What are DNA Tests?

DNA tests can optimise health & delay the onset of some diseases with personalised recommendations for nutrients, foods & lifestyle. The following will discuss the benefits, pitfalls and concerns with genetic testing.

In recent years these tests have proliferated driving costs down (NHMRC, 2021) and technology and expertise will continue to increase. This has resulted in DNA genetic tests becoming more affordable and providing more insight to our health than ever before. They can divulge your ancestry, locate long lost relatives and determine genetic variations which may make you more suseptible to diseases. One example of this is the BRCA gene which may make you more to breast cancer. However the presence of a gene does not automatically mean you will get the disease which is very important to note. These test can also show other genetic variations that can affect your reaction to foods such as caffeine metabolism & lactose intolerance. 

DNA tests can detect issues with metabolising nutrients such as vitamin C, D, B12, B9 and iron. Poor metabolism of these nutrients can increase the risk of certain diseases and abnormalities. Issues with nutrient metabolism may also result in suboptimal functioning of the body. 

Many experts believe these tests will revolutionise healthcare and personalised nutrition, whilst others think they have limited scope. Despite the latter, direct to consumer (DTC) genetic testing can be a useful tool to optimise health through dietary interventions. 

How Do DNA Tests Work?

Genomic testing can be used as a tool to predict the susceptibility of certain diseases, as well as diagnosing, treating and the prevention of diseases, however there are still many unknowns and limitations with this technology (Lappalainen et al., 2019). For example, there are approximately 1 million genetic variations, however only around 20,000 of these have been identified with many of them having little or no significance to health or development (NHMRC, 2021).

Traditional single-gene genetic testing may be used to predict risk and diagnosis of some diseases by identifying SNP’s that influence type 1 diabetes, Alzheimer’s or an individual’s “response to certain drugs” (Floris et al., 2020),

Due to the limitations of genetic testing focusing on only one gene mutation, testing has moved into genomics which involves multi-gene tests to find variants that can influence the risk for a variety of health problems “including cancer, autoimmune or cardiovascular diseases”. In addition to testing genotypes, genomic testing analyses gene expression unique to a specific patient as well as assist with “disease prognosis and treatment selection” (Floris et al., 2020).

DTC genetic tests usually do not sequence the whole genome, genomic tests almost do as well as gene variants, however the interpretation of these tests are challenging.

Issues with DNA Tests

Test results can be taken out of context due to an individual’s unique circumstances and other risk factors. For example, a risk factor doesn’t mean the disease will develop. It is also possible for tests to show a false positive or negative (Horton et al., 2019).

Legal implications for health professionals including malpractice are predicted to increase with the rapid advances and increasing complexity of tests. Consumers may face legal claims for failing “to warn family members” of genetic risks (Marchant et al., 2020). Test results are legally required to be shared with insurance providers which may affect your ability to afford or obtain life or income protection insurance (NHMRC, 2021).

It is important to go over the terms and conditions of DTC tests because some companies sell DNA data to third parties. Most genomic at home testing companies are based in other countries and therefore consumers are not protected under Australian jurisdiction (NHMRC, 202). 


In conclusion, although genetic and genomic tests serve a purpose and can provide useful information, they should not be relied on for clear cut insight into future health and are best interpreted by practitioners who specialise in this field. Consumers should also be aware of legal implications and ethical considerations – carefully reading the fine print – however most of these concerns are not relevant when using an Australian based company.




Floris, M., Cano, A., Porru, L., Addis, R., Cambedda, A., & Idda, M. et al. (2020). Direct-to-Consumer Nutrigenetics Testing: An Overview. Nutrients12(2), 566. https://doi.org/10.3390/nu12020566

Horton, R., Crawford, G., Freeman, L., Fenwick, A., Wright, C., & Lucassen, A. (2019). Direct-to-consumer genetic testing. BMJ, l5688. https://doi.org/10.1136/bmj.l5688

Lappalainen, T., Scott, A., Brandt, M., & Hall, I. (2019). Genomic Analysis in the Age of Human Genome Sequencing. Cell177(1), 70-84. https://doi.org/10.1016/j.cell.2019.02.032

Marchant, G., Barnes, M., Evans, J., LeRoy, B., & Wolf, S. (2020). From Genetics to Genomics: Facing the Liability Implications in Clinical Care. Journal Of Law, Medicine & Ethics48(1), 11-43. https://doi.org/10.1177/1073110520916994

NHMRC. (2021). Direct-to-Consumer genetic testing – statement. National Health and Medical Research Council. Retrieved 6 December 2021, from https://www.nhmrc.gov.au/about-us/publications/direct-consumer-genetic-testing-statement


By nutritionist Chrissy