What are polyunsaturated fatty acids?

I promised you only a small amount of chemistry in my first video on dietary fat 2 weeks ago on Babble prime – so here it is! Polyunsaturated fats are simply fat molecules that have more than one unsaturated carbon bond in the molecule (‘poly’ means many and ‘unsaturated’ refers to double bonds). If a fat molecule has one double bond, it’s called a monounsaturated fat (we will be looking at these soon), but if it has more than one, it’s called a polyunsaturated fat. Oils that contain polyunsaturated fats are typically liquid at room temperature but start to turn solid when chilled.

Our bodies cannot make Polyunsaturated fats. This is a type of fat found mostly in plant-based foods and oils found in some fish and oil, such as sunflower oil. Evidence shows that eating foods rich in polyunsaturated fatty acids improves blood cholesterol levels, which can decrease the risk of heart disease. These fatty acids may also help decrease the risk of type 2 diabetes.

Omega 3 fatty acids:

One type of polyunsaturated fat is the omega 3 fatty acids. These may be especially beneficial to your heart and fertility as well as other health conditions. Omega 3 appears to decrease the risk of coronary artery and heart disease and also helps to reduce inflammation in the body. Omega 3’s, sometimes referred to as ‘n-3s’ are present in certain foods such as flaxseed and fish, as well as dietary supplements such as fish oil and algae.  

There are three main omega 3 fatty acids; alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). ALA is mostly found in plants such as flaxseed, walnuts, chia seeds, soybean, and canola oils, while EPA and DHA are mostly found in animal foods like fatty fish and seafood. The ALA found in plant sources is not absorbed as well in the body as that from the fish sources.

The human body cannot make ALA, it is obtained through our diet. Our body can produce EPA out of ALA, but the conversion rate is very low. Our body can convert EPA to DHA to a limited extent too. Many people are deficient in omega 3 and it is important to be tested to find out your omega 6:3 status and to get the balance of EPA and DHA correct. Omega 3 supplementation may be recommended after this and for those eating a plant-based diet it may be recommended that you take an algae-based omega 3 supplement to meet your needs of omega 3’s.

Omega 3 and fertility

When it comes to fertility, Omega 3 fatty acids are important in ovulation, male sperm count/motility and DNA, conception and embryo development. 

Omega 3 and female fertility…how may they help? (Further studies are still required in order to provide more evidence in some areas)

– Increase the blood flow to the uterus

– Regulate monthly cycles and reducing inflammation (this is important re endometriosis as help to control inflammation, cramps and spasms and also may help to control heavy blood flow/clots due to fibroids)

– PCOS – in studies omega 3 has been found to lower testosterone, improve insulin  resistance, lower inflammation, reduce anxiety, reduce high tri glycerides and reduce hair loss.

–  During pregnancy- brain and retina development of the developing foetus

–  Helps to prevent pre-eclampsia and postnatal depression

Omega 3 and male fertility…how may they help? (Further studies are still required in order to provide more evidence in some areas)

  • Sperm membrane composition and integrity
  • Increase sperm count
  • Improve motility and morphology
  • Reduce damage to sperm DNA

Fish and seafood sources of omega 3 include:

  • Fresh tuna
  • Trout
  • Sardines
  • Oysters
  • Salmon
  • Herring
  • Halibut
  • Mackerel

Other excellent non-fish sources of omega 3 include:

  • Milk
  • Algae
  • Fruit juices
  • Soy milk
  • Yogurt
  • Eggs 
  • Margarine
  • Kale
  • Mint
  • Spinach
  • Watercress
  • Parsley
  • Brussel sprouts
  • Walnuts
  • Pumpkin seeds

Omega 6 fatty acids:

Like Omega 3 fatty acids,  Omega 6 are a type of polyunsaturated fatty acid and cannot be made by the body. They are an important source of energy for the body. The most common omega 6 fatty acid is linoleic and if too much of it is consumed it can become pro inflammatory. The problem is that in the western world we consume too much omega 6 and not enough omega 3 and so the ratios are ‘out’. The typical intake of omega-6 in western countries is high, and the ratio of the omega-6: omega-3 fatty acids in the UK are now thought to be greater than 10:1 and even as high as 25:1 in some adult diets. Many years ago, the omega-6: omega-3 ratio dietary intake of primitive man was closer to 1:1. Examples of omega 6 rich foods are corn, sunflower oil, safflower oil, firm tofu, peanut butter, cured meats.

