Glossary Detail

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name of the term: Long chain fatty acids

Short introduction

  • A triglyceride is composed of 1 glycerol molecule connected with 3 fatty acid molecules.
  • A fatty acid consists of a straight chain of an even number of carbon atoms (C), which hold each two hydrogen atoms (H). At one end, the chain has 3 H-atoms (methyl-end) and at the other end a carboxyl group (COOH). The carboxyl group makes it an acid.
  • Fatty acids vary in carbon chain length and the number of double bonds in the chain.
  • Long chain fatty acids: >12 C-atoms.
  • Fatty acids can be saturated or unsaturated.
  • Saturated fatty acids are straight chains, saturated with hydrogen (H). Each C-atom carries 2 H-atoms. These fatty acids have no double bond.
  • Unsaturated fatty acids have one or more double bonds between the C-atoms (and at this place missing 2 H-atoms).
  • The double bond in unsaturated fatty acids produces a kink or bend in the molecule. Bending causes the molecule to stay fluid at room temperature. These kinks in the structure make body cell membranes (layer that covers the cell) flexible and permeable, allowing nutrients to enter the cell and waste products to leave.
  • The number of double bonds classifies fatty acids as monounsaturated or polyunsaturated. The position of the first double bond classifies polyunsaturated fatty acids further.
  • Saturated long chain fatty acids e.g.: palmitic acid (C16:0), stearic acid (C18:0).
  • Unsaturated long chain fatty acids e.g.: palmitoleic acid (C16:1), oleic acid (C18:1), α-linolenic acid (ALA) C18:3, linoleic acid (LA) C18:2. ALA and LA are essential fatty acids: they cannot be synthesised by the body and need to be supplied by food. 

Main natural sources

  • Palmitic acid: palmoil.
  • Stearic acid acid: cocoa butter, sou bean oil, meat.
  • Palmitoleic acid: cod liver oil, sardine oil.
  • Oleic acid: olive oil.
  • α-linolenic acid (ALA): vegetable oils (flaxseed, linseed canola, soy, walnut), soybeans, pumpkin seed, chia seed, walnuts and tofu.
  • Linoleic acid (LA): vegetable oils (safflower, sunflower, evening primrose), nuts, sesame seeds and sunflower seeds.

Main function

  • For normal growth and development. Each type of long chain fatty acid has its own health effects.
  • ALA and LA are essential fatty acids; they cannot be synthesised by the body and have to be supplied by food. ALA is precursor (forerunner) of DHA. LA is precursor (forerunner) of ARA. DHA and ARA (LCPUFAs) are important for e.g. brain and visual development and, immune function.
  • Saturated fats are associated with increasing levels of LDL cholesterol, but all saturated fatty acids are not created equal. Studies show that stearic acid, either decreased or had no effect on LDL cholesterol, while other saturated fats raised LDL cholesterol.

Deficiency disease

  • Signs and symptoms of a deficiency in essential fatty acids (ALA and/or LA) e.g.: allergic or atopic tendencies (eczema, asthma, hay fever), visual symptoms (poor night vision, visual disturbances), attention problems (poor concentration, attention and memory problems), emotional sensitivity (depression, excessive mood swings, anxiety), disturbed sleep-wake cycle and decreased immunity (increased susceptibility to diseases and infection, poor wound healing).
  • In infants and children growth may be decreased and in children it may negatively influence cognitive (brain memory and performance) and behavioural performance.


DRIs (Dietary Reference Intakes) have only been established for α-linolenic acid (ALA) and linoleic acid (LA). 

Recommended daily intake

Latest Dietary Reference Intakes (DRIs) 
Institute of Medicine (IOM)

Age categoryPer day
ALA / LA
Pregnancy 
Lactation
1.4 g  / 13 g (AI)
1.3 g  / 13 g (AI)
Infants 6 – 12 months0.5 g / 4.6 g (AI)
Children
 1 – 3 years
 4 – 8 years
0.7 g /  7 g (AI)
0.9 g / 10 g (AI)
Males
 9 – 13 years
14 – 18 years
19 – 30 years
31 – 50 years
50 – 70 years
> 70 years
1.2 g / 12 g (AI)
1.6 g / 16 g (AI)
1.6 g / 17 g (AI)
1.6 g / 17 g (AI) 
1.6 g / 14 g (AI) 
1.6 g / 14 g (AI)
Females

9 – 13 years
14 – 18 years
19 – 30 years 
31 – 50 years
50 – 70 years
> 70 years

1.0 g / 10 g (AI)
1.1 g / 11 g (AI)
1.1 g / 12 g (AI)
1.1 g / 12 g (AI)
1.1 g / 11 g (AI)
1.1 g / 11 g (AI)


AI = Adequate Intake.


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