My Cart

Sign In

Register Kit

DNAFit Blog

Gene in Focus: Part 25 - TNF

Posted 547 Days Ago in: Training, Genetics


This edition’s gene is TNF, which creates tumor necrosis factor. TNF is a pro-inflammatory cytokine - higher levels of TNF are associated with higher levels of inflammation, which can have an impact on various health risks, as well as our ability to recover from exercise. Higher levels of TNF following exercise are associated with higher levels of C-Reactive Protein (CRP); this drives inflammation, requiring longer recovery times between hard training sessions.

The SNP within TNF that we are most interested in is called G-308A (rs1800629). Here, a substitution of the guanine (G) base nucleotide for adenine (A) leads to higher levels of TNF. We would therefore expect that AA genotypes would need for longer recovery times compared to G allele carriers. A study published in 2006 as part of the HERITAGE study  confirmed this. In almost 700 subjects, the researchers measured CRP before and after a 20-week endurance training programme. At baseline, AA genotypes were much more likely to have higher levels of CRP compared to G allele carriers. Following the 20-week training programme, this association was further confirmed; CRP levels increased to a greater extent in AA genotypes than G allele carriers – again indicating that A allele carriers might need longer recovery periods between intense exercise sessions.


The same is true when it comes to general health. A 2016 study found that the A allele was associated with an increased risk of frailty in the elderly. Similarly, a 2014 study found that there was an increased risk of rheumatoid arthritis, a disease with high levels of inflammation, in A allele carriers.


So what can we do about this? Well, omega-3 fatty acids have been found to be effective in reducing inflammation. These fats are polyunsaturated fatty acids, most commonly found in oily fish (but also in some vegetarian friendly sources such as flax seed). We can’t make omega-3 within our body, which means we depend on our diet to provide them. A meta-analysis published in 2014 found that fish oils had a  lowering effect on TNF levels. Similarly, a 2006 systematic review published found that an increased consumption of fish oil reduced the risk of all-cause mortality, cardiac death, and possibly stroke death. The recommended daily allowance (RDA) for omega-3 is 1.6g per day; we might consider that those a risk allele of TNF consume up to twice this amount (3g) per day. This is especially important, as omega-3 fatty acids appear to be more effective in individuals with a risk allele of TNF. For example, a 2002 study found that fish oil was the most effective in those with the highest levels of TNF pre-supplementation. It seems logical to suggest that, if we know someone is more likely to have higher levels of these inflammatory markers due to their genes, they might have an increased need for omega-3 fatty acids, especially fish oils


So we’ve seen that TNF can affect our speed of recovery and also our general health, and that omega-3s, most commonly found it fish, should help to reduce inflammation. 150g of oily fish such as salmon or mackerel will contain about 3g of omega-3 – so you can have oily fish every other day, or maybe an omega-3 tablet if you don’t eat fish. The below table summarises the effects of the TNF polymorphism.


TNF Genotype

Effect on Recovery

Effect on Nutrition


Associated with lower levels of inflammation after hard training sessions, leading to quicker recovery times.

The standard expression of TNF, associated with normal levels of cytokines.


May experience increased levels of inflammation after hard exercise. A longer rest period between training sessions might be required.

This genotype is associated with a moderately increased level of inflammation. Consume slightly higher amounts of omega-3.


May experience higher levels of inflammation after hard exercise, requiring longer recovery times between training sessions.

Associated with increased inflammation – aim for 3g of omega-3 per day.



Gene in Focus TNF Omega-3 Nutiriton Recovery Exercise Fitness Workout Gym


Other Articles

Posted 550 Days Ago in: Training, Genetics

The Guide To Training Over 40: What Happens To Your Body When You Get Older?

There are pros and cons as you get older, and a little more decline if you’re into training, but there are also interventions that you can make to adapt to changes and maintain a lifestyle of efficiency long into what is perceived as old age. First, we’ll take you through the changes that occur when you get older:

Read More

Posted 552 Days Ago in: Nutrition

Meal replacement shakes - are they healthy?

By now, even if you haven’t tried one, you should be well aware that there are shakes out there that are packed with all the nutrients of the whole foods you eat daily. It means that instead of actually making a meal or weighing up calories before engorging yourself you can just as easily get all the nutrients, vitamins and minerals you need in one foul slurp. But are these meal replacement shakes healthy?

Read More

Get your guide!

Receive our FREE 14-day guide, direct to your inbox, on how genetics impact every aspect of fitness and nutrition.

Get your guide!

Receive our FREE 14-day guide, direct to your inbox, on how genetics impact every aspect of fitness and nutrition.