Omega 3 fatty acids?

What are omega 3 fatty acids? Omega 3 fatty acids are a group of polyunsaturated fats which are known to be useful many areas of human health.

Omega 3 fatty acids?

What are omega 3 fatty acids?

Omega 3 fatty acids are a group of polyunsaturated fats which are known to be useful many areas of human health. The parent compound of this group is called alpha-linolenic acid (ALA) and is found predominantly in plant foods such as nuts and seeds. ALA is known as an essential fatty acid as it cannot be produced by the body and must be consumed in the diet.1,2 Once in the body ALA is converted via a series of steps to eicosapentaenoic acid (EPA) and then onwards to docosahexanoic acid (DHA). Whilst these fatty acids can be produced by the body from ALA, the conversion rate is relatively poor; only 5–10% of ALA makes it to EPA and the conversion to DHA is even lower at 0–5%.3,4,5 As this conversion is so poor it is sensible to ensure that both are consumed either in the diet from foods such as oily fish (salmon, mackerel, herring, pilchards and anchovies) or via supplements.

What are the roles of Omega 3 fatty acids?

1. Brain function

One of the main roles of omega 3s and DHA in particular is brain function.6 The brain is around 60% fats by weight and poor levels of the right kinds of fats have been linked to cognitive issues and decline. Fats will contribute to the production of chemical messengers; they allow messages to be transmitted properly and for nerve cells to function correctly. Brain ageing causes changes in fats which can lead to alterations which will affect cognitive function.7 DHA is the main fat found in brain tissue, particularly in areas associated with memory and cognition. It is also required for the brain cells and nerves to function correctly.8 DHA is also involved in increasing other compounds including phosphatidyl serine (PS), which is involved in maintaining cognitive function and nerve health and transmission.

2. Heart health

Both EPA and DHA are required for the health of the heart9 and a combined intake of 250mg of EPA and DHA can contribute to normal heart function. Evidence suggests that a sufficient intake can lower triglycerides10 and cholesterol absorption, increase good cholesterol11 and improve the ratio of total cholesterol to HDL. An intake of 3g of these two fatty acids a day can contribute to the maintenance of normal blood pressure12 and numerous studies have found a strong link between the use of fish oil and improvements in heart disease.13 These effects may be due to several mechanisms including the reduction of inflammation.

3. Joint health

Fish and Cod Liver oils, which are rich in omega 3 fatty acids are often recommended for supporting joint health. Evidence suggests that fish oil can reduce inflammation, by increasing the production of anti-inflammatory compounds.14 Studies suggest that fish oil can reduce symptoms such as pain15 associated with joint issues and knee function,16 as well as improving walking speed and reducing the need for painkillers and pain medications.17

4. During pregnancy and breastfeeding

Higher intakes of omega 3 fatty acids have been associated with a lower risk of pre-term and premature delivery and low-birth weight infants. DHA is also associated with normal brain and visual development.18 However, the NHS advises that frequent intake of oily fish is avoided, due to concerns regarding environmental contaminants. Furthermore, data from National Diet and Nutrition Surveys shows that the intake of oily fish is low, so a fish oil supplement should be considered.

5. Skin health

A diet low in essential fatty acids, particularly those which are classed as omega 3, can also lead to issues with the skin19,20 and particularly with the skin barrier. This can lead to dry, irritated, and sensitive skin.21 For the skin to function properly, there needs to be the correct balance of nutrients including fatty acids. Increasing omega 3 intake may be useful for skin conditions such as psoriasis22 and eczema,23 as these are associated both with increased inflammation and a compromised skin barrier.

6. Eye health

As the retina of the eye is closely related to some brain tissues, it is no surprise that both areas require similar nutrients for optimum function. DHA is of particular relevance, as it is needed for function of the retina24 and plays a role in reducing inflammation and supporting normal vision. Studies show that DHA improves the uptake of lutein into the macula,25 which may help with age related changes to this area. Higher omega 3 intakes may also be associated with a lower incidence of dry eyes.26

7. Other roles

The omega 3 fatty acids EPA and DHA have also been indicated for both physical and psychological symptoms of pre-menstrual syndrome (PMS) including irritability, anxiety, low mood and fatigue.27 These fatty acids have also been shown to reduce dysmenorrhoea (period pain).28 Studies in perimenopausal and postmenopausal women have shown a link between omega 3 intake and mental health symptoms.29,30

Why supplementation?

UK data shows that the intake of oily fish is low in the UK and omega 3 intakes are particularly poor when compared to other fats. The current recommendation is for two portions of fish per week, of which one should be an oily fish – equating to approximately 140g of fish a week or 20g a day. However, intakes continue to fall with the average intake for adults only reaching 5–8g of oily fish a day.31

Which supplement?

Choosing a fish oil supplement which is screened for toxins and undergoes an extensive purification process will ensure an adequate intake of the important omega 3 fatty acids. Choose a product which provides sufficient DHA and EPA to support your health concerns, whether they are normal brain function, vision and heart health or the maintenance of normal blood pressure. For those who cannot or choose not to use a fish-based supplement, an algal supplement, either in capsule or liquid formats, makes an excellent alternative.32

References

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  2. Sardesai VM. The essential fatty acids. Nutr Clin Pract. 1992;7(4):179-86.
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  4. Gerster H. Can adults adequately convert alpha-linolenic acid (18:3n-3) to eicosapentaenoic acid (20:5n-3) and docosahexaenoic acid (22:6n-3)? Int J Vitam Nutr Res. 1998;68(3):159-73.
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  23. Hodge W, Barnes D, Schachter HM, et al. Effects of omega-3 fatty acids on eye health: summary. In: AHRQ Evidence Report Summaries. Rockville (MD): Agency for Healthcare Research and Quality; 2005. Report No. 117.
  24. The influence of supplemental lutein and docosahexaenoic acid on serum, lipoproteins, and macular pigmentation.
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  27. Rahbar N, Asgharzadeh N, Ghorbani R. Effect of omega-3 fatty acids on intensity of primary dysmenorrhea. Int J Gynaecol Obstet. 2012;117(1):45-7.
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