Tuna Fajitas: a CardioKit recipe

. . . and a comment on the recent reports around fats and health


“Sugar, fat or confusing and inaccurate reporting . . . which is worse for the cardiovascular health of our patients and the population?”

There has been a lot of media attention around saturated fats and health. Lots of sensational headlines and soundbites encouraging us to abandon all our long held beliefs around healthy food and start eating more butter. The net result is that our patients are increasingly confused from the conflicting information about what actually constitutes a healthy diet —not helpful at all! We felt it important to give you a sensible and balanced summary.

Firstly, this is not a new concept. Many of us who are interested in contemporary dietary evidence have for some time been discussing and highlighted that saturated fats per se are not the prime evil they were once considered. Its also clear if you replace saturated fat with worse foods in your diet (transfats from partially hydrogenated vegetable oils, refined carbohydrates or sugars) which did occur as a result of the low fat health and food industry campaigns, then your overall health will be worse. We also agree that the guidelines from the 1980s which have rolled into the modern era without question are outdated and inaccurate—in fact this has clearly caused an increase in cardiovascular disease—one example being that margarine in the 1980s was pure trans fat! Its also clear that a low-fat diet is not healthy, low-fat products are usually bad for you and most of the low-fat focus which remains in mainstream healthcare is outdated. So far we are all in agreement. However, some of the extreme conclusion from the main author of the study which have been lapped up by a story hungry media have been bizarre and this has motivated a closer look at the background.

So, lets analyse the source of all this media attention. The main author of the study (who actually conceived and did most of the work) is not an objective scientist and it’s clear has pursued this project with preconceived intentions (conflicts of interest)—this explains the bizarre and exaggerated conclusions. She comes from a relatively extreme and evangelical anti-sugar (pro fat) background and openly questions the link between cholesterol and cardiovascular disease without much expertise, qualification or pedigree. Cholesterol is a complex issue and poorly understood in general, but an extreme opinion questioning any link with cardiovascular disease should immediately sound alarm bells. The author has no prior publications in scientific journals which is even more worrying considering she reveals being enrolled in a (?remote) PhD examining the evidence base for dietary fat guidelines at the University of West of Scotland since September 2012 — not an institution recognised for academic excellence in this area or cardiovascular research.

The study was published in open heart which is an open access (i.e. free) online only BMJ (British Medical Journal) with relatively low impact —as a result this journal will have a lower overall standard for the type of research published. You may wonder how a free journal can exist? By publishing articles which create impact and can be press-released to generate general interest, debate and penetration in the public and medical arenas, as in this case. I don’t think we can blame the media —it’s their job to sell news. I think the responsibility lies with the medical journals and the credible scientific community to counter ‘bad science’ and guide reporting bias without being seduced by the limelight and publicity. To be fair to openheart they did publish a parallel and much more balanced, credible accompanying editorial (by a Cardiologist) but clearly this balanced view did not get much press attention —not as exciting!

Now the intention is not to bash the authors of the study or publishing journal, but to highlight the complexities of the conclusions we hear summarised via the media and the confounding issues. We should have learnt by now that we cannot blame a single group of foods for health problems (other than the clearly damaging trans fats)—it will be very dangerous to swing from fat to another culprit (presently sugar). Observations of a given nutrient depend mainly on what you compare it to and therefore we should really move away from focusing on a single ingredient and repeating the mistakes of the past.

Saturated fats can be considered (at best) to be a neutral food —they are certainly not good for you but not as bad as once considered, and can be enjoyed in careful moderation— don’t go crazy with the butter. However, the fats in your diet should strongly favour the protective unsaturated fats from marine and plant sources. Your polyunsaturated fats should come from fish, nuts and seeds. We would avoid regular cooking with vegetable oils which are high in polyunsaturated fats (e.g. sunflower oil) and margarines (ultimately a highly processed food) based on recent evidence. The balance of evidence still favours olive oil for most cooking situations.

Back to the Tuna Fajitas — these are an amazing, fresh, tasty and fun meal. Clean Omega-3 rich tuna, combined with monounsaturated fat avocado, zingy and crunchy nitrate-rich salsa, spicy onions and peppers with cooling yogurt dressing. Although there are a number of steps below its also very quick to prepare and cook — ready in under 30 minutes.

Serves 2


For the fajitas:

  • 1 medium red onion
  • 1 large garlic clove
  • 2 peppers — red, yellow or orange mixed
  • 1– 2 green or red chillies (depending on your heat tolerance)
  • 1/2 packet of ready fajita seasoning mix — these are mostly a good product and consist of a ready combination of spices
  • 2 fresh tuna steaks cut thick — around an inch (works equally well with almost all meat and proteins)
  • wholemeal flat breads
  • olive oil, salt and black pepper

For the salsa:

  • 1/2 a fennel bulb
  • handful of cherry tomatoes
  • handful of radishes
  • handful of fresh coriander stalks
  • 1/2 fresh lime juiced

For the guacamole:

  • 1.5 ripe avocados
  • 1/2 a garlic clove
  • 1/2 fresh lime juiced

For the yoghurt dressing:

  • natural yoghurt
  • 1/4 long English cucumber
  • dried mint
  1. Roughly chop the onions, garlic, chilli and peppers into strips. Heat a large non-stick pan with a splash of olive or rapeseed oil. When hot, add in the mix and cook over a medium hot heat whilst stirring or tossing occasionally for around 7– 8 minutes. When the peppers and onion are softened and browned add in the spice mix with a little extra salt and black pepper seasoning. Cook together for another 2 minutes. Take off the heat, stir and leave in the pan for the flavours to mix.
  2. While the fajita mix is cooking you can start to prepare your easy side dishes.
  3. For the salsa, finely chop the tomato, radish and fennel (tough outer layer removed). You can pulse in a food processor for speed but its important to retain small pieces for crunchy texture and so a knife is best—you can simply roughly chop on a board and then run your knife through the mix several times. Wash a bunch of coriander thoroughly and then finely slice from the stalks up towards the leaves. Stop when you get to the leafy part. Mix together in a bowl with a splash of extra virgin olive oil, salt, black pepper and 1/2 lime, juiced.
  4. For the guacamole you need ripe, soft avocados. Cut in half, remove the stone and scoop out the flesh with a spoon into a bowl. Add a pinch of coarse sea salt and crush together with the back of a fork. Add half a crushed garlic clove and the juice of 1/2 a lime. You can add a drizzle of olive oil if the mix needs loosening. Taste and add more lime juice if required.
  5. Finally, the yogurt dressing is easy. Grate 1/4 of a long English cucumber and squeeze out the extra moisture in your hands, leaving the dry flesh. Mix this with some natural plain yogurt and a teaspoon of dried mint.
  6. Last of all — coat your tuna steaks in a little oil and season. If you have a griddle pan then this is ideal to create the nice char marks. Otherwise use a standard non-stick frying pan. Heat the pan until hot and add your steaks. Leave them without moving until you see the cooked line halfway up the outside of the fish—now flip them over and leave them for an equal amount of time. Take them off and rest on a board for a couple of minutes before slicing. This is best enjoyed medium rare but you can of course cook longer based on your preference.
  7. Enjoy the combination together on top of a freshly warmed wholemeal flat bread — delicious! Simply place the ingredients at the centre of the table and let everyone help themselves and build their own fajitas.
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