetes
  • poorer glycaemic control
  • a lower lactate threshold
  • increased sensitivity to gluten.

The last point, once again, is an important one. The rise of gluten free and people’s gluten intolerances could actually be a genuine cry for help by clients who know something is just not right within their bodies. However, in this case, changing from flour to rice or corn products will not help them, as it isn’t gluten that they aren’t tolerating, it is starch. Gluten free products are just as high in starch as gluten-containing products. Thus the introduction of genetic testing and individualised nutrition plans allows us to recommend specific foods, fruits and vegetables for a client, in combination with specific training programs that will help them get results.

Working with, not against, our genes

The great thing about genetics is that you cannot change them, but you can decide to work with them or against them. Once you present a patient with the facts about what works best for their genetic profile, it is really hard for them to justify the latest ‘fad’ over sound, evidence-based advice. The biggest advantage of being able to test a client’s Amy1-CN is the buy-in and compliance that the client then demonstrates once they have the knowledge at hand and understand why they have struggled to lose weight in the past, or why they feel ‘off’ after pasta.

Results can be achieved nutritionally by literally changing the type of fruit your client is eating and only allowing starch carbohydrate intake at certain times of the day (not even cutting it out). This is a great aspect of working with genetics: as health professionals it allows us to be extremely prescriptive, which clients really enjoy if they have had limited success previously.

Realising the true potential of genetic testing

The potential for buy-in and results with this new found knowledge is vast. However, my experience to date with the use of genetic testing in clinic has shown that it currently only attracts patients that are already ‘healthy informed’, i.e. that already eat well and are of a healthy weight, but want to validate that they are doing the correct thing for their bodies. Rarely does it attract the type of client it could benefit most – those with metabolic diseases that have given up on ever achieving a healthy weight.

The potential is huge for application of this gene to help those insulin resistant clients in the gym with some very small nutritional changes and specific training to suit their genetic make up. However, as a network we need to make sure that we are using genetic testing as an extra tool to help us unlock an already complex puzzle

Thankfully, people appear to be taking the latest advances in genetics seriously, and it is putting a whole new spin on ‘you can’t outrun your diet… you can’t outrun your genes’. We now know that all of our guns are literally loaded, however, our lifestyle is responsible for pulling the trigger.

Peta Carige is an Accredited Sports Dietitian who has worked for the past 12 years with elite teams including Brisbane Broncos, Newcastle Knights and the Newcastle Jets. She currently consults to Australian Rugby Sevens, NSW Waratahs, NSW Rugby League and Manly Sea Eagles. Peta also undertakes clinical and presenting work.