Recipe ideas:

Healthy homemade Fish Pie


600g fresh fish pie mix

1 cup of king prawns

3 large or 6 small sweet potatoes

½ pint of milk

Handful of fresh parsley and chives chopped

2 oz butter

2 leeks

2 handfuls of finely chopped spinach

1 courgette, chopped

25 g plain flour

Seasoning – to taste

200g grated cheese

To make:

  • Place 600g of mixed fish pie mix (salmon, cod, smoked haddock cubed) into a baking dish with a cup of king prawns. 
  • Splash some organic milk over the top (not too much but enough so the fish can cook without being dry) and add some fresh chopped parsley and chives along with a little seasoning and place into a preheated oven at 180 degrees C for 15 minutes.
  • Meanwhile on the hob boil the chopped up sweet potato until soft.
  • In another pan place a spoonful of butter along with the leeks, finely chopped spinach and courgettes. (If you are in a rush you can use frozen sweet corn and peas with some leeks instead.
  • Make a quick white sauce by placing a spoonful of butter in a pan with 25g plain flour and a splash of milk. Mix over a low heat and then add the remainder of the milk, stirring all of the time until thickened.
  • Remove the fish from the oven, place the vegetables and herbs on top of the fish in the baking dish and mix in with the white sauce. Next, drain and mash the potatoes and spoon on top of the fish pie mix and spread with a fork. Sprinkle some cheese over the top and place back into the oven for 40 minutes.

Sardine salad


  • 3 tablespoons lemon juice 
  • 2 tablespoons extra-virgin olive oil 
  • 1 clove garlic, crushed
  • A small handful of fresh oregano or 2 teaspoons of dried
  • ½ teaspoon freshly ground pepper 
  • 3 medium tomatoes, cut into large chunks
  • 1 large cucumber, cut into large chunks 
  • 1 block of crumbled feta cheese 
  • 1/2 thinly sliced red onion 
  • 2 tablespoons Kalamata olives 
  • 2 cans sardines with bones, packed in olive oil or water, drained 

How to make:

Gently whisk the lemon juice, oil, garlic, oregano and pepper in a large bowl and combine. Add the chopped tomatoes, cucumber, feta, onion and olives and mix together. Top with sardines and enjoy! 

If you are using fresh sardines, splash a little olive oil into a pan and saute the sardines until cooked. Add seasoning to taste.

Smoked salmon Poke bowl


1 medium free-range egg

250g Brown rice

3 tbsp soured cream

1 tsp finely grated fresh ginger

1tsp olive oil

Finely grated zest and juice ½ lime

75g smoked salmon, sliced

5cm cucumber, sliced

½ small bunch fresh coriander, roughly chopped

2 spring onions, thinly sliced, or a handful of watercress leaves

How to make:

Bring a small pan of water to the boil. Lower in the egg and cook for 5 minutes. Drain and rinse under cold running water, then peel and cut in half. Cook the rice according to the pack instructions.

In a small bowl, mix the soured cream, ginger, olive oil and the lime zest and juice to make a dressing. Season to taste.

Transfer the rice to a serving bowl and top with the smoked salmon, cucumber, coriander and spring onions/watercress. Drizzle over the dressing to serve. Change vegetables/salad ingredients to suit. Enjoy!

Further reading:

Epping, J (2011). “Omega-3 Consumed During Pregnancy Curbs Risk For Postpartum Depression Symptoms.” Medical News Today. MediLexicon, Accessed April 2014.

Gao, H., Geng, T., Huang, T. et al. Fish oil supplementation and insulin sensitivity: a systematic review and meta-analysis. Lipids Health Dis 16, 131 (2017). https://doi.org/10.1186/s12944-017-0528-0

Nadjarzadeh, A., Dehghani Firouzabadi, R., Vaziri, N., Daneshbodi, H., Lotfi, M. H., & Mozaffari-Khosravi, H. (2013). The effect of omega-3 supplementation on androgen profile and menstrual status in women with polycystic ovary syndrome: A randomized clinical trial. Iranian journal of reproductive medicine, 11(8), 665–672.

Safarinejad, M. R., & Safarinejad, S. (2012). The roles of omega-3 and omega-6 fatty acids in idiopathic male infertility. Asian journal of andrology, 14(4), 514–515. https://doi.org/10.1038/aja.2012.46

Saldeen, P and Saldeen, T (2004). Women and omega-3 Fatty acids. Obstet Gynecol Surv. ;59(10):pp722-30.

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