A Personal Look at Nutrigenetics and Nutrigenomics

20th May 2022 - Last modified 19th October 2023

By Rose Layton, PhD.

When I first heard the terms ‘nutrigenomics’, it had a fictious ring to it. It gave me the vibe that someone had slammed together some science-y words to describe a ‘fix all your problems’ type solution – with little scientific foundation. However, my scepticism was quickly squashed as I worked my way through a number of peer-reviewed papers.

Perhaps some of my scepticism was borne from other unfounded ideas that are sometimes irresponsibly tossed around. But nutrigenomics is a science. And while it may still be in the early-stages of research, it’s potential use to (at least help) treat disease is promising.

What is nutrigenetics and nutrigenomics?

Nutrigenomics defines the study of the role of nutrients and bioactive food compounds on gene and protein expression. At this point, with a background in genomics, I scolded myself. The term, and its derivation, made complete sense.

Nutrigenomics is not to be confused with nutrigenetics, which aims to uncover how the variation in genotypes could help explain the variability in response to food.

In either case, both approaches harness high-throughput genomics technologies – such as whole genome sequencing, transcriptomics, and proteomics – to gather data on the human genome or the expression of genes to help understand how we metabolise different nutrients.

Where can nutrigenetics/genomics make a difference?

From diabetes to cardiovascular disease, nutrigenetics and nutrigenomics has been used to help uncover how diet could exacerbate or manage disease. As someone who suffers from Crohn’s disease’s equally ugly sister, ulcerative colitis, the research focussed on inflammatory bowel disease (IBD) caught my attention. Since my diagnosis, I’ve been given lots of different advice relating to what I should and shouldn’t eat. For the most part, I’ve ignored it entirely.

I like to think that the reason I’ve turned a blind eye to dietary advice is the lack of science surrounding it. In reality, it’s probably because I am stubborn and like to eat what I want. Nevertheless, my personal investment in advancing treatments for Crohn’s and colitis, as well as a long-standing interest in genomics, supplied me with enough motivation to explore. So, back to the science.

IBD and nutrigenetics

Both genetic and environmental factors affect a person’s susceptibility to IBD and its disease state is intricately linked to diet[1]. However, several studies have shown that no single diet is suitable for all patients[2], [3]. Since nutrigenetics aims to quantify varying nutrient requirements in relation to different genotypes, it seems a particularly fitting technique to explore new approaches for the management of IBD.

One nutrient whose absorption can be impacted by genotype is beta-carotene. The gene BCMO1 encodes an enzyme (beta-carotene 15,15′-monooxygenase) important in the metabolism of the nutrient beta-carotene to vitamin A[4]. There are two polymorphisms in this gene that have been linked to poor absorption of vitamin A[5].

Impairment of our immune system has been linked to vitamin A deficiency and can ultimately lead to epithelial barrier dysfunction and inflammation – hallmarks of IBD[4]. In turn, if you have both IBD and one of the two polymorphisms of the BCMO1 gene, you may be at risk of vitamin A deficiency.

Identifying these ‘at-risk’ individuals and tailoring a diet based on their genotype illustrates the potential of nutrigenetics in a clinical setting.

IBD and nutrigenomics

Sitting comfortably among seaweed, goji berries, chia seeds, and similar ‘superfoods’ is green tea. Green tea is rich in compounds called polyphenols that have been shown to possess antioxidant and anti-inflammatory properties that could contribute to managing inflammation-related diseases[6] – such as IBD.

Interestingly, research into green tea and its health benefits for IBD patients is quite rich[6]. In one such study[7], researchers combined transcriptome and proteome analysis to explore the effect of green tea polyphenols on colonic inflammation in a mouse model.

Not only did the transcriptome and proteome analysis show that green tea does in fact modulate pathways associated with IBD but the researchers linked this to a significantly lower level of inflammation of the colonic tissues Essentially, it supports the idea that consumption of green tea may reduce IBD symptoms.

So, should all IBD sufferers start drinking green tea?

Well, I don’t think it could hurt. But, don’t start digging in the back of your cupboards looking for that year-old box of green tea just yet!

Back to scepticism?

Before we get too critical, it’s important to emphasise that the results from the paper discussed here are supported by numerous other studies on mouse models, polyphenols, and IBD.

My hesitation? Well, the fact that mice and humans are different species.

However, there are a few studies that have looked at the response of humans to green tea. One epidemiological study[8] suggested that tea consumption might decrease the risk of ulcerative colitis while a small pilot study[9] demonstrated that EGCG – a potent green tea polyphenolic component – might have a therapeutic benefit for some patients.

But studies are far from conclusive. To truly understand whether drinking green tea helps IBD, we need to take a deeper look at the human response.

Getting personal

So far, nutrigenomics has been used to demonstrate how food compounds modulate pathways associated with disease. This not only starts to build the foundation of using food as therapy for particular diseases, but also serves to highlight potential new drug or therapy targets.

When we consider nutrigenetics, some researchers have grander ideas. Several studies have shown that no single diet is suitable for all patients suffering from an IBD-related illness. Since nutrigenomics aims to quantify varying nutrient requirements in relation to different genotypes, we could, theoretically, harness the approach to develop personal nutrition plans.

Indeed, personal genomic testing is already giving consumers this option. Not so subtle marketing techniques aim to sell these ‘consumer genomics’ as empowering and transformative. But, again, this causes some suspicion.

As it turns out many of the gene–nutrient interactions in commercially available nutrigenetic tests lack sufficient evidence to be considered clinically valid and useful[10], [11].  

While nutrigenetics and nutrigenomics represent a valid field of science, it appears we are a long way off using them to provide tailored diets. Indeed, scientific results are often fraught with uncertain and incoherent results and factors such as delineating lifestyle and genetic predisposition will be a continuing, uphill battle (see Korthals and Komduur, 2009[12] for an interesting critical commentary). As such, I think a healthy dose of scepticism will remain on my plate – for now.

Food for thought

Hippocrates said, “Let food be thy medicine, and medicine be thy food.” Do you know what also contains polyphenols?

Chocolate and wine…

References

[1]     L. R. Ferguson, “Potential value of nutrigenomics in Crohn’s disease,” Nat. Rev. Gastroenterol. Hepatol., vol. 9, no. 5, pp. 260–270, 2012, doi: 10.1038/nrgastro.2012.41.

[2]     C. M. Triggs et al., “Dietary factors in chronic inflammation: food tolerances and intolerances of a New Zealand Caucasian Crohn’s disease population,” Mutat. Res., vol. 690, no. 1–2, pp. 123–138, Aug. 2010, doi: 10.1016/J.MRFMMM.2010.01.020.

[3]     R. Shamir, “Nutrition and Growth in Inflammatory Bowel Disease,” World Rev. Nutr. Diet., vol. 106, pp. 156–161, 2013, doi: 10.1159/000342579.

[4]     B. B. Laing, A. G. Lim, and L. R. Ferguson, “A Personalised Dietary Approach—A Way Forward to Manage Nutrient Deficiency, Effects of the Western Diet, and Food Intolerances in Inflammatory Bowel Disease,” Nutr. 2019, Vol. 11, Page 1532, vol. 11, no. 7, p. 1532, Jul. 2019, doi: 10.3390/NU11071532.

[5]     W. C. Leung et al., “Two common single nucleotide polymorphisms in the gene encoding beta-carotene 15,15’-monoxygenase alter beta-carotene metabolism in female volunteers,” FASEB J., vol. 23, no. 4, pp. 1041–1053, Apr. 2009, doi: 10.1096/FJ.08-121962.

[6]     S. M. Barbalho, H. Bosso, L. M. Salzedas-Pescinini, and R. de Alvares Goulart, “Green tea: A possibility in the therapeutic approach of inflammatory bowel diseases?: Green tea and inflammatory bowel diseases,” Complement. Ther. Med., vol. 43, pp. 148–153, Apr. 2019, doi: 10.1016/J.CTIM.2019.01.015.

[7]     M. P. G. Barnett et al., “Modulation of colonic inflammation in Mdr1a−/− mice by green tea polyphenols and their effects on the colon transcriptome and proteome,” J. Nutr. Biochem., vol. 24, no. 10, pp. 1678–1690, Oct. 2013, doi: 10.1016/J.JNUTBIO.2013.02.007.

[8]     J. Y. Nie and Q. Zhao, “Beverage consumption and risk of ulcerative colitis: Systematic review and meta-analysis of epidemiological studies,” Medicine (Baltimore)., vol. 96, no. 49, Dec. 2017, doi: 10.1097/MD.0000000000009070.

[9]     G. W. Dryden, A. Lam, K. Beatty, H. H. Qazzaz, and C. J. McClain, “A pilot study to evaluate the safety and efficacy of an oral dose of (-)-epigallocatechin-3-gallate-rich polyphenon E in patients with mild to moderate ulcerative colitis,” Inflamm. Bowel Dis., vol. 19, no. 9, pp. 1904–1912, Aug. 2013, doi: 10.1097/MIB.0B013E31828F5198.

[10]   U. Görman, J. C. Mathers, K. A. Grimaldi, J. Ahlgren, and K. Nordström, “Do we know enough? A scientific and ethical analysis of the basis for genetic-based personalized nutrition,” Genes Nutr., vol. 8, no. 4, pp. 373–381, Jul. 2013, doi: 10.1007/S12263-013-0338-6.

[11]   J. M. Ordovas, L. R. Ferguson, E. S. Tai, and J. C. Mathers, “Personalised nutrition and health,” BMJ, vol. 361, Jun. 2018, doi: 10.1136/BMJ.K2173.

[12]   M. Korthals and R. Komduur, “Uncertainties of Nutrigenomics and Their Ethical Meaning,” J. Agric. Environ. Ethics 2009 235, vol. 23, no. 5, pp. 435–454, Dec. 2009, doi: 10.1007/S10806-009-9223-0.